High-k gate dielectric and metal gate conductor stack for fin-type field effect transistors formed on type III-V semiconductor material and silicon germanium semiconductor material
09859279 ยท 2018-01-02
Assignee
Inventors
- Takashi Ando (Tuckahoe, NY)
- Martin M. Frank (Dobbs Ferry, NY, US)
- Pranita Kerber (Mount Kisco, NY, US)
- Vijay Narayanan (New York, NY, US)
Cpc classification
H10D64/691
ELECTRICITY
H10D30/0243
ELECTRICITY
H10D84/08
ELECTRICITY
H01L21/28264
ELECTRICITY
H10D64/667
ELECTRICITY
H01L21/28255
ELECTRICITY
H10D64/665
ELECTRICITY
H10D64/017
ELECTRICITY
International classification
Abstract
An electrical device that includes at least one n-type field effect transistor including a channel region in a type III-V semiconductor device, and at least one p-type field effect transistor including a channel region in a germanium containing semiconductor material. Each of the n-type and p-type semiconductor devices may include gate structures composed of material layers including work function adjusting materials selections, such as metal and doped dielectric layers. The field effect transistors may be composed of fin type field effect transistors. The field effect transistors may be formed using gate first processing or gate last processing.
Claims
1. A method of forming an electrical device comprising: providing a first fin structure of a type III-V semiconductor material and a second fin structure of a type IV germanium containing semiconductor material; depositing a conformal silicon layer on the first fin structure and the second fin structure; forming a first dopant layer of an aluminum containing composition on the first fin structure after said depositing the conformal silicon layer; forming a second dopant layer of group IIA elements, group IIIB elements or a combination thereof on the second fin structure; forming a gate structure comprised of a hafnium based gate dielectric, and a metal gate conductor on the first fin structure and the second fin structure; and forming n-type source and drain regions on opposing sides of the gate structure present on the first fin structure to provide an n-type FinFET, and p-type source and drain regions on opposing sides of the gate structure present on the second fin structure to provide a p-type FinFET.
2. The method of claim 1, wherein an effective work function of p-type FinFET is approximately 4.6 eV with a shift towards a valence band ranging from 100 mV to 200 mV, and wherein an effective work function of the n-type FinFET is approximately 4.6 eV with a shift towards a conduction band ranging from 300 mV to 400 mV.
3. The method of claim 1, wherein the n-type finFET comprises a first gate structure comprising a first dopant layer comprising aluminum oxide (Al.sub.2O.sub.3), a first high-k dielectric layer comprising hafnium oxide (HfO.sub.2), a first metal work function adjusting layer comprising a single layer of titanium nitride or a dual layer of titanium nitride and tantalum nitride, and a first conductive electrode comprising tungsten (W), and wherein the p-type finFET comprises a second gate structure comprising a second dopant layer comprising lanthanum oxide (La.sub.2O.sub.3), a second high-k dielectric layer comprising hafnium oxide (HfO.sub.2), a second metal work function adjusting layer comprising a single layer of titanium nitride or a dual layer of titanium nitride and tantalum nitride, and a second conductive electrode comprising tungsten (W).
4. The method of claim 1, wherein the p-type FINFET and n-type FINFET are formed using gate first processing with process temperatures less than 600 C.
5. A method of forming an electrical device comprising: providing a first fin structure of a type III-V semiconductor material and a second fin structure of a germanium containing semiconductor material; forming a first replacement gate structure on the first fin structure and a second replacement gate structure on the second fin structure; forming N-type source and drain regions are formed on the first fin structure on opposing sides of the first replacement gate structure and P-type source and drain regions on the second fin structure on opposing sides of the second gate structure; substituting the first replacement gate structure with a first functional gate structure including a high-k gate dielectric and a first gate conductor that produces a first oxygen vacancy concentration in the high-k gate dielectric; and substituting the second replacement gate structure with a second functional gate structure including the high-k gate dielectric and a second gate conductor that produces a second oxygen vacancy concentration in the high-k gate dielectric, wherein the second oxygen vacancy concentration is greater than the first oxygen vacancy concentration.
6. The method of claim 5, wherein gate electrode processing temperatures are less than 450 C.
7. The method of claim 5 further comprising forming an conformal silicon containing layer on the second fin structure prior to forming the second functional gate structure, wherein the conformal silicon containing layer is not present on the first fin structure.
8. The method of claim 5, wherein an effective work function for the n-type FinFET ranges from 4.7 to 4.8 eV, and an effective work function of the p-type FinFET ranges from 4.15 eV to 4.25 eV.
Description
DESCRIPTION OF THE DRAWINGS
(1) The following detailed description, given by way of example and not intended to limit the invention solely thereto, will best be appreciated in conjunction with the accompanying drawings, wherein like reference numerals denote like elements and parts, in which:
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DETAILED DESCRIPTION
(18) Detailed embodiments of the methods and structures of the present disclosure are described herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the disclosed methods and structures that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the disclosure are intended to be illustrative, and not restrictive. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the methods and structures of the present disclosure.
(19) References in the specification to one embodiment, an embodiment, an example embodiment, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. For purposes of the description hereinafter, the terms upper, lower, right, left, vertical, horizontal, top, bottom, and derivatives thereof shall relate to the invention, as it is oriented in the drawing figures. The terms overlying, atop, positioned on or positioned atop means that a first element, such as a first structure, is present on a second element, such as a second structure, wherein intervening elements, such as an interface structure, e.g. interface layer, may be present between the first element and the second element. The term direct contact means that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intermediary conducting, insulating or semiconductor layers at the interface of the two elements.
