Non-Final Rejection
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . This application was filed with claims 1-18, which are pending.
Claim Construction – Product-by-Process
The claims are device claims, drawn to “A VCSEL epitaxial structure” in claim 1 and “The VCSEL” in the dependent claims. However, the claims include many process limitations describing how the device is made, product-by-process features. Determination of patentability for product-by-process limitations are based on the product itself, not the process of making, and a claim will not be patentable if the structure is the same even if made by a different process. MPEP 2113. Process steps are only limitations for patentability to the extent that they imply or require a particular structure. More will be discussed as needed in the rejections below.
It almost seems like applicant would like to claim a method of making the device. Claims to a device have already been presented and an action on the merits is issued herein, so claims to a method, which is a different invention, will not be entertained in this application. MPEP 821.03. A continuation could be filed to include a method invention if desired.
Drawings
The drawings are objected to because the specification refers to etched post 110. This is supposedly shown in Figs. 19A, 20A, 22, which depicts 110 as two mesas on either side of the center mesa. However, this is not at all the etched post as described in the specification and the claims. The etched post is “between an active region 112 and a sacrificial layer 114.” [0034];1 claim 1. Fig. 12 is supposed to illustrate the etched post. [0037]. ALD is supposed to be done on the etched post as shown in Fig. 14. [0038]. Fig. 16 shows a regrown sacrificial layer and HCG layer around the etched post. [0040]-0041]; see also claim 1. The things that are shown as 110 in Figs. 19A, 20A, and 22 are simply not the etched post of the specification, they are perhaps the MEMS anchors discussed in [0042]. It is apparent that the etched post is instead the post between active layer 112 and sac layer 114 as shown in Fig. 13A, also called the small mesa 122. The drawings are therefore inaccurate in referring to etched post 110 in Figs. 19A, 20A, 22.
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they do not include the following reference sign(s) mentioned in the description: 118 in [0034].
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description: 12, 14, 16, 18, 20, 22, 24, 26, 28, 29, 30, 32, 34, 36, 38. Indeed, Figs. 1-10 are not described at all in the specification other than the brief description of the drawings.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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.
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claims 1-18 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 has the limitation “the etched post and regrowth provide . . . cavity volume small volume.” This does not make sense and is indefinite. Presumably “cavity volume” should be deleted and then this is adequate as “the etched post and regrowth provide . . . small volume.” While small could arguably be indefinite, it is not here because the claim additionally requires a volume of less than 50 cubic micrometers, so the volume is clear.
Claims 1 and 6 require “increased efficiency for applications of the VCSEL.” It is not clear what this means or how it is judged. How is this measured? Increased as compared to what baseline? What kinds of applications? It is not clear if there is any structural requirement here, what this actually requires.
Claim 4 requires that there is “regrowth including . . . a sacrificial layer.” A sacrificial layer was already included in claim 1, therefore it is not clear if this is meant to be the same layer or a different layer, particularly because multiple sacrificial layers are described in the specification.
Claim 4 also requires “a sacrificial layer with a thickness now greater than 100 nm.” The word “now” makes this indefinite, because it is not clear what this is supposed to mean—is applicant attempting to make some timing requirement, requiring the layer to be some other thickness at some other point, and only “now” is it 100 nm? This is a device claim, so applicant should just claim what the device is, and the word “now” should be deleted.
Each of claims 5, 10-12, and 14-18 depends from itself, therefore their scope is not clear.
Claim 8 requires “a small mesa step.” It is not clear what “small” means in this context, small compared to what? The specification also does not give sufficient guidance, so the metes and bounds are not clear as to what kind of mesa meets the claim.
Claim 10 requires “the implantation is done” but there is insufficient antecedent basis for the implantation. It appears the claim is intended to depend from claim 9.
Claim 10 requires “a thin sacrificial layer.” It is not clear what “thin” means in this context, thin compared to what? The specification also does not give sufficient guidance, so the metes and bounds are not clear as to how thin a layer meets the claim.
