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 .
Remarks
The 02/04/2026 amendment of claims 1, 4-6, 10, 13-15 and 19 have been noted and entered.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 02/04/2026 was filed after the mailing date of the application on 07/13/2022. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Response to Arguments
Applicant’s arguments, see Remarks pages 5-7, filed 02/04/2026, with respect to the rejection of claims 1, 10 and 19 under 35 U.S.C 112(b) have been fully considered but they are not persuasive. The applicant points out a portion of the specification that states: “ [0030] The inventors have surprisingly found that a “weak silicide” can be used to form a low resistivity contacts application…” along with a portion of paragraph [0038] of the specification of the instant application. In light of the available art references, some of which are used in this rejection and other references which are made of reference but not relied upon, which use the same materials used in the instant application but report higher formation energies, the referenced paragraphs of the instant application do not provide sufficient details that would enable a person having ordinary skill in the art to make the invention claimed with the low formation energy claimed. Nor does it allow for the clear determination of the metes and bounds of the claimed invention. Thus, the previous 35 U.S.C. 112(b) rejection is maintained.
Applicant’s arguments, see Remarks pages 7-15, filed 02/04/2026, with respect to the rejection(s) of claim(s) 1, 4-6, 8-10 and 13-22 under 35 U.S.C. 103 have been fully considered and are persuasive in light of the newly added amendments. However, upon further consideration, new grounds of rejection are made in view of Wang, KR 20210122629 A (Wang) and Park et al, US 20220037494 A1 (Park).
New Grounds of Rejection
New grounds of rejection, prior art references, Wang, KR 20210122629 A (Wang), and Park et al, US 20220037494 A1 (Park), appear below.
Specification
The specification is objected to as failing to provide proper antecedent basis for the claimed subject matter. See 37 CFR 1.75(d)(1) and MPEP § 608.01(o). Correction of the following is required: The specification of the incident application is missing the support for the claimed limitation: “… wherein the silicide is not deposited…” (emphasis added).
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Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1, 10 and 19 and all subsequently dependent claims (4-6, 8-9, 13-18 and 20-22) are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement.
The claims contain subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Regarding claim 1; claim 1 contains the limitation: “… wherein the silicide is not deposited…” (emphasis added). Support for this limitation is absent from the original disclosure. Therefore, there is no basis in the original disclosure (see MPEP 2173.05(i)).
Regarding claim 10; Claim 10 contains similar claim limitations to the ones detailed above for claim 1 and is rejected under 35 U.S.C. 112(a) for the same reasons detailed above.
Regarding claim 19; Claim 19 contains similar claim limitations to the ones detailed above for claims 1 and 10 and is rejected under 35 U.S.C. 112(a) for the same reasons detailed above.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
Claims 1, 10, and 19 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 1; claim 1 contains the limitation: “… wherein the work function layer and the source/drain region form a silicide,…” (emphasis added). While the specification of the instant application recites: “…forming a silicide layer on the exposed source/drain region by an epitaxial deposition process,…”, the absence of the required details of this silicide formation process such as the steps in which the process takes place, the concentration of pre-cursor gasses and materials used or the temperature at which the formation process takes place makes it impossible to clearly define the metes and bounds of the claimed subject matter. In addition, there is no basis in the original disclosure for the specific details or elements of how the alternative method, “not deposited”, is positively recited or implemented to help define the meets and bunds of the claim. The applicant’s attention is drawn to MPEP § 2173.05(i). See In re Johnson, 558 F.2d 1008, 1019, 194 USPQ 187, 196 (CCPA 1977) (“[the] specification, having described the whole, necessarily described the part remaining.”).
Additionally, claim 1 recites the limitation: “…wherein the work function layer and the source/drain region form a silicide having an energy of formation in the range of 0 to -0.4 eV/atom.” (emphasis added). The language used to express the limitations in the claim fails to specify the details of the conditions (such as concentration of the elements or the specific chemical composition of the compounds involved in the process) of creating the silicide which in its turn affects the energy of formation of the silicide layer. This presents a problem in defining the metes and bounds of the claim and consequently of the invention rendering the claim indefinite in scope given the dependence of the formation energy on these omitted variables. The applicant is reminded that the dependence on the specifications listing some of these details is not sufficient given that it is improper to import claim limitations from the specifications see MPEP 2111.01.