(20) The present disclosure is related to forming complementary metal oxide semiconductor (CMOS) devices, in which the p-type conductivity semiconductor devices, e.g., fin type field effect transistors (FinFETs), are formed on a silicon and germanium containing semiconductor surface, such as silicon germanium (SiGe), and the n-type conductivity semiconductor devices, e.g., fin type field effect transistors (FinFETs), are formed on a type III-V semiconductor surface, e.g., indium gallium arsenide (InGaAs), in which the gate structures of the n-type and p-type semiconductor devices have had work function adjustments. As used herein, semiconductor device refers to an intrinsic semiconductor material that has been doped, that is, into which a doping agent has been introduced, giving it different electrical properties than the intrinsic semiconductor. Doping involves adding dopant atoms to an intrinsic semiconductor, which changes the electron and hole carrier concentrations of the intrinsic semiconductor at thermal equilibrium. Dominant carrier concentration in an extrinsic semiconductor determines the conductivity type of the semiconductor. In the following description, the semiconductor device is a field effect transistor. Complementary metal oxide semiconductor (CMOS) is a type of semiconductor that use both N-type (negative polarity) and P-type (positive polarity) semiconductor circuits. Typically, since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. A field effect transistor is a transistor in which output current, i.e., source-drain current, is controlled by the voltage applied to a gate structure. A field effect transistor typically has three terminals, i.e., a gate structure, source region and drain region. As used herein, the term source is a doped region in the semiconductor device, in which majority carriers are flowing into the channel. As used herein, the term channel is the region underlying the gate structure and between the source and drain of a semiconductor device that becomes conductive when the semiconductor device is turned on. As used herein, the term drain means a doped region in semiconductor device located at the end of the channel, in which carriers are flowing out of the transistor through the drain. A gate structure means a structure used to control output current (i.e., flow of carriers in the channel) of a semiconducting device through electrical or magnetic fields.
(21) A FinFET is a field effect transistor in which at least the channel portion of the field effect transistor is present in a fin structure. As used herein, a fin structure refers to a semiconductor material, which can be employed as the body of a semiconductor device, in which the gate structure is positioned around the fin structure such that charge flows down the channel on the two sidewalls of the fin structure and optionally along the top surface of the fin structure. The term planar as used to describe a semiconductor device orientation, e.g., planar FET, denotes that the direction of charge carriers from the source region to the drain region of the semiconductor device is along a plane that is parallel to the upper surface of the substrate, wherein a gate structure is present on the upper surface of the substrate. In a planar semiconductor device, the gate structure does not wrap around the sidewalls of the channel region as in a fin structure.
(22) The term work function is used to describe a gate material that determines the threshold voltage of a semiconductor device. For example, a work function adjustment effectuates a threshold voltage shift either towards the valence band or conduction band. As used herein, threshold voltage is the lowest attainable gate voltage that will turn on a semiconductor device, e.g., transistor, by making the channel of the device conductive. A valence band is the highest range of electron energies where electrons are normally present at absolute zero. The conduction band is the lowest lying electron energy band of the doped material that is not completely filled with electrons.
(23) It has been determined that III-V nFET/SiGe pFET CMOS devices can require specific work function engineering, i.e., work function adjustments, to enable the appropriate functioning of FinFET and planar FET devices due to the different affinities of type III-V semiconductors, such as indium gallium arsenide (InGaAs) and germanium containing semiconductors, such as silicon germanium (SiGe), in comparison to conventional silicon (Si) substrates, e.g., single crystalline-Si (c-Si).
(24) In some embodiments, the methods and structures disclosed herein provide a single metal high-k metal gate stack to enable planar dual channel CMOS devices using III-V nFETs and SiGe pFETs (planar nFET and planar pFET). In some examples of CMOS arrangements including planar FETs, both the nFET and pFET gate stacks, require effective work functions (EWF) ranging from 4.4 to 4.6 eV for planar dual channel CMOS. The effective work function is defined relative to the vacuum level and extracted using measured C-V curves on silicon (Si), i.e., EWF of the gate stack is extracted from a CV curve of the gate stack deposited on silicon, and includes the work function of the electrode along with fixed charges and dipoles within the dielectric.