Claim 16 requires that “the regrowth layer is thick enough for relaxing defects.” It is not clear how thick the layer needs to be for this to occur. The specification is no help, as there is no description of this in the specification. As there is no indication whatsoever what type of thickness is required, the metes and bounds of the claim are unclear.
Claim 18 requires “wherein mesa confinement is provided.” It is not clear what “mesa confinement” means and this is not described in the specification. There is no discussion of how it would be “provided.” There is not even any mesa in the claim. The metes and bounds of the claim are therefore not clear, as it is not known what structure is needed to “provide” this. It is noted that claim 1 already requires that that etched post provides lateral current and optical confinement, so if this is what is meant then claim 18 is additionally not further limiting, see below.
Claims 5, 7, 10-12, and 14-18 are rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends.
Regarding claims 5, 10-12, and 14-18, each claim is improperly dependent because, again, each depends from itself.
Claim 5 is additionally rejected because it fails to further limit claim 1. Whatever claim it is supposed to depend from, claim 1 is the only independent claim and it therefore must ultimately depend from claim 1. Claim 5 requires that “the VCSEL is made with a regrowth of the sacrificial layer and the HCG layer is created around the etched post.” But claim 1 already requires “A VCSEL epitaxial structure, comprising . . . a regrowth of sacrificial layer and HCG layer around the etched post.” The VCSEL of claim 1 already comprises these things, therefore it is inherently “made with” these things. The examiner fails to see how anything could meet claim 1 but not meet claim 5.
Claim 7 only requires that “an optical path is preserved.” This is a VCSEL, which necessarily has some optical path. It is not clear to the examiner how a VCSEL would not have an optical path. The VCSEL of claim 1 must already have “an optical path [that is] preserved” so claim 7 is not further limiting.
Claim 18 requires “wherein mesa confinement is provided.” There is no mesa in the claims, the only thing that might provide confinement and be like a mesa is the etched post. But claim 1 already requires that that etched post provides lateral current and optical confinement, so there is already some sort of “mesa confinement” and claim 18 is not further limiting.
Claim Objections
Claim 1 is objected to because it includes a period in the middle of the claim, after “post” in line 3, which is improper. See MPEP 608.01(m).
Claim 8 is objected to because it does not have a period.
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.
Claims 1-8 and 13-18 are rejected under 35 U.S.C. 103 as being unpatentable over in view of WO 2020/231714 to Chang-Hasnain et al. (“Chang-Hasnain I”) in view of US 2021/0135429 to Chang-Hasnain et al. (“Chang-Hasnain II”).
1. A VCSEL epitaxial structure, comprising:
Chang-Hasnain I describes a VCSEL. Title. An “epitaxial structure” is drawn to how the device is made, via epitaxial growth, and is a process limitation that does not get weight. To the extent this does imply some structure, the Chang-Hasnain I device is epitaxially grown. [0023].
an etched post between an active region and a sacrificial layer; a regrowth of sacrificial layer and HCG layer around the etched post
Chang-Hasnain I Fig. 4 and the discussion thereof shows a VCSEL having a post, at least layer 78”, between the active region 90 and a sacrificial layer 100 or 102 or 112 which is above and around that. Note that “sacrificial layer” does not have any actual requirements and can be met by any layer. HCG layer 112b is also above and around the post. “A regrowth” is a process step that does not imply any structure and therefore does not get patentable weight. “Etched” is a process step that does not imply any structure and therefore does not get patentable weight, though this post is etched, see Fig. 3B.
providing a fully epitaxial grown tunable VCSEL
Again, “epitaxial grown” is either a pure process limitation or is disclosed. The laser operates over a range of wavelengths, see Fig. 6, and therefore may be considered tunable.
with a cavity volume no greater than 50 cubic micrometers,
Chang-Hasnain I shows apertures as small as 6 microns. A person of ordinary skill would recognize that VCSELs are generally cylindrical, so the volume is π r2 h and with a 6 micron diameter r here is 3. The cavity length or the thickness of the various layers is not given.
