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
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-3, 5, 8-12, 14, and 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Jia (Jia et al, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 997, 2021, 165166, ISSN 0168-9002, doi.org/10.1016/j.nima.2021.165166) in views of Quah (Hock Jin Quah et al., 2010, Electrochem. Solid-State Lett. 13 H396, DOI 10.1149/1.3481926) and Mandal (Mandal et al., Advances in High-Resolution Radiation Detection Using 4H-SiC Epitaxial Layer Devices. Micromachines 2020, 11, 254. doi.org/10.3390/mi11030254).
Regarding claim 1, Jia teaches a betavoltaic cell for power generation (SiC radiation detector; Fig. 1; Abstract) in harsh environment applications (4H-SiC substrate is a material that is suitable for extreme environments (page 1, col. 2, para. 1)) comprising:
at least one metal-oxide-semiconductor (Fig. 1b: the SiC detector is a metal-oxide-semiconductor device) comprising:
at least one layer of oxide (SiO2 layer, Fig. 1b; page 2, col. 1, para. 2) deposited on at least one n-type 4H-SiC epilayer (u-SiC epitaxial, Fig. 1b; page 2, col. 1, para. 2);
at least one first nickel contact (Ni/Au, Fig. 1; page 2, col. 1, para. 2), deposited on the at least one oxide layer (SiO2 layer, Fig. 1b), configured to act as a gate contact (Fig. 1b-c: the first contact acts as a gate contact as the device structure is identical to the one in the current application); and
at least one second contact (Ti/Al/Ti, Fig. 1b; page 2, col. 1, para. 2) formed on the at least one n-type 4H-SiC epilayer (u-SiC epitaxial, Fig. 1b) as a back contact (Ti/Al/Ti contact is on the back side of the device).
Jia, however, does not teach that
the oxide layer is an yttrium oxide layer deposited by pulse laser deposition; and
the second contact is a second nickel contact.
Quah, on the other hand, teaches a gate oxide layer formed from yttrium oxide, instead of silicon dioxide, on an n-doped 4H-SiC (page 1, col. 1, para. 1), which is advantageous due to the relatively high k-value of yttrium oxide (k=14-18 compared to k=3.9 for silicon dioxide; page 1, col. 1, para. 1). Quah further teaches that yttrium oxide layer deposited by pulsed laser deposition would provide a very high breakdown voltage of about 6.5 MVcm-1 at 10-6 Acm-2, which is higher than other high-k gate oxides.
Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to modify the betavoltaic cell of Jia the replace the silicon oxide layer with a pulse laser deposited yttrium oxide layer, as taught by Quah, to obtain a gate oxide layer with a high k-value (reduces leakage current) and a high breakdown voltage.
Quah, however, does not teach that
the second contact is a second nickel contact.
Mandal, on the other hand, teaches radiation detection with 4H-SiC epitaxial layer devices (Fig. 1) for harsh environment application (Abstract), wherein
the second contact is a second nickel contact (Fig. 1: Ni contact at the backside (bottom) of the n-type Ni/4H-SiC Schottky barrier device).
A person of ordinary skill in the art before the effective filing date of the claimed invention would already know that using nickel as a contact material on the n-doped 4H-SiC is a known method for forming ohmic contacts on 4H-SiC, as also evidenced by Mandal (page 4, para. 1). Selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945) "Reading a list and selecting a known compound to meet known requirements is no more ingenious than selecting the last piece to put in the last opening in a jig-saw puzzle." 325 U.S. at 335, 65 USPQ at 301. See also In re Leshin, 227 F.2d 197, 125 USPQ 416 (CCPA 1960) (selection of a known plastic to make a container of a type made of plastics prior to the invention was held to be obvious). Furthermore, it should also be noted that substituting nickel as disclosed by Mandal for Ti/Al/Ti as disclosed by Jia in view of Quah as ohmic contact is a simple substitution of one known element for another to obtain predictable results (see MPEP2143). Thus, 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 second contact of Jia in view of Quah such that the second contact is a second nickel contact, as disclosed by Mandal.
