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 Objections
Claim 13, 26 objected to because of the following informalities:
See the advisory action filed 1/23/2026, the Examiner noted that claim 13 was modified by removing the period at the end of the claim, however the ending period is required . Appropriate correction is required.
Claim 26 line 16 needs a semicolon after “second intrinsic GaAs layer”.
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.
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.
Claim(s) 1, 3, 6, 8, 11-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nabet et al. (US 7705415 B1) hereafter referred to as Nabet in view of Dowd et al. (US 20210399153 A1) hereafter referred to as Dowd
In regard to claim 1 Nabet teaches a [see “Having established the utility of the 2DEG and the 2DHG in collection of, respectively, electrons and holes, a photodetector device structure is shown in FIG. 9, which combines both clouds”] photodetector comprising:
a GaAs substrate [see Fig. 9a GaAs substrate];
a GaAs buffer layer [The Examiner notes that the claim does not state a way to differentiate GaAs substrate from GaAs buffer , thus the buffer is the top portion of the substrate, under broadest reasonable interpretation] on top of the substrate;
a plurality of XxGaAsYy layers on top of the buffer layer, wherein Xx and Yy is one of nothing, Al and In , the plurality of XxGaAsYy layers comprising, from bottom to top:
an AlxGa1-xAs layer [see Fig. 9a above the GaAs substrate is AlGaAs layer, part of 20 period Bragg reflector including a layer of P doped AlGaAs];
a P doped AlGaAs [see the part of 20 period Bragg reflector including a layer of P doped AlGaAs]
a first AlxGa1-xAs [see the uppermost P doped AlGaAs in the 20 period Bragg reflector] spacer layer;
an quantum well [see Fig. 9a a quantum well is formed which contains the 2DHG in the undoped GaAs layer adjacent the junction of the GaAs with the P doped AlGaAs, see “A 2DHG is formed in GaAs by p-type doping of the widegap AlGaAs”] two-dimensional hole gas (2DHG) channel;
an intrinsic GaAs layer [see Fig. 9a the undoped GaAs];
a second AlxGa1-xAs [see Fig. 9a there is shown an AlGaAs above the undoped GaAs see and compare to Fig. 5a this is “AlGaAs spacer layer 31”, see that it causes a 2DEG in the undoped GaAs, thus it is supplying electrons see “Similar to a high electron mobility transistor (HEMT), n-type doping of an AlGaAs/GaAs heterostructure produces a 2DEG at the heterointerface on the narrow gap side”] spacer layer;
an AlxGa1-xAs [see Fig. 9a there is shown an AlGaAs above the undoped GaAs and above that is another AlGaAs layer see and compare to Fig. 5a this is “AlGaAs material 30”] barrier layer.
but does not state in Fig. 9a:
that the quantum well is InxGa1-xAs quantum well;
that the P doped AlGaAs is a carbon p+ [see that p+ is a relative term, not an actual concentration] Delta doping layer;
that the intrinsic GaAs layer comprises an etch stop layer; and a first intrinsic GaAs layer; a dilute nitride absorption layer; a second intrinsic GaAs layer;
that the second AlxGa1-xAs layer comprises a silicon n+ [see that n+ is a relative term, not an actual concentration] delta doping layer.
See Dowd teaches optical absorption, see paragraph 0077 “absorber layer 412 can include materials such as GaAs, InGaAs or a dilute nitride material such as GaInNAs, GaInNAsSb, GaNAsSb, or GaInNAsBi. The absorber layer 412 is lattice-matched or pseudomorphically-strained to the second lattice constant” “Examples of dilute nitride materials and structures suitable for solar cells are disclosed in U.S. 2010/0319764, U.S. Pat. Nos. 8,912,433, 8,962,993, 9,214,580, U.S. 2017/0110613, and U.S. 2017/0213922, the disclosure of each of which is incorporated by reference herein. Dilute nitride sub-cells having graded doping profiles are disclosed in U.S. Pat. No. 9,214,580, U.S. 2016/0118526, and U.S. 2017/0338357, the disclosure of each of which is incorporated herein by reference. These dilute nitride base layers may include intentionally-doped region(s) with thicknesses between 0.4 microns and 3.5 microns, and with p-type doping levels between 1×10.sup.15 cm.sup.−3 and 1×10.sup.19 cm.sup.