Regarding claim 10; claim 10 contains the limitation: “… wherein the work function layer and the source/drain region form a silicide,…” (emphasis added). While the specification of the instant application recites: “…forming a silicide layer on the exposed source/drain region by an epitaxial deposition process,…”, the absence of the required details of this silicide formation process such as the steps in which the process takes place, the concentration of pre-cursor gasses and materials used or the temperature at which the formation process takes place makes it impossible to clearly define the metes and bounds of the claimed subject matter. In addition, there is no basis in the original disclosure for the specific details or elements of how the alternative method, “not deposited”, is positively recited or implemented to help define the meets and bunds of the claim. The applicant’s attention is drawn to MPEP § 2173.05(i). See In re Johnson, 558 F.2d 1008, 1019, 194 USPQ 187, 196 (CCPA 1977) (“[the] specification, having described the whole, necessarily described the part remaining.”).
Additionally, claim 10 recites the limitation: “…wherein the work function layer and the source/drain region form a silicide having an energy of formation in the range of 0 to -0.4 eV/atom.” (emphasis added). The language used to express the limitations in the claim fails to specify the details of the conditions (such as concentration of the elements or the specific chemical composition of the compounds involved in the process) of creating the silicide which in its turn affects the energy of formation of the silicide layer. This presents a problem in defining the metes and bounds of the claim and consequently of the invention rendering the claim indefinite in scope given the dependence of the formation energy on these omitted variables. The applicant is reminded that the dependence on the specifications listing some of these details is not sufficient given that it is improper to import claim limitations from the specifications see MPEP 2111.01.
Regarding claim 19; claim 19 contains the limitation: “… wherein the work function layer and the source/drain region form a silicide,…” (emphasis added). While the specification of the instant application recites: “…forming a silicide layer on the exposed source/drain region by an epitaxial deposition process,…”, the absence of the required details of this silicide formation process such as the steps in which the process takes place, the concentration of pre-cursor gasses and materials used or the temperature at which the formation process takes place makes it impossible to clearly define the metes and bounds of the claimed subject matter. In addition, there is no basis in the original disclosure for the specific details or elements of how the alternative method, “not deposited”, is positively recited or implemented to help define the meets and bunds of the claim. The applicant’s attention is drawn to MPEP § 2173.05(i). See In re Johnson, 558 F.2d 1008, 1019, 194 USPQ 187, 196 (CCPA 1977) (“[the] specification, having described the whole, necessarily described the part remaining.”).
Additionally, claim 19 recites the limitation: “…wherein the work function layer and the source/drain region form a silicide having an energy of formation in the range of 0 to -0.4 eV/atom.” (emphasis added). The language used to express the limitations in the claim fails to specify the details of the conditions (such as concentration of the elements or the specific chemical composition of the compounds involved in the process) of creating the silicide which in its turn affects the energy of formation of the silicide layer. This presents a problem in defining the metes and bounds of the claim and consequently of the invention rendering the claim indefinite in scope given the dependence of the formation energy on these omitted variables. The applicant is reminded that the dependence on the specifications listing some of these details is not sufficient given that it is improper to import claim limitations from the specifications see MPEP 2111.01.
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.
Claims 1 and 4-6 are rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav).
Regarding claim 1; Wang teaches a method of forming a contact (236), the method comprising: depositing a work function layer (232) directly on an exposed source/drain region ((230) within the area covered by (236) – see Fig (12) of Wang) of a transistor (400) on a substrate (202), the work function layer comprising titanium and a metal (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”), the titanium and the metal forming an alloy or intermetallic (see the specification of Wang: “the method 100 includes a block 126 in which a silicide layer 234 is formed over an extremely thin epitaxial feature. In an exemplary process, a metal layer 232 is deposited on the surfaces of thin epitaxial features 230 and inner spacer features 220 , causing a silicification reaction between the silicon and metal layers of thin epitaxial features 230 to cause a silicide layer. The workpiece 200 is annealed to form 234 .”) on the source/drain region ((230) within area covered by (236)), the metal selected from the group consisting of arsenic (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”), wherein the work function layer (232) and the source/drain region (230) form a silicide, wherein the silicide is not deposited (The description provided in the specification of Wang indicates that the process takes place in a sequence in which a metal layer (232) is deposited on a thin epitaxial layer (230) and that this deposition is what causes the “silicification” reaction between the epitaxial layer and the metal layer assisted by the annealing process. Such a sequence indicates that the silicide layer was not previously formed away from the substrate and its layers and then deposited on the underlying structures and layers but rather formed via a sequence of steps from materials that are not silicides but become a silicide after the annealing process. See the translated copy of Wang attached to this OA: page: 11, line: 48 to page: 12, line: 6).
