Patent Description:
A distributed Bragg reflector (DBR) is a reflector formed from multiple layers of alternating materials with alternating refractive indices. Planar DBR mirrors include multiple layers with alternating high- and low-refractive indices. DBRs are key components in vertical-cavity surface-emitting lasers (VCSELs) as well as other photonic, optical, and/or electronic devices.

A VCSEL is a type of semiconductor laser diode with emission perpendicular to the top and bottom surfaces. A cavity resonator for a VCSEL can be formed from an active region vertically surrounded by two DBR mirrors. Conventional VCSELs include epitaxially growing multiple alternating III-V semiconductor layers (e.g., AlxGa<NUM>-xAs/AlyGa<NUM>-yAs, <NUM> ≤ x, y ≤ <NUM>, x ≠ y) to form a DBR due to the periodically alternating refractive indices of the layers.

However, epitaxial growth of the alternating material layers is costly and time-consuming, taking upwards of ten hours to form top and bottom DBRs from different alternating epitaxial layers using standard metal-organic chemical vapor deposition (MOCVD) or molecular-beam epitaxy (MBE) methods, making throughput and yield low. Further, epitaxial growth of different alternating multiple layers to form the DBR can introduce unwanted strain and/or defects into the layered stack. In addition, conventional epitaxial DBRs require the same wavelength(s) to pass through the entire layered stack.

Accordingly, there is a need to improve the speed and efficiency of manufacturing DBRs in a layered structure for photonic, optical, and/or electronic devices, reduce induced strain and/or defects in the layered structure from the manufacturing process, reduce the overall size (e.g., thickness) of the layered structure for a more compact and simplistic design, and/or increase manufacturing throughput and yield. Known resonant cavity layered structures including at least one porous DBR reflector are known from any of <CIT>; <CIT>; <CIT>; <CIT>; <CIT>;.

Porous DBR reflectors are described in <NPL>.

The invention relates to a method as defined in independent claim <NUM>.

In accordance with the invention, a layered structure includes a first substrate layer and a layer. The first substrate layer is a single material. The first layer includes a porous region to form a first DBR. The porous region includes alternating first porous and second porous sublayers of the single material to form the first DBR. The layer is coupled to the first layer. The layer includes an active region to generate radiation, detect radiation, or both. Advantageously, the first layer includes only a single material to form the first DBR, which improves the efficiency of manufacturing the DBR (e.g., does not require multiple epitaxial layers), reduces strain in the first layer (e.g., lattice matched), and reduces the size (e.g., thickness) of the layered structure.

In some examples, the first layer has substantially no lattice mismatch. Advantageously, strain is reduced in the first layer since there is substantially no lattice mismatch (e.g., single material), which increases throughput and overall yield.

In some examples, a lattice mismatch between the alternating first porous and second porous sublayers is less than <NUM>%. Advantageously, strain is reduced in the porous region (i.e., the first DBR) since there is substantially no lattice mismatch (e.g., less than <NUM>%), which increases throughput and overall yield.

In some examples, the alternating first porous and second porous sublayers include alternating porous and substantially non-porous sublayers. Advantageously, DBR fabrication is faster (e.g., less than five minutes) utilizing substantially non-porous sublayers to efficiently and reproducibly form alternating sublayers of low and high indices of refraction to form the first DBR.

In some examples not in accordance with the invention, the first and second porous sublayers have the same porosity. Advantageously, strain is reduced in the porous region since there is substantially no lattice mismatch (e.g., same material). Further advantageously, DBR fabrication is faster (e.g., less than five minutes) utilizing different porosification techniques (e.g., electrolyte concentration, acid current density, acid current fluid velocity, anodization time, temperature, material doping, etc.) for the first and second porous sublayers to efficiently and reproducibly form alternating sublayers of low and high indices of refraction to form the first DBR.

In some examples, the single material of the first layer is a dielectric. Advantageously, the first layer includes only a single material to form the first DBR (e.g., multiple material layers are not required). Further advantageously, the dielectric (e.g., oxide, nitride, oxynitride, ceramic, glass, spin-on-glass (SOG), polymer, plastic, thermoplastic, resin, laminate, etc.) can be formed by any suitable methods including vacuum deposition, thermal evaporation, arc vaporization, ion beam deposition, e-beam deposition, sputtering, laser ablation, pulsed laser deposition (PLD), physical vapor deposition (PVD), atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), low pressure CVD (LPCVD), MOCVD, liquid source misted chemical deposition, spin-coating, epitaxy, and/or any other suitable deposition methods (e.g., epitaxy can be used but is not required).

In some examples, the single material of the first layer is silicon (Si), germanium (Ge), silicon-germanium (SiGe), gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), gallium antimonide (GaSb), indium phosphide (InP), indium antimonide (InSb), a Group III-V semiconductor, or sapphire. Advantageously, the first layer includes only a single material to form the first DBR (e.g., multiple material layers are not required). Further advantageously, the single material can be formed by any suitable methods including vacuum deposition, thermal evaporation, arc vaporization, ion beam deposition, e-beam deposition, sputtering, laser ablation, PLD, PVD, ALD, CVD, PECVD, LPCVD, MOCVD, liquid source misted chemical deposition, epitaxy, vapor-phase epitaxy (VPE), liquid-phase epitaxy (LPE), solid-phase epitaxy (SPE), MBE, atomic layer epitaxy (ALE), and/or any other suitable deposition methods (e.g., epitaxy can be used but is not required).

The first layer is a monolithic substrate. Advantageously, the first layer includes only a single (e.g., bulk) substrate to form the first DBR (e.g., multiple material layers are not required). Further advantageously, the substrate (e.g., wafer) itself is porosified to form the first DBR within the substrate which avoids forming a separate layer and/or material to form the first DBR.

In some examples, the layered structure further includes a second layer to form a second DBR. In some examples, the first layer contacts a first side of the cavity and the second layer contacts a second side of the cavity. Advantageously, a resonant cavity can be formed with the first and second DBRs for tuning the intensity and/or wavelength of the radiation.

In some examples, the second layer is a second single material. In some examples, the second layer includes a second porous region to form the second DBR. In some examples, the second porous region includes alternating first porous and second porous sublayers of the second single material to form the second DBR. Advantageously, the second layer includes only a single material to form the second DBR, which improves the efficiency of manufacturing the second DBR (e.g., does not require multiple epitaxial layers), reduces strain in the second layer (e.g., lattice matched), and reduces the size (e.g., thickness) of the layered structure.

In some examples, the second layer has substantially no lattice mismatch. Advantageously, strain is reduced in the second layer since there is substantially no lattice mismatch (e.g., single material), which increases throughput and overall yield.

In some examples, a lattice mismatch between the alternating first porous and second porous sublayers is less than <NUM>%. Advantageously, strain is reduced in the porous region (i.e., the second DBR) since there is substantially no lattice mismatch (e.g., less than <NUM>%), which increases throughput and overall yield.

In some examples, the cavity includes one or more embedded contacts to apply current to the active region. Advantageously, intracavity contacts can be formed within the cavity itself, reducing the overall size (e.g., thickness) of the layered structure. Further advantageously, the first layer and/or the second layer is not required to be doped (e.g., p-type) in order to apply a current to the active region of the cavity.

In some examples, the layered structure forms a VCSEL, a light-emitting diode (LED), a resonant cavity LED, an optical detector, a wireless receiver, a wireless transmitter, a wireless transceiver, or a combination thereof. Advantageously, the layered structure provides a platform for a variety of photonic, optical, and/or electronic devices in a compact and simplistic design, including non-optical (e.g., wireless) radiation emission and/or detection applications.

In accordance with the invention, a method of forming a layered structure includes forming a layer over a substrate being a single material, wherein the layer is coupled to the substrate, the layer comprising an active region to generate radiation or detect radiation. The method further includes porosifying the substrate to form a porous region to form a first distributed Bragg reflector (DBR). The porous region includes alternating first porous and second porous sublayers of the single material to form the first DBR. Advantageously, the first layer includes only a single material to form the first DBR by porosification, which improves the efficiency of manufacturing the DBR (e.g., does not require multiple epitaxial layers), allows greater freedom of the first layer material selection, reduces strain in the first layer (e.g., lattice matched), and reduces the size (e.g., thickness) of the layered structure.

In some aspects, the porosifying the first layer includes a porosification rate of at least <NUM>/min. Advantageously, DBR manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and induced strain and/or defects from DBR manufacturing are reduced in the layered structure. For example, a porous DBR with a thickness of <NUM> can be manufactured in ten minutes.

In some aspects, the porosification rate is at least <NUM>/min. Advantageously, DBR manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and induced strain and/or defects from DBR manufacturing are reduced in the layered structure. For example, a porous DBR with a thickness of <NUM> can be manufactured in four minutes.

In some aspects, the alternating first porous and second porous sublayers include alternating porous and substantially non-porous sublayers. Advantageously, DBR fabrication is faster (e.g., less than five minutes) utilizing substantially non-porous sublayers to efficiently and reproducibly form alternating sublayers of low and high indices of refraction to form the first DBR.

In some aspects, the first and second porous sublayers have the same porosity. Advantageously, strain is reduced in the porous region since there is substantially no lattice mismatch (e.g., same material). Further advantageously, DBR fabrication is faster (e.g., less than five minutes) utilizing different porosification techniques (e.g., electrolyte concentration, acid current density, acid current fluid velocity, anodization time, temperature, material doping, etc.) for the first and second porous sublayers to efficiently and reproducibly form alternating sublayers of low and high indices of refraction to form the first DBR.

