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 .
Response to Arguments
Regarding claims 10-11 and 19 rejected under 35 U.S.C. 112(b), applicant amendment has been fully considered. The amendment overcomes the 35 U.S.C. 112(b) rejections. However, the amendment introduces new indefiniteness issues. Hence, claims 1-20 are rejected under 35 U.S.C. 112(b).
Applicant’s arguments with respect to claim(s) 12 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. Office now relies on Salokatve (US 6053981 A) to address the amended MBE chamber having a substrate holder configured to rotate the substrate about an axis normal to the surface.
Claim Rejections - 35 USC § 112
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.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-20 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.
Claim 1 recites “… substantially oxygen-free vacuum environment…”. The specification does not provide a standard for determining the degree of oxygen that is encompassed by “substantially oxygen-free. Similarly, claim 1 further recites “…damage-free p- Ga203 features having substantially vertical sidewalls”. The specification does not provide a standard for determining when a sidewall is considered “substantially vertical”, for example, the specification does not define an angular range, allowable taper structure, etc. Therefore, the scope of the limitation cannot be determined with reasonable certainty.
Claim 6 recites “…maintain the lateral-to-vertical etch-rate ratio between 0.1 and 0.3 so as to preserve substantially vertical sidewalls of the etched structure”. The specification does not provide a standard for determining when a sidewall is considered “substantially vertical”, for example, the specification does not define an angular range, allowable taper structure, etc. Therefore, the scope of the limitation cannot be determined with reasonable certainty.
Claim 12 recites “… substantially oxygen-free molecular bean epitaxy…”. The specification does not provide a standard for determining the degree of oxygen that is encompassed by “substantially oxygen-free”. Similarly, claim 12 further recites “…damage-free p- Ga203 features having substantially vertical sidewalls”. The specification does not provide a standard for determining when a sidewall is considered “substantially vertical”, for example, the specification does not define an angular range, allowable taper structure, etc. Therefore, the scope of the limitation cannot be determined with reasonable certainty.
Claim 18 recites “…etch stop layer configured to remain substantially unetched under the Ga-flux etch conditions…”. The specification does not provide a standard for determining the degree of oxygen that is encompassed by “substantially unetched”. Therefore, the scope of the limitation cannot be determined with reasonable certainty.
Claims 2-11 and 13-20 inherit the indefiniteness of their corresponding independent claims 1 and 12, hence rejected under 35 U.S.C. 112(b).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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) 12-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over LV (US 20210043778 A1) in view of Okochi (JP 2010208925 A) and further in view of Salokatve (US 6053981 A).
Re: Independent Claim 12 (Currently Amended), LV discloses a system comprising:
a patterning device, wherein the patterning device is adapted to pattern a Ga2O3 epilayer surface according to a desired structure (LV teaches, in ¶ [0015], an embodiment for depositing a mask layer on the N− low-concentration Ga₂O₃ epitaxial layer; and then selectively removing portions of the mask layer to define where processing occurs. LV further teaches removing the part of the mask layer outside a corresponding area (i.e., leaving the mask in the “desired” region) to obtain a sample having a defined patterned area. LV further teaches that the mask layer may be removed by dry etching or wet etching, which is consistent with implementing a pattern. Accordingly, LV teaches a patterning device (mask layer and associated lithography/formation/removal) adapted to pattern a Ga2O3 epilayer surface).
LV is silent regarding,
a vacuum environment comprising a substantially oxygen-free molecular beam epitaxy (MBE) chamber;
a gallium source;
wherein the vacuum environment is adapted to receive the patterned Ga2O3 epilayer surface; and heat the patterned Ga2O3 epilayer surface to a desired temperature and to rotate the Ga203 epilayer surface about an axis normal to the surface; and wherein the gallium source is adapted to supply a Ga flux to the patterned Ga2O3 epilayer surface for an amount of time to etch the Ga2O3 epilayer surface.