Chang-Hasnain II describes a similar HCG VCSEL and Fig. 1 shows an electron microscope view of the various layers. Given the 200 nm scale, it is apparent that the cavity length shown here is approximately 1.2 microns. This is therefore a reasonable and possible cavity length. Given that Chang-Hasnain I does not tell us the thickness of the layers, it would have been obvious to a person of ordinary skill in the art to use any layer thickness and cavity length that is possible and known in the art, such as that shown in Chang-Hasnain II. It is therefore apparent that the cavity volume could be less than 50 cubic micrometers. It is furthermore generally well known in semiconductor device fabrication that those skilled in the art are continually trying to get smaller and smaller devices, so it would have been obvious to a person of ordinary skill in the art to try and make these lasers as small as possible.
This is particularly so as applicant does not in any way explain why the invention uniquely results in this claimed cavity volume. Applicant merely states that it is an object of the invention, [0014]-[0015], but does not in any way explain how or why the claimed structure somehow results in this lowered cavity volume.
lateral electrical current and optical confinement; and wherein the etched post and regrowth provide lateral current and optical confinement, cavity volume small volume and an increased efficiency for applications of the VCSEL epitaxial structure.
Chang-Hasnain I is explicit that current only goes through the BJT, [0023], so there is lateral current confinement in the etched post. Tunnel junctions generally also provide at least some measure of optical confinement. Whether this provides “small volume and an increased efficiency” is merely the intended result and does not get patentable weight any further than the volume requirement above, particularly because it is not clear what “increased efficiency” actually means, see 112 rejection above.
2. The VCSEL of claim 1, wherein current flows through the etched post.
The current flows through the TJ layer, this is the point of the TJ layer. [0023] (“current only goes through the BTJ”).
3. The VCSEL of claim 1, wherein optical confinement is defined by the post which acts as a waveguide.
The BTJ and the surrounding materials are different, thus will have different refractive indices. This therefore can be considered to “act as a waveguide.” A VCSEL generally emits from the center, so optical confinement occurs in the center, and this is where the BTJ post is located.
4. The VCSEL of claim 1, wherein the VCSEL is made with a first regrowth including a bottom DBR, active layer, top DBR/other spacing layers, and a sacrificial layer with a thickness now greater than 100 nm.
Made with a first regrowth is a process step that does not get patentable weight. The actual layers that are required do get patentable weight. Chang-Hasnain I Fig. 4 shows bottom DBR 96, active layer 90, and sacrificial layers such as 100, 102, 112. The BTJ may be 100 nm, [0023], so layer 100, which is larger, is greater than 100 nm.
5. The VCSEL of claim 5, wherein the VCSEL is made with a regrowth of the sacrificial layer and the HCG layer is created around the etched post.
As discussed above this claim is not deemed to be further limiting of claim 1. Additionally, it is purely a process limitation and therefore does not get patentable weight.
6. The VCSEL of claim 1, wherein the etched post provides for increased efficiency because the optical wave and the lateral currents overlap.
Again the current is said to go through tunnel junction 78”. The optical wave likewise goes through the center of the device as this is how a VCSEL works, so these overlap.
7. The VCSEL of claim 1, wherein an optical path is preserved.
As discussed above this claim is not deemed to be further limiting of claim 1. In any event, the art shows a VCSEL and therefore there is necessarily an optical path in the device.
8. The VCSEL of claim 1, wherein the sacrificial layer is around a small mesa step
Layers 100, 102, 112 are around 78” which can be called a small mesa step.
13. The VCSEL of claim 1, wherein a full regrowth of a full sacrificial layer and HCG on top is performed.
This is a pure process limitation and therefore does not get patentable weight. It is not apparent how this implies any structure different than that already found in claim 1. The sacrificial layer and HCG are already present in claim 1, and it is not seen how there is a structural distinction whether a regrowth is “full” or not.
14. The VCSEL of claim 14, wherein an interface is etched away and a regrowth is provided around the etched post.
This is a pure process limitation and therefore does not get patentable weight. It is not apparent how this implies any structure different than that already found in claim 1.
15. The VCSEL of claim 15, wherein a regrowth interface is out of optical/current paths.
An interface between layers 100 and 86 on the outside edge of the device is outside of the optical/current paths.