−3, and further contain an intrinsic (or unintentionally doped) diluted nitride layer or an intentionally doped dilute nitride layer with a constant dopant concentration, having a thickness from 0.1 microns and about 1 micron. The subcell is shown as a single layer. However, it will be understood that subcell 608 comprises multiple layers, including back surface field, base, emitter, front-surface filed and window layers. A subcell 610 including GaAs, InGaAs or InAlGaAs is then formed overlying dilute nitride subcell 608”, see etch stop layers “In the embodiment 700, an etch stop layer 704 is formed on GaAs substrate 702” “In one example, the contact layer is a GaAs or InGaAs layer and is directly adjacent to etch stop layer 704. The high etch selectivity between the contact layer and the etch stop layer permits the substrate and etch stop layer to be removed by a sequence of mechanical lapping and/or chemical etch steps after the epitaxial growth of all layers has been completed”, see dopants paragraph 0096 “with the first layer 808A having a high n-type doping level, and the second layer 308A having a high p-type doping level. Typical compositions, thicknesses and doping levels required to form tunnel junctions are known in the art. For example, n-dopants can include Si, Se, and Te and n-type doping levels can range from 1×10.sup.19 cm.sup.−3 to 2×10.sup.20 cm.sup.−3. P-type dopants can include Be and C, and doping levels greater than about 1×10.sup.19 cm.sup.−3 and up to 2×10.sup.20 cm.sup.−3 can be used. Thicknesses for the doped layers in tunnel junctions can be between about 5 nm and 40 nm” , see the use of InGaAs, see paragraph 0077 “absorber layer 412 can include materials such as GaAs, InGaAs or a dilute nitride material such as GaInNAs, GaInNAsSb, GaNAsSb, or GaInNAsBi. The absorber layer 412 is lattice-matched or pseudomorphically-strained to the second lattice constant. Absorber layer 412 is configured to absorb light at wavelengths shorter than about 2 microns. For example, the absorber layer 412 can comprise Ga.sub.1-xIn.sub.xN.sub.yAs.sub.1-y-zSb.sub.z, where x, y and z can be 0≤x<0.4, 0<y≤0.10 and 0<z≤0.20, respectively. X, y and z values can be defined as 0.01≤x≤0.4, 0.02≤y≤0.10 and 0.001≤z≤0.20, respectively”.
See in Nabet the opening on the left side is deeper than the opening on the right, so as to make electrical connection to the 2DHG and the 2DEG, and a person having ordinary skill in the art knows that an etch stop allows stopping at specific layers during etching, see that such dopant layers of Si and C can provide the electrons and holes needed for the 2DHG and 2DEG of Nabet.
Thus, it 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 to modify Nabet to include that the quantum well is InxGa1-xAs quantum well; that the P doped AlGaAs is a carbon p+ Delta doping layer; that the intrinsic GaAs layer comprises an etch stop layer; and a first intrinsic GaAs layer; a dilute nitride absorption layer; a second intrinsic GaAs layer; that the second AlxGa1-xAs layer comprises a silicon n+ delta doping layer.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that heavily doped thin layers of Si and C can provide the electrons and holes needed for the 2DHG and 2DEG of Nabet, that the 2DEG and 2DHG can be controlled by adding In to adjust band gap of GaAs, that multilayer absorption layer including dilute nitride embedded in the intrinsic GaAs of Nabet gives good results for absorption of light and for ease of manufacture using etch stop to perform etching to contact the 2DHG and the 2DEG in order to make the trench connections of the device as taught by Nabet.
In regard to claim 3 Nabet and Dowd as combined teaches [see combination Dowd see paragraph 0077 “absorber layer 412 can include materials such as GaAs, InGaAs or a dilute nitride material such as GaInNAs, GaInNAsSb, GaNAsSb, or GaInNAsBi. The absorber layer 412 is lattice-matched or pseudomorphically-strained to the second lattice constant”] whereinthe dilute nitride layer comprises InGaAsN.
In regard to claim 6 Nabet and Dowd as combined teaches [see combination Dowd see paragraph 0077 “absorber layer 412 can include materials such as GaAs, InGaAs or a dilute nitride material such as GaInNAs, GaInNAsSb, GaNAsSb, or GaInNAsBi. The absorber layer 412 is lattice-matched or pseudomorphically-strained to the second lattice constant” see that In.2Ga.8As is the lattice-matched composition] wherein the InxGa1-xAs comprises In.2Ga.8As.
In regard to claim 8 Nabet and Dowd as combined teaches [see combination Dowd see that In is added to control band gap] wherein Xx is Indium (In).
In regard to claim 11 Nabet and Dowd as combined teaches wherein a 2D hole gas (2DHG) heterojunction is formed [see Nabet Fig. 9a see combination dilute nitride layer is in absorber GaAs i.e. 2DHG is below and 2DEG is above] below the dilute nitride layer.