In some aspects, the single material of the first layer is a dielectric. Advantageously, the first layer includes only a single material to form the first DBR (e.g., multiple material layers are not required). Further advantageously, the dielectric (e.g., oxide, nitride, oxynitride, ceramic, glass, SOG, polymer, plastic, thermoplastic, resin, laminate, etc.) can be formed by any suitable methods including vacuum deposition, thermal evaporation, arc vaporization, ion beam deposition, e-beam deposition, sputtering, laser ablation, PLD, PVD, ALD, CVD, PECVD, LPCVD, MOCVD, liquid source misted chemical deposition, spin-coating, and/or any other suitable deposition methods (e.g., epitaxy can be used but is not required).

In some aspects, the single material of the first layer is Si, Ge, SiGe, GaAs, GaN, GaP, GaSb, InP, InSb, a Group III-V semiconductor, or sapphire. Advantageously, the first layer includes only a single material to form the first DBR (e.g., multiple material layers are not required). Further advantageously, the single material can be formed by any suitable methods including vacuum deposition, thermal evaporation, arc vaporization, ion beam deposition, e-beam deposition, sputtering, laser ablation, PLD, PVD, ALD, CVD, PECVD, LPCVD, MOCVD, liquid source misted chemical deposition, epitaxy, VPE, LPE, SPE, MBE, ALE, and/or any other suitable deposition methods (e.g., epitaxy can be used but is not required).

In accordance with the invention, the first layer is a monolithic substrate. Advantageously, the first layer includes only a single (e.g., bulk) substrate to form the first DBR (e.g., multiple material layers are not required). Further advantageously, the substrate (e.g., wafer) itself is porosified to form the first DBR within the substrate which avoids forming a separate layer and/or material to form the first DBR.

In some aspects, the method further includes forming a second layer to form a second DBR. In some aspects, the first layer contacts a first side of the cavity and the second layer contacts a second side of the cavity. Advantageously, a resonant cavity can be formed with the first and second DBRs for tuning the intensity and/or wavelength of the radiation.

In some aspects, the second layer is a second single material. In some aspects, the method further includes porosifying the second layer to form a second porous region to form the second DBR. In some aspects, the second porous region includes alternating first porous and second porous sublayers of the second single material to form the second DBR. Advantageously, the second layer includes only a single material to form the second DBR, which improves the efficiency of manufacturing the second DBR (e.g., does not require multiple epitaxial layers), reduces strain in the second layer (e.g., lattice matched), and reduces the size (e.g., thickness) of the layered structure.

In some aspects, the method further includes forming one or more embedded contacts within the cavity to apply current to the active region. Advantageously, intracavity contacts can be formed within the cavity itself, reducing the overall size (e.g., thickness) of the layered structure. Further advantageously, the first layer and/or the second layer is not required to be doped (e.g., p-type) in order to apply a current to the active region of the cavity.

In some aspects, the method further includes forming a VCSEL, LED, a resonant cavity LED, an optical detector, a wireless receiver, a wireless transmitter, a wireless transceiver, or a combination thereof with the layered structure. Advantageously, the layered structure provides a platform for a variety of photonic, optical, and/or electronic devices in a compact and simplistic design, including non-optical (e.g., wireless) radiation emission and/or detection applications.

In some aspects, the first DBR is fabricated in less than ten minutes. Advantageously, DBR manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in the layered structure. For example, the first DBR with a thickness of <NUM> micron can be manufactured in less than ten minutes (e.g., porosification rate of <NUM>/min).

In some aspects, the first DBR is fabricated in less than five minutes. Advantageously, DBR manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in the layered structure. For example, the first DBR with a thickness of <NUM> can be manufactured in less than five minutes (e.g., porosification rate of <NUM>/min).

In some aspects, the first DBR is fabricated in less than two minutes. Advantageously, DBR manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in the layered structure. For example, the first DBR with a thickness of <NUM> can be manufactured in less than two minutes (e.g., porosification rate of <NUM>/min).

In some aspects, the cavity is an electromagnetic (EM) cavity to generate EM radiation, detect EM radiation, or both. Advantageously, the layered structure provides a platform for a variety of photonic, optical, and/or electronic devices in a compact and simplistic design, including non-optical (e.g., wireless) radiation emission and/or detection applications with the EM cavity.

In some aspects, the EM radiation includes RF radiation. Advantageously, the layered structure provides RF radiation (e.g., about <NUM> to about <NUM>) emission, detection, or both for wireless applications (e.g., WiFi, Bluetooth, RF receiver, RF transmitter, RF transceiver, etc.). For example, the EM cavity can include a planar antenna having a resonance of about <NUM> to detect incident RF radiation and/or emit RF radiation. Further advantageously, the layered structure provides bandwidth and/or frequency filtering of RF signals. For example, the layered structure can include one or more DBR layers having a thickness of about <NUM> to about <NUM> to filter wavelengths of about <NUM> to about <NUM>.

In some aspects, the EM radiation includes microwave radiation. Advantageously, the layered structure provides microwave radiation (e.g., about <NUM> to about <NUM>) emission, detection, or both for telecommunication applications (e.g., radar, satellite, wireless, networks, etc.). For example, the EM cavity can include a planar antenna having a resonance of about <NUM> to detect incident microwave radiation and/or emit microwave radiation. Further advantageously, the layered structure provides bandwidth and/or frequency filtering of microwave signals. For example, the layered structure can include one or more DBR layers having a thickness of about <NUM> to about <NUM> to filter wavelengths of about <NUM> to about <NUM>.

In some aspects, the EM radiation includes IR, VIS, and/or UV radiation. Advantageously, the layered structure provides IR-VIS-UV radiation (e.g., about <NUM> to about <NUM>) emission, detection, or both for optical applications (e.g., VCSELs, LEDs, lasers, detectors, photodiodes, short-range wireless, spectroscopy, etc.). For example, the EM cavity can include an active region (e.g., quantum well) having a response between about <NUM> to about <NUM> to detect incident IR radiation and/or emit IR radiation. For example, the EM cavity can include an active region (e.g., quantum well) having a response between about <NUM> to about <NUM> to detect incident VIS radiation and/or emit VIS radiation. Further advantageously, the layered structure provides bandwidth and/or wavelength filtering of optical signals. For example, the layered structure can include one or more DBR layers having a thickness of about <NUM> to about <NUM> to filter wavelengths of about <NUM> to about <NUM>. For example, the layered structure can include one or more DBR layers having a thickness of about <NUM> to filter wavelengths of about <NUM>.

In some aspects, the cavity is an acoustic cavity to generate acoustic radiation, detect acoustic radiation, or both. Advantageously, the layered structure provides acoustic radiation (e.g., about <NUM> to about <NUM>) emission, detection, or both for acoustic and sensing applications (e.g., ultrasound, non-contact sensor, telecommunication, imaging, etc.). For example, the acoustic cavity can include a planar acoustic membrane (e.g., microelectromechanical system (MEMS) oscillator, MEMS microphone, surface acoustic wave (SAW) sensor, etc.) having a response between about <NUM> to <NUM> to detect incident acoustic radiation and/or emit acoustic radiation. Further advantageously, the layered structure provides bandwidth and/or frequency filtering of acoustic signals. For example, the layered structure can include one or more DBR layers having a thickness of about <NUM> to filter acoustic radiation of about <NUM>.

In some aspects, a layered structure includes: a first layer being a single material and including a porous region to form a first DBR, the porous region including alternating porous and substantially non-porous sublayers of the single material to form the first DBR; a second layer opposite the first layer, the second layer to form a second DBR; and an optical cavity between the first layer and the second layer, the optical cavity including an active region to generate light, detect light, or both. Advantageously, the first layer includes only a single material to form the first DBR, which improves the efficiency of manufacturing the DBR (e.g., does not require multiple epitaxial layers), reduces strain in the first layer (e.g., lattice matched), and reduces the size (e.g., thickness) of the layered structure.

In some aspects, a thickness of the first layer is less than a thickness of the second layer. Advantageously, the first layer reduces the size (e.g., thickness) of the layered structure.

In some aspects, the second layer is a second single material and includes a second porous region to form the second DBR, the second porous region including alternating porous and substantially non-porous sublayers of the second single material to form the second DBR. Advantageously, a resonant optical cavity can be formed with the first and second DBRs for tuning the intensity and/or wavelength of the light.

In some aspects, the layered structure forms a VCSEL, an LED, an optical detector, or a combination thereof. Advantageously, the layered structure provides a platform for a variety of photonic, optical, and/or optoelectronic devices in a compact and simplistic design.

In some aspects, a method of forming a layered structure includes: forming a first layer, the first layer being a single material; porosifying the first layer to form a porous region to form a first DBR, the porous region including alternating porous and substantially non-porous sublayers of the single material to form the first DBR; forming a second layer opposite the first layer, the second layer to form a second DBR; and forming an optical cavity between the first layer and the second layer, the optical cavity including an active region to generate light, detect light, or both. Advantageously, the first layer includes only a single material to form the first DBR by porosification, which improves the efficiency of manufacturing the DBR (e.g., does not require multiple epitaxial layers), allows greater freedom of the first layer material selection, reduces strain in the first layer (e.g., lattice matched), and reduces the size (e.g., thickness) of the layered structure.

