Systems and methods for thin-film deposition of metal oxides using excited nitrogen-oxygen species

Abstract

The present invention relates to a process and system for depositing a thin film onto a substrate. One aspect of the invention is depositing a thin film metal oxide layer using atomic layer deposition (ALD).

Claims

1. A system comprising: a reaction chamber; a precursor reactant source, comprising a precursor reactant gas, coupled to the reaction chamber; a first oxidizer gas source, configured to produce an oxidizer comprising ozone and activated nitrogen compounds generated from a mixture of O.sub.2 and N.sub.2 having an N.sub.2/O.sub.2 ratio greater than 0.001, coupled to the reaction chamber; an N.sub.xO.sub.y species source configured to produce an N.sub.xO.sub.y species gas and coupled to the reaction chamber, the N.sub.xO.sub.y species source comprising: a second oxidizer gas source; a nitrogen gas source; a nitrogen-containing species generator coupled to the second oxidizer gas source and the nitrogen gas source; and a sensor coupled to the nitrogen-containing species generator to monitor a composition of a N.sub.xO.sub.y species gas, created by the nitrogen-containing species generator, prior to introducing the N.sub.xO.sub.y species gas to the reaction chamber; a system operation and control mechanism coupled to the precursor reactant source, the first oxidizer gas source, the second oxidizer gas source, the nitrogen gas source, a power unit of the nitrogen-containing species generator, and the sensor; and a first control input to the system operation and control mechanism, wherein the first control input is an output from the sensor; at least a first control output from the system operation and control mechanism, generated in response to the output from the sensor, to control a ratio of the second oxidizer gas source and the nitrogen gas source input into the nitrogen-containing species generator in conjunction with controlling the power unit of the nitrogen-containing species generator to achieve a desired type of N.sub.xO.sub.y species gas and composition of the N.sub.xO.sub.y species gas being output from the nitrogen-containing species generator; wherein the system operation and control mechanism is configured to cause the system to apply an atomic layer deposition cycle to a substrate, the cycle comprising: exposing the substrate to the precursor reactant gas for a precursor pulse interval; and then exposing the substrate to the first oxidizer, comprising the ozone and the activated nitrogen compounds from the first oxidizer gas source, and the NxOy species gas from the N.sub.xO.sub.y species source for an oxidation pulse interval, wherein, during the oxidation pulse interval, a pulse of the first oxidizer to the reaction chamber and a pulse of the N.sub.xO.sub.y species gas to the reaction chamber are independently controlled prior to entering the reaction chamber.

2. The system of claim 1, wherein the N.sub.xO.sub.y species gas comprises activated ionic or radical species comprising at least one of NO*, N.sub.2O*, NO.sub.2*, NO.sub.3* and N.sub.2O.sub.5*.

3. The system of claim 1, wherein the oxidizer comprises about 5 atomic percent to about 25 atomic percent ozone.

4. The system of claim 1, wherein the sensor further monitors a volume of an output stream of the nitrogen-containing species source.

5. The system of claim 1, wherein the sensor comprises one or more of the group consisting of a Fourier Transform Infrared Spectroscopy analyzer, a UV absorption sensor, a density sensor, a conductivity/permittivity sensor, a chemiluminescence sensor, and a gas chromatography sensor.

6. The system of claim 1, wherein the sensor monitors a ratio of ozone and the N.sub.xO.sub.y species gas.

7. The system of claim 1, wherein the system operation and control mechanism is configured to adjust at least one of a power input of the nitrogen-containing species generator, a temperature of a housing of the nitrogen-containing species generator, a flowrate of an oxygen gas to the nitrogen-containing species generator, and a flowrate of a nitrogen gas to the nitrogen-containing species generator.

8. The system of claim 1, wherein the system operation and control mechanism is configured to adjust at least one of a power input of the nitrogen-containing species generator, a temperature of a housing of the nitrogen-containing species generator, a flowrate of an oxygen gas to the nitrogen-containing species generator, and a flowrate of a nitrogen gas to the nitrogen-containing species generator to achieve a predetermined criterion.

9. The system of claim 8, wherein the predetermined criterion is selected from one or more of a flow rate of the oxidizer; an oxidant/N.sub.xO.sub.y species concentration ratio; an active N.sub.xO.sub.y species concentration; a ratio of active N.sub.xO.sub.y species, wherein the N.sub.xO.sub.y species gas comprises an excited N.sub.xO.sub.y species gas containing a plurality of excited nitrogen-oxygen compounds; and a concentration of a particular active nitrogen-oxygen compound.

10. The system of claim 1, wherein the system operation and control mechanism is configured to control the first oxidizer gas source.

11. The system of claim 1, wherein the nitrogen-containing species generator is an ozone generator.

12. The system of claim 1, wherein the system operation and control mechanism is configured to control the first oxidizer gas source to produce O.sub.2/O.sub.3 in a desired ratio.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a process flow for an example embodiment of the present invention.

(2) FIG. 2 shows a schematic illustration of a thin film processing system according to an example embodiment of the present invention.

(3) FIG. 3A shows a schematic illustration of a thin film processing system according to an example embodiment of the present invention with separated oxidizer and NxOy species sources.

(4) FIG. 3B shows a schematic illustration of a thin film processing system according to an example embodiment of the present invention with an NxOy species source within the reaction chamber.

(5) FIG. 4 illustrates one example embodiment of the oxidizer/NxOy species source of the present invention.

(6) FIG. 5 illustrates a simplified DBD ozone generator cell of the prior art.

(7) FIG. 6 depicts a metal oxide transistor with a dielectric layer formed by methods consistent with an example embodiment of the present invention

(8) FIG. 7 shows a memory cell with at least one dielectric layer formed by methods consistent with an example embodiment of the present invention.

(9) FIG. 8 illustrates a general system incorporating an electronic component that includes a dielectric layer formed by methods consistent with an example embodiment of the present invention.