(25) In some embodiments, the methods and structures disclosed herein provide a high-k metal gate stack to enable CMOS devices using FinFET semiconductor devices, in which the effective work function (EWF) of the p-type device is less than the n-type conductivity device. For example, n-type FinFETs require effective work functions (EWF) ranging from 4.7 to 4.8 eV (undoped channel). P-type FinFETs require effective work functions (EWF) ranging from 4.15 to 4.25 eV (undoped channel). The effective work function is defined relative to the vacuum level and extracted using measured C-V curves on silicon (Si), i.e., EWF of the gate stack is extracted from a CV curve of the gate stack deposited on silicon. Adjustments to the required work function may then be made based on InGAs and SiGe band offsets. In some embodiments, gate first processing and gate last processing, i.e., replacement gate processing, use a combination of dielectric doping and single metal/dual metal gate structure solutions. The work function adjustments for the FinFETs on type III-V semiconductor materials and germanium containing materials are opposite in polarity to what is practiced on silicon. The methods and structures of the present disclosure are now discussed with greater detail referring to
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(27) The term III-V semiconductor material denotes a semiconductor material that includes at least one element from Group IIIB of the Periodic Table of Elements under the Old International Union of Pure and Applied Chemistry (IUPAC) classification system, or Group 13 of the New International Union of Pure and Applied Chemistry classification system; and at least one element from Group VB of the Periodic Table of Elements, or Group 15 of the New International Union of Pure and Applied Chemistry classification system. In some embodiments, the III-V semiconductor material that is present in the first portion 15 of the substrate may be selected from the group of (AlSb), aluminum arsenide (AlAs), aluminum nitride (AlN), aluminum phosphide (AlP), gallium arsenide (GaAs), gallium phosphide (GaP), indium antimonide (InSb), indium arsenic (InAs), indium nitride (InN), indium phosphide (InP), aluminum gallium arsenide (AlGaAs), indium gallium phosphide (InGaP), aluminum indium arsenic (AlInAs), aluminum indium antimonide (AlInSb), gallium arsenide nitride (GaAsN), gallium arsenide antimonide (GaAsSb), aluminum gallium nitride (AlGaN), aluminum gallium phosphide (AlGaP), indium gallium nitride (InGaN), indium arsenide antimonide (InAsSb), indium gallium antimonide (InGaSb), aluminum gallium indium phosphide (AlGaInP), aluminum gallium arsenide phosphide (AlGaAsP), indium gallium arsenide phosphide (InGaAsP), indium arsenide antimonide phosphide (InArSbP), aluminum indium arsenide phosphide (AlInAsP), aluminum gallium arsenide nitride (AlGaAsN), indium gallium arsenide nitride (InGaAsN), indium aluminum arsenide nitride (InAlAsN), gallium arsenide antimonide nitride (GaAsSbN), gallium indium nitride arsenide aluminum antimonide (GaInNAsSb), gallium indium arsenide antimonide phosphide (GaInAsSbP), and combinations thereof. The germanium containing material that provides the second portion 20 of the substrate 10 may be substantially 100 at. % germanium (Ge), e.g., greater than 95 at % germanium (Ge), such as 99 at. % germanium (Ge), silicon germanium (SiGe), silicon germanium doped with carbon (SiGe:C) or combinations thereof. It is noted that in one example, the III-V semiconductor material that provides the first portion 15 of the substrate 10 is In.sub.0.53Ga.sub.0.47As, and the germanium containing material that provides the second portion 20 of the substrate 10 is silicon germanium (SiGe) having greater than 50 at. % germanium. It is noted that the above atomic percent that are provide to describe the material of the first and second portions 15, 20 of the substrate describe a base material, i.e., intrinsic semiconductor, which does not include a measurement of the dopants that provided the conductivity type of the device, e.g., whether the FET is a p-type or n-type FET.
(28) Each of the n-type and p-type field effect transistors 100a, 100b include a gate structure having work function adjustments, which in some embodiments provides an effective work function ranging from 4.3 to 4.7 eV for each of the n-type and p-type field effect transistors 100a, 100b. The n-type field effect transistor 100a may include a first gate structure 30a that includes a first interface dielectric layer 31a formed on the channel region of the first portion 15 of the substrate 10; a first high-k gate dielectric layer 32a that is present on the first interface dielectric layer 31a; a first metal work function adjusting layer 33a that is present on the first high-k gate dielectric layer 32a; and a first conductive electrode 34a. The p-type field effect transistor 100b may include a second gate structure 30b that includes a second interface dielectric layer 31b formed on the channel region of the second portion 20 of the substrate 10; a second high-k gate dielectric layer 32b that is present on the second interface dielectric layer 31b; a second metal work function adjusting layer 33b that is present on the second high-k gate dielectric layer 32b; and a second conductive electrode 34b.
(29) The first and second interface dielectric layer 31a, 31b may be an oxide, such as silicon oxide (SiO.sub.2). In some embodiments, the first and second interface dielectric layers 31a, 31b may also be provided by a doped dielectric material. For example, the first and second interface dielectric layers 31a, 31b may be comprised of a dopant selected from Group IIA or Group IIIB of the periodic table of elements under the Old International Union of Pure and Applied Chemistry (IUPAC) classification system. Examples of dielectric dopants may be selected from the group consisting of beryllium (Be), magnesium (Mg), barium (Ba), lanthanum (La), yttrium (Y) and combinations thereof. For example, at least one of the first and second interface dielectric layer 31a, 31b may be composed of lanthanum oxide (La.sub.2O.sub.3). In some embodiments, only the second interface dielectric layer of the second gate stack to the p-type conductivity planar field effect transistor (FET) is composed of a doped dielectric including a dopant selected from Group IIA or Group IIIB of the periodic table of elements, such as lanthanum oxide (La.sub.2O.sub.3). The thickness for each of the first and second interface dielectric layer 31a, 31b may range from 1 to 10 . In some examples, the thickness for each of the first and second interface dielectric layers 31a, 31b may be on the order of 2 to 6 .
(30) The term high-k as used to describe the first and second high-k gate dielectric layers 32a, 32b denotes a dielectric material having a dielectric constant greater than silicon oxide (SiO.sub.2) at room temperature (20 C. to 25 C.) and atmospheric pressure (1 atm). For example, a high-k dielectric material may have a dielectric constant greater than 4.0. In another example, the high-k gate dielectric material has a dielectric constant greater than 7.0. In some embodiments, the first and second high-k gate dielectric layers 32a, 32b are composed of a hafnium-based dielectric. The term Hf-based dielectric is intended herein to include any high k dielectric containing hafnium (Hf). Examples of such Hf-based dielectrics comprise hafnium oxide (HfO.sub.2), hafnium silicate (HfSiO.sub.x), Hf silicon oxynitride (HfSiON) or multilayers thereof. In some embodiments, the Hf-based dielectric comprises a mixture of HfO.sub.2 and ZrO.sub.2 or rare earth oxide such as La.sub.2O.sub.3. MgO or MgNO can also be used. Typically, the Hf-based dielectric is hafnium oxide or hafnium silicate. Hf-based dielectrics typically have a dielectric constant that is greater than about 10.0. In one embodiment, the thickness for each of the first and second high-k gate dielectric layers 32a, 32b is greater than 0.8 nm. More typically, the at least one first gate dielectric layer 13 has a thickness ranging from about 1.0 nm to about 6.0 nm.