Implementations of any of the techniques described above can include a system, a method, a process, a device, and/or an apparatus.

Further features and exemplary aspects of the aspects, as well as the structure and operation of various aspects, are described in detail below with reference to the accompanying drawings. It is noted that the aspects are not limited to the specific aspects described herein. Such aspects are presented herein for illustrative purposes only. The invention is defined by the claims, and additional aspects falling within the scope of the claims will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein.

The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the aspects and, together with the description, further serve to explain the principles of the aspects and to enable a person skilled in the relevant art(s) to make and use the aspects.

The features and exemplary aspects of the aspects will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. Unless otherwise indicated, the drawings provided throughout the disclosure should not be interpreted as to-scale drawings.

This specification discloses one or more aspects that incorporate the features of this present invention. The disclosed aspect(s) merely exemplify the present invention. The scope of the invention is not limited to the disclosed aspect(s). The present invention is defined by the claims appended hereto.

The aspect(s) described, and references in the specification to "one aspect," "an aspect," "an example aspect," "an exemplary aspect," etc., indicate that the aspect(s) described can include a particular feature, structure, or characteristic, but every aspect may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same aspect. Further, when a particular feature, structure, or characteristic is described in connection with an aspect, it is understood that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other aspects whether or not explicitly described.

Spatially relative terms, such as "beneath," "below," "lower," "above," "on," "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The apparatus can be otherwise oriented (rotated <NUM> degrees or at other orientations) and the spatially relative descriptors used herein can likewise be interpreted accordingly.

The term "about" or "substantially" or "approximately" as used herein means the value of a given quantity that can vary based on a particular technology. Based on the particular technology, the term "about" or "substantially" or "approximately" can indicate a value of a given quantity that varies within, for example, <NUM>-<NUM>% of the value (e.g., ±<NUM>%, ±<NUM>%, ±<NUM>%, ±<NUM>%, or ±<NUM>% of the value).

The term "radiation" as used herein means electromagnetic radiation or acoustic radiation. Electromagnetic radiation includes radio frequency (RF), microwave, infrared (IR), visible (VIS), ultraviolet (UV), x-rays, and gamma radiation. Acoustic radiation includes ultrasound or sound waves.

The term "epitaxy" or "epitaxial" as used herein means crystalline growth of material, for example, via high temperature deposition. Epitaxy can be effected in a MBE tool in which layers are grown on a heated substrate in an ultra-high vacuum environment. Elemental sources are heated in a furnace and directed towards the substrate without carrier gases. The elemental constituents react at the substrate surface to create a deposited layer. Each layer is allowed to reach its lowest energy state before the next layer is grown so that bonds are formed between the layers.

Epitaxy can also be performed in a metal-organic vapor phase epitaxy (MOVPE) tool, also known as a MOCVD tool. Compound metal-organic and hydride sources are flowed over a heated surface using a carrier gas, for example, hydrogen. Epitaxial deposition in the MOCVD tool occurs at much higher pressures than in an MBE tool. The compound constituents are broken in the gas phase and then reacted at the surface to grow layers of desired composition.

The term "substrate" as used herein means a planar wafer on which subsequent layers may be deposited, formed, or grown. A substrate may be formed of a single element (e.g., Si) or a compound material (e.g., GaAs), and may be doped or undoped. In some aspects, for example, a substrate can include Si, Ge, SiGe, silicon-germanium tin (SiGeSn), GaAs, GaN, GaP, GaSb, InP, InSb, a Group IV semiconductor, a Group III-V semiconductor, a Group II-VI semiconductor, graphene, silicon carbide (SiC), or sapphire.

A substrate may be on-axis, that is where the growth surface aligns with a crystal plane. For example, a substrate can have <<NUM>> crystal orientation. Reference herein to a substrate in a given crystal orientation also encompass a substrate which is miscut by up to <NUM>° towards another crystallographic direction. For example, a (<NUM>) substrate miscut towards the (<NUM>) plane.

The term "monolithic" as used herein means a layer or substrate comprising bulk (e.g., single) material throughout. The monolithic layer or substrate may be porous for some or all of its thickness.

The term "compound material" or "Group III-V semiconductor" as used herein means comprising one or more materials from Group III of the periodic table (e.g., group <NUM> elements: boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl)) with one or more materials from Group V of the periodic table (e.g., group <NUM> elements: nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi)). The compounds have a <NUM>:<NUM> combination of Group III and Group V regardless of the number of elements from each group. Subscripts in chemical symbols of compounds refer to the proportion of that element within that group. For example, Al<NUM>GaAs means the Group III part comprises <NUM>% Al, and thus <NUM>% Ga, while the Group V part comprises <NUM>% As.

The term "Group IV semiconductor" as used herein indicates comprising one or more materials from Group IV of the periodic table (e.g., group <NUM> elements: carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb)).

The term "Group II-VI semiconductor" as used herein indicates comprising one or more materials from Group II of the periodic table (e.g., group <NUM> elements: zinc (Zn), cadmium (Cd), mercury (Hg)) with one or more materials from Group VI of the periodic table (e.g., group <NUM> elements: oxygen (O), sulfur (S), selenium (Se), tellurium (Te)).

The term "distributed Bragg reflector layer" or "DBR layer" as used herein means a layer or material that includes alternating refractive indices and can operate as a reflector. A DBR layer may be formed of a single element (e.g., Si) or a compound material (e.g., GaAs). In some aspects, for example, a DBR layer can include Si, Ge, SiGe, SiGeSn, GaAs, GaN, GaP, GaSb, InP, InSb, a Group IV semiconductor, a Group III-V semiconductor, a Group II-VI semiconductor, graphene, SiC, or sapphire.

The term "reflectivity" or "reflectance" or "R" as used herein means the effectiveness of a surface to reflect radiation. Reflectivity (R) can be described as a percentage (e.g., R = <NUM>%), for example, R = <NUM>% means complete reflection of incident radiation and R = <NUM>% means no reflection (e.g., absorption) of incident radiation.

The term "cavity" as used herein means a layer or material that includes an active region configured to generate and/or detect radiation. Such an active region layer may be formed of a single element (e.g., Si), a compound material (e.g., GaAs), or several different materials (e.g., GaInAsSb/AlGaAsSb) to form one or more quantum wells or quantum dots. In some aspects, for example, a cavity can include Si, Ge, SiGe, SiGeSn, GaAs, GaN, GaP, GaSb, InP, InSb, a Group IV semiconductor, a Group III-V semiconductor, a Group II-VI semiconductor, graphene, SiC, or sapphire.

The term "intracavity" as used herein means a layer or material formed within the active region layer (e.g., doping), atop the active region layer, below the active region layer, or within the layered structure to form one or more electrical contacts to the active region.

The term "dielectric" as used herein means a layer or material that is electrically insulating. In some aspects, for example, dielectric can include oxide, nitride, oxynitride, ceramic, glass, spin-on-glass (SOG), polymer, plastic, thermoplastic, resin, laminate, high-k dielectric, and/or any other electrically insulating material.

The term "doping" or "doped" as used herein means that a layer or material contains a small impurity concentration of another element (dopant) which donates (donor) or extracts (acceptor) charge carriers from the parent material and therefore alters the conductivity. Charge carriers may be electrons or holes. A doped material with extra electrons is called n-type while a doped material with extra holes (fewer electrons) is called p-type.

The term "crystalline" as used herein means a material or layer with a single crystal orientation. In epitaxial growth or deposition, subsequent layers with the same or similar lattice constant follow the registry of the previous crystalline layer and therefore grow with the same crystal orientation or crystallinity. As will be understood by a person of ordinary skill in the art, crystal orientation, for example, <<NUM>> means the face of cubic crystal structure and encompasses [<NUM>], [<NUM>], and [<NUM>] orientations using the Miller indices. Similarly, for example, <<NUM>> encompasses [<NUM>] and [<NUM>-<NUM>], except if the material polarity is critical. Also, integer multiples of any one or more of the indices are equivalent to the unitary version of the index. For example, (<NUM>) is equivalent to (<NUM>).

The term "lattice matched" as used herein means that two crystalline layers have the same, or similar, lattice spacing such that the second layer will tend to grow isomorphically (e.g., same crystalline form) on the first layer.

The term "lattice constant" as used herein means the unstrained lattice spacing of the crystalline unit cell.

The term "lattice coincident" as used herein means that a crystalline layer has a lattice constant which is, or is close to, an integer multiple of the previous layer so that the atoms can be in registry with the previous layer.

The term "lattice mismatch" as used herein means the lattice constants of two adjacent layers are neither lattice matched nor lattice coincident. Lattice mismatch introduces elastic strain into the layered structure, for example, the second layer, as the second layer adopts the in-plane lattice spacing of the first layer. The strain is compressive where the second layer has a larger lattice constant and tensile where the second layer has a smaller lattice constant.

Where the strain is too great, the layered structure relaxes to minimize energy through defect generation, for example, dislocations, known as slip, or additional interstitial bonds, each of which allows the layer to revert towards its lattice constant. The strain may be too great due to a large lattice mismatch or due to an accumulation of small mismatches over many layers.