16. The VCSEL of claim 16, wherein the regrown layer is thick enough for relaxing defects before arriving at the HCG layer.
Again, nothing in the specification explains what kind of thickness should be provided or what is required to provide this claimed result of relaxing defects. The metes and bounds are therefore unclear and it is not clear to the examiner how to apply the art against the claim. To the extent that a person of ordinary skill would have already known what thickness might be enough for relaxing defects, then it likewise it would have been obvious to that skilled person to make the layer of such a thickness because defects are disfavored and thus would be avoided.
17. The VCSEL of claim 17, wherein a mesa grows laterally during regrowth.
This is a pure process limitation and therefore does not get patentable weight. It is not apparent how this implies any structure different than that already found in claim 1. The only structure it implies is that the mesa that is grown has some lateral width. But any mesa will have some lateral dimension (it cannot have zero width) so any mesa will have the same structure implied by the claim.
18. The VCSEL of claim 18, wherein mesa confinement is provided.
Again, it is not clear how this structurally provides anything different than is already found in claim 1. It is considered met in the same way as claim 1.
Claims 9-10 are rejected under 35 U.S.C. 103 as being unpatentable over Chang-Hasnain I and Chang-Hasnain II as applied to the parent claims, and further in view of US 2011/0280269 to Chang-Hasnain et al. (“Chang-Hasnain III”).
9. The VCSEL of claim 6, wherein ion implantation is done on a structure with a bottom DBR, active, and a thin sacrificial layer.
10. The VCSEL of claim 10, wherein the implantation is done on a layer between the active layer, and a thin sacrificial layer.
As discussed above re: claim 4 Chang-Hasnain I has a bottom DBR, active layer, and sacrificial layer that could be considered “thin.”
Chang-Hasnain III describes a similar HCG VCSEL having a tunnel junction 28 and uses ion implantation 46 around it. Fig. 1, [0066]. It would have been obvious to a person of ordinary skill in the art to do this as it provides additional electrical confinement, as taught by Chang-Hasnain III. It would be done next to the BTJ as in Chang-Hasnain III, and that is between the active layer and one of the upper sacrificial layers.
Claims 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Chang-Hasnain I and Chang-Hasnain II as applied to the parent claims, and further in view of Cheng et al., 29 GHz single-mode vertical-cavity surface-emitting lasers passivated by atomic layer deposition, Optics Express, vol. 30 no. 26 (Dec. 2022) (“Cheng”).
The primary references teach the limitations of claim 1 as in the rejections above. They do not teach that ALD is performed on the sidewalls of the etched post as in claim 11.
Cheng teaches that it was known in the art to perform ALD on etched sidewalls in a VCSEL. Abstract. It would have been obvious to a person of ordinary skill in the art to do so as it mitigates processing induced damage, improving performance and reliability, as taught by Cheng.
Regarding claim 12, the claim gives the intent behind using ALD, which does not give patentable weight. The reason behind using ALD does not change the structure, and the structure is what matters in a device claim. The claim further states that ALD provides isolation from the surrounding air, which would also be true of Cheng’s ALD. ALD by definition is depositing a layer, so it will provide at least some amount of1 isolation.
Other Pertinent Art
US 2012/0128019 also shows a tunable HCG VCSEL. It also teaches that buried tunnel junctions provide optical confinement. [0072].
US 2012/0189024 (Fig. 3), US 2014/0376580 (Fig. 3), US 2017/0018908, US 2017/0149212 (Fig. 1C), US 2018/0301870 (Fig. 2) also show a HCG VCSEL with what can be considered an etched post.
US 2018/0301870 also shows that a HCG VCSEL can have an effective cavity length of 1-2 microns. [0063]; see also Fig. 10.
US 10,615,571 also shows a VCSEL that may use a HCG and having a cavity (between mirrors, see Fig. 8) of only a couple microns.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to James Menefee whose telephone number is (571)272-1944. The examiner can normally be reached M-F 7-4.
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/JAMES A MENEFEE/ Primary Examiner, Art Unit 2828
1 Citations are to the published application US 2025/0079796.