In regard to claim 12 Nabet and Dowd as combined teaches wherein a 2D electron gas (2DEG) heterojunction is formed [see Nabet Fig. 9a see combination dilute nitride layer is in absorber GaAs i.e. 2DHG is below and 2DEG is above] above the dilute nitride layer.
In regard to claim 13 Nabet and Dowd as combined teaches wherein an absorption layer is formed [see Nabet Fig. 9a see combination dilute nitride layer is in absorber GaAs i.e. 2DHG is below and 2DEG is above] between the 2DHG and 2DEG heterojunctions.
In regard to claim 14 Nabet and Dowd as combined teaches wherein an internal electric field is formed in the dilute nitride layer, the internal electric field forcing [see Nabet “FIG. 9a shows a diagram of an embodiment of a device containing both 2DHG and 2DEG for fast collection of optically generated carriers” “Having established the utility of the 2DEG and the 2DHG in collection of, respectively, electrons and holes, a photodetector device structure is shown in FIG. 9, which combines both clouds. Two heterojunctions are formed and doped such that 2DEG and 2DHG are both present in the absorption region. The thickness of this region is typically chosen as a resonant cavity for the wavelength of interest. An electric field is established in the GaAs absorption region due to doping of the widegaps that separates the electrons and holes. They travel in opposite direction the short distance of the absorption region and once they reach their respective reservoir of carriers, they can be considered collected”] optically generated electron hole pairs towards the 2DEG and 2DHG heterojunctions, before the 2DEG and 2DHG heterojunctions recombine and disappear.
Claim(s) 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nabet et al. (US 7705415 B1) hereafter referred to as Nabet in view of Dowd et al. (US 20210399153 A1) hereafter referred to as Dowd
In regard to claim 26 Nabet teaches a [see “Having established the utility of the 2DEG and the 2DHG in collection of, respectively, electrons and holes, a photodetector device structure is shown in FIG. 9, which combines both clouds”] photodetector comprising:
from bottom to top:
a GaAs substrate [see Fig. 9a GaAs substrate];
a GaAs buffer layer [The Examiner notes that the claim does not state a way to differentiate GaAs substrate from GaAs buffer , thus the buffer is the top portion of the substrate, under broadest reasonable interpretation] on top of the substrate;
an AlxGa1-xAs layer [see Fig. 9a above the GaAs substrate is AlGaAs layer, part of 20 period Bragg reflector including a layer of P doped AlGaAs];
a P doped AlGaAs [see the part of 20 period Bragg reflector including a layer of P doped AlGaAs]
a first AlxGa1-xAs [see the uppermost P doped AlGaAs in the 20 period Bragg reflector] spacer layer;
an quantum well [see Fig. 9a a quantum well is formed which contains the 2DHG in the undoped GaAs layer adjacent the junction of the GaAs with the P doped AlGaAs, see “A 2DHG is formed in GaAs by p-type doping of the widegap AlGaAs”] two-dimensional hole gas (2DHG) channel;
a lower Schottky [see Fig. 9a see the Schottky on the left] contact;
an intrinsic GaAs layer [see Fig. 9a the undoped GaAs];
a second AlxGa1-xAs [see Fig. 9a there is shown an AlGaAs above the undoped GaAs see and compare to Fig. 5a this is “AlGaAs spacer layer 31”, see that it causes a 2DEG in the undoped GaAs, thus it is supplying electrons see “Similar to a high electron mobility transistor (HEMT), n-type doping of an AlGaAs/GaAs heterostructure produces a 2DEG at the heterointerface on the narrow gap side”] spacer layer;
an AlxGa1-xAs [see Fig. 9a there is shown an AlGaAs above the undoped GaAs and above that is another AlGaAs layer see and compare to Fig. 5a this is “AlGaAs material 30”] barrier layer;
an upper Schottky [see Fig. 9a see the Schottky on the right] contact,
but does not state in Fig. 9a:
that the quantum well is InxGa1-xAs quantum well;
that the P doped AlGaAs is a carbon p+ [see that p+ is a relative term, not an actual concentration] Delta doping layer;
that the intrinsic GaAs layer comprises an etch stop layer; and a first intrinsic GaAs layer; a dilute nitride layer; a second intrinsic GaAs layer;
that the second AlxGa1-xAs layer comprises a silicon n+ [see that n+ is a relative term, not an actual concentration] delta doping layer.
