METHODS, APPARATUS AND SYSTEM FOR PROVIDING SOURCE-DRAIN EPITAXY LAYER WITH LATERAL OVER-GROWTH SUPPRESSION
20170200797 ยท 2017-07-13
Inventors
Cpc classification
H10D64/018
ELECTRICITY
H10D64/015
ELECTRICITY
H10D84/013
ELECTRICITY
International classification
H01L29/417
ELECTRICITY
H01L21/8234
ELECTRICITY
H01L29/66
ELECTRICITY
H01L27/088
ELECTRICITY
H01L29/06
ELECTRICITY
Abstract
At least one method, apparatus and system disclosed herein for suppressing over-growth of epitaxial layer formed on fins of fin field effect transistor (finFET) to prevent shorts between fins of separate finFET devices. A set of fins of a first transistor is formed. The set of fins comprises a first outer fin, an inner fin, and a second outer fin. An oxide deposition process is performed for depositing an oxide material upon the set of fins. A first recess process is performed for removing a portion of oxide material. This leaves a portion of the oxide material remaining on the inside walls of the first and second outer fins. A spacer nitride deposition process is performed. A spacer nitride removal process is performed, leaving spacer nitride material at the outer walls of the first and second outer fins. A second recess process is performed for removing the oxide material from the inside walls of the first and second outer fins. An epitaxial layer deposition processed upon the set of fins. A portion of the lateral over-growth of epitaxial layer on the outer walls of the first and second outer fins is suppressed by the spacer nitride material.
Claims
1.-9. (canceled)
10. A fin field effect transistor (finFET) comprising: a fin set extending upward from a substrate, said fin set comprising a first outer fin, an inner fin, and a second outer fin to a first height; a plurality of spacer nitride layers on a first portion of the outer walls of the first and second outer fins; a first epitaxial feature formed on said first outer fin; a second epitaxial feature formed on said second outer fin; wherein a second portion of the outer walls of the first and second outer fins comprises lateral over-growth of said first and second epitaxial layers and the first portion of the outer walls of the first and second outer fins lacks lateral over-growth of said first and second epitaxial layers.
11. The finFET of claim 10, wherein said first and second epitaxial features do not contact a feature of an adjacent fin of an adjacent finFET.
12. The finFET of claim 10, wherein said first and second epitaxial features comprises silicon germanium, silicon carbon, or silicon phosphate.
13. The finFET of claim 10, further comprising an inner fin between said first and second outer fins, wherein said inner fin comprises a third epitaxial feature of which the lateral over-growth is not suppressed.
14. The finFET of claim 13, wherein said first outer fin, said inner fin, and said first second outer fin are at least one of source fins or drain fins.
15. A system, comprising: a semiconductor device processing system to manufacture a semiconductor device comprising at least one fin field effect transistor (finFET); and a processing controller operatively coupled to said semiconductor device processing system, said processing controller configured to control an operation of said semiconductor device processing system; wherein said semiconductor device processing system is adapted to: form a set of fins of a first transistor, said set of fins comprising a first outer fin, an inner fin, and a second outer fin; perform an oxide deposition process for depositing an oxide material upon said set of fins and within spaces between said fins; perform a first recess process for removing a portion of oxide material, leaving a portion of the oxide material on the inside walls of said first and second outer fins; perform a spacer nitride deposition process for depositing a spacer nitride material upon said set of fins and on outer walls of the first and second outer fins; perform a spacer nitride removal process, leaving spacer nitride material on a first portion of the outer walls of the first and second outer fins; perform a second recess process for removing said oxide material from the inside walls of said first and second outer fins; and perform an epitaxial layer deposition process upon said set of fins, wherein any lateral over-growth of epitaxial layer on said outer walls of said first and second outer fins is suppressed by said spacer nitride material at the first portion, and wherein lateral overgrowth of the epitaxial layer occurs on a second portion of the outer walls of said first and second outer fins.
16. The system of claim 15, further comprising a design unit configured to generate a first design comprising a definition for a process mask and a definition for an operation of a FinFET device that comprises a plurality of fins, wherein data from said design unit is used by said process controller to control an operation of said semiconductor device processing system.
17. The system of claim 15, wherein the width of said epitaxial layer is based upon said width of said fin, wherein said width of said epitaxial layer is proportional to said width of said fin.
18. The system of claim 15, wherein said semiconductor device processing system is further adapted to perform an epitaxial layer deposition process upon a third outer fin of a second transistor adjacent to said first transistor, wherein performing an epitaxial layer deposition process upon said set of fins comprises suppressing said lateral over-growth of the epitaxial layer on said first portion such that the epitaxial layer on said first outer fin does not touch said epitaxial layer deposited on said third outer fin.
19. The system of claim 15, wherein said semiconductor device processing system is further adapted to deposit silicon dioxide of a consistency to deposit said silicon dioxide between the inside walls of said first and second outer fins.
20. The system of claim 15, wherein at least a portion of vertical over-growth of the epitaxial layers on said outer walls of said first and second outer fins is suppressed by said spacer nitride material.