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Wang’s first embodiment disclosed above does not teach that the metal is selected to be aluminum.
However, a second embodiment of Wang discloses that the metal selected is aluminum (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, along with boron (B) or aluminum (Al)”).
The two embodiments of Wang are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify the first embodiment of Wang by using aluminum as the metal mixed with titanium to form a silicide to improve the conductivity and reduce resistivity of the silicide and the contact on which it is formed leading to a more efficient device.
Wang does not teach that the metal is selected to be antimony.
Deniz teaches wherein the metal selected is antimony (see col 7 lines 25-31 of the specifications of Deniz: “In some embodiments, silicide 140 may include a titanium-tantalum-silicide and may include an implanted species of at least one of: silicon, germanium, arsenic, phosphorous, antimony, selenium, boron, xenon, indium, aluminum, gallium, and combinations thereof.”).
Wang and Deniz are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang by using antimony in the formation of the silicide layer as disclosed in Deniz to improve the conductivity of the silicide layer and the contact structure leading to a more efficient device.
Wang in view of Deniz does not teach wherein the silicide has an energy of formation in the range of 0 to -0.4 eV/atom.
Yadav teaches wherein the silicide has an energy of formation in the range of 0 to -0.4 eV/atom (see Yadav: “For example, the excess free energy of mixing of the ternary alloy at cross-section XAl / XSi = 1:9 is about -48 KJ/mol while it is about -13 KJ/mol for the cross-section XAl / XSi = 9:1. However, the peak value of the excess free energy of mixing was found to be at the same concentration (XTi =0.5 at all cross-sections in all cases. The variation of the excess free energy of mixing of the ternary Ti–Al–Si alloy in liquid state with temperature at different corners has also been studied in the present work (Figure 4(f)). The excess free energy of mixing was found to be changing linearly with temperature at all corners.”.
Wang in view of Deniz and Yadav are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Deniz by using a silicide forming method that yields the formation energy of 0 to -0.4 eV/atom as disclosed in Yadav to lower the energy requirements for forming the silicide leading to a more efficient device construction process.
Regarding claim 4; Wang teaches wherein the metal comprises arsenic (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”).
Regarding claim 5; Wang’s first embodiment does not teach wherein the metal consists essentially of aluminum.
However, Wang teaches in a second embodiment wherein the metal consists essentially of aluminum (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, along with boron (B) or aluminum (Al)”).
The two embodiments of Wang are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify the first embodiment of Wang by using aluminum as the metal mixed with titanium to form a silicide to improve the conductivity and reduce resistivity of the silicide and the contact on which it is formed leading to a more efficient device.
Regarding claim 6; Wang does not teach wherein the metal consists essentially of antimony.
Deniz teaches wherein the metal consists essentially of antimony (see col 7 lines 25-31 of the specifications of Deniz: “In some embodiments, silicide 140 may include a titanium-tantalum-silicide and may include an implanted species of at least one of: silicon, germanium, arsenic, phosphorous, antimony, selenium, boron, xenon, indium, aluminum, gallium, and combinations thereof.”).
Wang and Deniz are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang by using antimony in the formation of the silicide layer as disclosed in Deniz to improve the conductivity of the silicide layer and the contact structure leading to a more efficient device.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav) in further view of Park et al, US 20220037494 A1 (Park).
Regarding claim 8; Wang in view of Deniz in further view of Yadav does not teach wherein the work function layer forms nitrides.
Park teaches wherein the work function layer forms nitrides (see paragraph [0028] of Park: “[0028] The gate electrode layer 182 may include a work function layer and a buried layer. The work function layer may include, e.g., aluminum (Al), copper (Cu), titanium (Ti), tantalum (Ta), tungsten (W), molybdenum (Mo), tantalum nitride (TaN), nickel silicide (NiSi), cobalt silicide (CoSi), titanium nitride (TiN)”.