However, Okochi teaches
a vacuum environment comprising a substantially oxygen-free molecular beam epitaxy (MBE) chamber (Okochi teaches, in Second embodiment description, introducing as substrate/sample into a vacuum chamber equipped with an MBE apparatus, and transferring the sample between vacuum chambers via a vacuum tunnel, i.e., system comprising vacuum environment)
a gallium source (Okochi teaches, in Second embodiment description, depositing Ga in an ultra-high vacuum atmosphere to form Ga metal droplets, thus teaches a gallium source); and
wherein the vacuum environment is adapted to receive the Ga2O3 epilayer surface (Okochi teaches, in Second embodiment description, gallium oxide (Ga₂O₃) is used as the material of the thin film 43, and this sample is introduced again into a vacuum chamber equipped with a molecular beam epitaxy (MBE) device through a vacuum tunnel in an ultra-high vacuum atmosphere, thus the vacuum environment is adapted to receive the Ga2O3); and
heat the Ga2O3 epilayer surface to a desired temperature (Okochi teaches, in Second embodiment description, the Ga₂O₃ in contact with the Ga is modified into a Ga2O that is easily desorbed by heat treatment (i.e., heated to a desired temperature) in the MBE environment); and
wherein the gallium source is adapted to supply a Ga flux to the Ga2O3 epilayer surface (Okochi teaches, in Second embodiment description, supplying/depositing Ga in an ultra-high vacuum atmosphere (e.g., Ga is deposited for 5 atomic layers to form Ga metal droplets) for an amount of time to etch the Ga2O3 epilayer surface (Ga₂O₃ thin film is chemically converted according to Ga₂O₃ + 4Ga [Wingdings font/0xE0]3Ga2O and is locally removed (etched) by the heat treatment, thereby etching into the Ga₂O₃ surface over time).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of LV and Okochi to arrive at the claimed system, such that the vacuum environment of Okochi is adapted to receive the patterned Ga2O3 epilayer surface formed by LV, and the gallium source supplies Ga flux to etch the patterned Ga2O3 epilayer surface, because both references are directed to processing Ga2O3 semiconductor layers, and the combination merely applies Okochi’s known vacuum Ga-assisted etching process to a pre-patterned Ga2O3 epilayer.
LV and Okochi are silent regarding rotating the Ga203 epilayer surface about an axis normal to the surface.
However, Salokatve teaches, in summary of the invention, an MBE apparatus having a substrate holder configured to rotate the substrate about an axis perpendicular, and therefore normal to the substrate surface while the substrate receives molecular flux from and effusion source.
It would further have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to modify Okochi’s MBE system to include the rotating substrate holder taught by Salokatve in order to provide more uniform exposure of the substrate surface to the GA flux and thereby improve uniformity of the Ga-assisted etching process.
Further, the recitation that the vacuum environment, gallium source, and patterning device are “adapted to” perform various functions are interpreted as functional limitations of the claimed apparatus. Under MEPE 2114, apparatus claims cover what a device is, not what a device does. A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Accordingly, LV’s conventional mask-deposition and selective-removal equipment is reasonably capable of patterning a Ga2O3 epilayer according to a selected fin, trench, undercut, or combination pattern. Okochi’s MBE chamber is capable of receiving a previously patterned Ga2O3 sample. Okochi’s MBE substrate-heating arrangement is capable of heating the sample during Ga-assisted processing, including operation within the recited substrate-temperature range od 500C to 800C. Okochi’s independently operable gallium source is capable of supplying Ga flux while no active-oxygen source is operated.
Also, Under MPEP 2115, inclusion of the material or article worked upon by a structure being claimed does not impart patentability to the claims. Accordingly, the recitation concerning: a desired three-dimensional structure comprising a fin, trench, undercut or combination thereof; sub-micron features; damage-free p-Ga203 features; and substantially vertical sidewalls principally describe the configuration or condition of the Ga2O3 article worked upon or the intended result produced by operating the system. These recitations do not positively require additional structure of the patterning device, MBE chamber, gallium source, or substrate holder beyond the apparatus structure taught by LV, Okochi and Salokatve.