(31) The first and second gate structures 30a, 30b may be formed using a single metal electrode, i.e., first and second metal work function adjusting layer 33a, 33b and first and second conductive electrode 34a, 34b, for both of the first and second gate structures 30a, 30b. By single metal electrode it is meant that the composition for both the first and metal work function adjusting layers 33a, 33b, as well as the composition for both of the first and second gate electrode 34a, 34b, is the same. For example, the first and second metal work function adjusting layers 33a, 33b may each be composed of metal nitride, such as titanium nitride (TiN). In some examples, stoichiometry tuning of titanium nitride (TiN) may be used to for fine tuning the work function adjustments provided by the first and second metal work function adjusting layers 33a, 33b. Stoichiometric tuning can be accomplished by adjusting the titanium (Ti) to nitrogen (N) ratio during the physical vapor deposition (PVD) sputtering program for forming the material layer. Although titanium nitride (TiN) is described above as an embodiment of a material suitable for the first and second metal work function adjusting layers, other metal nitrides may be suitable for use with the present disclosure. For example, the metal layers may further comprise aluminum. In other examples, the first and second metal work function adjusting layers may include other metals from Groups IVB to VIB in the Periodic Table, including, e.g., tantalum nitride (TaN), niobium nitride (NbN), vanadium nitride (VN), tungsten nitride (WN), and the like with a thickness of about 20 Angstroms to about 30 Angstroms.
(32) The conductive electrodes 34a, 34b may be composed of any metal containing material. For example, the conductive electrodes 34a, 34b may be composed of tungsten (W) or a tungsten including alloy. In other examples, the conductive electrodes 34a, 34b are composed of aluminum (Al), copper (Cu), platinum (Pt), silver (Ag) or an alloy thereof including allows with tungsten (W).
(33) The first and second gate structures 30a, 30b is suitable for activation anneals for the source and drain regions of the n-type planar FET 100a and the p-type planar FET 100b at temperatures of greater than 500 C. for gate first processing.
(34) Still referring to
(35) The n-type planar FET 100a includes n-type dopants in the first portion 15 of the substrate 10 for the source region 40a and drain region 45a that are positioned on opposing sides of the first gate structure 30a. In some embodiments, a n-type dopant in a type III-V semiconductor material, such as InGaAs, can be element from Group IIA or VIA of the Periodic Table of Elements). As used herein, n-type refers to the addition of impurities that contributes free electrons to an intrinsic semiconductor. In some embodiments, the dopant for providing an n-type device in a type III-V semiconductor material may be from Group IV of the periodic table of elements, such as silicon.
(36) The p-type planar FET 100b includes p-type dopants in the second portion 20 of the substrate 10 for the source region 40b and drain region 45b that are positioned on opposing sides of the second gate structure 30b. As used herein, p-type refers to the addition of impurities to an intrinsic semiconductor that creates deficiencies of valence electrons. In a type IV semiconductor surface, such as the germanium containing second portion 20, e.g., silicon germanium (SiGe) second portion 20, of the substrate, examples of p-type dopants, i.e., impurities, include but are not limited to boron, aluminum, gallium and indium. The p-type dopant within the source and drain regions 40b, 45b is typically present in a concentration ranging from about 10.sup.11 to about 10.sup.15 atoms/cm.sup.2, with a concentration of dopant within the doped region from about 10.sup.11 to about 10.sup.13 atoms/cm.sup.2 being more typical.
(37) Although not depicted in the supplied figures the source and drain regions 40a, 40b, 45a, 45b for the p-type planar FET 100b and the n-type planar FET 100a may further include raised source and drain regions. Raised source and drain regions may include in-situ doped epitaxially formed semiconductor material that is formed on the upper surface of the substrate 10 in which the source and drain regions 40a, 40b, 45a, 45b are present.
(38) Referring to
(39) In another embodiment, the aforementioned effective work functions (EWF) can be provided for each of the p-type planar semiconductor device and the n-type planar semiconductor device using a titanium nitride (TiN) atomic layer deposition (ALD) formed material layer for the first and second metal work function adjusting layers 33a, 33b in combination with a first and second interface layer 31a, 31b comprising doping with Group IIA and/or Group IIIB dielectric doping.
(40) Although the semiconductor devices described herein are field effect transistors (FETs), the present disclosure is equally applicable to any semiconductor device that exhibits a change in conductivity in response to the application of a threshold voltage.
(41) The CMOS device depicted in
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(43) The interface layer 31 may be formed using a thermal oxidation method. For example, when the interface layer 31 is composed of silicon oxide it can be formed using thermal oxidation. In the embodiments, in which the interface layer 31 is formed with a group IIA or group IIIB dielectric doping layer, the interface layer 31 may be formed using a deposition method, such as chemical vapor deposition (CVD) or atomic layer deposition (ALD). Variations of CVD processes suitable for forming the interface layer 31 include, but not limited to, Atmospheric Pressure CVD (APCVD), Low Pressure CVD (LPCVD) and Plasma Enhanced CVD (PECVD), Metal-Organic CVD (MOCVD) and combinations thereof may also be employed.