Wang in view of Deniz in further view of Yadav and Park are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Deniz in further view of Yadav by constructing a work function layer that forms nitrides to improve the resistance of the device contact layers to the adverse effects of high temperatures.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav) in further view of Ohse, US 20200258996 A1 (Ohse).
Regarding claim 9; Wang in view of Deniz in further view of Yadav does not teach wherein the work function layer has a melting temperature greater than 500⁰ C.
Ohse teaches wherein the work function layer has a melting temperature greater than 500⁰ C (see paragraph [0155] of the specifications of Ohse: “["0155] The increased temperature by laser light irradiation then also leads to melting of the titanium layer (melting point: 1668° C.), the silicon of the molten nickel silicide reacting with titanium to produce titanium silicide. Presumably, upon reaching a temperature at which the n.sup.+-type silicon carbide substrate is also decomposed (SiC.fwdarw.Si+C), it reacts with titanium to produce titanium carbide and titanium silicide, and reacts with nickel to produce nickel silicide.").
Wang in view of Deniz in further view of Yadav and Ohse are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in further view of Yadav by constructing the work function layer to have a melting temperature above 500-⁰ C given that the main component of the layer is titanium as disclosed in Ohse to increase the resilience of the device to high temperature and high current use situations leading to a more reliable device.
Claims 10 and 13-15 are rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Chung et al, US 20180166288 A1 (Chung) in further view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav).
Regarding claim 10; Wang teaches a method of forming a contact (236), the method comprising: forming a work function layer (232) directly on the source/drain region ((230) within the area covered by (236) – see Fig (12) of Wang), the work function layer comprising titanium and a metal (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”), the titanium and the metal forming an alloy or intermetallic (see the specification of Wang: “the method 100 includes a block 126 in which a silicide layer 234 is formed over an extremely thin epitaxial feature. In an exemplary process, a metal layer 232 is deposited on the surfaces of thin epitaxial features 230 and inner spacer features 220 , causing a silicification reaction between the silicon and metal layers of thin epitaxial features 230 to cause a silicide layer. The workpiece 200 is annealed to form 234 .”) on the source/drain region ((230) within the area covered by (236)), the metal selected from the group consisting of arsenic (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”), wherein the work function layer (232) and the source/drain region ((230) within the area covered by (236)) form a silicide, wherein the silicide is not deposited (The description provided in the specification of Wang indicates that the process takes place in a sequence in which a metal layer (232) is deposited on a thin epitaxial layer (230) and that this deposition is what causes the “silicification” reaction between the epitaxial layer and the metal layer assisted by the annealing process. Such a sequence indicates that the silicide layer was not previously formed away from the substrate and its layers and then deposited on the underlying structures and layers but rather formed via a sequence of steps from materials that are not silicides but become a silicide after the annealing process. See the translated copy of Wang attached to this OA: page: 11, line: 48 to page: 12, line: 6).
Wang’s first embodiment disclosed above does not teach that the metal is selected to be aluminum.
However, a second embodiment of Wang discloses that the metal selected is aluminum (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, along with boron (B) or aluminum (Al)”).
The two embodiments of Wang are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify the first embodiment of Wang by using aluminum as the metal mixed with titanium to form a silicide to improve the conductivity and reduce resistivity of the silicide and the contact on which it is formed leading to a more efficient device.
Wang does not teach pre-cleaning an exposed surface of a source/drain region of a transistor on a substrate.
Chung teaches pre-cleaning an exposed surface of a source/drain region of a transistor on a substrate (see paragraph [0013] of the specification of Chung: “[0013]… In operation 102, a substrate is subjected a pre-clean process. The substrate is a silicon substrate, such as an n-type silicon substrate, however the substrate may alternatively be a germanium or silicon-germanium substrate. The substrate includes one or more source/drain (S/D) regions, contact trenches, or the like, formed thereon.”).
Wang and Chung are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang by using a pre-cleaning step disclosed in Chung to improve the bonding between the work function layer and the contact leading to a more reliable device.
Wang in view of Chung does not teach that the metal is selected to be antimony.
Deniz teaches wherein the metal selected is antimony (see col 7 lines 25-31 of the specifications of Deniz: “In some embodiments, silicide 140 may include a titanium-tantalum-silicide and may include an implanted species of at least one of: silicon, germanium, arsenic, phosphorous, antimony, selenium, boron, xenon, indium, aluminum, gallium, and combinations thereof.”).