Regarding claim 2, Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1, wherein
Jia further teaches that the betavoltaic cell (SiC radiation detector; Fig. 1) is mounted on a printed circuit board (Fig. 1a; page 2, col. 1, last paragraph).
Regarding claim 3, while Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1,
Jia, Quah and Mandal do not disclose that the betavoltaic cell is heteroepitaxial.
Jia in views of Quah and Mandal, however, teaches that the n-type 4H-SiC epilayer is an epitaxial layer (u-SiC epitaxial, Fig. 1). A person of ordinary skill in the art would already be familiar with that the pulsed laser deposition can be used to deposit epitaxial yttrium oxide layers, as evidenced by Zhang (page 8, Conclusion; Zhang and Xiao, J. Appl. Phys. 83, 3842–3848 (1998), doi.org/10.1063/1.366615), and epitaxial growth leads to a better crystal structure with less defects. Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to grow the yttrium oxide layer (gate oxide layer) also epitaxially in the betavoltaic cell of Jia in views of Quah and Mandel, which would lead to a single crystal structure with less defects and reduces leakage current.
Thus, the combination of Jia, Quah, and Mandal meets the limitation of claim 3 that
the betavoltaic cell is heteroepitaxial (n-type SiC and yttrium oxide layers are epitaxial).
Regarding claim 5, while Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1,
Jia, Quah, and Mandal do not disclose that the betavoltaic cell has less surface recombination velocity as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer.
However, it is known in the field of SiC-based radiation detectors that the surface recombination velocity depends on the point defects and surface recombination due to surface traps in 4H-SiC, as evidenced by Ichikawa (page 2, col. 1, para. 1; Ichikawa et al, 2018, ECS J. Solid State Sci. Technol. 7 Q127, DOI 10.1149/2.0031808jss) and high quality oxide layers is applicable to suppress surface recombination (Ichikawa; page 2, col. 1, para. 1) for decreasing the surface recombination. Quah further teaches that yttrium dioxide can be such an oxide layer and can decrease the oxide-semiconductor trap densities significantly according to conditions of a post annealing process (Quah; pages 2-3, Results and Discussion section). Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to use the yttrium oxide layer in the betavoltaic cell of Jia, Quah, and Mandal to reduce to oxide semiconductor interface trap density and obtain a betavoltaic cell that has less surface recombination velocity as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer, which would provide the benefit of increased carrier lifetimes and detection efficiency.
Regarding claim 8, Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1, wherein
Jia further teaches that the betavoltaic cell (SiC radiation detector; Fig. 1) further comprises a 4H-SiC buffer layer (u-SiC buffer; Fig. 1b; page 2, col. 1, para. 2).
Regarding claim 9, Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1, wherein
Jia further teaches that the betavoltaic cell (SiC radiation detector; Fig. 1) further comprises a depletion layer edge (page 2, col. 2, last paragraph: a depletion layer is formed, and therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would know that there would be a depletion layer edge).
Regarding claim 10, teaches a method for making a betavoltaic cell for power generation ((SiC radiation detector; Fig. 1; page 2, Section 2.1 Detector Fabrication) in harsh environment applications (4H-SiC substrate is a material that is suitable for extreme environments (page 1, col. 2, para. 1)) comprising:
forming at least one vertical metal-oxide-semiconductor (Fig. 1b: the SiC detector is a metal-oxide-semiconductor device) via:
growing at least one layer of oxide (SiO2 layer, Fig. 1b; page 2, Section 2.1 Detector Fabrication), on at least one n-type 4H-SiC epilayer (u-SiC epitaxial, Fig. 1b; page 2, Section 2.1 Detector Fabrication);
depositing at least first one nickel contact (Ni/Au, Fig. 1; page 2, Section 2.1 Detector Fabrication) on the at least one oxide layer (SiO2 layer, Fig. 1b) configured to act as a gate contact (Fig. 1b-c: the first contact acts as a gate contact as the device structure is identical to the one in the current application); and
depositing at least one second contact (Ti/Al/Ti, Fig. 1b; page 2, Section 2.1 Detector Fabrication) on the at least one n-type 4H-SiC epilayer (u-SiC epitaxial, Fig. 1b) to form a back contact (Ti/Al/Ti contact is on the back side of the device).