(44) In the embodiment depicted in
(45) The high-k gate dielectric layer 32 can be formed by a thermal growth process such as, for example, oxidation, nitridation or oxynitridation. The high-k gate dielectric layer 32 can also be formed by a deposition process such as, for example, chemical vapor deposition (CVD), plasma-assisted CVD, metal-organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), evaporation, reactive sputtering, chemical solution deposition and other like deposition processes. The high-k gate dielectric layer 32 may also be formed utilizing any combination of the above processes. The high-k gate dielectric layer 32 typically has a thickness ranging from 1 nm to 10 nm. In one example, the high-k gate dielectric layer 32 has a thickness ranging from 2 nm to 5 nm. The high-k gate dielectric layer 32 may be composed of a single composition high-k dielectric layer that provides the same composition for the first and second high-k gate dielectric layers 32a, 32b following gate patterning.
(46) Referring to
(47) In some embodiments, the first and second metal work function adjusting layers 33a, 33b can be formed with the deposition of a single layer of work function adjusting material. In this example, the composition of the first metal work function layer 33a is the same as the composition of the second metal work function layer 33b. In the example that is depicted in
(48) In one embodiment, each of the first and second metal work function adjusting layers 33a, 33b may be formed of titanium nitride with stoichiometric tuning to provide the appropriate work function adjustments for the n-type field effect transistor 100a and the p-type field effect transistor 100b. Stoichiometric tuning can be accomplished by adjusting the titanium (Ti) to nitrogen (N) ratio during the physical vapor deposition (PVD) sputtering program for forming the material layer. In some embodiments, the titanium nitride layers may be formed using atomic layer deposition (ALD).
(49) Still referring to
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(51) Referring to
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(53) Although
(54) Following formation of the source and drain regions 40a, 40b, 45a, 45b they may be activated using an activation anneal. For example, the anneal process may include a temperature greater than 500. In other embodiments, the anneal process can include a temperature ranging from 850 C. to 1350 C.
(55) The above process sequence can provide the CMOS device depicted in
(56) The present disclosure also provide methods and structures for providing work function adjustments for CMOS devices having planar n-type FETs formed on III-V semiconductor materials, and planar p-type FETs formed on germanium containing semiconductor materials using gate last processing, which may also be referred to as replacement gate processing or replacement metal gate (RMG) processing.
(57) The substrate 10 that is depicted in
(58) Similar to the n-type field effect transistor 100a that is depicted in
(59) The description of the first interface dielectric layer 31a, and the first conductive electrode 34a, of the n-type field effect transistor 100a that is depicted in
(60) The first metal work function adjusting layer 33c that is present in the first gate structure 30a to the n-type planar FET 100c formed using gate last processing may be a composite layer, i.e., a multi-layered structure, including at least one aluminum (Al) containing layer. For example, the first metal work function adjusting layer 33c may be composed of a first layer of titanium nitride (TiN) that is present on the first high-k dielectric layer 32c, a second layer of titanium aluminum carbide (TiAlC) that is present on the first layer of titanium nitride (TiN), and a third layer of titanium nitride (TiN) that is present on the second layer of titanium aluminum carbide (TiAlC). In another example, the first metal work function adjusting layer 33c may be composed of a first layer of titanium nitride (TiN) that is present on the first high-k dielectric layer 32c, a second layer of titanium aluminide (TiAl) that is present on the first layer of titanium nitride (TiN), and a third layer of titanium nitride (TiN) that is present on the second layer of titanium aluminide (TiAl). The thickness of each layer in the composite layer that provides the first metal work function adjusting layer may range from about 30 Angstroms to about 60 Angstroms.
(61) Similar to the p-type field effect transistor 100b that is depicted in
(62) The description of the second interface dielectric layer 31b, and the second conductive electrode 34b, of the p-type field effect transistor 100b that is depicted in
(63) The second metal work function adjusting layer 33d that is present in the second gate structure 30b to the p-type planar FET 100d formed using gate last processing may be a composite layer, i.e., a multi-layered structure, including at least one aluminum (Al) containing layer. For example, the second metal work function adjusting layer 33d may be composed of a first layer of titanium nitride (TiN) that is present on the second high-k dielectric layer 32d, a second layer of titanium aluminum carbide (TiAlC) that is present on the first layer of titanium nitride (TiN), and a third layer of titanium nitride (TiN) that is present on the second layer of titanium aluminum carbide (TiAlC). In another example, the second metal work function adjusting layer 33d may be composed of a first layer of titanium nitride (TiN) that is present on the second high-k dielectric layer 32d, a second layer of titanium aluminide (TiAl) that is present on the first layer of titanium nitride (TiN), and a third layer of titanium nitride (TiN) that is present on the second layer of titanium aluminide (TiAl). The thickness of each layer in the composite layer that provides the second metal work function adjusting layer 33d may range from about 30 Angstroms to about 60 Angstroms.
(64) The composition of each material layer in the first gate structure 30a may be the same as the composition of each material layer in the second gate structure 30b. In some embodiments, the composition of at least one material layer in the first gate structure 30a may be different from the composition of at least one material layer in the second gate structure 30b.