Lattice mismatch (Δa) between multiple layers can lead to increased strain in the layered structure. Lattice mismatch (Δa) can be normalized (e.g., Δa/a) and expressed as a percentage (%). The mismatch in lattice structures between any two layers (e.g., material <NUM> and material <NUM>) induces a strain between the two layers. Lattice strain induced by a second layer over a first layer is represented as a product of the lattice mismatch between the first and second layers and the second layer thickness: strain = Δa·t<NUM>.

Further, a first layer (e.g., material <NUM>) atop a substrate and a second layer (e.g., material <NUM>) atop the first layer are strain balanced with respect to the substrate if: <MAT> where Δa<NUM> is the lattice mismatch of material <NUM> to the substrate, t<NUM> is the thickness of the first layer, Δa<NUM> is the lattice mismatch of material <NUM> to the substrate, and t<NUM> is the thickness of the second layer. This is further described in <CIT>, which is incorporated by reference herein in its entirety.

The term "substantially no lattice mismatch" as used herein means a lattice mismatch of less than <NUM>% (e.g., Δa ≤ <NUM>%).

The term "deposition" as used herein means the depositing of a layer on another layer or substrate. Deposition encompasses epitaxy, PVD, CVD, powder bed deposition, and/or other known techniques to deposit material in a layer.

The term "lateral" or "in-plane" as used herein means parallel to the surface of the substrate and perpendicular to the growth direction.

The term "vertical" or "out-of-plane" as used herein means perpendicular to the surface of the substrate and in the growth direction.

The term "porous region" as used herein means a layer that includes air or vacuum pores, with the porosity defined as the proportion of the area which is occupied by the pores rather than the bulk (e.g., single) material (e.g., a percentage %). The porosity can vary through the thickness of the layer. For example, the layer may be porous in one or more sublayers. The layer may include an upper portion which is porous and a lower portion that is non-porous. The porosity may be constant or variable within the porous region. Where the porosity is variable, the porosity may be linearly varied through the thickness, or may be varied according to a different function, for example, quadratic, logarithmic, or a step function.

Alternatively, the layer may include one or more discrete, non-continuous portions (domains) that are porous with the remainder being non-porous (e.g., with bulk material properties). The portions may be non-continuous within the plane of a sublayer and/or through the thickness of the layer (e.g., horizontally and/or vertically with respect to the growth direction). The portions may be distributed in a regular array or irregular pattern across the layer and/or through the layer.

The term "substantially non-porous" as used herein means a layer with bulk material properties having a low porosity (e.g., less than <NUM>%) and long-range crystallinity. For example, a substantially non-porous layer is relatively crystalline and long-range crystallinity of the layer is not significantly affected by a porosification process. A substantially non-porous layer contains at least some porosity in order for an acid current (e.g., electrolyte) to pass through the substantially non-porous layer to a lower layer or sublayer located below the substantially non-porous layer.

The term "porosifying" or "porosification" as used herein means forming a porous region with a particular porosity in a layer or substrate. The porosity of a material is affected by electrolyte concentration, acid current density, acid current fluid velocity, anodization time, temperature, and/or material doping. Porosifying can include electrochemical (EC) etching or photoelectrochemical (PEC) etching to form one or more porous sublayers in a layer or substrate. For example, an acid current (e.g., hydrofluoric acid (HF) at <NUM> mA/cm<NUM> and <NUM>) can be periodically applied to a layer to form alternating first porous and second porous layers. This is further described in <CIT>.

The index of refraction (n) decreases with increasing porosity. The index of refraction determines how much the path of light is bent or refracted when entering the material and how fast light travels through the material (e.g., n = c/v, where c is the speed of light, <NUM> × <NUM><NUM> m/s). The refractive index of a porous material is based on the porosity and the refractive index of the non-porous base material. Increasing the porosity in a material can decrease the refractive index since the pores allow light to travel faster than in the base material (e.g., the empty pores approximate that of air (n ≈ <NUM>) or vacuum (n = <NUM>)).

For example, different alternating first porous and second porous sublayers can be formed by periodically changing an acid current (e.g., high porosity, low porosity, high porosity, etc.) such that the sublayers have alternating different indices of refraction (e.g., low-refractive index, high-refractive index, low-refractive index, etc.) to form a DBR. In another example, different alternating porous and substantially non-porous sublayers can be formed by periodically changing the acid current (e.g., first porosity, low porosity, first porosity, etc.) such that the sublayers have alternating different indices of refraction (e.g., low-refractive index, high-refractive index, low-refractive index, etc.) to form a DBR.

The term "porosification rate" as used herein means a rate of forming or etching a porous region in a layer. For example, a porosification rate of <NUM>/min forms a porous region (e.g., alternating first porous and second porous sublayers) having <NUM> micron thickness in <NUM> minute.

Numerical values, including endpoints of ranges, can be expressed herein as approximations preceded by the term "about," "substantially," "approximately," or the like. In such cases, other aspects include the particular numerical values. Regardless of whether a numerical value is expressed as an approximation, two aspects are included in this disclosure: one expressed as an approximation, and another not expressed as an approximation. It will be further understood that an endpoint of each range is significant both in relation to another endpoint, and independently of another endpoint.

Aspects of the disclosure can be implemented in hardware, firmware, software, or any combination thereof. Aspects of the disclosure can also be implemented as instructions stored on a machine-readable medium, which can be read and executed by one or more processors. A machine-readable medium can include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium can include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, and/or instructions can be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc..

As discussed above, a DBR is a reflector formed from multiple layers of alternating materials with alternating refractive indices (n). Planar DBR mirrors include multiple layers (e.g., pairs) with alternating high- and low-refractive indices. Each layer boundary causes a partial reflection of a wave (e.g., optical wave) and the partial reflections can constructively interfere to act as a high-quality reflector (e.g., reflectivity R ≥ <NUM>%) for a range of wavelengths. Increasing the number of pairs in a DBR increases the reflectivity (R), and increasing the refractive index contrast (Δn) increases both the reflectivity and bandwidth. DBRs are key components in VCSELs as well as other photonic, optical, and/or electronic devices (e.g., LEDs, RF switches) since DBRs can be used to form a cavity resonator (e.g., optical cavity).

A VCSEL is a type of semiconductor laser diode with emission perpendicular to the top and bottom surfaces. A cavity resonator (e.g., optical cavity) for a VCSEL can include an active region (e.g., one or more quantum wells or quantum dots) between two DBRs. Conventional VCSELs utilize multiple alternating Group III-V semiconductor layers (e.g., AlxGa<NUM>-xAs/AlyGa<NUM>-yAs, <NUM> ≤ x, y ≤ <NUM>, x ≠ y) that are epitaxially grown to form a DBR due to the periodically alternating refractive indices of the layers.

However, epitaxial growth of the alternating material layers is costly and time-consuming, taking upwards of <NUM> hours using standard MOCVD or MBE methods, which reduces throughput and yield. Further, epitaxial growth of multiple layers to form the DBR can introduce unwanted strain and/or defects into the layered stack. In addition, previous epitaxial DBRs require the same wavelength(s) to pass through the entire layered stack.

Aspects of porous DBR apparatuses, systems, and methods as discussed below can improve the speed and efficiency of manufacturing DBRs in a layered structure for photonic, optical, and/or electronic devices, reduce induced strain and/or defects in the layered structure from the manufacturing process, reduce the overall size (e.g., thickness) of the layered structure for a more compact and simplistic design, and increase manufacturing throughput and yield.

<FIG> illustrates a conventional layered structure <NUM>, not in accordance with the claimed invention. As shown in <FIG>, layered structure <NUM> can have thickness <NUM> and include substrate <NUM>, first epitaxial DBR layer <NUM>, optical cavity <NUM>, and second epitaxial DBR layer <NUM>. Layered structure <NUM> can be configured to form a VCSEL or other optical device. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, substrate <NUM> can be doped (e.g., n-type, n+) to provide current to optical cavity <NUM> and/or act as a platform for growing first epitaxial DBR layer <NUM>.

First epitaxial DBR layer <NUM> is configured to form a bottom DBR in layered structure <NUM>. First epitaxial DBR layer <NUM> is formed from multiple alternating epitaxial layers (e.g., AlGaAs/AlGaAs, GaSb/AlAsSb, or the like) of alternating refractive indices by MOCVD or MBE methods and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. First epitaxial DBR layer <NUM> takes about two hours to about five hours to form using MOCVD or MBE methods. In some aspects, first epitaxial DBR layer <NUM> can be a planar DBR mirror with alternating epitaxial layers of high- and low-refractive indices. In some aspects, first epitaxial DBR layer <NUM> can be doped (e.g., n-type, n+) to act as a contact to provide current to optical cavity <NUM>.

Optical cavity <NUM> is configured to generate light in layered structure <NUM>. Optical cavity <NUM> can include one or more quantum wells or quantum dots to generate laser light in between and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, optical cavity <NUM> can generate light wavelengths of about <NUM> to about <NUM>.

Second epitaxial DBR layer <NUM> is configured to form a top DBR in layered structure <NUM>. Similar to first epitaxial DBR layer <NUM>, second epitaxial DBR layer <NUM> is also formed from multiple alternating epitaxial layers (e.g., AlGaAs/AlGaAs, GaSb/AlAsSb, or the like) of alternating refractive indices by MOCVD or MBE methods and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. Second epitaxial DBR layer <NUM> takes about two hours to about five hours to form using MOCVD or MBE methods. In some aspects, second epitaxial DBR layer <NUM> can be a planar DBR mirror with alternating epitaxial layers of high- and low-refractive indices. In some aspects, second epitaxial DBR layer <NUM> can be doped (e.g., p-type, p+) to provide current to optical cavity <NUM>. In some aspects, second epitaxial DBR layer <NUM> can have the same materials in the multiple alternating epitaxial layers as in first epitaxial DBR layer <NUM>.