Jia, however, does not teach that
the oxide layer is an yttrium oxide layer deposited via pulse laser deposition; and
the second contact is a second nickel contact.
Quah, on the other hand, teaches a method for forming a gate oxide layer from yttrium oxide, instead of silicon dioxide, on an n-doped 4H-SiC (page 1, col. 1, para. 1), which is advantageous due to the relatively high k-value of yttrium oxide (k=14-18 compared to k=3.9 for silicon dioxide; page 1, col. 1, para. 1). Quah further teaches that yttrium oxide layer deposited by pulsed laser deposition would provide a very high breakdown voltage of about 6.5 MVcm-1 at 10-6 Acm-2, which is higher than other high-k gate oxides.
Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to modify the method of Jia the replace the silicon oxide layer with a yttrium oxide layer by growing at least one layer of yttrium oxide, via pulsed laser deposition, on at least one n-type 4H-SiC epilayer, as taught by Quah, to obtain a gate oxide layer with a high k-value (reduces leakage current) and a high breakdown voltage.
Quah, however, does not teach that
the second contact is a second nickel contact.
Mandal, on the other hand, teaches a radiation detection with 4H-SiC epitaxial layer devices (Fig. 1) for harsh environment application (Abstract), wherein
the second contact is a second nickel contact (Fig. 1: Ni contact at the backside (bottom) of the n-type Ni/4H-SiC Schottky barrier device).
A person of ordinary skill in the art before the effective filing date of the claimed invention would already know that using nickel as a contact material on the n-doped 4H-SiC is a known method for forming ohmic contacts on 4H-SiC, as also evidenced by Mandal (page 4, para. 1). Selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945) "Reading a list and selecting a known compound to meet known requirements is no more ingenious than selecting the last piece to put in the last opening in a jig-saw puzzle." 325 U.S. at 335, 65 USPQ at 301. See also In re Leshin, 227 F.2d 197, 125 USPQ 416 (CCPA 1960) (selection of a known plastic to make a container of a type made of plastics prior to the invention was held to be obvious). Furthermore, it should also be noted that substituting nickel as disclosed by Mandal for Ti/Al/Ti as disclosed by Jia in view of Quah as ohmic contact is a simple substitution of one known element for another to obtain predictable results (see MPEP2143). Thus, 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 Ji in view of Quah such that the second contact is formed from nickel, as disclosed by Mandal, instead of Ti/Al/Ti by
depositing at least one second nickel contact on the at least one n-type 4H-SiC epilayer to form a back contact.
Regarding claim 11, Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10, wherein
Jia further teaches that the method comprises
mounting the betavoltaic cell (SiC radiation detector; Fig. 1) on a printed circuit board (Fig. 1b; page 2, col. 1, last paragraph).
Regarding claim 12, while Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10,
Jia, Quah, and Mandel do not disclose that the method further comprises configuring betavoltaic cell to be heteroepitaxial.
Jia in views of Quah and Mandal, however, teaches that the n-type 4H-SiC epilayer is an epitaxial layer (u-SiC epitaxial, Fig. 1). A person of ordinary skill in the art would already be familiar with that the pulsed laser deposition can be used to deposit epitaxial yttrium oxide layers, as evidenced by Zhang (page 8, Conclusion; Zhang and Xiao, J. Appl. Phys. 83, 3842–3848 (1998), doi.org/10.1063/1.366615), and epitaxial growth leads to a better crystal structure with less defects. Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to modify the method of Jia in views of Quah and Mandal to grow the yttrium oxide layer (gate oxide layer) also epitaxially, which would lead to a single crystal structure with less defects and reduces leakage current.
Thus, the combination of Jia, Quah, and Mandal meets the limitation of claim 12 that the method further comprises configuring the betavoltaic cell to be heteroepitaxial (n-type SiC and yttrium oxide layers are epitaxial).
Regarding claim 14, while Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10,
Jia, Quah, and Mandel do not disclose that the method further comprises configuring the betavoltaic cell to have less surface recombination velocity as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer.