(65) Referring to
(66) Still referring to
(67) Referring to
(68) The CMOS device depicted in
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(71) The method may continue with activating the source and drain regions 40a, 40b, 45a, 45b. Activation of the source and drain regions 40a, 40b, 45a, 45b may be done with the replacement gate structure present on the substrate 10. This provides that the later formed functional gate structure is not subjected to the high temperature anneal process. Further details regarding the activation anneal have been described above with reference to
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(73) After the replacement gate structures 60 are removed, gate openings 65 are present to the channel regions of the first portion 15 of the substrate 10 and the second portion 15 of the substrate 10. The gate openings 65 may then be filled with the material layers that provide the function gate structures for each of the n-type planar FET 100c and the p-type planar FET 100d, as depicted in
(74) In some embodiments, the gate last process flow that is illustrated with reference to
(75)
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(77) Each of the fin structures 70, 75 may be positioned on a dielectric layer 71, which may be an oxide or nitride material layer. In one example, the dielectric layer 71 is composed of silicon oxide (SiO.sub.2). A supporting substrate 72 may be present underlying the dielectric layer 71. In some embodiments, the supporting substrate 72 may be composed of a semiconductor material, such as silicon (Si). In some other embodiments, the supporting substrate 72 can be composed of a dielectric material or a metal.
(78) Each of the n-type and p-type fin field effect transistors 100e, 100f include a gate structure 30e, 30f having work function adjustments, which in some embodiments provides an effective work function ranging from 4.3 to 4.7 eV for each of the n-type and p-type fin field effect transistors 100e, 100f. In one example, an effective work function ranging from 4.4 eV to 4.6 eV can be provided for each of the n-type and p-type field effect transistors 100e, 100f.
(79) The first and second fin structures 70, 75 may be further processed to form a conformal silicon containing layer 29a, 29b on their sidewall and upper surfaces. The conformal silicon containing layer 29a, 29b may be composed of amorphous silicon (-Si), and may be deposited using chemical vapor deposition.
(80) The n-type fin field effect transistor 100e may include a first gate structure 30e that includes a first interface dielectric layer 31e formed over the channel region of the first fin structure 70; a first high-k gate dielectric layer 32e that is present on the first interface dielectric layer 31e; a first metal work function adjusting layer 33e that is present on the first high-k gate dielectric layer 32e; and a first conductive electrode 34e.
(81) The p-type fin field effect transistor 100f may include a second gate structure 30f that includes a second interface dielectric layer 31f formed on the channel portion of the second fin structure 75; a second high-k gate dielectric layer 32f that is present on the second interface dielectric layer 31f; a second metal work function adjusting layer 33f that is present on the second high-k gate dielectric layer 32f; and a second conductive electrode 34f.
(82) In some embodiments, the n-type fin field effect transistor 100e is doped by an aluminum containing dielectric that provides the first interface dielectric layer 31e. For example, the aluminum containing dielectric that provides the first interface dielectric layer 31e may be composed of aluminum oxide (Al.sub.2O.sub.3), aluminum oxynitride, aluminum nitride (AlN), as well as other aluminum containing dielectrics. The first interface dielectric layer 31e may be present on the sidewalls surfaces and upper surface of the portion of the first fin structure 70 that contains the channel region of the device.
(83) In some embodiments, the p-type fin field effect transistor 100f is doped by an dopant selected from Group IIA or Group IIIB of the Periodic Table of Elements that is integrated into the second interface dielectric layer 31f. Examples of dielectric dopants from Group IIA or Group IIIB of the Periodic Table of Elements may be selected from the group consisting of beryllium (Be), magnesium (Mg), barium (Ba), lanthanum (La), yttrium (Y) and combinations thereof. For example, the second interface dielectric layer 31f may be composed of lanthanum oxide (La.sub.2O.sub.3).
(84) The thickness for each of the first and second interface dielectric layer 31e, 31f may range from 1 to 10 . In some examples, the thickness for each of the first and second interface dielectric layers 31e, 31f may be on the order of 2 to 6 .
(85) The composition of the first high-k gate dielectric layer 32e and the second high-k dielectric layer 32f that are depicted in
(86) The first and second gate structures 30e, 30f may be formed using a single metal electrode, i.e., first and second metal work function adjusting layer 33e, 33f and first and second conductive electrode 34e, 34f for both of the first and second gate structures 30e, 30f. By single metal electrode it is meant that the composition for both the first and metal work function adjusting layers 33e, 33f as well as the composition for both of the first and second gate electrode 34e, 34f, is the same. For example, the first and second metal work function adjusting layers 33e, 33f may each be composed of metal nitride, such as titanium nitride (TiN). The first and second work function adjusting layers 3e, 33f may be deposited using atomic layer deposition (ALD). Although titanium nitride (TiN) is described above as an embodiment of a material suitable for the first and second metal work function adjusting layers, other metal nitrides may be suitable for use with the present disclosure. For example, the first and second metal work function adjusting layers may include other metals from Groups IVB to VIB in the Periodic Table, including, e.g., tantalum nitride (TaN), and the like with a thickness of about 30 Angstroms to about 60 Angstroms.
(87) The first and second gate electrodes 34e, 34f that are depicted in
(88) The first and second gate structures 30e, 30f is suitable for activation anneals for the source and drain regions of the n-type fin FET 100e and the p-type fin FET 100e to temperatures greater than 500 C.
