DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-8,16-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Reznicek (US Patent No. 10256301), in view of Lee et al (US Pub No. 20210082914).
With respect to claim 1, Reznicek discloses forming a stack (105,107,Fig.1) over a substrate (102), wherein the stack comprises a plurality of channel layers (105) interleaved by a plurality of sacrificial layers (107); forming a fin-shaped structure from the stack and the substrate (Fig.2), the fin-shaped structure comprising a channel region (105) and a source/drain region (between 110,Fig.2); recessing the source/drain region to form a source/drain trench that exposes sidewalls of the plurality of channel layers and the plurality of sacrificial layers (Fig.3); selectively and partially recessing the plurality of sacrificial layers to form a plurality of inner spacer recesses (Fig.4); forming a plurality of inner spacer features in the plurality of inner spacer recesses (121,Fig.7); after the forming of the plurality of inner spacer features forming source and drain features (140,Fig.8). However, Reznicek does not explicitly disclose depositing an outer epitaxial layer in the source/drain trench, the outer epitaxial layer comprising a first p- type dopant; and depositing an inner epitaxial layer over the outer epitaxial layer, the inner
epitaxial layer comprising a second p-type dopant different from the first p-type dopant, wherein the inner epitaxial layer is spaced apart from the plurality of channel layers by the outer epitaxial layer. On the other hand, Lee et al discloses depositing an outer epitaxial layer (142,Fig.13A) in the source/drain trench (Fig.13A), to interface the plurality of channel layers (NS) and the substrate (110); the outer epitaxial layer comprising a first p- type dopant (Para 43,para 49); and depositing an inner epitaxial layer over the outer epitaxial layer (144), the inner epitaxial layer comprising a second p-type dopant different from the first p-type dopant (para 48-49, particularly para 49 discloses that impurities such carbon are present in the layer 142, carbon are known p-type dopant), wherein the inner epitaxial layer is spaced apart from the plurality of channel layers(NS) by the outer epitaxial layer (Fg.13A). It would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify Reznicek according to the teachings of the Lee et al such that depositing an outer epitaxial layer in the source/drain trench, the outer epitaxial layer comprising a first p- type dopant; and depositing an inner epitaxial layer over the outer epitaxial layer, the inner epitaxial layer comprising a second p-type dopant different from the first p-type dopant, wherein the inner epitaxial layer is spaced apart from the plurality of channel layers by the outer epitaxial layer, in order to reduce the short channel effect and a reliable source and drain structure to improve the device performance. The arts cite above do not explicitly disclose forming a fin shaped structure from the stack. However, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that a fin like structure is formed from the stack
With respect to claim 2, Lee et al discloses wherein the plurality of channel layers comprise germanium (Ge) (Para 26) and the plurality of sacrificial layers comprise silicon germanium (SiGe) (Para 81).
With respect to claim 3, Lee et al discloses wherein the outer epitaxial layer and the
inner epitaxial layer comprise germanium (Ge) (Para 47) or germanium tin (GeSn).
With respect to claim 4, Lee et al discloses wherein the first p-type dopant comprises boron (B) (Para 43) and the second p-type dopant comprises gallium (Ga).
With respect to claim 5, the arts cited above do not explicitly disclose wherein a doping concentration of the first p-type dopant in the outer epitaxial layer is between about 5x10¹⁹ atoms/cm³ and about 5x10²⁰ atoms/cm³. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that the first p-type dopant in the outer epitaxial layer is between about 5x10¹⁹ atoms/cm³ and about 5x10²⁰ atoms/cm³, in order to adjust the resistivity of the outer epitaxial layer to a desired value.
With respect to claim 6, wherein a doping concentration of the
second p-type dopant in the inner epitaxial layer is between about 3x10²⁰ atoms/cm³ and
about 1x10²¹ atoms/cm³. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that the second p-type dopant in the inner epitaxial layer is between about 3x10²⁰ atoms/cm³ and about 1x10²¹ atoms/cm³, in order to adjust the resistivity of the inner epitaxial layer to a desired value.
With respect to claim 7, the arts cited above do not explicitly disclose wherein the outer epitaxial layer comprises a thickness between about 1 nm and about 6 nm. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).On the other hand, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that outerepitaxial layer comprises a thickness between about 1 nm and about 6 nm, in order to minimize the size of the device; thereby saving space.