As discussed above, layered structure <NUM> is conventional and is costly and time-consuming to manufacture, taking upwards of ten hours or more to manufacture using standard MOCVD and MBE methods. Further, first and second epitaxial DBR layers <NUM>, <NUM> introduce unwanted strain and/or defects into layered structure <NUM> due to the numerous alternating epitaxial layers. Additionally, layered structure <NUM> is limited to outputting the same wavelength(s) through the entire stack (e.g., from substrate <NUM> to second epitaxial DBR layer <NUM>).

<FIG> illustrate layered structures <NUM>, <NUM>, <NUM>, <NUM>', <NUM>, according to various exemplary aspects. Although layered structure <NUM>, <NUM>, <NUM>, <NUM>', <NUM> is shown in <FIG>, respectively, as a stand-alone apparatus and/or system, the aspects of this disclosure can be used with other apparatuses, systems, and/or methods.

As shown in <FIG>, layered structure <NUM> which is not in accordance with the claimed invention, can have thickness <NUM> and include substrate <NUM>, second DBR layer <NUM>, cavity <NUM>, and first DBR layer <NUM>. Layered structure <NUM> can be configured to include a porous DBR (e.g., first DBR layer <NUM>) fabricated from a single material for faster manufacturing and reduced strain. Layered structure <NUM> can be further configured to form various photonic, optical, and/or electronic devices (e.g., VCSEL, LED, resonant cavity LED, optical detector, photodiode, wireless receiver, wireless transmitter, wireless transceiver, etc.). Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, substrate <NUM> can include a dielectric, a semiconductor, a compound semiconductor, and/or any other suitable material. In some aspects, substrate <NUM> can be monolithic. In some aspects, substrate <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM> and/or act as a platform for forming second DBR layer <NUM>. In some aspects, as shown in <FIG>, second DBR layer <NUM> can contact a bottom side of cavity <NUM> and first DBR layer <NUM> can contact a top side of cavity <NUM>. In some aspects, layered structure <NUM> forms a VCSEL, an LED, a resonant cavity LED, an optical detector, a wireless receiver, a wireless transmitter, a wireless transceiver, or a combination thereof.

Second DBR layer <NUM> is configured to form a bottom DBR in layered structure <NUM>. Similar to first epitaxial DBR layer <NUM>, second DBR layer <NUM> can be formed from multiple alternating epitaxial layers (e.g., AlGaAs/AlGaAs, GaSb/AlAsSb, or the like) of alternating refractive indices by MOCVD or MBE methods and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, second DBR layer <NUM> can be a planar DBR mirror with alternating epitaxial layers of high- and low-refractive indices. In some aspects, second DBR layer <NUM> can be doped (e.g., n-type, n+, n++) to act as a contact to provide current to cavity <NUM>. For example, as shown in <FIG>, second DBR layer <NUM> can include bottom contact <NUM> that is highly doped (e.g., n++). In some aspects, second DBR layer <NUM> can include an external conductive contact to provide current to cavity <NUM>. For example, as shown in <FIG>, bottom contact <NUM> can include a conductive layer (e.g., metal, metal-oxide, etc.).

Cavity <NUM> can include active region <NUM> and has thickness <NUM>. Active region <NUM> is configured to generate and/or detect radiation in layered structure <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, active region <NUM> can include one or more quantum wells or quantum dots to generate radiation in between. In some aspects, active region <NUM> can generate wavelengths of about <NUM> to about <NUM>. In some aspects, active region <NUM> can include a planar circuit and/or conductive pattern (e.g., transducer, antenna, transmitter, transceiver, etc.) to generate and/or detect radiation (e.g., EM radiation, acoustic radiation, etc.). For example, active region <NUM> can generate and/or detect wireless, RF, microwave, and/or acoustic radiation. In some aspects, cavity <NUM> can include an embedded contact (e.g., p-type, p+, p++, tunnel junction, buried tunnel junction (BTJ), etc.) to provide current to active region <NUM>. For example, as shown in <FIG>, cavity <NUM> can include top contact <NUM> (intracavity) that is highly doped (e.g., n++). In some aspects, layered structure <NUM> can include an external conductive top contact (e.g., metal, metal-oxide, etc.) to provide current to cavity <NUM>.

First DBR layer <NUM> is configured to form a top porous DBR in layered structure <NUM>. First DBR layer <NUM> is formed from a single material (e.g., dielectric, semiconductor, compound semiconductor, bulk material, etc.) and includes porous region <NUM> and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, thickness <NUM> of first DBR layer <NUM> is less than thickness <NUM> of second DBR layer <NUM>. Porous region <NUM> is formed by porosifying the single material. Porous region <NUM> includes alternating first and second porous sublayers <NUM>-<NUM> (shown in <FIG>, not in accordance with the claimed invention) of alternating refractive indices. In some aspects, first DBR layer <NUM> can be a planar DBR mirror with alternating layers of high- and low-refractive indices. For example, as shown in <FIG> and <FIG>, alternating first and second porous sublayers <NUM>-<NUM> can have alternating layers of high- and low-refractive indices. In some aspects, first DBR layer <NUM> can be doped (e.g., p-type, p+) to provide current to cavity <NUM>.

In some aspects, first DBR layer <NUM> can have substantially no lattice mismatch. For example, first DBR layer <NUM> can have a lattice mismatch of less than <NUM>% since first DBR layer <NUM> is a single material. In some aspects, a lattice mismatch between alternating first and second porous sublayers <NUM>-<NUM> can be less than <NUM>%. For example, alternating first and second porous sublayers <NUM>-<NUM> can have a lattice mismatch of less than <NUM>% since they are formed from the same single material. In some aspects, alternating first and second porous sublayers <NUM>-<NUM> can have first and second porosities, respectively. For example, alternating first and second porous sublayers <NUM>-<NUM> (e.g., high porosity, low porosity, high porosity, etc.) can form alternating sublayers of low and high indices of refraction. In some aspects, alternating first and second porous sublayers <NUM>-<NUM> can be alternating porous and substantially non-porous sublayers. For example, alternating first and second porous sublayers <NUM>-<NUM> (e.g., high porosity, low porosity, high porosity, etc.) can form alternating sublayers of low and high indices of refraction. In some aspects, alternating first and second porous sublayers <NUM>-<NUM> can have the same porosity. For example, alternating first and second porous sublayers <NUM>-<NUM> with the same porosity can form alternating sublayers of low and high indices of refraction by utilizing different porosification techniques for each porous sublayer (e.g., by varying the electrolyte concentration, acid current density, acid current fluid velocity, anodization time, temperature, and/or material doping).

In some aspects, the single material of first DBR layer <NUM> can be a dielectric. For example, the dielectric can be an oxide, nitride, oxynitride, ceramic, glass, SOG, polymer, plastic, thermoplastic, resin, laminate, or a combination thereof. In some aspects, the single material of first DBR layer <NUM> can be a semiconductor, a compound semiconductor, a bulk material, and/or any other suitable material. For example, the single material can be Si, Ge, SiGe, SiGeSn, GaAs, GaN, GaP, GaSb, InP, InSb, a Group III-V semiconductor, or sapphire.

As shown in <FIG>, layered structure <NUM> can have thickness <NUM> and include second DBR layer <NUM>, cavity <NUM>, and first DBR layer <NUM>. Layered structure <NUM> can be configured to include a porous DBR (e.g., first DBR layer <NUM>) fabricated from a single material for faster manufacturing and reduced strain. Layered structure <NUM> can be further configured to form various photonic, optical, and/or electronic devices (e.g., VCSEL, LED, resonant cavity LED, optical detector, photodiode, wireless receiver, wireless transmitter, wireless transceiver, etc.). Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, first DBR layer <NUM> can be formed from a substrate (e.g., wafer). For example, as shown in <FIG>, first DBR layer <NUM> is formed from substrate <NUM> that can include a dielectric, a semiconductor, a compound semiconductor, and/or any other suitable material. Substrate <NUM> is monolithic. In some aspects, substrate <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM> and/or act as a platform for forming first DBR layer <NUM>. In some aspects, as shown in <FIG>, first DBR layer <NUM> can contact a bottom side of cavity <NUM> and second DBR layer <NUM> can contact a top side of cavity <NUM>. In some aspects, layered structure <NUM> forms a VCSEL, an LED, a resonant cavity LED, an optical detector, a wireless receiver, a wireless transmitter, a wireless transceiver, or a combination thereof.

Second DBR layer <NUM> is configured to form a top DBR in layered structure <NUM>. Similar to second DBR layer <NUM> shown in <FIG>, second DBR layer <NUM> can be formed from multiple alternating epitaxial layers (e.g., AlGaAs/AlGaAs, GaSb/AlAsSb, or the like) of alternating refractive indices by MOCVD or MBE methods and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, second DBR layer <NUM> can be a planar DBR mirror with alternating epitaxial layers of high- and low-refractive indices. In some aspects, second DBR layer <NUM> can be doped (e.g., p-type, p+, p++) to act as a contact to provide current to cavity <NUM>. For example, as shown in <FIG>, second DBR layer <NUM> can include top contact <NUM> that is highly doped (e.g., p++). In some aspects, second DBR layer <NUM> can include an external conductive contact to provide current to cavity <NUM>. For example, as shown in <FIG>, top contact <NUM> can include a conductive layer (e.g., metal, metal-oxide, etc.).