(10) FIG. 9 shows an information processing device such as a computer that incorporates electronic components including a dielectric layer formed by methods consistent with an example embodiment of the present invention.

(11) FIG. 10 shows a chart depicting another trial measuring thickness and uniformity of deposited hafnium oxide when nitrogen feed gas concentration was being varied, and represents the leftmost portion of FIG. 11.

(12) FIG. 11 shows a chart depicting a trial measuring thickness and uniformity of deposited hafnium oxide when nitrogen feedgas concentration was being varied according to an example embodiment of the present invention.

(13) FIG. 12 shows a chart depicting a trial measuring thickness and uniformity of deposited hafnium oxide when nitrogen feedgas flow rate was being varied according to an example embodiment of the present invention.

(14) FIG. 13 illustrates a chart showing improvements of the thickness and uniformity of a deposited lanthanum oxide film as an amount of nitrogen feedgas supplied to an ozone generator is increased according to an example embodiment of the present invention.

(15) FIG. 14 is a block diagram of an example embodiment of a process that may be utilized in the fabrication of various devices according to an example embodiment of the present invention.

(16) FIG. 15 illustrates an example embodiment of a metal oxide semiconductor (MOS) that may be fabricated from the process depicted in FIG. 14.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(17) Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings.

(18) Some embodiments of the invention provide methods for preparing thin films used in a variety of applications, especially for depositing high-k dielectric materials and barrier materials used in transistor, capacitor, and memory cell fabrication. Some embodiments may include the use of an atomic layer deposition (ALD) process to deposit a metal oxide thin film layer on a substrate.

(19) The material deposited in a film during ALD deposition may be any desired material such as a dielectric material, a barrier material, a conductive material, a nucleation/seed material or an adhesion material. In one embodiment, the deposited material may be a dielectric material containing oxygen and at least one additional element, such as lanthanum, hafnium, silicon, tantalum, titanium, aluminum, zirconium, or combinations thereof, and in an example embodiment, the deposited material comprises a metal oxide, and more particularly a rare earth metal oxide. In additional embodiments, the dielectric material may contain hafnium oxide, zirconium oxide, tantalum oxide, aluminum oxide, lanthanum oxide, titanium oxide, silicon oxide, silicon nitride, oxynitrides thereof (e.g., HfO.sub.xN.sub.y), silicates thereof (e.g., HfSi.sub.xO.sub.y), aluminates thereof (e.g., HfAl.sub.xO.sub.y), silicon oxynitrides thereof (e.g., HfSi.sub.xO.sub.yN.sub.z), and combinations thereof. The dielectric material may also contain multiple layers of varying compositions. For example, a laminate film may be formed by depositing a silicon oxide layer onto a hafnium lanthanum oxide layer to form a hafnium lanthanum silicate material.

(20) In one embodiment, methods and systems of the present invention utilize an activated gas containing ions and active species of nitrogen-oxygen compounds in the form of free radicals (hereinafter referred to as active NxOy species) to enhance deposition of thin film metal oxides including rare earth oxides. In an embodiment, the NxOy species are presented to a substrate during a pulse of an ALD process following a metal precursor pulse, possibly with an oxidizer such as ozone.

(21) Commercially available ozone delivery systems such as those utilized in conjunction with ALD processes commonly rely on the dielectric barrier discharge and often utilize nitrogen in the feed gas to provide consistent ozone generation. Through a complex series of plasma reactions, various NxOy species can also form within the corona from O.sub.2 in the presence of N.sub.2. These species, while present in various concentrations in the generator effluent, are unregulated by the delivery system which measures and actively controls the O.sub.3 concentration only.

(22) Several ALD processes using ozone are extremely sensitive to the conditions of ozone generation. For example, a wide response in HfO.sub.2 deposition rate and film uniformity has been experimentally observed as a function of O.sub.2:N.sub.2 feed gas ratio and reactor temperature in a cross-flow, thermal ALD reactor HfCl.sub.4/O.sub.3 ALD (using pure O.sub.3) has a process window at low reactor temperature (200-250 C.). At higher temperatures (e.g., 300 C.), uniform HfO.sub.2 layers were experimentally obtained when N.sub.2 was added during O.sub.3 generation. These experimental results support a hypothesis that the reactive species in ozone-based ALD may not be exclusively O.sub.3, but at 300 C. NxOy species contribute as well.

(23) Therefore, studies were conducted to first characterize the gaseous species entering (from ozone delivery system) and exiting the ALD reactor as a function of O.sub.2:N.sub.2 feed gas ratio, O.sub.3 concentration, and generator power levels using FTIR. N.sub.2O.sub.5 and N.sub.2O are detected at the outlet of the O.sub.3 delivery unit with N.sub.2:O.sub.2 feed gas. The lifetime of O.sub.3 and the NxOy species were investigated as a function of the reactor temperature and material of coating (HfO.sub.2, AhO.sub.3, etc.). FTIR analysis of the reactor effluent during the ozone half-reaction with adsorbed HfO.sub.2-HfCh was employed to elucidate the role of NxOy species on deposition. ALD deposition rates, film uniformities, and various bulk and electrical film properties for HfO.sub.2 deposited under various ozone delivery conditions, and based on FTIR, and theories surrounding the role of O.sub.3 and NxOy species on potential reaction paths are were determined. As a result, some embodiments of the present invention include improved ALD deposition in layer thickness and consistency when using various molecular and excited NxOy species that were introduced to the reaction chamber as an additional output from ozone generation.

