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 § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-3, 5-6, 8, 11-13, 15-16, 18 and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by WO 2020/013923 A1 to Chan (hereinafter “Chan” – using related US 2021/0249552 A1 for citation).
Regarding claim 1, Chan discloses a Geiger mode avalanche photodiode comprising:
a first semiconductor alloy forming a compositionally graded gain region configured to form a conduction band having free electrons (avalanche photodiode capable of being a Geiger-mode device and having superlattice multiplication region comprising an alloy A1 with a variable x1 composition, which produces a graded gain region, and a conduction band having free electrons, where alloy may be InP/InAlGaAs; Fig. 1; paragraphs [0124], [0128]-[0134], [0146]), a valence band having free holes (alloy A1 having valence band with free holes; Fig. 1; paragraphs [0098], [0124]), and a bandgap between the valence band and the conduction band that varies in size across the graded gain region (bandgap of superlattice multiplication region periodically varies in size thereacross in a sawtooth manner; Fig. 1);
a second semiconductor alloy forming an absorber region (InGaAs absorption layer; Fig. 1; paragraph [0121]); and
a semiconductor substrate (InP semiconductor substrate; Fig. 1; paragraph [0121]).
Regarding claim 2, Chan discloses the Geiger mode avalanche photodiode as recited in claim 1, wherein the bandgap periodically varies in size across the graded gain region (bandgap of superlattice multiplication region periodically varies in size thereacross in a sawtooth manner; Fig. 1).
Regarding claim 3, Chan discloses the Geiger mode avalanche photodiode as recited in claim 1, wherein the bandgap decreases in size from one end of the graded gain region to another end of the graded gain region (bandgap of superlattice multiplication region periodically varies in size thereacross in a sawtooth manner such that bandgap in part at one end is larger than bandgap in part at other end; Fig. 1).
Regarding claim 5, Chan discloses the Geiger mode avalanche photodiode as recited in claim 1, wherein the first semiconductor alloy and second semiconductor alloy are positioned in accordance with one of 1) the second semiconductor alloy being positioned between the first semiconductor alloy and the semiconductor substrate or 2) the first semiconductor alloy being positioned between the second semiconductor alloy and the semiconductor substrate (absorption layer disposed between substrate and superlattice multiplication region; Fig. 1).
Regarding claim 6, Chan discloses the Geiger mode avalanche photodiode as recited in claim 1, wherein the first semiconductor alloy is composed of two or more lattice-matched semiconductor alloys (alloy may be lattice-matched InP/InAlGaAs; Fig. 1; paragraph [0123]).
Regarding claim 8, Chan discloses the Geiger mode avalanche photodiode as recited in claim 1, wherein the first semiconductor alloy and second semiconductor alloy are lattice matched to the semiconductor substrate (superlattice multiplication region and absorption layer are lattice-matched to substrate; paragraph [0121]).
Regarding claim 11, Chan discloses a method comprising:
creating a Geiger mode avalanche photodiode (avalanche photodiode capable of being a Geiger-mode device; Fig. 1; paragraphs [0124], [0128]-[0134], [0146]) by:
forming a semiconductor substrate (forming InP semiconductor substrate; Fig. 1; paragraph [0121]);
forming a first semiconductor alloy to include a compositionally graded gain region configured to form a conduction band having free electrons (APD having superlattice multiplication region comprising an alloy A1 with a variable x1 composition, which produces a graded gain region, and a conduction band having free electrons, where alloy may be InP/InAlGaAs; Fig. 1; paragraphs [0124], [0128]-[0134], [0146]), a valence band having free holes (alloy A1 having valence band with free holes; Fig. 1; paragraphs [0098], [0124]), and a bandgap between the valence band and the conduction band that varies in size across the graded gain region (bandgap of superlattice multiplication region periodically varies in size thereacross in a sawtooth manner; Fig. 1); and
forming a second semiconductor alloy to include an absorber region (InGaAs absorption layer; Fig. 1; paragraph [0121]).
Regarding claim 12, Chan discloses the method as recited in claim 11, wherein forming the first semiconductor alloy comprising forming the bandgap to periodically vary in size across the graded gain region (bandgap of superlattice multiplication region periodically varies in size thereacross in a sawtooth manner; Fig. 1).
Regarding claim 13, Chan discloses the method as recited in claim 11, wherein forming the first semiconductor alloy comprising forming the bandgap to decrease in size from one end of the graded gain region to another end of the graded gain region (bandgap of superlattice multiplication region periodically varies in size thereacross in a sawtooth manner such that bandgap in part at one end is larger than bandgap in part at other end; Fig. 1).
Regarding claim 15, Chan discloses the method as recited in claim 11, wherein forming the first semiconductor alloy and forming the second semiconductor alloy comprising one of 1) forming the second semiconductor alloy to be positioned between the first semiconductor alloy and the semiconductor substrate, or 2) forming the first semiconductor alloy to be positioned between the second semiconductor alloy and the semiconductor substrate (absorption layer disposed between substrate and superlattice multiplication region; Fig. 1).