Cavity <NUM> can include active region <NUM> and has thickness <NUM>. Active region <NUM> is configured to generate and/or detect radiation in layered structure <NUM>. The aspects of cavity <NUM> shown in <FIG>, for example, and the aspects of cavity <NUM> shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of cavity <NUM> shown in <FIG> and the similar features of the aspects of cavity <NUM> shown in <FIG>. In some aspects, cavity <NUM> can include an embedded contact (e.g., n-type, n+, n++, tunnel junction, BTJ, etc.) to provide current to active region <NUM>. For example, as shown in <FIG>, cavity <NUM> can include bottom contact <NUM> (intracavity) that is highly doped (e.g., n++). In some aspects, layered structure <NUM> can include an external conductive bottom contact (e.g., metal, metal-oxide, etc.) to provide current to cavity <NUM>.

First DBR layer <NUM> is configured to form a bottom porous DBR in layered structure <NUM>. First DBR layer <NUM> is formed from a single material (e.g., dielectric, semiconductor, compound semiconductor, bulk material, etc.) and includes porous region <NUM> and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. In some aspects, thickness <NUM> of first DBR layer <NUM> is less than thickness <NUM> of second DBR layer <NUM>. Porous region <NUM> is formed by porosifying the single material (e.g., substrate <NUM> shown in <FIG>). Porous region <NUM> includes alternating first and second porous sublayers <NUM>-<NUM> (shown in <FIG>) of alternating refractive indices. In some aspects, first DBR layer <NUM> can be a planar DBR mirror with alternating layers of high- and low-refractive indices. For example, as shown in <FIG> and <FIG>, alternating first and second porous sublayers <NUM>-<NUM> can have alternating layers of high- and low-refractive indices. In some aspects, first DBR layer <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM>.

The aspects of first DBR layer <NUM> shown in <FIG>, for example, and the aspects of first DBR layer <NUM> shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of first DBR layer <NUM> shown in <FIG> and the similar features of the aspects of first DBR layer <NUM> shown in <FIG>.

As shown in <FIG>, layered structure <NUM> can have thickness <NUM> and include second DBR layer <NUM>, cavity <NUM>, and first DBR layer <NUM>. Layered structure <NUM> can be configured to include two (<NUM>) porous DBRs (e.g., second DBR layer <NUM> and first DBR layer <NUM>) each fabricated from a single material for faster manufacturing and reduced strain. Layered structure <NUM> can be further configured to form various photonic, optical, and/or electronic devices (e.g., VCSEL, LED, resonant cavity LED, optical detector, photodiode, wireless receiver, wireless transmitter, wireless transceiver, etc.). Thickness <NUM> is about <NUM> to about <NUM>. First DBR layer <NUM> is formed from a substrate (e.g., wafer). For example, as shown in <FIG>, first DBR layer <NUM> can be formed from substrate <NUM> that can include a dielectric, a semiconductor, a compound semiconductor, and/or any other suitable material. Substrate <NUM> is monolithic. In some aspects, substrate <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM> and/or act as a platform for forming first DBR layer <NUM>. In some aspects, as shown in <FIG>, first DBR layer <NUM> can contact a bottom side of cavity <NUM> and second DBR layer <NUM> can contact a top side of cavity <NUM>. In some aspects, layered structure <NUM> forms a VCSEL, an LED, a resonant cavity LED, an optical detector, a wireless receiver, a wireless transmitter, a wireless transceiver, or a combination thereof.

Second DBR layer <NUM> is configured to form a top porous DBR in layered structure <NUM>. Second DBR layer <NUM> is formed from a single material (e.g., dielectric, semiconductor, compound semiconductor, bulk material, etc.) and includes porous region <NUM> and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. Porous region <NUM> is formed by porosifying the single material. Porous region <NUM> includes alternating first and second porous sublayers <NUM>-<NUM> (shown in <FIG>) of alternating refractive indices. In some aspects, second DBR layer <NUM> can be a planar DBR mirror with alternating layers of high- and low-refractive indices. For example, as shown in <FIG> and <FIG>, alternating first and second porous sublayers <NUM>-<NUM> can have alternating layers of high- and low-refractive indices. In some aspects, second DBR layer <NUM> can be doped (e.g., p-type, p+) to provide current to cavity <NUM>.

The aspects of first DBR layer <NUM> shown in <FIG>, for example, and the aspects of second DBR layer <NUM> shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of first DBR layer <NUM> shown in <FIG> and the similar features of the aspects of second DBR layer <NUM> shown in <FIG>.

Cavity <NUM> can include active region <NUM> and has thickness <NUM>. Active region <NUM> is configured to generate and/or detect radiation in layered structure <NUM>. The aspects of cavity <NUM> shown in <FIG> and cavity <NUM> shown in <FIG>, for example, and the aspects of cavity <NUM> shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of cavity <NUM> shown in <FIG> and cavity <NUM> shown in <FIG> and the similar features of the aspects of cavity <NUM> shown in <FIG>. In some aspects, cavity <NUM> can include one or more embedded contacts (e.g., n-type, n+, n++, p-type, p+, p++, tunnel junction, BTJ, etc.) to provide current to active region <NUM>. For example, as shown in <FIG>, cavity <NUM> can include bottom contact <NUM> (intracavity) that is highly doped (e.g., n++) and top contact <NUM> (intracavity) that is highly doped (e.g., p++). In some aspects, layered structure <NUM> can include an external conductive bottom contact (e.g., metal, metal-oxide, etc.) and an external conductive top contact (e.g., metal, metal-oxide, etc.) to provide current to cavity <NUM>. For example, as shown in <FIG>, layered structure <NUM>' with thickness <NUM>' can include bottom contact <NUM>' (e.g., n+ doped, metal, etc.) and top contact <NUM>' (e.g., p+ doped, metal, etc.).

First DBR layer <NUM> is configured to form a bottom porous DBR in layered structure <NUM>. First DBR layer <NUM> is formed from a single material (e.g., dielectric, semiconductor, compound semiconductor, bulk material, etc.) and includes porous region <NUM> and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. Porous region <NUM> is formed by porosifying the single material (e.g., substrate <NUM> shown in <FIG>). Porous region <NUM> includes alternating first and second porous sublayers <NUM>-<NUM> (shown in <FIG>) of alternating refractive indices. In some aspects, first DBR layer <NUM> can be a planar DBR mirror with alternating layers of high- and low-refractive indices. For example, as shown in <FIG> and <FIG>, alternating first and second porous sublayers <NUM>-<NUM> can have alternating layers of high- and low-refractive indices. In some aspects, first DBR layer <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM>.

As shown in <FIG>, layered structure <NUM>' can have thickness <NUM>' and include second DBR layer <NUM>, cavity <NUM>, and first DBR layer <NUM>. The aspects of layered structure <NUM> shown in <FIG>, for example, and the aspects of layered structure <NUM>' shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of layered structure <NUM> shown in <FIG> and the similar features of the aspects of layered structure <NUM>' shown in <FIG>. Layered structure <NUM>' includes external bottom contact <NUM>' (e.g., n+ doped, metal, etc.) and top contact <NUM>' (e.g., p+ doped, metal, etc.) rather than intracavity bottom and top contacts <NUM>, <NUM> as in layered structure <NUM> shown in <FIG>.

As shown in <FIG>, layered structure <NUM> can have thickness <NUM> and include DBR layer <NUM> and cavity <NUM>. Layered structure <NUM> can be configured to include a porous DBRs (e.g., DBR layer <NUM>) fabricated from a single material for faster manufacturing and reduced strain and an exposed cavity <NUM>. Layered structure <NUM> can be further configured to form various photonic, optical, and/or electronic devices (e.g., VCSEL, LED, resonant cavity LED, optical detector, photodiode, wireless receiver, wireless transmitter, wireless transceiver, etc.). Thickness <NUM> is about <NUM> to about <NUM>. DBR layer <NUM> is formed from a substrate (e.g., wafer). For example, as shown in <FIG>, DBR layer <NUM> can be formed from substrate <NUM> that can include a dielectric, a semiconductor, a compound semiconductor, and/or any other suitable material. Substrate <NUM> is monolithic. In some aspects, substrate <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM> and/or act as a platform for forming DBR layer <NUM>. In some aspects, as shown in <FIG>, DBR layer <NUM> can contact a bottom side of cavity <NUM> and a top side of cavity <NUM> can be exposed. In some aspects, layered structure <NUM> forms a VCSEL, an LED, a resonant cavity LED, an optical detector, a wireless receiver, a wireless transmitter, a wireless transceiver, or a combination thereof.

Cavity <NUM> can include active region <NUM> and has thickness <NUM>. Active region <NUM> is configured to generate and/or detect radiation in layered structure <NUM>. The aspects of cavity <NUM> shown in <FIG>, for example, and the aspects of cavity <NUM> shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of cavity <NUM> shown in <FIG> and the similar features of the aspects of cavity <NUM> shown in <FIG>. In some aspects, cavity <NUM> can include one or more embedded contacts (e.g., n-type, n+, n++, p-type, p+, p++, tunnel junction, BTJ, etc.) to provide current to active region <NUM>. For example, as shown in <FIG>, cavity <NUM> can include bottom contact <NUM> (intracavity) that is highly doped (e.g., n++) and top contact <NUM> (intracavity) that is highly doped (e.g., p++). In some aspects, layered structure <NUM> can include a lens and/or a filter on a top side of cavity <NUM>.