With respect to claim 8, the arts cited above do not explicitly disclose wherein the inner epitaxial layer comprises a thickness between about 1 nm and about 6 nm. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). On the other hand, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that innerepitaxial layer comprises a thickness between about 1 nm and about 6 nm, in order to minimize the size of the device; thereby saving space.
With respect to claim 16, Reznicek discloses forming a stack (105,107,Fig.1) over a substrate (102), wherein the stack comprises a plurality of channel layers (105) interleaved by a plurality of sacrificial layers (107); forming a fin-shaped structure from the stack and the substrate (Fig.2), the fin-shaped structure comprising a channel region (Fig.3) and a source/drain region (between 110,Fig.2); forming a dummy gate stack (110) over the channel region of the fin-shaped structure; depositing a gate spacer layer over the dummy gate stack (120); recessing the source/drain region to form a source/drain trench that exposes
sidewalls of the plurality of channel layers (Fig.3) and the plurality of sacrificial layers (Fig.3); selectively and partially recessing the plurality of sacrificial layers to form a plurality of inner spacer recesses (Fig.4); forming a plurality of inner spacer features in the plurality of inner spacer recesses (121,Fig.7); removing the dummy gate stack (Fig.8-9); selectively removing the plurality of sacrificial layers in the channel region (Fig.9); and forming a gate structure around each of the plurality of channel layers in the channel region (150,Fig.9). However, Reznicek does not explicitly disclose depositing an outer epitaxial layer in the source/drain trench, the outer epitaxial layer comprising a first p-type dopant; depositing an inner epitaxial layer over the outer epitaxial layer, the inner epitaxial layer comprising a second p-type dopant different from the first p-type dopant; wherein the plurality of channel layers comprise germanium (Ge) and the
plurality of sacrificial layers comprise silicon germanium (SiGe). On the other hand, Lee et al discloses depositing an outer epitaxial layer in the source/drain trench (142,Fig.13A), to interface the plurality of channel layers (NS) and the substrate (110), the outer epitaxial layer comprising a first p-type dopant (Para 43); depositing an inner epitaxial layer over the outer epitaxial layer (144), the inner epitaxial layer comprising a second p-type dopant different from the first p-type dopant (Para 43-49, outer epitaxial layer comprises carbon); wherein the plurality of channel layers comprise germanium (Ge) (Para 26) and the plurality of sacrificial layers comprise silicon germanium (SiGe) (Para 81). It would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify Reznicek according to the teachings of the Lee et al such that an outer epitaxial layer in the source/drain trench, the outer epitaxial layer comprising a first p-type dopant; depositing an inner epitaxial layer over the outer epitaxial layer, the inner epitaxial layer comprising a second p-type dopant different from the first p-type dopant; wherein the plurality of channel layers comprise germanium (Ge) and the plurality of sacrificial layers comprise silicon germanium (SiGe), in order to make effective source and drain structure for P-type transistors, and having different material for the channel and sacrificial layers would make the sacrificial material more selective for a particular etching, thereby the channel structure would be intact during the etching of the sacrificial layes.
With respect to claim 17, Lee et al discloses wherein the first p-type dopant comprises
boron (B) (Para 43-48). However, the arts cited above do not explicitly disclose and the second p-type dopant comprises gallium (Ga).However, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that gallium is used instead of boron because they are interchangeable or as a design choice.
With respect to claim 18, Reznicek in view of Lee et al discloses wherein the depositing of the outer epitaxial layer (Fig13A) comprises depositing the outer epitaxial layer over the plurality of inner spacer features (Fig.9, this is accordance to applicants specification).
With respect to claim 19, the arts cited above do not explicitly disclose wherein a doping concentration of the boron in the outer epitaxial layer is between about 5x10¹⁹ atoms/cm³ and about 5x10²⁰ atoms/cm³. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that the first boron in the outer epitaxial layer is between about 5x10¹⁹ atoms/cm³ and about 5x10²⁰ atoms/cm³, in order to adjust the resistivity of the outer epitaxial layer to a desired value.
With respect to claim 20, the arts cited above do not explicitly disclose wherein a doping concentration of gallium (Ga) in the inner epitaxial layer is between about 3x10²⁰ atoms/cm³ and about 1x10²¹ atoms/cm³. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the invention to have the concentration of the gallium in the inner layer accordance to claim 20, in order to adjust the resistivity of the source or drain region to a desired value.