(24) Referring to FIG. 1, a method 100 for depositing a thin metal oxide film using activated gas compounds such as NxOy species is presented. At the beginning (105) of the process 100, a substrate is located within a reaction chamber, and heated to a predetermined temperature. The predetermined temperature may comprise any desired temperature, and some embodiments of the present invention may include temperatures such as about 130 C. to 300 C. During execution of the process 100, the reaction chamber is maintained at any desired pressure range such as from about 1 mTorr to about 200 Ton, and in an example embodiment of the present invention from about 2 Torr to 6 Torr, and in another embodiment, from about 3 Torr to 4 Torr, and in yet another example embodiment the reaction chamber pressure is maintained at about 3.5 Torr.

(25) A carrier gas may be continually or intermittently admitted into the reaction chamber, and may be utilized to distribute precursor products, reaction products, and oxidation products or to purge remaining gasses or reaction byproducts from the reaction chamber. Suitable carrier gases or purge gases may include argon, nitrogen, helium, hydrogen, forming gas, or combinations thereof.

(26) After the ALD process is initiated (105), a precursor gas is pulsed (110) into a reaction chamber with or without a carrier gas. The precursor gas may comprise any desired compound such as metallic, organo-metallic, or metal halide compounds, including, but not limited to hafnium tetrachloride (HfCl.sub.4); titanium tetrachloride (TiCl.sub.4); tantalum pentachloride (TaCl.sub.5); tantalum pentafluoride (TaF.sub.5); zirkonium tetrachloride (ZrCl.sub.4); rare earth betadiketonate compounds including (La(THD).sub.3) and (Y(THD).sub.3); rare earth cyclopentadienyl (Cp) compounds including La(iPrCp).sub.3; rare earth amidinate compounds including lanthanum tris-formamidinate La(FAMD.sub.3; cyclooctadienyl compounds including rare earth metals; alkylamido compounds including: tetrakis-ethyl-methylamino hafnium (TEMAHf); tetrakis (diethylamino) hafnium ((Et.sub.2N).sub.4Hf or TDEAH); and tetrakis (dimethylamino) hafnium ((Me.sub.2N).sub.4Hf or TDMAH); alkoxides; halide compounds of silicon; silicon tetrachloride; silicon tetrafluoride; and silicon tetraiodide.

(27) During the gas pulses as referred to herein, the substrate in the reaction chamber is exposed to the admitted gas for a predetermined period of time, and this period of time is herein referred to as a pulse interval. The pulse interval for the presentation of the precursor gas to the substrate may be predetermined to be any desired time, and for example may include a time in the range of approximately 300 milliseconds to 5 seconds, and in one embodiment the pulse interval is in the range of 1 second to 3 seconds.

(28) After the substrate has been exposed to the precursor gas for a predetermined pulse interval, the precursor gas is purged (120) from the reaction chamber by admission of a purge gas and/or by evacuation or pumping. Purging time, or the time during which a purging gas is admitted to the reaction chamber to displace and/or remove other gasses or reaction products, may be selected to be any desired time such as approximately 3 to 10 seconds, and may in some embodiments be approximately 500 milliseconds to 5 seconds.

(29) An activated NxOy species gas as defined above is introduced (130) to the reaction chamber, and in one embodiment, a layer of precursor material deposited in step (110) is oxidized by introduction of the activated NxOy species with or without an additional oxidizer. During this step (130) an oxidizer/oxidant gas or combination of oxidizer/oxidant gasses may be admitted concurrently or sequentially into the reaction chamber to react with the first precursor. The NxOy species gas may also be introduced with or without a carrier gas such as nitrogen N.sub.2, and further in possible combination with an oxidant gas or mixture of oxidant gasses. As mentioned previously, the NxOy species may comprise any activated, ionic or radical NO compound such as activated nitrous oxide (N.sub.2O*), nitric oxide (NO*), dinitrogen pentoxide (N.sub.2O.sub.5*), or nitrogen dioxide (NO.sub.2*). The NxOy species gas may be generated in any desired manner, and in one embodiment, the NxOy species are created by plasma discharge from an ozone generator being supplied O.sub.2, N.sub.2, N.sub.2O, NO, NH.sub.3 or any nitrogen bearing molecule wherein concentration of nitrogen bearing molecule is greater than 5 sccm/2000 sccm or 2000 ppm. In another embodiment, the NxOy species are created within or supplied to the reaction chamber by remote or direct plasma methods such as inductively coupled, ECR (electron cyclotron resonance), capactively coupled methods, with any desired feedgas. In yet another embodiment, NxOy species are created by feeding a nitrogen-oxygen gas such as NO or N.sub.2O into a coronal discharge (such as provided by an ozone generator) (or alternatively a remote or direct plasma source) with no additional oxygen. Additional N.sub.2 may be provided to the coronal discharge or plasma source along with the nitrogen-oxygen gasses. In yet another embodiment, a stoichiometric amount of N.sub.2+O.sub.2 is provided to a coronal discharge or plasma source to produce NxOy* (e.g., NO radicals).

(30) Any desired oxidizing gas may be used in any step in the present ALD process, and such oxidizing gas may include oxygen (O.sub.2), ozone (O.sub.3), atomic-oxygen (O), water (H.sub.2O), hydrogen peroxide (H.sub.2O.sub.2), nitrous oxide (N.sub.2O), nitric oxide (NO), dinitrogen pentoxide (N.sub.2O.sub.5), nitrogen dioxide (N.sub.2), derivatives thereof or combinations thereof. In an example embodiment, the oxidizing gas is an ozone/oxygen (O.sub.3/O.sub.2) mixture, such that the ozone is at a concentration within a range from about 5 atomic percent O.sub.3 of the O.sub.3/O.sub.2 mixture to about 25 atomic percent O.sub.3. In one embodiment where the NxOy species is introduced concurrently with an oxidant gas such as an ozone/oxygen (O.sub.3/O.sub.2) mixture, the NxOy species may represent greater than 1% of oxidizing flow stream by volume. In an alternate embodiment, the oxidant gas added to the NxOy species gas is an ozone/oxygen (O.sub.3/O.sub.2) mixture, such that the ozone is at a concentration within a range from about 12 atomic percent O.sub.3 of the O.sub.3/O.sub.2 mixture to about 18 atomic percent O.sub.3.