(89) Referring to
(90) In one example, an n-type finFET 100e formed using a gate first process including a first gate structure 30e composed of a first conductive electrode 34e of tungsten (W), a first metal work function layer 33e of a single metal layer atomic layer deposited (ALD) titanium nitride (TiN), a first high-k gate dielectric layer 32e of hafnium oxide (HfO.sub.2), and an interface layer 31e of aluminum oxide (Al.sub.2O.sub.3), which is present on a deposited silicon layer present on a first fin structure 70 that is composed of In.sub.0.53Ga.sub.0.47As can provide an effective work function of approximately 4.6 eV with a 100 to 200 mV pFET shift. This shift is to an effective work function that is greater than 4.6 eV. In the same example, the second gate structure 30f of the p-type FinFET semiconductor device 100f that is present on the same substrate 10 as the n-type FinFET semiconductor device 100c may include a second conductive electrode 34f of tungsten (W), a second metal work function layer 33f that is a composed of a single metal layer atomic layer deposited (ALD) titanium nitride (TiN), a second high-k gate dielectric layer 32e of hafnium oxide (HfO.sub.2), and an interface layer 31e of lanthanum oxide (La.sub.2O.sub.3) in which the second gate structure 30f is present on a second fin structure 75 composed of silicon germanium (SiGe) having a germanium (Ge) concentration that is greater than 50 at. %, the effective work function for the p-type finFET 100f may be approximately 4.6 eV with a 300 mV to 400 mV nFET shift. This shift is to an effective work function that is less than 4.6 eV. In some examples, a dual metal atomic layer deposited (ALD) stack of titanium nitride and tantalum nitride may be substituted for the single metal atomic layer deposited (ALD) layer of titanium nitride (TiN) for each of the first and second metal work function adjusting layers 32e, 32f.
(91) The CMOS device depicted in
(92) The interface layer 31, 31 that is processed to provide the first and second interface layer 31e, 32f may be formed using deposition processes in combination with block masks to control the positioning of the material being deposited. For example, a first block mask may be formed over the first fin structure, while an interface layer 31 is deposited including dopant from Group IIA or Group IIIB of the periodic table of elements over the second fin structure 75 composed of the germanium containing material. Thereafter, the first block mask may be removed, and a second block mask may be formed over the previously deposited interface layer 31 and the second fin structure 75. A first interface layer 31 of an aluminum containing dopant may then be formed over the first fin structure 70 of the type III-V semiconductor material. The first and second interface layers 31, 31 may be deposited using chemical vapor deposition (CVD), such as plasma enhanced chemical vapor deposition.
(93) Following formation of the first and second interface layers, a blanket deposited layers of high-k dielectric material 32 may be deposited on the first and second interface layers 31, 31 over the first and second fin structures 70, 75. The high-k dielectric material 31 is later processed to provide the first high-k dielectric layer 31e and the second high-k dielectric layer 31f during patterning of the first and second gate structures 30e, 30f. The high-k dielectric material layer 32 may be deposited using any method that has been described above for forming the first and second high-k dielectric material layer 32a, 32b that has been described above with reference to
(94) In some embodiments, the first and second work function metal layers 33e, 33f that are formed on the first and second fin structures 70, 75 have the same composition. Forming the first and second work function metal layers 33e, 33f may begin with a blanket deposition of a work function metal layer 33 on the high-k gate dielectric layer 32, as well as over the first and second fin structures 70, 75. The work function metal layer 33 may be deposited using any method that has been described above for forming the first and second work function material layers 33a, 33b that have been described above with reference to
(95) The gate electrode material layer 34 for the first and second gate electrodes 34e, 34f may then be formed atop the work function metal layer 33. The gate electrode material layer 34 is similar to the material layers deposited for the first and second gate electrodes 34a, 34b that are described in
(96) In a following process step, the gate electrode material layer 34, the work function metal layer 33, the layer of high-k dielectric material 32 and the first and second interface layers 31, 31 may be patterned to provide a first and second gate structure 30a, 30b. The first and second gate structures 30a, 30b may be patterned using deposition, photolithography and etching processes, similar to the methods for patterning the gate structures to the planar CMOS device described above with reference to
(97)
(98)
(99) For finFETs that are formed using gate last processing, a silicon containing conformal layer 29a, 29b may be present on each of the first and second fin structures 70, 75. The silicon containing conformal layers 29a, 29b may be composed of amorphous silicon. In some embodiments, when using gate last processing, the silicon containing conformal layer 29b may be omitted from the nFinFET, so that the sole silicon containing conformal layer 29a is present on the pFinFET. The silicon containing conformal layers 29a, 29b may be formed using chemical vapor deposition.
(100) The n-type fin field effect transistor 100g may include a first gate structure 30g that includes a first interface dielectric layer 31g formed on the channel region of the first fin structure 70; a first high-k gate dielectric layer 32g that is present on the first interface dielectric layer 31g; a first metal work function adjusting layer 33g that is present on the first high-k gate dielectric layer 32g; and a first conductive electrode 34g.
(101) The first interface dielectric layer 31g may be an oxide, such as silicon oxide (SiO.sub.2). In some embodiments, the first dielectric layers 31g may also be provided by a doped dielectric material deposited by Atomic Layer Deposition (ALD). For example, the first interface dielectric layer 31g may be composed of an aluminum containing dielectric. For example, the aluminum containing dielectric that provides the first interface dielectric layer 31g may be composed of aluminum oxide (Al.sub.2O.sub.3), aluminum oxynitride, as well as other aluminum containing dielectrics. The first interface dielectric layer 31g may be present on the sidewalls surfaces and upper surface of the portion of the first fin structure 70 that contains the channel region of the device. In some examples, the thickness of the first interface dielectric layer 31g may be on the order of 1 to 10 .