Claim(s) 9-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Reznicek (US Patent No. 10256301), in view of Lee et al (US Pub No. 20210082914), in view of Wu et al (US Pub No. 20210305104).
With respect to claim 9, Reznicek discloses forming a stack (105,107) over a substrate (102), wherein the stack comprises a plurality of channel layers (105) interleaved by a plurality of sacrificial layers (107); forming a fin-shaped structure from the stack and the substrate (Fig.2), the fin-shaped structure comprising a channel region (105) and a source/drain region (between 110); recessing the source/drain region to form a source/drain trench that exposes sidewalls of the plurality of channel layers (Fig.3), a portion of the substrate and sidewall of (Fig.3) the plurality of sacrificial layers (107); selectively and partially recessing the plurality of sacrificial layers to form a plurality of inner spacer recesses (Fig.4); forming a plurality of inner spacer features in the plurality of inner spacer recesses (121,Fig.7); after the forming of the plurality of inner spacer features, depositing source and drain features (140,Fig.8) to interface the plurality of channel layers (NS) and the substrate (110). However, Reznicek does not explicitly disclose depositing an outer epitaxial layer in the source/drain trench, the outer epitaxial layer being doped with boron (B); and depositing an inner epitaxial layer over the outer epitaxial layer, the inner epitaxial layer being doped with gallium (Ga), wherein the inner epitaxial layer is spaced apart from the plurality of channel layers by the outer epitaxial layer. On the other hand, Lee et al discloses depositing an outer epitaxial layer in the source/drain trench (142,Fig.13A), the outer epitaxial layer being doped with boron (B) (Para 43); and depositing an inner epitaxial layer over the outer epitaxial layer (144), the outer epitaxial layer is doped (Para 43-48), wherein the inner epitaxial layer is spaced apart from the plurality of channel layers by the outer epitaxial layer (Fig.13A). The arts cited above do not explicitly disclose the inner epitaxial layer being doped with gallium (Ga), furthermore, Wu et al discloses that boron and gallium are interchangeable (Para 34). However, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited to use Ga instead of boron to dope the inner epitaxial layer since they are interchangeable or as a design choice. The arts cite above do not explicitly disclose forming a fin shaped structure from the stack. However, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that a fin like structure is formed from the stack
With respect to claim 10, Lee et al discloses wherein the plurality of channel layers
comprise germanium (Ge) (para 26) and the plurality of sacrificial layers comprise silicon
germanium (SiGe) (para 81).
With respect to claim 11, Lee et al discloses wherein the outer epitaxial layer and the
inner epitaxial layer comprise germanium (Ge) (Para 47) or germanium tin (GeSn).
With respect to claim 12, Reznicek discloses forming a dummy gate stack (110) over the channel region (Fig.2) of the fin-shaped structure (Fig.2); depositing a gate spacer layer over the dummy gate stack (120); removing the dummy gate stack (Fig.9); selectively removing the plurality of sacrificial layers in the channel region (it is replaced by 150); and forming a gate structure around each of the plurality of channel layers in the channel region (Fig.9).
With respect to claim 13, the arts cited above do not explicitly disclose wherein a doping concentration of boron (B) in the outer epitaxial layer is between about 5x10¹⁹ atoms/cm³ and about 5x10²⁰ atoms/cm³. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that boron in the outer epitaxial layer is between about 5x10¹⁹ atoms/cm³ and about 5x10²⁰ atoms/cm³, in order to adjust the resistivity of the outer epitaxial layer to a desired value.
With respect to claim 14, the arts cited above do not explicitly disclose wherein a doping concentration of gallium (Ga) in the inner epitaxial layer is between about 3x10²⁰ atoms/cm³ and about 1x10²¹ atoms/cm³. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to modify the arts cited above such that a doping concentration of gallium (Ga) in the inner epitaxial layer is between about 3x10²⁰ atoms/cm³ and about 1x10²¹ atoms/cm³ in order to adjust the resistivity of the inner epitaxial layer to a desired value.
With respect to claim 15, the arts cited above do not explicitly disclose wherein the outer epitaxial layer comprises a thickness between about 1 nm and about 6 nm, wherein the inner epitaxial layer comprises a thickness between about 1 nm and about 6 nm. However, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Response to Arguments
Applicant’s arguments with respect to claim(s) 1-20 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Furthermore, layer 142 in LEE et al comprises carbon which is a well-known p type dopant (Para 49).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ALI NARAGHI/Primary Examiner, Art Unit 2817
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