(31) The NxOy/oxidizer step (130) continues for a predetermined pulse interval, and the duration thereof may be any appropriate time range such as approximately 50 milliseconds to 10 seconds, and in another embodiment, the first oxidation pulse interval is in the range of 50 milliseconds to 2 seconds. The NxOy gas or NxOy/oxidant gas is then purged (140) from the reaction chamber by admission of a purge gas or by evacuation or pumping. Purging time may be selected to be any suitable time such as approximately 3-10 seconds, and may in some embodiments be approximately 500 milliseconds.

(32) Once the NxOy species gas or NxOy/oxidant gas has been purged from the reaction chamber, the process 100 of FIG. 1 continues, wherein a determination is made (150) whether to repeat (160) the sequence. Such a determination may be made based on any desired criteria. For example, it may be based upon the number of precursor gas pulse sequences required to achieve a particular concentration, thickness, and/or uniformity of a deposited substance. The determination may also be made in the case of another embodiment incorporating a plurality of precursor/purge steps before the NxOy pulse step a desired ratio of a precursors, especially in embodiment wherein multiple different precursors are applied to the substrate before exposure to the NxOy species to obtain a desired substrate such as a ternary metal oxide. For example, in any order, a lanthanum-containing precursor could be used in one precursor pulse and a hafnium-containing precursor in another precursor pulse producing an HfLaO oxide layer after an NxOy pulse step. The process 100 iterates (160) until the predetermined criteria are satisfied, whereupon, the process terminates (155).

(33) FIG. 2 schematically illustrates an embodiment of a thin film processing system 200 including a reaction chamber that further includes mechanism for retaining a substrate (not shown) under predetermined pressure, temperature, and ambient conditions, and for selectively exposing the substrate to various gasses. A precursor reactant source 220 is coupled by conduits or other appropriate means 220A to the reaction chamber, and may further couple to a manifold, valve control system, mass flow control system, or other mechanism to control a gaseous precursor originating from the precursor reactant source 220. A precursor (not shown) supplied by the precursor reactant source 220 the reactant (not shown) may be liquid or solid under room temperature and standard atmospheric pressure conditions. Such a precursor may be vaporized within a reactant source vacuum vessel, which may be maintained at or above a vaporizing temperature within a precursor source chamber. In such embodiments, the vaporized precursor may be transported with a carrier gas (e.g., an inactive or inert gas) and then fed into the reaction chamber 210 through conduit 220A. In other embodiments, the precursor may be a vapor under standard conditions. In such embodiments, the precursor does not need to be vaporized and may not require a carrier gas. For example, in one embodiment the precursor may be stored in a gas cylinder.

(34) A purge gas source 230 is also coupled to the reaction chamber 210, and selectively supplies various inert or noble gasses to the reaction chamber 210 to assist with removal of precursor gasses, oxidizer gasses, NxOy species gasses or waste gasses from the reaction chamber. The various inert or noble gasses that may be supplied may originate from a solid, liquid, or stored gaseous form. An oxidizer/NxOy species source 240 is coupled 240A to the reaction chamber 210, again through conduits or other appropriate means 220A to the reaction chamber, and may further couple to a manifold, valve control system, mass flow control system, or other mechanism to control a gaseous oxidizer/NxOy species gas originating from the precursor reactant source 220.

(35) The oxidizer/NxOy species source 240 generates ozone and NxOy species through any desired mechanism and any desired feedgasses including conventional ozone generators, direct or remote plasma generators, or the like. FIG. 4 illustrates one embodiment of the oxidizer/NxOy species source 240 of the present invention, wherein an output stream 240A including NxOy species is created by plasma discharge from a generator 430 being supplied an oxidizer such as O.sub.2 from an oxidizer source 410 coupled 420 to the generator 430, and a nitrogen source 430 coupled 440 to the generator 430 and supplying N.sub.2, N.sub.2O, NO, NH.sub.3 or any nitrogen bearing molecule. The generator 430 may further comprise an ozone generator such as a DBD generator, or a generator utilizing any remote or direct plasma activation method such as inductively coupled, ECR (electron cyclotron resonance), or capacitively coupled methods.

(36) In alternate embodiments (not shown) NxOy species are created by feeding a nitrogen-oxygen gas such as NO or N.sub.2O into a coronal discharge in the generator 430 with no additional oxidizer. Additional N.sub.2 may be provided to the generator 430 along with the nitrogen-oxygen gasses. In yet another embodiment, a stoichiometric amount of N.sub.2+O.sub.2 is provided to the generator 430 to produce NxOy* (e.g. NO radicals).

(37) A sensor 450 may be utilized to monitor the amount, composition, and/or concentration of oxidizer and NxOy species being created by the generator 430. The sensor 450 may comprise any appropriate hardware, mechanism, or software to detect the presence of desired NxOy radical or ionic species and/or oxidizers, and may include in various embodiments, a sensor including a Fourier Transform Infrared Spectroscopy analyzer, a UV absorption sensor, a density sensor, a conductivity/permittivity sensor, a chemiluminescence sensor, or a gas chromatography sensor. The sensor 450 may be further coupled to a NxOy species generator control 460, which through various user or automated inputs 470, configures the generator 430, oxidizer source 410, nitrogen source 430, and optional carrier gas source (not shown) to produce a desired composition and volume of NxOy species and other gasses in the output stream 240A. Such other gases in some embodiments may include oxidizers such as O.sub.2/O.sub.3 in desired ratios or other gasses. For example, but not by way of limitation, the generator control 460 may modulate a power input (not shown) to the generator 430 to change the composition of the types of activated ionic or free radical NO compounds in the gaseous output stream 240A. By virtue of the sensor's 450 coupling to the generator 430 and/or its output stream 240A, and by the control 460 being configured to receive signals from sensor 450 indicating changes in the composition and volume of the output stream 240A, closed-loop control can be implemented by software and/or electronic hardware to operate electrically- or pneumatically-controlled valves to control the flow of nitrogen source gasses, oxidizer source gasses, carrier gasses, or other gasses in addition to controlling a power and/or frequency input to the generator 430 to achieve a desired output gas composition including NxOy species.