21. A semiconductor device, comprising: a first fin field effect transistor (finFET) comprising: a fin set extending upward from a substrate, said fin set comprising a first outer fin, an inner fin, and a second outer fin to a first height; a plurality of spacer nitride layers on a first portion of the outer walls of the first and second outer fins; a first epitaxial feature formed on said first outer fin; a second epitaxial feature formed on said second outer fin; wherein a second portion of the outer walls of the first and second outer fins comprises lateral over-growth of said first and second epitaxial layers and the first portion of the outer walls of the first and second outer fins lacks lateral over-growth of said first and second epitaxial layers; and a second finFET comprising: at least one fin comprising at least one feature; wherein said first and second epitaxial features do not contact said feature of said fin of said second finFET.
22. The finFET of claim 21, wherein said first and second epitaxial features comprises silicon germanium, silicon carbon, or silicon phosphate.
23. The finFET of claim 21, further comprising an inner fin between said first and second outer fins, wherein said inner fin comprises a third epitaxial feature of which the lateral over-growth is not suppressed.
24. The finFET of claim 23, wherein said first outer fin, said inner fin, and said second outer fin are at least one of source fins or drain fins.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The disclosure may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:
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[0039] While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION
[0040] Various illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
[0041] The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
[0042] Embodiments herein provide for increasing at least a portion of one or more source or drain fins of finFET devices using epitaxial (EPI) deposition/growth. Embodiments herein provide for increasing the current drive of a finFET by controlling the deposition of an EPI layer, e.g., single-domain (SD) EPI layer, on the top regions of source-drain fins of a finFET. Embodiments herein provide for controlling the lateral growth of EPI layer on source-drain fins substantially without impeding the vertical growth of EIP layer. In this manner, shorts caused by over-growth of EPI layers on densely formed fins are reduced, while maintaining sufficient EPI growth.
[0043] Turning now to
[0044] Subsequently, a recess process to remove the silicon oxide is performed (block 430). The recess process may comprise implementing a wet etch process, a SiCoNi etch process, or a combination of both, which results in substantial removal of silicon oxide layer. This process results in removal of the silicon oxide from the fins while leaving silicon oxide material between the fins of a single finFET device, i.e., between the narrow gap of fins of each finFET device.
[0045] A spacer nitride deposition process may then be performed (block 440). The spacer nitride deposition process comprises depositing silicon nitride over the source-drain fins of the finFET. A nitride removal process may then be performed (block 450). This process leave nitride spacer material (e.g., silicon nitride) between the devices, i.e., on the outer walls for the fins of each finFET.
[0046] Subsequently, an etching process for removing the remaining silicon oxide between the fins may be performed (block 460). This process leaves the exposed part of the fins (i.e., the portion of the fins above the STI layer) substantially bare except for the silicon nitride remaining on the outer walls of the outer fins of each finFET.
[0047] At this point, an EPI deposition process is performed (block 470), which results in growth of the EPI layer in a laterally suppressed manner, as described in further details below. That is, the remaining silicon nitride materials on the outer fin wall suppress the lateral and/or partial downward vertical growth of the EPI layers on the outer portions of the outer walls of the source-drain fins. Accordingly, EPI growth at the top of the source-drain fins are controlled by embodiments herein, wherein lateral growth of the outer fins are limited as to prevent shorts to fins or to other features of adjacent finFET devices.
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[0049] Moreover, a plurality of fins 510 are formed on the layer 502 and comprise respective end portions 510E and a central portion 510C, which is covered by a gate electrode structure 520. Furthermore, a gate insulation material may be formed at least on sidewalls of the fins 510 (not shown in
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[0052] The source-drain fins 730 are be surrounded by gates 910 and 920 (
[0053] On top of the base layer 710 (
[0054] Referring simultaneously to
[0055] The source-drain fins 730 are be surrounded by gates 910 and 920 (
[0056] Referring simultaneously to
[0057] The recess process may comprise implementing a wet etch process, a SiCoNi etch process, or a combination of both. As shown in
[0058] Referring simultaneously to
[0059] In one embodiment, the order of processes provided herein call for performing the oxide recess process prior to performing the spacer nitride deposition process. Since the oxide recess process is performed first, the remaining oxide between the fins 730a-c prevent the spacer nitride material 1210 from being deposited into the inner walls of the fins 730a-c. Therefore, EPI deposition/growth can take place between the inner walls for the fins 730a-c.