Re: Claim 13 (Original), LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
LV further discloses,
wherein the patterning device is adapted to pattern the Ga2O3 epilayer using SiO2 (LV teaches, in ¶¶ [0015] – [0016], the mask layer used for patterning device may be SiO2, thereby teaching that the patterning device is adapted to pattern the Ga2O3 epilayer using SiO2).
Re: Claim 14 (Original), LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
LV further discloses,
wherein the patterning device is adapted to pattern the Ga2O3 epilayer using optical lithography (LV teaches, in ¶ [0047], “a photoresist layer can be coated on the corresponding area… and then the mask layer is removed…”, hence teaching the patterning device is adapted to pattern the Ga2O3 epilayer using optical lithography).
Re: Claim 15 (Original), LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
Okochi further discloses,
wherein the vacuum environment comprises a molecular beam epitaxy (MBE) chamber (Okochi teaches, in Second embodiment description, placing the Ga2O3 surface into a vacuum chamber comprising MBE device through a vacuum tunnel).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to modify LV to further utilize a vacuum environment comprising an MBE chamber, as taught by Okochi, on order to enable continuous processing in a highly controlled vacuum environment without exposing the sample to the atmosphere, which improves process integration and surface/film quality during fabrication (Okochi, Second embodiment description).
Re: Claim 16 (Currently amended), LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
Regarding “wherein the desired structure comprises one or more vertical sidewalls, one or more undercut structures, and one or more fins having a lateral width of 100 nm or less formed by simultaneous vertical and lateral Ga-flux etching in the oxygen- free MBE chamber while the β -Ga203 epilayer surface is rotated”, Okochi further teaches, in the second embodiment description, Ga-assisted etching of Ga2O3 in a ultra-high vacuum MBE chamber, wherein Ga reacts with exposed Ga2O3 to form volatile Ga2O that is removed by heat treatment. The disclosed Ga-assisted chemical removal is reasonably capable of etching exposed Ha2O3 both vertically and laterally during the same etching process. Salokatve teaches rotating the substrate about an axis normal to the substate surface during MBE processing, as explained for claim 12.
Further, under MPEP 2115, the recitations of vertical sidewalls, undercut structures, fins having a lateral width of 100nm or less, and β-Ga2O3 features merely describe the geometry and characteristics of the article produced by the system and do not require additional structural limitations of the claimed apparatus. Accordingly, these limitations do not patentably distinguish the claimed system over the applied references under MPEP 2115.
Claim(s) 17, 20 are rejected under 35 U.S.C. 103 as being unpatentable over LV (US 20210043778 A1) in view of Okochi (JP 2010208925 A) further in view of Salokatve (US 6053981 A) and further in view of Sasaki (US 20140331919 A1).
Re: Claim 17 (Original), LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
LV, Okochi and Salokatve are silent regarding,
wherein the Ga2O3 epilayer surface comprises β-Ga2O3 surface.
However, Sasaki teaches
wherein the Ga2O3 epilayer surface comprises β-Ga2O3 surface (Sasaki teaches, in ¶ [0040], the β-Ga2O3 based crystal is epitaxially grown on the Ga2O3 based crystal substrate).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of LV to further include a β-Ga2O3 surface as taught by Sasaki, in order to form the most stable crystalline form.
Re: Claim 20 (Original), LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
LV, Okochi and Salokatve are silent regarding,
wherein the vacuum environment is further adapted to rotate the Ga2O3 epilayer surface while Ga flux is applied.
However, Sasaki teaches wherein the vacuum environment is further adapted to rotate the Ga2O3 epilayer surface while Ga flux is applied (Sasaki, in ¶ [0038] and Fig. 2, teaches rotating the substrate holder while Ga is evaporated and are radiated as a molecular beam onto the surface of the Ga2O3 based crystal substrate (i.e., rotation during Ga delivery/flux exposure)).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of LV (including Okochi’s Ga-flux vacuum processing/ etching mechanism) to adapt the vacuum environment to rotate the patterned Ga2O3 surface while supplying the Ga flux, as taught by Sasaki, in order to promote more uniform exposure of the patterned surface to the Ga flux during processing, thereby improving process uniformity and device fabrication quality (Sasaki, ¶ [0004]).
