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 .
Allowable Subject Matter
Claims 192-196,199-201, 208-211 allowed.
The following is a statement of reasons for the indication of allowable subject matter:
See previously indicated allowable subject matter, see Applicant arguments filed 8/27/2025.
Claim Objections
Claims 191, 202 objected to because of the following informalities:
Claims 191, 202 appear to be the same. Appropriate correction is required.
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) 190, 191, 202-207 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stange et al. (see PTO-892 Stange et al. "High Sn‐Content GeSn Light Emitters for Silicon Photonics,") hereafter referred to as Stange in view of Prineas et al. (US 20200006592 A1) hereafter referred to as Prineas. LaChapelle et al. (US 20180284274 A1) hereafter referred to as LaChapelle is provided as evidence.
In regard to claim 190 Stange teaches a light-emitting diode [see Fig. 3 , see page 185], comprising:
a silicon-based [see Fig. 3 marked as Si(100)] substrate;
a heterostructure [see the p-i-n GeSn LED] at least partially extending over the silicon-based substrate, the heterostructure comprising a stack [see the p-i-n layers] of coextending [see the top part of P doped layer at the bottom shares a common sidewall with the layers above, so coextending limitation is satisfied at that point] layers, the stack of coextending layers comprising buffer layers [the p and n can be called as “buffer layers”, the Applicant can narrow the definition of buffer based on the specification] and a photoactive [see the undoped “i” layer] layer, each coextending layer comprising at least two [Ge, Sn] group IV elements and being configured for emitting [see “Power-dependent measurements at room temperature show the suitability of these group IV alloys as light emitters at low current densities of 55A/cm2 (see Fig. 4(c))”, the Examiner notes that a range of emission from 0.4eV to 0.6eV is shown i.e. 2.066 μm (i.e. short-wave) to 3.099 μm (i.e. mid-wave), see LaChapelle as evidence, see paragraph 0132 “near infrared ranges (NIR, 750-1000 nm), short-wave infrared ranges (SWIR, 1-2.5 μm), mid-wave infrared ranges (MWIR, 3-5 μm), or long-wave infrared ranges (LWIR, 8-12 μm)”] short-wave infrared and mid-wave infrared radiation, the short-wave infrared and mid-wave infrared radiation comprising some wavelengths in a wavelength range extending from about 1 μm to about 8 μm, depending on a relative concentration [see Ge is 0.89 Sn is 0.11] of said at least two group IV elements and a corresponding strain [“The LEDs presented here are p–i–n structures based on GeSn. They contain a Sn concentration of about 11.5% with a residual strain of −0.8%”] of each layer of the stack of coextending layers; and
electrodes [see the metal contacts in Fig. 3] operatively connected to the heterostructure,
but Stange does not show a plurality of photoactive layers however under broadest reasonable interpretation, since the claim does not state that the photoactive layers are different, they can be the upper and lower portions of the undoped “i” layer of Stange, thus a secondary reference is not required, the claim can be narrowed to require the photoactive layers be different.
However, the Examiner provides a secondary reference, see Stange “It is, however, obvious that GeSn p–i–n homojunction LEDs do not provide a good confinement of carriers inside the active region (when targeting optimized LED structures and designing electrically pumped lasers). Also, heterostructures likeGe/GeSn/Ge do not offer high band offsets. The Ge layer sitting on top of the thick, nearly fully relaxed GeSn layer, is necessarily under tensile strain, making type I band alignment difficult to reach. Therefore, it seems mandatory to use SiGeSn as a cladding material. In addition, multiquantum well (MQW) structures may offer low threshold powers given their 2D density of states” see also “Another approach consists in growing GeSn layers with high amounts of tin. This reduces the energy separation between conduction band valleys and the valence band as Sn content increases, with a stronger effect for the Γ-valley than for the L-valley,8–10 leading to a transition from an indirect to a direct bandgap for sufficiently high Sn content. The transition point for unstrained GeSn compounds was calculated to occur at a Sn concentration between 5% and 12%”, thus the concentration in the example of Fig. 3 is only one example.