However, it is known in the field of SiC-based radiation detectors that the surface recombination velocity depends on the point defects and surface recombination due to surface traps in 4H-SiC, as evidenced by Ichikawa (page 2, col. 1, para. 1; Ichikawa et al, 2018, ECS J. Solid State Sci. Technol. 7 Q127, DOI 10.1149/2.0031808jss) and high quality oxide layers is applicable to suppress surface recombination (Ichikawa; page 2, col. 1, para. 1) for decreasing the surface recombination. Quah further teaches that yttrium dioxide can be such an oxide layer and can decrease the oxide-semiconductor trap densities significantly according to conditions of a post annealing process (Quah; pages 2-3, Results and Discussion section). Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to modify the method of Jia, Quah, and Mandel to use the yttrium oxide layer in the method of Jia, Quah, and Mandal to reduce to oxide semiconductor interface trap density, and thereby configuring the betavoltaic cell to have less surface recombination velocity as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer, which would provide the benefit of increased carrier lifetimes and detection efficiency.
Regarding claim 17, Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10, wherein
Jia further teaches that the method comprises configuring the betavoltaic cell (SiC radiation detector; Fig. 1) to include a 4H-SiC buffer layer (u-SiC buffer, Fig. 1b; page 2, Section 2.1 Detector Fabrication).
Regarding claim 18, Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10, wherein
Jia further teaches that the method comprises configuring the betavoltaic cell to include a depletion layer edge (page 2, col. 2, last paragraph: a depletion layer is formed, and therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would know that there would be a depletion layer edge).
Claims 4 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Jia in views of Quah and Mandal as applied to claims 1-3, 5, 8-12, 14, and 17-18 above, and further in view of Choi (Choi et al., Appl. Phys. Lett. 107, 252101 (2015), https://doi.org/10.1063/1.4938070).
Regarding claim 4, while Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1,
Jia, Quah, and Mandal do not disclose that the betavoltaic cell has reduced dark current as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer.
Choi, on the other hand, teaches an oxide film (Al2O3 film, Abstract) used as a thin spacer (analogous to the oxide layer of the current application and Jia in views of Quah and Mandal) between the Ni contact and the n-type 4H-SiC (page 2, col. 1, para. 2), which forms a device analogous to the betavoltaic cell of the current application (page 2, col. 1, para. 1-2. Choi further discloses that the inclusion of the oxide spacer introduces an energy barrier or increases the energy barrier between the contact and 4H-SiC layer which would reduce the dark current (Fig. 4, page 5, col. 1, last paragraph).
Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to construct the betavoltaic cell of Jia in view of Quah and Mandel such that the dark current is dominated by the energy barrier between the n-type 4H-SiC layer and Ni contact as disclosed by Choi, so that the betavoltaic cell has reduced dark current as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer, which will provide the benefit of reducing the noise in the betavoltaic cell.
Furthermore, given that the Schottky barrier diode fabricated on at least one 4H-SiC epilayer is identical to the betavoltaic cell except the inclusion of the oxide layer, the reduction of the dark current, compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer, in the betavoltaic device of Jia in views of Quah and Mandel is an inherent feature of the structural and material composition of the betavoltaic cell (see MPEP 2112).
Thus, the combination of Jia, Quah, and Mandel meets all the limitations of claim 4
Regarding claim 13, while Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10,
Jia, Quah, and Mandel do not disclose that the method further comprises configuring the betavoltaic cell to have reduced dark current as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer.
Choi, on the other hand, teaches an oxide film (Al2O3 film, Abstract) used as a thin spacer (analogous to the oxide layer of the current application and Jia in views of Quah and Mandal) between the Ni contact and the n-type 4H-SiC (page 2, col. 1, para. 2), which forms a device analogous to the betavoltaic cell of the current application (page 2, col. 1, para. 1-2. Choi further discloses that the inclusion of the oxide spacer introduces an energy barrier or increases the energy barrier between the contact and 4H-SiC layer which would reduce the dark current (Fig. 4, page 5, col. 1, last paragraph).
Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to modify the method of Jae in views of Quah and Mandal to construct the betavoltaic cell such that the dark current is dominated by the energy barrier between the n-type 4H-SiC layer and Ni contact as disclosed by Choi, so that the method further comprises configuring the betavoltaic cell to have reduced dark current as compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer, which will provide the benefit of reducing the noise in the betavoltaic cell.
Furthermore, given that the Schottky barrier diode fabricated on at least one 4H-SiC epilayer is identical to the betavoltaic cell except the inclusion of the oxide layer, the reduction of the dark current, compared to a Schottky barrier diode fabricated on at least one 4H-SiC epilayer, in the betavoltaic device of Jia in views of Quah and Mandel is an inherent feature of the structural and material composition of the betavoltaic cell (see MPEP 2112).
Thus, the combination of Jia, Quah, and Mandel meets all the limitations of claim 13.
Claims 6 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Jia in views of Quah and Mandal as applied to claims 1-3, 5, 8-12, 14, and 17-18 above, and further in view of Thomas (Thomas et al., Appl. Phys. Lett. 108, 013505 (2016), doi.org/10.1063/1.4939203).
Regarding claim 6, while Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1,
Jia, Quah, and Mandal do not teach that the betavoltaic cell has at least a maximum power density output of 11 nW/cm3.
Thomas, on the other hand, teaches that the betavoltaic power sources find potential utilization in systems, which require power in the range of 0.01–100 µW, and are space constrained (less than 1 cm3) (page 2, col. 1, para. 1), which makes at least a maximum power density of 10nW/cm3.
Therefore, the range of maximum power density output provided by the prior art overlaps with the range of maximum power density output provided in the claimed invention, and a prima facie case of obviousness exists (see MPEP 2144.05(I)), as the range of maximum power density output can be optimized by design and routine experimentation to adapt the betavoltaic cell to specific practical applications (see MPEP 2144.05(II)). Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to configure the betavoltaic cell of Jia, Quah, and Mandal in such a way that the betavoltaic cell has at least a maximum power density output of 11 nW/cm3, which would increase the potential applications of the betavoltaic cell.
Regarding claim 15, while Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10,
Jia, Quah, and Mandel do not disclose that the method further comprises configuring the betavoltaic cell to have at least a maximum power density output of 11 nW/cm3.
Thomas, on the other hand, teaches that the betavoltaic power sources find potential utilization in systems, which require power in the range of 0.01–100 µW, and are space constrained (less than 1 cm3) (page 2, col. 1, para. 1), which makes at least a maximum power density of 10nW/cm3.
Therefore, the range of maximum power density output provided by the prior art overlaps with the range of maximum power density output provided in the claimed invention, and a prima facie case of obviousness exists (see MPEP 2144.05(I)), as the range of maximum power density output can be optimized by design and routine experimentation to adapt the betavoltaic cell to specific practical applications (see MPEP 2144.05(II)). Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would be motivated to modify the method of Jia, Quah, and Mandal to configure the betavoltaic cell to have at least a maximum power density output of 11 nW/cm3, which would increase the potential applications of the betavoltaic cell.
Claims 7 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Jia in views of Quah and Mandal as applied to claims 1-3, 5, 8-12, 14, and 17-18 above, and further in view of Chandrashekar (Chandrashekar et al, Appl. Phys. Lett. 88, 033506 (2006), doi.org/10.1063/1.2166699).
Regarding claim 7, while Jia in views of Quah and Mandal teaches the betavoltaic cell of claim 1,
Jia, Quah, and Mandal do not disclose that the betavoltaic cell has at least a fill factor of 66% when exposed to a 2.5 mCi 63Ni beta particle emitter.
Chandrashekar, on the other hand, teaches a 4H-SiC betavoltaic cell (Abstract) wherein the betavoltaic cell has at least a fill factor of 51% (Fig. 2 and Table I) when exposed to a 1mCi 63Ni beta particle emitter (page 3, col. 1, para. 1).