DBR layer <NUM> is configured to form a bottom porous DBR in layered structure <NUM>. DBR layer <NUM> is formed from a single material (e.g., dielectric, semiconductor, compound semiconductor, bulk material, etc.) and includes porous region <NUM> and has thickness <NUM>. Thickness <NUM> is about <NUM> to about <NUM>. Porous region <NUM> is formed by porosifying the single material (e.g., substrate <NUM> shown in <FIG>). Porous region <NUM> includes alternating first and second porous sublayers <NUM>-<NUM> (shown in <FIG>) of alternating refractive indices. In some aspects, DBR layer <NUM> can be a planar DBR mirror with alternating layers of high- and low-refractive indices. For example, as shown in <FIG> and <FIG>, alternating first and second porous sublayers <NUM>-<NUM> can have alternating layers of high- and low-refractive indices. In some aspects, DBR layer <NUM> can be doped (e.g., n-type, n+) to provide current to cavity <NUM>.

The aspects of first DBR layer <NUM> shown in <FIG>, for example, and the aspects of DBR layer <NUM> shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of first DBR layer <NUM> shown in <FIG> and the similar features of the aspects of DBR layer <NUM> shown in <FIG>.

<FIG> illustrates porosification system <NUM>, which may be used in the method according to the present invention. Although porosification system <NUM> is shown in <FIG> as a stand-alone apparatus and/or system, the aspects of this disclosure can be used with other apparatuses, systems, and/or methods, for example, layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>, manufacturing diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or flow diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

As shown in <FIG>, porosification system <NUM> can include illumination source <NUM>, bath <NUM>, and current source <NUM>. Porosification system <NUM> can be configured to porosify or form a porous region within a layer or substrate (e.g., layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>). Porosification system <NUM> can be further configured to form one or more porous sublayers in a layer or substrate (e.g., layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>). Porosification system <NUM> can be further configured to conduct EC etching, PEC etching, or a combination thereof to porosify the layer or substrate. In some aspects, a portion of a layer or substrate (e.g., in-plane or out-of-plane) can be exposed to an acid current such that the portion is etched and a porous region remains. In some aspects, a porosity of the porous region can be controlled by adjusting electrolyte concentration, acid current density, acid current fluid velocity, anodization time, temperature, material doping, illumination power, and/or illumination wavelength.

Illumination source <NUM> is configured to supplement EC etching of a layer or substrate (e.g., layered structure <NUM>) in bath <NUM> with PEC etching to form a porous region in the layer or substrate. PEC etching is dopant and bandgap selective and creates holes at the surface of the layer or substrate. Illumination source <NUM> can include a UV source (e.g., mercury lamp, arc lamp, etc.) and generate PEC illumination <NUM> over a portion or all of the layer or substrate. In some aspects, illumination source <NUM> can be a pulsed light source or include a mechanical modulator (e.g., chopper), an acousto-optical modulator (AOM), or an electro-optical modulator (EOM) to generate pulsed illumination having a particular frequency. In some aspects, illumination source <NUM> can have a power of about <NUM> mW to <NUM> W. In some aspects, illumination source <NUM> can include an optical filter to apply a particular wavelength(s) to the layer or substrate. In some aspects, illumination source <NUM> can be omitted for pure EC etching.

Bath <NUM> is configured to provide EC etching (e.g., chemical etch) of a layer or substrate (e.g., layered structure <NUM>) to form a porous region in the layer or substrate. Bath <NUM> can include electrolyte <NUM>, electrode <NUM>, and layered structure <NUM> (e.g., layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>). In some aspects, electrolyte <NUM> can include any material (e.g., acid, oxidizer, etc.) to facilitate EC etching of layered structure <NUM>. For example, electrolyte <NUM> can include hydrofluoric (HF) acid, hydrochloric (HCl) acid, hydrobromic (HBr) acid, sulfuric acid (H<NUM>SO<NUM>), nitric acid (HNO<NUM>), oxalic acid (C<NUM>H<NUM>O<NUM>), hydrogen peroxide (H<NUM>O<NUM>), or any other suitable acid or oxidizer. Electrode <NUM> can include any suitable conductor (e.g., metal, copper (Cu), aluminum (Al), platinum (Pt), etc.). In some aspects, bath <NUM> can maintain a temperature of about <NUM> to about <NUM>. In some aspects, layered structure <NUM> can include layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM> or a portion (e.g., layer) of layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>).

Current source <NUM> is configured to provide EC etching (e.g., current etch) of a layer or substrate (e.g., layered structure <NUM>) to form a porous region in the layer or substrate. Current source <NUM> can include cathode <NUM> and anode <NUM>. When combined, current source <NUM> and bath <NUM> form an acid current. As shown in <FIG>, cathode <NUM> can be connected to electrode <NUM> and anode <NUM> can be connected to layered structure <NUM> to complete the circuit. When current is applied, layered structure <NUM> is etched (e.g., porosified), with or without illumination source <NUM>, and current flow is away from layered structure <NUM> towards electrode <NUM>. Electrons resonate at pore tips in layered structure <NUM> and porosity extends through layered structure <NUM>. In some aspects, the acid current density is about <NUM> mA/cm<NUM> to about <NUM> mA/cm<NUM>. For example, the acid current density can be about <NUM> mA/cm<NUM> to about <NUM> mA/cm<NUM>. The lattice parameter of the starting material (e.g., layered structure <NUM>) remains relatively unchanged following the porosification process. In some aspects, a porosification rate in layered structure <NUM> can be about <NUM>/min to about <NUM>/min. For example, the porosification rate can be about <NUM>/min to about <NUM>/min.

<FIG> illustrate manufacturing diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM> for forming layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>, according to various exemplary aspects. It is to be appreciated that not all steps in <FIG> are needed to perform the disclosure provided herein. Further, some of the steps can be performed simultaneously, sequentially, and/or in a different order than shown in <FIG>. Manufacturing diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM> shall be described with reference to <FIG>. However, manufacturing diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are not limited to those example aspects.

As shown in <FIG>, not in accordance with the claimed invention, manufacturing diagram <NUM> is configured to form layered structure <NUM> shown in <FIG>. In step <NUM>, substrate <NUM> is selected. In step <NUM>, second DBR layer <NUM> is formed (e.g., deposited) atop substrate <NUM>. In some aspects, bottom contact <NUM> can be formed (e.g., doped n++) during step <NUM>. In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop second DBR layer <NUM>. In step <NUM>, top contact <NUM> is formed (e.g., doped p++) within cavity <NUM> (intracavity) or atop cavity <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, first DBR layer <NUM> is formed (e.g., deposited) with a single material atop cavity <NUM>. In step <NUM>, first DBR layer <NUM> is porosified (e.g., with porosification system <NUM> shown in <FIG>) to form porous region <NUM> with alternating first and second porous sublayers <NUM>-<NUM> to form a top porous DBR and layered structure <NUM> as shown in <FIG>.

As shown in <FIG>, manufacturing diagram <NUM> is configured to form layered structure <NUM> shown in <FIG>. In step <NUM>, substrate <NUM> is selected from a single material (e.g., bulk material). In step <NUM>, bottom contact <NUM> is formed (e.g., doped n++) as part of cavity <NUM> (intracavity) or atop substrate <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> and bottom contact <NUM>. In step <NUM>, second DBR layer <NUM> is formed (e.g., deposited) atop cavity <NUM>. In step <NUM>, substrate <NUM> is thinned. In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In some aspects, substrate <NUM> can be thinned by etching, polishing, grinding, chemical-mechanical polishing (CMP), or other suitable material reducing process. In step <NUM>, thinned substrate <NUM> (e.g., first DBR layer <NUM>) is porosified (e.g., with porosification system <NUM> shown in <FIG>) to form porous region <NUM> with alternating first and second porous sublayers <NUM>-<NUM> to form a bottom porous DBR and layered structure <NUM> as shown in <FIG>.

As shown in <FIG>, manufacturing diagram <NUM> is configured to form layered structure <NUM> shown in <FIG>. In step <NUM>, substrate <NUM> is selected from a single material (e.g., bulk material). In step <NUM>, bottom contact <NUM> is formed (e.g., doped n++) as part of cavity <NUM> (intracavity) or atop substrate <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> and bottom contact <NUM>, and top contact <NUM> is formed (e.g., doped p++) within cavity <NUM> (intracavity) or atop cavity <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, second DBR layer <NUM> is formed (e.g., deposited) with a single material atop cavity <NUM>. In step <NUM>, substrate <NUM> is thinned to form first DBR layer <NUM>. In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In some aspects, substrate <NUM> can be thinned by etching, polishing, grinding, CMP, or other suitable material reducing process. In step <NUM>, second DBR layer <NUM> and first DBR layer <NUM> are porosified (e.g., with porosification system <NUM> shown in <FIG>) to form porous region <NUM> with alternating first and second porous sublayers <NUM>-<NUM> to form a top porous DBR and porous region <NUM> with alternating first and second porous sublayers <NUM>-<NUM> to form a bottom porous DBR, respectively, to form layered structure <NUM> as shown in <FIG>.