(102) The first high-k dielectric layer 32g is similar to the first high-k dielectric layer 32a depicted in
(103) The first metal work function adjusting layer 33g that is depicted in
(104) The first conductive electrode 34g is similar to the first conductive electrode 34a depicted in
(105) The p-type fin field effect transistor 100h may include a second gate structure 30h that includes a second interface dielectric layer 31h formed on the channel portion of the second fin structure 75; a second high-k gate dielectric layer 32h that is present on the second interface dielectric layer 31h; a second metal work function adjusting layer 33h that is present on the second high-k gate dielectric layer 32h; and a second conductive electrode 34h.
(106) The second interface dielectric layer 31h may be amorphous silicon (Si) doped with a dopant selected from Group IIA or Group IIIB of the Periodic Table of Elements that is integrated into the second interface dielectric layer 31f. Examples of dielectric dopants from Group IIA or Group IIIB of the Periodic Table of Elements may be selected from the group consisting of beryllium (Be), magnesium (Mg), barium (Ba), lanthanum (La), yttrium (Y) and combinations thereof. For example, the second interface dielectric layer 31h may be composed of a chemical vapor deposited layer of silicon that is conformally deposited, upon which another layer is deposited by ALD and comprises dopants introduced by dopant gas including Group IIA or Group IIIB elements. In some examples, the thickness of the second interface dielectric layer 31h may be on the order of 1 to 2 nm. The second interface dielectric layer 31g may be present on the sidewalls surfaces and upper surface of the portion of the first fin structure 70 that contains the channel region of the device.
(107) The second high-k dielectric layer 32h is similar to the second high-k dielectric layer 32b depicted in
(108) The second metal work function adjusting layer 33h that is depicted in
(109) The second conductive electrode 34h is similar to the second conductive electrode 34b depicted in
(110) The dual metal, i.e., different compositions for the first metal work function adjusting layer 33g and the second metal work function adjusting layer 33h, enables a different oxygen vacancy concentration between the n-type finFET 100g and the p-type finFET 100h. For example, the p-type finFET 100h will typically have a gate structure with a high oxygen vacancy concentration and the n-type finFET 100g will typically have a gate structure with a low vacancy concentration. As used herein, the term low concentration when describing a oxygen vacancy concentration means a concentration of 10.sup.14/cm.sup.2 or below. As used herein, the term high concentration when describing a oxygen vacancy concentration means For example, the oxygen vacancy concentration of the p-type finFET 100h may range from 10.sup.14/cm.sup.2 to 610.sup.14/cm.sup.2, while the oxygen vacancy concentration in the n-type finFET 100g may range from 10.sup.13/cm.sup.2 to 610.sup.13/cm.sup.2. By providing a p-type FinFET 100h including a gate structure 30h having a high concentration of oxygen vacancies, the present disclosure provides an effective work function shift towards the conduction band. By providing an n-type FinFET 100g including a gate structure 30g having a low concentration of oxygen vacancies, the present disclosure provides an effective work function shift towards the valence band
(111) The first and second gate structures 30e, 30f is suitable for use in a replacement metal gate (RMG) process with temperatures reaching approximately 400 C. In a replacement gate process flow, i.e., gate last process flow, the electrodes are not chemically or thermally stable for temperatures greater than 400 C., and can lead to unwanted threshold voltage shifts.
(112) The n-type fin field effect transistor 100g includes n-type source regions and n-type drain regions, and the p-type fin field effect transistor 100h includes p-type source regions and p-type drain regions. The description of the n-type source regions 40e and n-type drain regions 45e, the p-type source regions 40f and the p-type drain regions 45f depicted in
(113) Still referring to
(114) In one example, an n-type finFET 100g formed using a gate last process including a first gate structure 30g composed of a first conductive electrode 34g of tungsten (W), a first metal work function layer 33g of a single metal layer atomic layer deposited (ALD) titanium nitride (TiN), a first high-k gate dielectric layer 32g of hafnium oxide (HfO.sub.2), and an interface layer 31e of silicon oxide (SiO.sub.2), which is present on a first fin structure 70 that is composed of In.sub.0.53Ga.sub.0.47As can provide an effective work function of approximately 4.6 eV with a 100 to 200 mV nFET shift. In some examples, the 100 to 200 mV nFET shift is to a value greater than 4.6 eV. In the same example, the second gate structure 30h of the p-type FinFET semiconductor device 100h that is present on the same substrate 10 as the n-type FinFET semiconductor device 100g may include a second conductive electrode 34h of tungsten (W), a second metal work function layer 33h that is a composed of a single metal layer atomic layer deposited (ALD) titanium nitride (TiN), a second high-k gate dielectric layer 32h of hafnium oxide (HfO.sub.2), and an interface layer 31h of amorphous silicon (a-Si) doped with group IIA or group IIIB dopant of the periodic table of elements, in which the second gate structure 30h is present on a second fin structure 75 composed of silicon germanium (SiGe) having a germanium (Ge) concentration that is greater than 50 at. %; the effective work function for the p-type finFET 100h may be approximately 4.6 eV with a 300 mV to 400 mV shift. For example, the effective work function shift may be 300 mV to 400 mV less than 4.6 eV.
(115) The CMOS device depicted in
(116)
(117)
(118)
(119) Referring to
(120) While the present invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in forms and details may be made without departing from the spirit and scope of the present invention. It is therefore intended that the present invention not be limited to the exact forms and details described and illustrated, but fall within the scope of the appended claims.