Wang in view of Chung and Deniz are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Chung by using antimony in the formation of the silicide layer as disclosed in Deniz to improve the conductivity of the silicide layer and the contact structure leading to a more efficient device.
Wang in view of Chung in further view of Deniz does not teach wherein the silicide has an energy of formation in the range of 0 to -0.4 eV/atom.
Yadav teaches wherein the silicide has an energy of formation in the range of 0 to -0.4 eV/atom (see Yadav: “For example, the excess free energy of mixing of the ternary alloy at cross-section XAl / XSi = 1:9 is about -48 KJ/mol while it is about -13 KJ/mol for the cross-section XAl / XSi = 9:1. However, the peak value of the excess free energy of mixing was found to be at the same concentration (XTi =0.5 at all cross-sections in all cases. The variation of the excess free energy of mixing of the ternary Ti–Al–Si alloy in liquid state with temperature at different corners has also been studied in the present work (Figure 4(f)). The excess free energy of mixing was found to be changing linearly with temperature at all corners.”.
Wang in view of Chung in further view of Deniz and Yadav are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Chung in further view of Deniz by using a silicide forming method that yields the formation energy of 0 to -0.4 eV/atom as disclosed in Yadav to lower the energy requirements for forming the silicide leading to a more efficient device construction process.
Regarding claim 13; Wang teaches wherein the metal comprises arsenic (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”).
Regarding claim 14; Wang’s first embodiment disclosed above does not teach wherein the metal consists essentially of aluminum.
However, Wang’s second embodiment teaches wherein the metal consists essentially of aluminum (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, along with boron (B) or aluminum (Al)”).
The two embodiments of Wang are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify the first embodiment of Wang by using aluminum as the metal mixed with titanium to form a silicide to improve the conductivity and reduce resistivity of the silicide and the contact on which it is formed leading to a more efficient device.
Regarding claim 15; Wang does not teach wherein the metal consists essentially of antimony.
Deniz teaches wherein the metal consists essentially of antimony (see col 7 lines 25-31 of the specifications of Deniz: “In some embodiments, silicide 140 may include a titanium-tantalum-silicide and may include an implanted species of at least one of: silicon, germanium, arsenic, phosphorous, antimony, selenium, boron, xenon, indium, aluminum, gallium, and combinations thereof.”).
Wang and Deniz are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Yadav by using antimony in the formation of the silicide layer as disclosed in Deniz to improve the conductivity of the silicide layer and the contact structure leading to a more efficient device.
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Chung et al, US 20180166288 A1 (Chung) in further view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav) in further view of Cai et al, CN 110660736 A (Cai).
Regarding claim 16; Wang in view of Chung in further view of Deniz in further view of Yadav does not teach wherein the work function layer forms oxides.
Cai teaches wherein the work function layer forms oxides (see the specifications of Cai: "The n-type metal oxide semiconductor source electrode/drain electrode area, which can be doped with phosphorous or arsenic, and increase the dosage to reduce the source/drain resistor is limited by: (i) maximum dopant concentration process can be achieved, (ii) n-type metal oxide semiconductor dopant in the subsequent silicide (e.g., titanium silicide) is formed, and (iii) the reaction/heavy doped source/drain caused by the short channel effect.").
Wang in view of Chung in further view of Deniz in further view of Yadav and Cai are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Chung in further view of Deniz in further view of Yadav by introducing the oxides in the functional layer as disclosed in Cai to improve the thermal stability of the contacts leading to a more reliable device.
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Chung et al, US 20180166288 A1 (Chung) in further view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav) in further view of Park et al, US 20220037494 A1 (Park).
Regarding claim 17; Wang in view of Chung in further view of Deniz in further view of Yadav does not teach wherein the work function layer forms nitrides.
Park teaches wherein the work function layer forms nitrides (see paragraph [0028] of Park: “[0028] The gate electrode layer 182 may include a work function layer and a buried layer. The work function layer may include, e.g., aluminum (Al), copper (Cu), titanium (Ti), tantalum (Ta), tungsten (W), molybdenum (Mo), tantalum nitride (TaN), nickel silicide (NiSi), cobalt silicide (CoSi), titanium nitride (TiN)”.