See Dowd teaches optical absorption, see paragraph 0077 “absorber layer 412 can include materials such as GaAs, InGaAs or a dilute nitride material such as GaInNAs, GaInNAsSb, GaNAsSb, or GaInNAsBi. The absorber layer 412 is lattice-matched or pseudomorphically-strained to the second lattice constant” “Examples of dilute nitride materials and structures suitable for solar cells are disclosed in U.S. 2010/0319764, U.S. Pat. Nos. 8,912,433, 8,962,993, 9,214,580, U.S. 2017/0110613, and U.S. 2017/0213922, the disclosure of each of which is incorporated by reference herein. Dilute nitride sub-cells having graded doping profiles are disclosed in U.S. Pat. No. 9,214,580, U.S. 2016/0118526, and U.S. 2017/0338357, the disclosure of each of which is incorporated herein by reference. These dilute nitride base layers may include intentionally-doped region(s) with thicknesses between 0.4 microns and 3.5 microns, and with p-type doping levels between 1×10.sup.15 cm.sup.−3 and 1×10.sup.19 cm.sup.−3, and further contain an intrinsic (or unintentionally doped) diluted nitride layer or an intentionally doped dilute nitride layer with a constant dopant concentration, having a thickness from 0.1 microns and about 1 micron. The subcell is shown as a single layer. However, it will be understood that subcell 608 comprises multiple layers, including back surface field, base, emitter, front-surface filed and window layers. A subcell 610 including GaAs, InGaAs or InAlGaAs is then formed overlying dilute nitride subcell 608”, see etch stop layers “In the embodiment 700, an etch stop layer 704 is formed on GaAs substrate 702” “In one example, the contact layer is a GaAs or InGaAs layer and is directly adjacent to etch stop layer 704. The high etch selectivity between the contact layer and the etch stop layer permits the substrate and etch stop layer to be removed by a sequence of mechanical lapping and/or chemical etch steps after the epitaxial growth of all layers has been completed”, see dopants paragraph 0096 “with the first layer 808A having a high n-type doping level, and the second layer 308A having a high p-type doping level. Typical compositions, thicknesses and doping levels required to form tunnel junctions are known in the art. For example, n-dopants can include Si, Se, and Te and n-type doping levels can range from 1×10.sup.19 cm.sup.−3 to 2×10.sup.20 cm.sup.−3. P-type dopants can include Be and C, and doping levels greater than about 1×10.sup.19 cm.sup.−3 and up to 2×10.sup.20 cm.sup.−3 can be used. Thicknesses for the doped layers in tunnel junctions can be between about 5 nm and 40 nm”, see the use of InGaAs, see paragraph 0077 “absorber layer 412 can include materials such as GaAs, InGaAs or a dilute nitride material such as GaInNAs, GaInNAsSb, GaNAsSb, or GaInNAsBi. The absorber layer 412 is lattice-matched or pseudomorphically-strained to the second lattice constant. Absorber layer 412 is configured to absorb light at wavelengths shorter than about 2 microns. For example, the absorber layer 412 can comprise Ga.sub.1-xIn.sub.xN.sub.yAs.sub.1-y-zSb.sub.z, where x, y and z can be 0≤x<0.4, 0<y≤0.10 and 0<z≤0.20, respectively. X, y and z values can be defined as 0.01≤x≤0.4, 0.02≤y≤0.10 and 0.001≤z≤0.20, respectively”.
See in Nabet the opening on the left side is deeper than the opening on the right, so as to make electrical connection to the 2DHG and the 2DEG, and a person having ordinary skill in the art knows that an etch stop allows stopping at specific layers during etching, see that such dopant layers of Si and C can provide the electrons and holes needed for the 2DHG and 2DEG of Nabet.
Thus, it 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 to modify Nabet to include that the quantum well is InxGa1-xAs quantum well; that the P doped AlGaAs is a carbon p+ Delta doping layer; that the intrinsic GaAs layer comprises an etch stop layer; and a first intrinsic GaAs layer; a dilute nitride layer; a second intrinsic GaAs layer; that the second AlxGa1-xAs layer comprises a silicon n+ delta doping layer.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that heavily doped thin layers of Si and C can provide the electrons and holes needed for the 2DHG and 2DEG of Nabet, that the 2DEG and 2DHG can be controlled by adding In to adjust band gap of GaAs, that multilayer absorption layer including dilute nitride embedded in the intrinsic GaAs of Nabet gives good results for absorption of light and for ease of manufacture using etch stop to perform etching to contact the 2DHG and the 2DEG in order to make the trench connections of the device as taught by Nabet.
Response to Arguments
Applicant's arguments filed 1/19/2026 have been fully considered but they are not persuasive.
On page 1, 2 the Applicant argues that the claim amendments are not shown by the prior art.
The Examiner responds that see the amended rejection using Nabet as primary reference, the modifications to Nabet have good motivation for combination, thus the amended rejection is proper.
Conclusion
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/SITARAMARAO S YECHURI/ Primary Examiner, Art Unit 2893