As shown in <FIG>, manufacturing diagram <NUM> is configured to form layered structure <NUM>', similar to layered structure <NUM> shown in <FIG>. In step <NUM>, substrate <NUM> is selected from a single material (e.g., bulk material). In step <NUM>, substrate <NUM> is porosified (e.g., with porosification system <NUM> shown in <FIG>) to form porous region <NUM>' with alternating first and second porous sublayers <NUM>'-<NUM>' to form a bottom porous DBR. In some aspects, porous region <NUM>' can be formed approximately to a middle or midpoint depth of substrate <NUM>. In some aspects, for example, porous region <NUM>' can be formed by edge porosification wherein an edge portion of substrate <NUM> is exposed (e.g., fabrication mask, e.g., silicon nitride) and porosified laterally through the edge portion of substrate <NUM>. In some aspects, for example, porous region <NUM>' can be formed by applying a low current acid etch for a period of time until the acid etch reaches a middle of midpoint depth of substrate <NUM>, at which point porosification of substrate <NUM> can begin with a high current acid etch.

In step <NUM>, bottom contact <NUM> is formed (e.g., doped n++) as part of cavity <NUM> (intracavity) or atop substrate <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> and bottom contact <NUM>. In step <NUM>, second DBR layer <NUM> is formed (e.g., deposited) atop cavity <NUM>. In step <NUM>, substrate <NUM> (e.g., first DBR layer <NUM>) is thinned to form a bottom porous DBR and layered structure <NUM>'. In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned.

The aspects of layered structure <NUM> shown in <FIG>, for example, and the aspects of layered structure <NUM>' shown in <FIG> may be similar. Similar reference numbers are used to indicate features of the aspects of layered structure <NUM> shown in <FIG> and the similar features of the aspects of layered structure <NUM>' shown in <FIG>.

As shown in <FIG>, manufacturing diagram <NUM> is configured to form layered structure <NUM> shown in <FIG>. In step <NUM>, substrate <NUM> is selected from a single material (e.g., bulk material). In step <NUM>, bottom contact <NUM> is formed (e.g., doped n++) as part of cavity <NUM> (intracavity) or atop substrate <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> and bottom contact <NUM>. In step <NUM>, top contact <NUM> is formed (e.g., doped p++) within cavity <NUM> (intracavity) or atop cavity <NUM> (intracavity) as a separate external conductive contact. In step <NUM>, substrate <NUM> is thinned. In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In some aspects, substrate <NUM> can be thinned by etching, polishing, grinding, chemical-mechanical polishing CMP, or other suitable material reducing process. In step <NUM>, thinned substrate <NUM> (e.g., DBR layer <NUM>) is porosified (e.g., with porosification system <NUM> shown in <FIG>) to form porous region <NUM> with alternating first and second porous sublayers <NUM>-<NUM> to form a bottom porous DBR and layered structure <NUM> as shown in <FIG>.

<FIG> illustrate flow diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM> to describe the process of forming layered structures <NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>, according to various exemplary aspects. It is to be appreciated that not all steps in <FIG> are needed to perform the disclosure provided herein. Further, some of the steps can be performed simultaneously, sequentially, and/or in a different order than shown in <FIG>. Flow diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM> shall be described with reference to <FIG>. However, flow diagrams <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are not limited to those example aspects.

As shown in <FIG>, not in accordance with the claimed invention, flow diagram <NUM> describes the process to form layered structure <NUM> shown in <FIG> and <FIG>. In step <NUM>, as shown in the example of <FIG> and <FIG>, second DBR layer <NUM> is formed (e.g. deposited) atop substrate <NUM> to form a bottom DBR. In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop second DBR layer <NUM> with active region <NUM> to generate and/or detect radiation. In step <NUM>, first DBR layer <NUM> being a single material is formed (e.g., deposited) atop cavity <NUM>. In step <NUM>, first DBR layer <NUM> is porosified to form a top DBR. In some aspects, first DBR layer <NUM> is porosified at a porosification rate of about <NUM>/min to about <NUM>/min. In some aspects, first DBR layer <NUM> is manufactured in a time of about two minutes to about five minutes. For example, first DBR layer <NUM> manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in layered structure <NUM>.

As shown in <FIG>, flow diagram <NUM> describes the process to form layered structure <NUM> shown in <FIG> and <FIG>. In step <NUM>, as shown in the example of <FIG> and <FIG>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> with active region <NUM> to generate and/or detect radiation. In step <NUM>, second DBR layer <NUM> is formed (e.g. deposited) atop cavity <NUM> to form a top DBR. In step <NUM>, substrate <NUM> is thinned (e.g., first DBR layer <NUM>), substrate <NUM> being a single material (e.g., bulk material). In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In step <NUM>, first DBR layer <NUM> is porosified to form a bottom DBR. In some aspects, first DBR layer <NUM> is porosified at a porosification rate of about <NUM>/min to about <NUM>/min. In some aspects, first DBR layer <NUM> is manufactured in a time of about two minutes to about five minutes. For example, first DBR layer <NUM> manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in layered structure <NUM>.

As shown in <FIG>, flow diagram <NUM> describes the process to form layered structure <NUM> shown in <FIG> and <FIG>. In step <NUM>, as shown in the example of <FIG> and <FIG>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> with active region <NUM> to generate and/or detect radiation. In step <NUM>, second DBR layer <NUM> being a single material is formed (e.g., deposited) atop cavity <NUM>. In step <NUM>, substrate <NUM> is thinned (e.g., first DBR layer <NUM>), substrate <NUM> being a single material (e.g., bulk material). In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In step <NUM>, second DBR layer <NUM> and first DBR layer <NUM> are porosified to form a top DBR and a bottom DBR, respectively. In some aspects, second DBR layer <NUM> and/or first DBR layer <NUM> is porosified at a porosification rate of about <NUM>/min to about <NUM>/min. In some aspects, second DBR layer <NUM> and/or first DBR layer <NUM> is manufactured in a time of about two minutes to about five minutes. For example, second DBR layer <NUM> and/or first DBR layer <NUM> manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in layered structure <NUM>.

As shown in <FIG>, not in accordance with the claimed invention, flow diagram <NUM> describes the process to form layered structure <NUM>' shown in <FIG>, similar to layered structure <NUM> shown in <FIG> and <FIG>. In step <NUM>, as shown in the example of <FIG>, <FIG>, and <FIG>, substrate <NUM> being a single material (e.g., bulk material) is porosified to form a bottom DBR (e.g., first DBR layer <NUM>). In step <NUM>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> with active region <NUM> to generate and/or detect radiation. In step <NUM>, second DBR layer <NUM> is formed (e.g. deposited) atop cavity <NUM> to form a top DBR. In step <NUM>, substrate <NUM> is thinned (e.g., first DBR layer <NUM>). In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In some aspects, substrate <NUM> (e.g., first DBR layer <NUM>) is porosified at a porosification rate of about <NUM>/min to about <NUM>/min. In some aspects, first DBR layer <NUM> is manufactured in a time of about two minutes to about five minutes. For example, first DBR layer <NUM> manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in layered structure <NUM>'.

As shown in <FIG>, flow diagram <NUM> describes the process to form layered structure <NUM> shown in <FIG> and <FIG>. In step <NUM>, as shown in the example of <FIG> and <FIG>, cavity <NUM> is formed (e.g., deposited) atop substrate <NUM> with active region <NUM> to generate and/or detect radiation. In step <NUM>, substrate <NUM> is thinned (e.g., DBR layer <NUM>), substrate <NUM> being a single material (e.g., bulk material). In some aspects, step <NUM> can be omitted and substrate <NUM> can be porosified without being thinned. In step <NUM>, DBR layer <NUM> is porosified to form a bottom DBR. In some aspects, DBR layer <NUM> is porosified at a porosification rate of about <NUM>/min to about <NUM>/min. In some aspects, DBR layer <NUM> is manufactured in a time of about two minutes to about five minutes. For example, DBR layer <NUM> manufacturing is faster, high quality (e.g., R ≥ <NUM>%), more efficient, and reduces induced strain and/or defects in layered structure <NUM>.

It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by those skilled in relevant art(s) in light of the teachings herein.

The following examples are illustrative, but not limiting, of the aspects of this disclosure. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in the field, and which would be apparent to those skilled in the relevant art(s), are within the scope of the invention which is defined by the claims.

While specific aspects have been described above, it will be appreciated that the aspects can be practiced otherwise than as described. The description is not intended to limit the scope of the claims.

The aspects have been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof.

Claim 1:
A method (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) of forming a layered structure (<NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>), the method comprising:
forming a layer (<NUM>, <NUM>, <NUM>, <NUM>) over a monolithic substrate, the substrate being a single material, wherein the layer is coupled to the substrate, the layer comprising an active region (<NUM>, <NUM>, <NUM>, <NUM>) to generate radiation or detect radiation; and thereafter
porosifying the substrate to form a porous region (<NUM>, <NUM>', <NUM>, <NUM>', <NUM>, <NUM>) to form a first distributed Bragg reflector ,DBR, the porous region comprising alternating first porous and second porous sublayers (<NUM>-<NUM>, <NUM>-<NUM>, <NUM>'-<NUM>', <NUM>-<NUM>, <NUM>-<NUM>) of the single material to form the first DBR, wherein the first porous and second porous sublayers have different porosities.