Wang in view of Chung in further view of Deniz in further view of Yadav and Park are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Chung in further view of Deniz in further view of Yadav by constructing a work function layer that forms nitrides to improve the resistance of the device contact layers to the adverse effects of high temperatures.
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Chung et al, US 20180166288 A1 (Chung) in further view of Deniz et al, US 9583397 B1 (Deniz) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav) in further view of Ohse, US 20200258996 A1 (Ohse).
Regarding claim 18; Wang in view of Chung in further view of Deniz in further view of Yadav does not teach wherein the work function layer has a melting temperature greater than 500⁰ C.
Ohse teaches wherein the work function layer has a melting temperature greater than 500⁰ C (see paragraph [0155] of the specifications of Ohse: “["0155] The increased temperature by laser light irradiation then also leads to melting of the titanium layer (melting point: 1668° C.), the silicon of the molten nickel silicide reacting with titanium to produce titanium silicide. Presumably, upon reaching a temperature at which the n.sup.+-type silicon carbide substrate is also decomposed (SiC.fwdarw.Si+C), it reacts with titanium to produce titanium carbide and titanium silicide, and reacts with nickel to produce nickel silicide.").
Wang in view of Chung in further view of Deniz in further view of Yadav and Ohse are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Chung in further view of Deniz in further view of Yadav by constructing the work function layer to have a melting temperature above 500-⁰ C given that the main component of the layer is titanium as disclosed in Ohse to increase the resilience of the device to high temperature and high current use situations leading to a more reliable device.
Claims 19-22 are rejected under 35 U.S.C. 103 as being unpatentable over Wang, KR 20210122629 A (Wang) in view of Deniz et al, US 9583397 B1 (Deniz) in further view of Ohse, US 20200258996 A1 (Ohse) in further view of in further view of Yadav SK, Mehta U, Adhikari D. Optimization of thermodynamic and surface properties of ternary Ti-Al-Si alloy and its sub-binary alloys in molten state. Heliyon. 2021 Mar 16;7(3):e06511. doi: 10.1016/j.heliyon.2021.e06511. PMID: 33768181; PMCID: PMC798007 (Yadav).
Regarding claim 19; Wang teaches a semiconductor device comprising: depositing a source/drain region ((230) within the area covered by (236) – see Fig (12) of Wang) on a substrate (202), the source/drain region ((230) within the area covered by (236)) comprising silicon; a work function layer (232) directly on the source/drain region ((230) within the area covered by (236) – see Fig (12) of Wang), the work function layer comprising an alloy or intermetallic of titanium and a metal (see the specification of Wang: “ The workpiece 200 is annealed to form 234 . In some embodiments, the metal layer 232 may include titanium (Ti), nickel (Ni), cobalt (Co), tantalum (Ta), or tungsten (W).” also see “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”), the metal selected from the group consisting of arsenic (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”), and a metal contact (236) on the work function (232) wherein the work function layer (232) and the source/drain region (230) form a silicide (234), wherein the silicide (234) is not deposited (The description provided in the specification of Wang indicates that the process takes place in a sequence in which a metal layer (232) is deposited on a thin epitaxial layer (230) and that this deposition is what causes the “silicification” reaction between the epitaxial layer and the metal layer assisted by the annealing process. Such a sequence indicates that the silicide layer was not previously formed away from the substrate and its layers and then deposited on the underlying structures and layers but rather formed via a sequence of steps from materials that are not silicides but become a silicide after the annealing process. See the translated copy of Wang attached to this OA: page: 11, line: 48 to page: 12, line: 6).
Wang’s first embodiment disclosed above does not teach that the metal is selected to be aluminum.
However, a second embodiment of Wang discloses that the metal selected is aluminum (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, along with boron (B) or aluminum (Al)”).
The two embodiments of Wang are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify the first embodiment of Wang by using aluminum as the metal mixed with titanium to form a silicide to improve the conductivity and reduce resistivity of the silicide and the contact on which t is formed leading to a more efficient device.
Wang does not teach that the metal selected is antimony.
Deniz teaches wherein the metal selected is antimony (see col 7 lines 25-31 of the specifications of Deniz: “In some embodiments, silicide 140 may include a titanium-tantalum-silicide and may include an implanted species of at least one of: silicon, germanium, arsenic, phosphorous, antimony, selenium, boron, xenon, indium, aluminum, gallium, and combinations thereof.”).