Chandrashekar further discloses that numerical modeling of the betavoltaic cell shows that the betavoltaic cell is capable of providing a fill factor of 68% for the same exposure (Table I). Furthermore, a person of ordinary skill in the art before the effective filing date of the claimed invention would know that the device geometry and size would further affect the fill factor. In addition, the incorporation of the oxide layer in the betavoltaic cell of Jia, Quah, and Mandal would further provide the benefit of reducing the surface recombination at the SiC-oxide interface, as evidenced by Ichikawa (page 2, col. 1, para. 1; Ichikawa et al, 2018, ECS J. Solid State Sci. Technol. 7 Q127, DOI 10.1149/2.0031808jss), which would increase the fill factor. Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would realize that the betavoltaic cell of Jia, Quah, and Mandel would be able to provide a fill factor of at least 66% when exposed to a 2.5 mCi 63Ni beta particle emitter, and would be motivated to the design the betavoltaic cell such that the betavoltaic cell has at least a fill factor of 66% when exposed to a 2.5 mCi 63Ni beta particle emitter.
Regarding claim 16, while Jia in views of Quah and Mandal teaches the method for making a betavoltaic cell of claim 10,
Jia, Quah, and Mandel do not disclose that the method further comprises configuring the betavoltaic cell has at least a fill factor of 66% when exposed to a 2.5 mCi 63Ni beta particle emitter.
Chandrashekar, on the other hand, teaches a 4H-SiC betavoltaic cell (Abstract) wherein the betavoltaic cell has at least a fill factor of 51% (Fig. 2 and Table I) when exposed to a 1mCi 63Ni beta particle emitter (page 3, col. 1, para. 1).
Chandrashekar further discloses that numerical modeling of the betavoltaic cell shows that the betavoltaic cell is capable of providing a fill factor of 68% for the same exposure (Table I). Furthermore, a person of ordinary skill in the art before the effective filing date of the claimed invention would know that the device geometry and size would further affect the fill factor. In addition, the incorporation of the oxide layer in the betavoltaic cell of Jia, Quah, and Mandal would further provide the benefit of reducing the surface recombination at the SiC-oxide interface, as evidenced by Ichikawa (page 2, col. 1, para. 1; Ichikawa et al, 2018, ECS J. Solid State Sci. Technol. 7 Q127, DOI 10.1149/2.0031808jss), which would increase the fill factor. Therefore, a person of ordinary skill in the art before the effective filing date of the claimed invention would realize that the betavoltaic cell of Jia in views of Quah and Mandel would be able to provide a fill factor of at least 66% when exposed to a 2.5 mCi 63Ni beta particle emitter, and would be motivated to modify the method of Jia in views of Quah, and Mandel to configure the betavoltaic cell to have at least a fill factor of 66% when exposed to a 2.5 mCi 63Ni beta particle emitter.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Kil (Kil et al., "Impacts of Al2O3/SiO2 Interface Dipole Layer Formation on the Electrical Characteristics of 4H-SiC MOSFET," in IEEE Electron Device Letters, vol. 43, no. 1, pp. 92-95, Jan. 2022, doi: 10.1109/LED.2021.3125945) teaches the impacts of oxide layers in electrical characteristics of 4H-SiC, which is relevant to all claims.
Zhou (Zhou et al, 2021 ECS J. Solid State Sci. Technol. 10 027005, DOI 10.1149/2162-8777/abe423) reviews betavoltaic cells, which is relevant to all claims.
Siddiqui (Siddiqui et al, J. Mater. Chem. C, 2021,9, 5055-5081) teaches the effect of high-k dielectrics on the electrical properties of 4H-SiC-oxide interface, which is relevant to all claims.
Guo (Guo et al, "Fabrication of SiC p-i-n betavoltaic cell with 63Ni irradiation source," 2011 IEEE International Conference of Electron Devices and Solid-State Circuits, Tianjin, China, 2011, pp. 1-2, doi: 10.1109/EDSSC.2011.6117636) teaches A SiC-based betavoltaic cell with optimized fill factor, which is relevant to claims 7 and 16.
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/ILKER NMN OZDEN/Examiner, Art Unit 2812
/William B Partridge/Supervisory Patent Examiner, Art Unit 2812