(38) FIG. 2 also illustrates a system operation and control mechanism 260 that provides electronic circuitry and mechanical components to selectively operate valves, manifolds, pumps, and other equipment included in the system 200. Such circuitry and components operate to introduce precursors, purge gasses, oxidizers/NxOy species from the respective precursor sources 220, purge gas source 230, and oxidizer/NxOy source to the reaction chamber 210. The system operation and control mechanism 260 also controls timing of gas pulse sequences, temperature of the substrate and reaction chamber, and pressure of the reaction chamber and various other operations necessary to provide proper operation of the system 200. The operation and control mechanism 260 can include control software and electrically or pneumatically controlled valves to control the flow of precursors, reactants, oxidizers, NxOy species, and purge gases into and out of the reaction chamber 210. In one embodiment that is particularly suited for ALD reactors, the operation and control mechanism 260 also controls the flow of the treatment gas into the reaction chamber 210 to deactivate the surface against ALD reactions, such as by forming a protective layer on an inner surface of the reaction space. After deactivating the surfaces, the control system loads substrate(s) such as silicon wafers into the chamber 210 and flows precursor, oxidizer, NxOy species, and/or purge gases into the chamber 210 to form a deposit on the substrate. The control system can include modules such as a software or hardware component, e.g., a FPGA or ASIC, which performs certain tasks. A module can advantageously be configured to reside on the addressable storage medium of the control system and be configured to execute one or more processes.

(39) Those of skill in the relevant arts appreciate that other configurations of the present system are possible, including different number and kind of precursor reactant sources, purge gas sources, and/or oxidizer/NxOy sources. Further, such persons will also appreciate that there are many arrangements of valves, conduits, precursor sources, purge gas sources carrier gas sources, and/or oxidizer sources that may be used to accomplish the goal of selectively feeding gasses into the reactor reaction chamber 210. Further, as a schematic representation of a thin film processing system, many components have been omitted for simplicity of illustration, and such components may include, for example, various valves, manifolds, purifiers, heaters, containers, vents, and/or bypasses.

(40) FIG. 3A shows an alternative schematic implementation of the processing system 200, where a oxidizer/reactant source 340 is coupled 340A to the reaction chamber 210 separate from an NxOy species source 360 that is also coupled 360A to the reaction chamber. Through this configuration, the system operation and control 260 may introduce oxidizer or other reactants from the oxidizer reactant source 340 independently from introducing NxOy species-bearing gasses to the reaction chamber 210. Through this configuration, it may be possible to apply independent gas pulses of oxidizers, NxOy species-bearing gasses, or a combination of the two to the reaction chamber to achieve a particular layer deposition result. In one implementation, alternating pulses of oxidizer and NxOy species-bearing gasses may be applied to obtain enhanced growth rates or uniformity of metal oxide films deposited on the substrate within the reaction chamber 210.

(41) FIG. 3B shows yet another schematic implementation of the processing system 200, where a oxidizer/reactant source 340 is coupled 340A to the reaction chamber 210 separate from an NxOy species source 390 that is integrated within the reaction chamber 210. Not shown are conduits and couplings that supply various source feedgasses such as oxygen- or nitrogen-bearing gasses to the NxOy species source 390, or its output connection that relays NxOy species-bearing gasses to the substrate located within the reaction chamber 210. Similarly to the illustrated of the system 200 depicted in regards to FIG. 3A, the system operation and control 260 may introduce oxidizer or other reactants from the oxidizer/reactant source 340 independently from introducing NxOy species-bearing gasses to the reaction chamber 210. Also, through this configuration, it may be possible to apply independent gas pulses of oxidizers, NxOy species-bearing gasses, or a combination of the two to the reaction chamber to achieve a particular layer deposition result. In one implementation, alternating pulses of oxidizer and NxOy species-bearing gasses may be applied to obtain enhanced growth rates or uniformity of metal oxide films deposited on the substrate within the reaction chamber 210.

(42) FIG. 6 illustrates a single metal oxide (MOS) transistor 600 fabricated with an example embodiment of the invention to form a dielectric layer 620 containing an ALD-deposited gate insulator layer. The use of high-k dielectrics such as HfO.sub.2, ZrO.sub.2, La.sub.2O.sub.3 and Ta.sub.2O.sub.5, HfLaO, and HfZrO deposited through methods and systems forming example embodiments of the present invention provides for fabrication of increasingly smaller transistors that have improved leakage currents and other characteristics such compared with traditional silicon oxide-type dielectrics. A substrate 605 is prepared for deposition, typically a silicon or silicon-containing material. As described above in relation to substrate types, however, other semiconductor materials such as germanium, gallium arsenide, and silicon-on-sapphire substrates may also be used. Prior to depositing a gate dielectric 620, various layers within the substrate 605 of the transistor are formed and various regions of the substrate are prepared, such as the drain diffusion 610 and source diffusion 615 of the transistor 600. The substrate 605 is typically cleaned to provide an initial substrate depleted of its native oxide. The substrate may also be cleaned to provide a hydrogen-terminated surface to improve the rate of chemisorption. The sequencing of the formation of the regions of the transistor being processed may follow typical sequencing that is generally performed in the fabrication of a MOS transistor, as is known to those skilled in the art.