[0060] Referring simultaneously to
[0061] Further, the nitride spacer material 1210 remains on the outside walls of the outer fins 730a, 730c of the first device as wells as the fin 730d of the second device. The remaining nitride space materials 1210 adjacent to the fins 730a, 730c and 730d are capable of suppressing the lateral growth and/or downward vertical growth of EPI layers grown on the outer portions fins 730a, 730c, 730d. This suppression may be achieved while not suppressing vertical growth of the EPI layers on the outer portions, and not suppressing any EIP growth on the inner portions of the fins 730a and 730c
[0062] Referring simultaneously to
[0063] The EPI fill oxide recess process is performed for removing oxide in a manner that an EPI layer may be deposited into the regions from which oxide was removed. As shown in
[0064]
[0065] Referring simultaneously to
[0066] In some embodiments, the EPI layers 1820 may be grown to a size of about 5 nm to about 20 nm (lateral EPI width). The EPI layers 1820 may be deposited using a chemical vapor deposition process (CVD), e.g., reduced pressure CVD (RPCVD), ultra-high vacuum CVD (UHVCVD), metal organic CVD (MOCVD), etc. The precursors for the EPI layers 1820 may comprise gases comprising silicon (e.g., SiH.sub.4, Si.sub.2H.sub.4Cl.sub.2, Si.sub.2H.sub.6, Si.sub.3H.sub.8) and/or gases comprising germanium (e.g., GeH.sub.4). The partial pressures of these gases may be adjusted to adjust the atomic ratio of germanium to silicon. In one embodiment, the EPI layers may be grown at 700 C., and may be decreased to 550 C. with source gas.
[0067] The deposition of the EPI layers 1820 may be performed as a plurality of deposition-etch cycles to provide epitaxial layers that are more conformal. As illustrated in
[0068] In one embodiment, the dimensions of the EIP layers (e.g., the width) may be controlled in such a manner that they are proportional to respective widths of the fins 730. The over-growth of EPI layers 1820 is curtailed by the presence of the spacer nitride material 1210. Therefore, the lateral growth and the downward vertical growth of the EPI layer on the out fins (730a, 730c) and the fin 730d may be curtailed by the presence of the nitride material 1210. Moreover, the EPI growths at the inner portions of the outer fins 730a, 730c and around the inner fin 730b are not suppressed and thus, free to grow in the lateral and the vertical dimensions.
[0069] As indicated in
[0070] Subsequent processing known to those skilled in the art having benefit of the present disclosure may be performed to form a complete finFET device (e.g., patterning, lithography, etch, metal gate, etc.). Such subsequent processing steps may be used to form finFET devices that comprise source-drain fins that comprise EPI growth with lateral over-growth of the EPI being substantially curtailed on the outer walls of the fins.
[0071] Turning now to
[0072] The semiconductor device processing system 2110 may comprise various processing stations, such as etch process stations, photolithography process stations, CMP process stations, etc. One or more of the processing steps performed by the processing system 2110 may be controlled by the processing controller 2120. The processing controller 2120 may be a workstation computer, a desktop computer, a laptop computer, a tablet computer, or any other type of computing device comprising one or more software products that are capable of controlling processes, receiving process feedback, receiving test results data, performing learning cycle adjustments, performing process adjustments, etc.
[0073] The semiconductor device processing system 2110 may produce integrated circuits on a medium, such as silicon wafers. More particularly, the semiconductor device processing system 2110 produce integrated circuits having finFET devices that source-drain fins that comprise EPI growth with lateral over-growth of the EPI being substantially curtailed on the outer walls of the fins, as described above.
[0074] The production of integrated circuits by the device processing system 2110 may be based upon the circuit designs provided by the integrated circuits design unit 2140. The processing system 2110 may provide processed integrated circuits/devices 2115 on a transport mechanism 2150, such as a conveyor system. In some embodiments, the conveyor system may be sophisticated clean room transport systems that are capable of transporting semiconductor wafers. In one embodiment, the semiconductor device processing system 2110 may comprise a plurality of processing steps, e.g., the 1.sup.st process step, the 2.sup.nd process set, etc., as described above.
[0075] In some embodiments, the items labeled 2115 may represent individual wafers, and in other embodiments, the items 2115 may represent a group of semiconductor wafers, e.g., a lot of semiconductor wafers. The integrated circuit or device 2115 may be a transistor, a capacitor, a resistor, a memory cell, a processor, and/or the like. In one embodiment, the device 2115 is a transistor and the dielectric layer is a gate insulation layer for the transistor.
[0076] The integrated circuit design unit 2140 of the system 2100 is capable of providing a circuit design that may be manufactured by the semiconductor processing system 2110. The integrated circuit design unit 2140 may be capable of determining the number of devices (e.g., processors, memory devices, etc.) to place in a device package. The integrated circuit design unit 2140 may also determine the height of the gate fins, the dimensions of EPI growth on fins of the finFET devices, etc. These dimensions may be based upon data relating to drive currents/performance metrics, device dimensions, etc. Based upon such details of the devices, the integrated circuit design unit 2140 may determine specifications of the finFETs that are to be manufactured. Based upon these specifications, the integrated circuit design unit 2140 may provide data for manufacturing a semiconductor device package described herein.
[0077] The system 2100 may be capable of performing analysis and manufacturing of various products involving various technologies. For example, the system 2100 may design and production data for manufacturing devices of CMOS technology, Flash technology, BiCMOS technology, power devices, memory devices (e.g., DRAM devices), NAND memory devices, and/or various other semiconductor technologies.
[0078] The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the process steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.