Regarding claim 16, Chan discloses the method as recited in claim 11, wherein forming the first semiconductor alloy comprising forming the first semiconductor alloy of two or more lattice-matched semiconductor alloys (alloy may be lattice-matched InP/InAlGaAs; Fig. 1; paragraph [0123]).
Regarding claim 18, Chan discloses the method as recited in claim 11, wherein forming the first semiconductor alloy comprising forming the first semiconductor alloy and second semiconductor alloy as lattice matched to the semiconductor substrate (superlattice multiplication region and absorption layer are lattice-matched to substrate; paragraph [0121]).
Regarding claim 20, Chan discloses a photon detection method, comprising: receiving, by the Geiger mode avalanche photodiode recited in claim 1, a photon incident to the second semiconductor alloy; generating, by the first semiconductor alloy, a gain by amplifying a current, produced by the photon, across the compositionally graded gain region; and outputting, by the avalanche photodiode, an electrical signal based on the gain (photon incident to absorption layer which generates a corresponding electrical gain in multiplication region and outputting a signal based upon the generated current as shown in Fig. 1; paragraphs [0082], [0151]).
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 4, 7, 9-10, 14, 17 and 19 are rejected under 35 U.S.C. 103 as being obvious over Chan in view of US 4,383,269 A to Capasso (hereinafter “Capasso”).
Regarding claims 4 and 14, Chan discloses the Geiger mode avalanche photodiode and method as recited in claims 1 and 11. Chan fails to disclose wherein the bandgap is configured to generate a quasi-field having a different sign for the free electrons than the free holes.
However, Capasso discloses wherein the bandgap is configured to generate a quasi-field having a different sign for the free electrons than the free holes (APD that creates quasi-electric field where initiating carrier moves toward decreasing bandgap energy and the other toward increasing it; abstract; Fig. 1; column 2, line 50 to column 3, line 23).
Chan and Capasso are both considered to be analogous to the claimed invention because they are in the same field of avalanche photodiodes. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Chan to incorporate the teaching of Capasso in order to potentially provide a split of the effective field seen by the two carriers, lower excess noise, higher avalanche probability at a given bias, and reduced required field to generate gain.
Regarding claims 7 and 17, Chan discloses the Geiger mode avalanche photodiode and method as recited in claims 1 and 11. Chan fails to disclose wherein the avalanche photodiode has a mesa structure.
However, Capasso discloses wherein the avalanche photodiode has a mesa structure (APD 40 having graded bandgap region and mesa structure with tapered sidewalls; Fig. 4; column 4, lines 27-61).
Chan and Capasso are both considered to be analogous to the claimed invention because they are in the same field of avalanche photodiodes. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Chan to incorporate the teaching of Capasso in order to potentially provide junction isolation without a deep diffusion and lower capacitance to improve bandwidth and timing.
Regarding claim 9, Chan discloses the Geiger mode avalanche photodiode as recited in claim 1. Chan fails to disclose wherein each of the first semiconductor alloy and the second semiconductor alloy have tapered sidewalls to produce a mesa structure.
However, Capasso discloses wherein each of the first semiconductor alloy and the second semiconductor alloy have tapered sidewalls to produce a mesa structure (APD 40 having semiconductor alloy regions 42-44 in a tapered mesa structure; Fig. 4; column 4, lines 27-61).
Chan and Capasso are both considered to be analogous to the claimed invention because they are in the same field of avalanche photodiodes. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Chan to incorporate the teaching of Capasso in order to potentially provide junction isolation without a deep diffusion and lower capacitance to improve bandwidth and timing.
Regarding claims 10 and 19, Chan discloses the Geiger mode avalanche photodiode and method as recited in claims 1 and 11. Chan fails to disclose wherein the first semiconductor alloy includes: one or more enhancement regions; and one or more retrace regions, wherein the one or more enhancement regions and the one or more retrace regions are configured to be cascaded with respect to each other in the first semiconductor alloy.
However, Capasso discloses wherein the first semiconductor alloy includes: one or more enhancement regions; and one or more retrace regions, wherein the one or more enhancement regions and the one or more retrace regions are configured to be cascaded with respect to each other in the first semiconductor alloy (region 62 having plurality of cascaded zones 62a-62c, where each zone comprises a graded bandgap with variable composition along their lengths; Fig. 5; column 5, line 16 through column 6, line 34).
Chan and Capasso are both considered to be analogous to the claimed invention because they are in the same field of avalanche photodiodes. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Chan to incorporate the teaching of Capasso in order to potentially provide longer high-field path, larger unipolar gain without increasing the field, and the ability for lattice-matching while reducing band-to-band tunneling.
Conclusion
The following prior art made of record and not relied upon is considered pertinent to applicant's disclosure: US 2022/0099813 A1 to Gates et al., US 2016/0372623 A1 to Bank et al., and US 2009/0101919 A1 to Yao each discloses avalanche photodiodes with graded gain regions having related structures and relative structural orientations.
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/IAN DEGRASSE/Examiner, Art Unit 2818
/JEFF W NATALINI/Supervisory Patent Examiner, Art Unit 2818
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