(43) In various embodiments, the dielectric 620 covering the area on the substrate 605 between the source and drain diffused regions 615 and 610 is deposited by the ALD process described in accordance with FIG. 1 of the present invention, and comprises a layer of a metal oxide in molecular proportion that was deposited through at least partial exposure to NxOy species-bearing gasses. The single dielectric layer 620 shown is merely one embodiment, and may in other embodiments also include additional layers of thin-film metal oxides or other suitable dielectrics or barrier materials deposited in accordance with some embodiments of the present invention.

(44) The transistor 600 has a conductive material forming a single gate electrode 625 over the gate dielectric 620. Typically, forming the gate 625 may include forming a polysilicon layer, though a metal gate may be formed in an alternative process. Fabricating the substrate 605, the source and drain regions 615 610, and the gate 625, is performed by using standard processes known to those skilled in the art or those processes enhanced by some embodiments of the present invention. Additionally, the sequencing of the various elements of the process for forming a transistor is conducted with standard fabrication processes, also as known to those skilled in the art.

(45) In the illustrated embodiment, the dielectric layer 620 is shown as being the first layer and in direct contact with the substrate 605; however, the invention is not so limited. In various embodiments, a diffusion barrier layer may be inserted between the dielectric layer 620 and the substrate 605 to prevent metal contamination from affecting the electrical properties of the device. The transistor 600 shown in FIG. 6 has a conductive material forming a single gate electrode 625, but the gate dielectric may also be used in a floating gate device such as flash memory as depicted in FIG. 7.

(46) FIG. 7 illustrates a single memory cell 700 fabricated according to one example embodiment of the invention. In this embodiment, the memory cell 700 is a floating gate memory cell appropriate for use in FLASH or other memory devices. Similar to the transistor 600 shown in FIG. 6, the memory cell 700 includes a substrate 705 (usually silicon but may be other substrates as described herein) in which a source region 715 and a drain region 710 are formed. Typically, memory cell 700 also includes a first dielectric layer 720 (which may be referred to as a tunnel layer), a storage element or floating gate 725 (formed of conductive material such as polysilicon), a second dielectric layer 725, and a control gate 735 (also formed of conductive material such as polysilicon).

(47) Similarly to the transistor 600 described in relation to FIG. 6, the memory cell 700 is fabricated with an example embodiment of the invention to form either or both dielectric layers 720, 730. Dielectric layers 720, 730 may be fabricated in whole or in part by using an ALD-deposited metal oxide gate insulator layer that is formed by methods in accordance with example embodiments the present invention. The substrate 705 is prepared for deposition, typically a silicon or silicon-containing material. As described above in relation to substrate types, however, other semiconductor materials such as germanium, gallium arsenide, and silicon-on-sapphire substrates may also be used. Prior to depositing the dielectric 720, various layers within the substrate 705 of the transistor are formed and various regions of the substrate are prepared, such as the drain diffusion 710 and source diffusion 715 of the memory cell 700. The substrate 705 is typically cleaned to provide an initial substrate depleted of its native oxide. The substrate may also be cleaned to provide a hydrogen-terminated surface to improve the rate of chemisorption. The sequencing of the formation of the regions of the transistor being processed may follow typical sequencing that is generally performed in the fabrication of a MOS transistor, as is well known to those skilled in the art.

(48) In various embodiments, the dielectric 720 covering the area on the substrate 705 between the source and drain diffused regions 715 and 710 is deposited by the ALD process described in accordance with FIG. 1, and comprises a layer of metal oxide deposited through at least partial exposure to NxOy species-bearing gasses. The dielectric layers shown 720, 730 may in other embodiments also include additional layers of metal oxides or other suitable dielectrics or barrier materials.

(49) The memory cell 700 has conductive materials forming a control gate electrode 735 and floating gate 725 in a region over the dielectric 720. Typically, forming the gates 725, 735 may include forming polysilicon layers, though metal gates may be formed in an alternative process. The process to fabricate the substrate 705, the source and drain regions 715 710, and the gate 725, 735 is performed using standard processes known to those skilled in the art. Additionally, the sequencing of the various elements of the process for forming a memory cell is conducted with standard fabrication processes, which are also known to those skilled in the art.

(50) In the illustrated embodiment, the dielectric layers 720, 730 are shown as being in direct contact with the substrate 705, the floating gate 725, and the control gate 735. In other embodiments, diffusion barrier layers may be inserted between the dielectric layers 720, 730 and/or the substrate 705, the floating gate 725, and the control gate 735 to prevent metal contamination from affecting the electrical properties of the memory cell 700.

(51) FIG. 14 depicts a possible process 1400 that may be utilized in the fabrication of a various devices such as, but not limited to, a MOS like MOS 1800 depicted in FIG. 15. MOS 1500 contains a thin inter oxide layer 1510 between a high dielectric layer 1515 and the substrate 1505. Substrate 1505 may be a wafer of any semiconductor material. For instance, silicon or a silicon containing material may be utilized. In the alternative or in combination, other semiconductor materials such as, but not limited to, germanium, gallium arsenide, and/or silicon-on-sapphire substrates may be utilized. The inter oxide layer 1510 may comprise an oxide of the substrate 1505. In combination or the alternative, the inter oxide layer may comprise the oxide of another material deposited on the substrate 1505. Nitrogen from a nitrogen containing oxidizer may also be deposited within oxide layer 1510, possibly increasing the dielectric constant of layer 1510. The high dielectric layer 1515 above the inter oxide layer 1510 may comprise a dielectric material containing oxygen and at least one additional element, such as lanthanum, hafnium, silicon, tantalum, titanium, aluminum, zirconium, or combinations thereof. In addition to the layers 1510 and 1515 deposited onto substrate 1505, MOS 1500 comprises a gate 1530. Any conductive material may be utilized to form gate 1530. For example, gate 1530 may be formed from polysilicon and/or a metal deposited onto dielectric layer 1515. MOS 1500 may also comprise a source region 1520 and/or a drain region 1525.