See Prineas teaches , see Fig. 2, see Abstract “Methods and a device for cascading broadband emission are described. An example device can comprise a substrate, a bottom contact layer above at least a portion of the substrate, and a plurality of emission regions above the bottom contact layer. The plurality of emission regions can be disposed one above another. Each of the plurality of emission regions can be configured with different respective band gaps to emit radiation of different wavelengths. The device can comprise a plurality of tunnel junctions. Each of the tunnel junctions can be disposed between at least two corresponding emission regions of the plurality of emission regions. The device can comprise a top contact layer above the plurality of emission regions”, see Fig. 2, see paragraph 0033, 0042 “the tunnel junction used for such device may differ from the one disclosed herein, but can be one known by those of ordinary skill in the art” “tunnel junctions for the materials can be chosen to be wider gap than the emission regions to provide blocking layers to prevent electron/hole leakage between the emission regions prior to radiative recombination”.
See that the “tunnel junctions” of Prineas has similarity to “mandatory to use SiGeSn as a cladding material” of Stange i.e. SiGeSn is a buffer/cladding layer.
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 Stange to include a plurality of photoactive layers of differing Sn concentration, with SiGeSn cladding which are stacked.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to obtain a broader emission spectrum than is possible with only a single photoactive layer.
In regard to claim 191 Stange and Prineas as combined teaches wherein said at least two group IV elements are selected [see Stange, see combination Prineas , see GeSn as light emitting layer and SiGeSn as cladding] from the group consisting of: Si, Ge and Sn.
In regard to claim 202 Stange and Prineas as combined teaches wherein said at least two group IV elements are selected [see Stange, see combination Prineas , see GeSn as light emitting layer and SiGeSn as cladding] from the group consisting of: Si, Ge and Sn.
In regard to claim 203 Stange and Prineas as combined teaches wherein the stack of coextending photoactive layers comprises [see Stange, see combination Prineas , see GeSn as light emitting layer and SiGeSn as cladding] at least one GeSn-based layer.
In regard to claim 204 Stange and Prineas as combined teaches wherein the stack of coextending photoactive layers comprises at least two GeSn-based layers [see Stange, see combination Prineas , see plurality of GeSn as light emitting layer of differing Sn concentration and SiGeSn as cladding, see Stange “transition point for unstrained GeSn compounds was calculated to occur at a Sn concentration between 5% and 12%”, see Fig. 3 uses strain, see “The LEDs presented here are p–i–n structures based on GeSn. They contain a Sn concentration of about 11.5% with a residual strain of −0.8%”], each of said at least two GeSn-based layers having a different chemical composition one from another, the different chemical composition comprising an Sn content, the Sn content being comprised in a range extending between 1 at% and 25 at%, each of said at least two GeSn-based layers having a different lattice strain one from another.
In regard to claim 205 Stange and Prineas as combined teaches further comprising a Ge-based virtual substrate [see Stange Fig. 3 see Ge-VS] extending over the silicon-based substrate.
In regard to claim 206 Stange and Prineas as combined teaches wherein the light-emitting diode is operable [see Stange Fig. 2, Fig. 4 see temperature] at room temperature.
In regard to claim 207 Stange and Prineas as combined teaches wherein the light-emitting diode is operable at a cryogenic temperature [see Stange Fig. 2, Fig. 4 see temperature], the cryogenic temperature being equal or greater than about 77 K.
Response to Arguments
Applicant's arguments filed 8/27/2025 have been fully considered but they are not persuasive.
Applicant’s arguments with respect to claim(s) 190,191,202-207 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.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Bertrand et al. (see PTO-892 Bertrand et al., "Optoelectrical Characterizations of GeSn ...”) is provided as evidence of stacking different concentration GeSn layers for optoelectronic purposes.
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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/SITARAMARAO S YECHURI/ Primary Examiner, Art Unit 2893