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over LV (US 20210043778 A1) in view of Okochi (JP 2010208925 A) further in view of Salokatve (US 6053981 A) and further in view of Heo (US 20230079059 A1).
Re: Claim 18, LV, Okochi and Salokatve disclose all the limitations of claim 12 on which this claim depends.
LV, Okochi and Salokatve are silent regarding,
wherein the Ga2O3 epilayer surface further comprises an etch stop layer configured to remain substantially unetched under the Ga-flux etch conditions used by the system such that exposure of the etch stop layer limits a vertical etch depth.
However, Heo teaches, in ¶¶ [0176] – [0182], providing an etch stop layer in an etching-based fabrication flow, including “forming an etch stop layer” and then performing an etch to a predetermined depth where the etch stop layer functions to stop/define the etch).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of LV in view of Okochi to further include an etch stop layer associated with the Ga2O3 epilayer surface, as taught by Heo, because providing an etch stop layer is a known, predictable way to improve etch depth control and reduce over-etch/processing variability when etching semiconductor-related structure (Heo, ¶ [0182]).
Further, claim 18 is directed to a system, while etch-stop layer forms part of the Ga2O3 article processed by the system. Under MPEP 2115, the particular article worked upon does not patentably distinguish the claimed system where it does not require additional structure of the chamber, gallium source, patterning device, or substrate holder. The combined prior art system is reasonably capable of receiving and Ga-flux etching a Ga2)3 epilayer containing such an etch-stop layer, consistent with MPEP 2115.
Claims 19 are rejected under 35 U.S.C. 103 as being unpatentable over LV (US 20210043778 A1) in view of Okochi (JP 2010208925 A) further in view of Salokatve (US 6053981 A) and further in view of Heo (US 20230079059 A1) and further in view of Zhao (US 20210388526 A1).
Re: Claim 19 (Currently amended), LV, Okochi, Salokatve and Heo disclose all the limitations of claim 18 on which this claim depends.
LV, Okochi, Salokatve and Heo are silent regarding,
wherein the etch stop layer comprises β-(AlxGa1-x)2O3.
However, Zhoa teaches wherein the etch stop layer comprises β-(AlxGa1-x)2O3 (Zhoa teaches, in ¶ [0003], β-Ga2O3 is known to have very wide bandgap energy (˜4.8 eV), and its higher thermal/chemical stability. Zhoa further teaches, in ¶ [0004], Energy bandgap engineering by alloying β-Ga2O3 with Al2O3 can expand the accessible bandgap of AlGaO alloy up to 8.8 eV.; thus, higher thermal/chemical stability is achieved with AlGaO alloy which makes (AlxGa1-x)2O3 a predictable great choice to be used as a stop etch layer in semiconductor fabrication).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of LV in view of Okochi to further include an etch stop layer associated with the Ga2O3 epilayer surface as taught by Heo, and to use (AlxGa1-x)2O3 as the etch stop layer as taught by Zhoa, in order to achieve better control over the etch process.
Allowable Subject Matter
Claim 1-11 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action.
The following is a statement of reasons for the indication of allowable subject matter:
The closest prior arts to the present invention are LV (US 20210043778 A1) and Okochi (JP 2010208925 A). LV and Okochi disclose a similar method of patterning a Ga2O3 epilayer surface. Regarding independent claims 1, there is no teaching or suggestion in the prior art of record to provide the specific limitation recited in the claim 1 of the instant invention, e.g., a method comprising: patterning a Ga203 epilayer surface according to a desired three-dimensional structure comprising at least one fin, trench, undercut, or combination thereof; and to form sub-micron, damage-free p- Ga203 features having vertical sidewalls.
Claims 2-11 would be allowable by virtue of their dependence on claim 1 if claims 1 and 6 would be rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BIPANA ADHIKARI DAWADI whose telephone number is (571)272-4149. The examiner can normally be reached Monday-Friday 11:30am-7:30pm.
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/BIPANA ADHIKARI DAWADI/Examiner, Art Unit 2898
/JESSICA S MANNO/SPE, Art Unit 2898
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