(52) Cleaning the substrate 1505 at 1405 may assist in depositing the inter oxide layer 1510. Various methods of cleaning substrate 1505 to remove native oxides and/or expose a surface capable of receiving the desired oxide layer 1510 may be utilized. For example, dipping substrate 1505 in a solution of hydrofluoric acid and rinsing with de-ionized water may remove native oxides from substrate 1505.

(53) Heating substrate 1505 at 1410 within the reaction chamber may also assist in depositing the inter oxide layer 1510. Maintaining the temperature of the reaction chamber at approximately 130 C. to 300 C. may sufficiently heat substrate 1505.

(54) Exposing the substrate within the reaction chamber to an oxidizer comprising an oxidant gas and a nitrogen containing gas at 1415 deposits inter oxide layer 1510 onto substrate 1505. The oxidant gas may be any oxidizing agent, such as but not limited to ozone. The ozone within the oxidant gas may be generated in a variety of manners. For example, the plasma discharge form an ozone generator connected to the reaction chamber may generate the ozone from a stream of an oxygen containing gas and a nitrogen containing gas such as, but not limited to, O.sub.2 and N.sub.2. In addition to providing the oxidant gas, an ozone generator connected to the reaction chamber may allow deposition of the inter oxide layer 1510 and formation of the oxidant gas to occur in-situ limiting and/or preventing air breaks. Generating ozone from a N.sub.2/O.sub.2 mixture having a N.sub.2/O.sub.2 ratio of less than one percent may minimize the equivalent oxide thickness. Maintaining high ozone dilution may also minimize the thickness of the inter oxide layer 1510. Limiting the ozone concentration of the first oxidizer gas to 5 to 25 atomic percent and injecting the oxidant gas into the chamber at a flow rate of approximately 100-500 standard cubic centimeters per minutes within a total flow of 3200 standard cubic centimeters per minute may assist in further minimizing the thickness of the layer 1510. For example, feeding a gas containing 12 atomic percent ozone generated by exposing a 2.5 standard liter per minute flow of O.sub.2 and 5 standard cubic centimeter per minute flow of N.sub.2 to a plasma discharge into a 300 C. reaction chamber at 100 standard cubic centimeters per minute within a total flow of 32000 standard cubic centimeters per minute for approximately 30 to 60 second may deposit a SiO.sub.2 inter oxide layer 1810 on substrate 1805 of approximately 3 to 3.75 Angstroms.

(55) Nitrogen within the oxidizer gas may be incorporated into inter oxide layer 1510 formed on substrate 1505 at 1415. This may increase the dielectric constant of inter oxide layer 1510. Embodiments of MOS 1500 in which high dielectric layer 1515 and/or other layers are formed from deposing HfO.sub.2, Ta.sub.2O.sub.5 and/or like molecules, a higher N.sub.2 addition may be desired. Achieving a higher N.sub.2 addition may be accomplished by exposing the substrate 1505 within the reaction chamber to an oxidizer comprising ozone gas generated from an N.sub.2O.sub.2 mixture have a N.sub.2O.sub.2 flow ratio of at least 0.072 at 1415.

(56) The first oxidizer gas may be purged and/or evacuated from the chamber at 1420. Evacuating or otherwise pumping the first oxidizer gas out of the chamber may purge the chamber. In combination or the alternative, introducing a gas such as, but not limited to, argon, nitrogen, helium, hydrogen, forming gas or combinations thereof that will not adversely react with the substrate and/or oxide layer into the reaction chamber to displace the first oxidant may be utilized to purge the chamber. Purging time may be selected to be any suitable time capable of evacuating the chamber.

(57) Depending on the exact variant of ALD utilized, it may be desirable not to purge the reaction chamber but proceed instead to the introduction of a precursor gas at 1425. The precursor gas utilized to form dielectric layer 1515 may be injected with or without a carrier gas that will not adversely react with the precursor gas, substrate and/or oxide layer, such as, but not limited to, argon, nitrogen, helium, hydrogen, forming gas or combinations thereof. The precursor gas may include any appropriate metal, including one or more rare earth metals such as, but not limited to, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and/or Lo. In combination or the alternative, the precursor gas may comprise any desired metallic, organo-metallic, or metal halide compounds, including, but not limited to hafnium tetrachloride (HfCl.sub.4) titanium tetrachloride (TiCl.sub.4), tantalum pentachloride (TaCl.sub.5), tantalum pentaflouride (TaF.sub.5), zirconium tetrachloride (ZrCl.sub.4), rare earth betadiketonate compounds including La(THD.sub.3 and Y(THD.sub.3, rare earth cyclopentadienyl (Cp) compound including La(iPrCp.sub.3, rare earth amidinate compounds including lanthanum tris-formamidinate La(FMD.sub.3, cyclooctadienyl compounds including rare earth metals, alkylamido compounds including: tetrakis-ethyl-methylamino hafnium (TEMAHf), tetrakis (diethylamino) hafnium (Et.sub.2N).sub.4Hf or TDEAH) and tetrakis (dimethylamino) hafnium ((Me.sub.2N).sub.4Hf or TDMAH), alkoxides, halide compounds of silicon, silicon tetrachloride, silicon tetraflouride and/or silicon tetraiodide. Injection of the precursor gas into the reaction chamber deposits a thin layer of the compounds within the gas onto inter oxide layer 1510.

(58) After a predetermined exposure time to the precursor gas ranging from approximately 300 milliseconds to 5 seconds or approximately 1 to 3 seconds, the precursor gas is purged at 1430 from the reaction chamber. Evacuating or otherwise pumping the precursor gas out of the chamber may purge the chamber. In combination or the alternative, introducing a gas such as, but not limited to, argon, nitrogen, helium, hydrogen, forming gas or combinations thereof that will not adversely react with the precursor gas, substrate and/or oxide layer into the chamber to displace the precursor gas may be utilized to purge the chamber. Purging time may be selected to be any suitable time capable of evacuating the chamber such as approximately 3 to 10 seconds or approximately 500 milliseconds to 5 seconds.