Wang and Deniz are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang by using antimony in the formation of the silicide layer as disclosed in Deniz to improve the conductivity of the silicide layer and the contact structure leading to a more efficient device.
Wang in view of Deniz does not teach the work function layer having a melting temperature greater than 500⁰ C.
Ohse teaches the work function layer having a melting temperature greater than 500⁰ C (see paragraph [0155] of the specifications of Ohse: “["0155] The increased temperature by laser light irradiation then also leads to melting of the titanium layer (melting point: 1668° C.), the silicon of the molten nickel silicide reacting with titanium to produce titanium silicide. Presumably, upon reaching a temperature at which the n.sup.+-type silicon carbide substrate is also decomposed (SiC.fwdarw.Si+C), it reacts with titanium to produce titanium carbide and titanium silicide, and reacts with nickel to produce nickel silicide.").
Wang in view of Deniz and Ohse are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Deniz by constructing the work function layer to have a melting temperature above 500-⁰ C given that the main component of the layer is titanium as disclosed in Ohse to increase the resilience of the device to high temperature and high current use situations leading to a more reliable device.
Wang in view of Deniz in further view of Ohse does not teach wherein the silicide has an energy of formation in the range of 0 to -0.4 eV/atom.
Yadav teaches wherein the silicide has an energy of formation in the range of 0 to -0.4 eV/atom (see Yadav: “For example, the excess free energy of mixing of the ternary alloy at cross-section XAl / XSi = 1:9 is about -48 KJ/mol while it is about -13 KJ/mol for the cross-section XAl / XSi = 9:1. However, the peak value of the excess free energy of mixing was found to be at the same concentration (XTi =0.5 at all cross-sections in all cases. The variation of the excess free energy of mixing of the ternary Ti–Al–Si alloy in liquid state with temperature at different corners has also been studied in the present work (Figure 4(f)). The excess free energy of mixing was found to be changing linearly with temperature at all corners.”.
Wang in view of Deniz in further view of Ohse and Yadav are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang in view of Deniz in further view of Ohse by using a silicide forming method that yields the formation energy of 0 to -0.4 eV/atom as disclosed in Yadav to lower the energy requirements for forming the silicide leading to a more efficient device construction process.
Regarding claim 20; Wang’s first embodiment disclosed above does not teach that the metal is aluminum.
However, a second embodiment of Wang discloses that the metal is aluminum (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, along with boron (B) or aluminum (Al)”).
The two embodiments of Wang are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify the first embodiment of Wang by using aluminum as the metal mixed with titanium to form a silicide to improve the conductivity and reduce resistivity of the silicide and the contact on which t is formed leading to a more efficient device.
Regarding claim 21; Wang does not teach that the metal is antimony.
Deniz teaches wherein the metal is antimony (see col 7 lines 25-31 of the specifications of Deniz: “In some embodiments, silicide 140 may include a titanium-tantalum-silicide and may include an implanted species of at least one of: silicon, germanium, arsenic, phosphorous, antimony, selenium, boron, xenon, indium, aluminum, gallium, and combinations thereof.”).
Wang and Deniz are considered analogous art. Thus, it would have been obvious, prior to the effective filing date of the instant application, to a person having ordinary skill in the art to modify Wang by using antimony in the formation of the silicide layer as disclosed in Deniz to improve the conductivity of the silicide layer and the contact structure leading to a more efficient device.
Regarding claim 22; Wang teaches wherein the metal comprises arsenic (see the specification of Wang: “the silicide layer 234 is formed of titanium silicide, with phosphorus (P) or arsenic (As)”).
Conclusion
Art references that are made of record but not relied upon for the rejection are:
Kematick et al, Thermodynamics of the Phase Formation of the Titanium Silicides, Chem. Mater. 1996, 8, 1, 287–291, https://doi.org/10.1021/cm950386q.
Poltaev et al, Ab initio-based prediction and TEM study of silicide precipitation in titanium, Computational Materials Science Volume 95, December 2014, Pages 456-463, https://doi.org/10.1016/j.commatsci.2014.08.010.
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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/M.K./Examiner, Art Unit 2815
/JOSHUA BENITEZ ROSARIO/Supervisory Patent Examiner, Art Unit 2815
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