(59) Oxidizing the precursor deposited onto inter layer 1510 with a second oxidizer gas introduced into the reaction chamber at 1435 forms high dielectric layer 1415. The second oxidizer gas may comprise an oxidant and/or a nitrogen containing species gas. The nitrogen species may be an N.sub.xO.sub.y species, where x and y designate any appropriate whole number integers. Utilizing nitrogen and oxygen compounds, particularly excited NO species obtained from exposure of the component gases to a plasma source, may promote uniform growth of the dielectric layer 1515. In combination or the alternative, including activated NO species, such as but limited to NO, N.sub.2O, NO.sub.2, NO.sub.3 and/or N.sub.2O.sub.5 in the form of ionic and/or free radicals within the second oxidizer may enhance the deposition of the dielectric layer 1515.

(60) The oxidant gas within the second oxidizer gas may comprise any appropriate oxidant. A nitrogen containing species gas may serve as the oxidant gas. In combination or the alternative, the oxidant may contain ozone in combination with one or more gases such as, but not limited to O, O.sub.2, NO, N.sub.2O, NO.sub.2, NO.sub.3, N.sub.2O.sub.5, NO.sub.R, an N.sub.xO.sub.y radical species N.sub.xO.sub.y ionic species, an N.sub.xO.sub.y molecular species or combinations thereof. The second oxidizer gas may include various active concentrations of ozone, including approximately 5 to 25 atomic percent ozone and 12 to 18 atomic percent ozone. Subjecting a flow of O.sub.2 and a nitrogen containing gas such as, but not limited to, N.sub.2, NO, N.sub.2O, NO.sub.2, NO.sub.3 and/or N.sub.2O.sub.5 to a plasma discharge may be utilized to generate the ozone and/or N.sub.xO.sub.y species within the second oxidizer gas. Other methods of generating ozone and/or a N.sub.xO.sub.y species may be equally as effectively. Additionally, any desired flow N.sub.2/O.sub.2 ratio may be utilized to generate the ozone and N.sub.xO.sub.y species, including flow ratios exceeding 0.1 percent, such as 5 standard cubic centimeters per minute N.sub.2 to 2 standard liters per minute O.sub.2.

(61) At the conclusion of a determined pulse interval, the second oxidizer gas is purged at 1440. Exposure to the second oxidizer gas may continue for any range of time such as, approximately 50 milliseconds to 2 or 10 seconds. Evacuating or otherwise pumping the oxidant gas out of the chamber may purge the chamber. In combination or the alternative, introducing a gas such as, but not limited to, argon, nitrogen, helium, hydrogen, forming gas or combinations thereof that will not adversely react with the oxidant gas, substrate and/or oxide layer into the chamber to displace the precursor gas may be utilized to purge the chamber. Purging time may be selected to be any suitable time capable of evacuating the chamber, such as approximately 3 to 10 seconds or approximately 500 milliseconds.

(62) After the second oxidizer gas has been purged, a determination is made at 1445 whether to continue depositing dielectric layer 1515 by returning to 1425 and introducing a second pulse interval of the same and/or different precursor gas or to terminate the process. The determination may be based on any desired criteria such as, but not limited to, the number of precursor gas pulse sequences required to achieve a particular concentration, thickness, and/or uniformity of a dielectric layer 1515.

(63) Embodiments of methods for forming metal oxide dielectric layers may also be applied to methods to fabricate capacitors in various integrated circuits, memory devices, and electronic systems. In an embodiment for fabricating a capacitor, a method includes forming a first conductive layer, forming a dielectric layer containing a metal oxide layer on the first conductive layer by embodiments of the ALD cycle described herein, and forming a second conductive layer on the dielectric layer. ALD formation of the metal oxide dielectric layer allows the dielectric layer to be engineered within a predetermined composition providing a desired dielectric constant and/or other controllable characteristics.

(64) Electronic components such as transistors, capacitors, and other devices having dielectric layers fabricated by embodiments of the present invention described herein may be implemented into memory devices, processors, and electronic systems. Generally, as depicted in FIG. 8, such electronic components 810 may be incorporated into systems 820 such as information processing devices. Such information processing devices may include wireless systems, telecommunication systems, mobile subscriber units such as cellular phones and smart phones, personal digital assistants (PDAs), and computers. An embodiment of a computer including components having a dielectric layer, such as an HfLaO dielectric layer, formed by atomic layer deposition using methods described herein is shown in FIG. 9 and described below. While specific types of memory devices and computing devices are shown below, it will be recognized by one skilled in the art that several types of memory devices and electronic systems including information handling devices utilize the present subject matter.

(65) A personal computer 900, as shown in FIG. 9, may include an output device such as screen or monitor 910, keyboard input device 905 and a central processing unit 920. Central processing unit 920 typically may include circuitry 925 that utilizes a processor 935, and a memory bus circuit 937 coupling one or more memory devices 940 to the processor 935. The processor 935 and/or memory 940 of the personal computer 900 also includes at least one transistor or memory cell having a dielectric layer formed by atomic layer deposition using methods described herein according an embodiment of the present subject matter. Those of skill in the art are aware that other electronic components in the computer 900 may utilize a dielectric layer formed by atomic layer deposition using methods described herein, such as those formed through at least partial exposure to NxOy species-bearing gasses. Such components may include many types of integrated circuits including processor chip sets, video controllers, memory controllers, I/O handlers, BIOS memory, FLASH memory, audio and video processing chips, and the like. Those of skill in the art also appreciate that other information handling devices such as personal digital assistants (PDAs) and mobile communication devices such as cell phones and smart phones may incorporate dielectric layers that are formed by using embodiments of the present invention.

(66) Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and embodiments disclosed herein, and as supplemented by the technical disclosure described in the following exemplary claims.