35 results about "Photoelectrochemical etching" patented technology

The invention is directed to methods for direct patterning of silicon. The invention provides the ability to fabricate complex surfaces in silicon with three dimensional features of high resolution and complex detail. The invention is suitable, for example, for use in soft lithography as embodiments of the invention can quickly create a master for use in soft lithography. In an embodiment of the invention, electrochemical etching of silicon, such as a silicon wafer, for example, is conducted while at least a portion of the silicon surface is exposed to an optical pattern. The etching creates porous silicon in the substrate, and removal of the porous silicon layer leaves a three-dimensional structure correlating to the optical pattern.

A method for ensuring the structural integrity of III-nitride opto-electronic or opto-mechanical air-gap nano-structured devices, comprising (a) performing ion beam implantation in a region of the III-nitride opto-electronic and opto-mechanical air-gap nano-structured device, wherein the milling significantly locally modifies a material property in the region to provide the structural integrity; and (b) performing a band-gap selective photo-electro-chemical (PEC) etch on the III-nitride opto-electronic and opto-mechanical air-gap nano-structured device. The method can be used to fabricate distributed Bragg reflectors or photonic crystals, for example. The method also comprises the suitable design of distributed Bragg reflector (DBR) structures for the PEC etching and the ion-beam treatment, the suitable design of photonic crystal distributed Bragg reflector (PCDBR) structures for PEC etching and the ion-beam treatment, the suitable placement of protection layers to prevent the ion-beam damage to optical activity and PEC etch selectivity, and a suitable annealing treatment for curing the material quality after the ion-beam treatment.

A photoelectrochemical (PEC) etch is performed for chip shaping of a device comprised of a III-V semiconductor material, in order to extract light emitted into guided modes trapped in the III-V semiconductor material. The chip shaping involves varying an angle of incident light during the PEC etch to control an angle of the resulting sidewalls of the III-V semiconductor material. The sidewalls may be sloped as well as vertical, in order to scatter the guided modes out of the III-V semiconductor material rather than reflecting the guided modes back into the III-V semiconductor material. In addition to shaping the chip in order to extract light emitted into guided modes, the chip may be shaped to act as a lens, to focus its output light, or to direct its output light in a particular way.

Photoelectrochemical (PEC) etching is restricted to a group III nitride semiconductor-barrier interface to laterally etch or undercut the target group III nitride. The barrier interface is provided by the transparent sapphire substrate on which the target group III nitride is epitaxially grown or by a layer of material in intimate contact with the target group III nitride material and having a bandgap sufficiently high to make it resistant to PEC etching. Due to the first orientation in which this effect was first observed, it has been named backside-Illuminated photoelectrochemical (BIPEC) etching. It refers to a preferential etching at the semiconductor-barrier layer interface. The assembly can be exposed to light from any direction to effectuate bandgap-selective PEC etching. An opaque mask can be applied to limit the lateral extent of the photoelectrochemical etching.

In a method of forming a gate recess, on a surface of an epitaxial wafer including an epitaxial substrate, having a semiconductor layer having the band gap energy varying therein in the depth-wise direction, and a SiN surface protective layer, having a sidewall forming a gate opening and coating the surface of the epitaxial substrate, ultraviolet light having its energy equivalent to the band gap energy of the specific semiconductor layer is irradiated, while the specific semiconductor layer is photoelectrochemically etched from the gate opening with the SiN surface protective layer used as a mask. The gate recess free from plasma ion-induced damage is thus obtained.

A method for photoelectrochemical (PEC) etching of a p-type semiconductor layer simply and efficiently, by providing a driving force for holes to move towards a surface of a p-type cap layer to be etched, wherein the p-type cap layer is on a heterostructure and the heterostructure provides the driving force from an internal bias generated internally in the heterostructure; generating electron-hole pairs in a separate area of the heterostructure than the surface to be etched; and using an etchant solution to etch the surface of the p-type layer.

A method for fabricating a semiconductor laser device, by etching facets using a photoelectrochemical (PEC) etch, so that the facets are sufficiently smooth to support optical modes within a cavity bounded by the facets.

Quantum-size-controlled photoelectrochemical (QSC-PEC) etching provides a new route to the precision fabrication of epitaxial semiconductor nanostructures in the sub-10-nm size regime. For example, quantum dots (QDs) can be QSC-PEC-etched from epitaxial InGaN thin films using narrowband laser photoexcitation, and the QD sizes (and hence bandgaps and photoluminescence wavelengths) are determined by the photoexcitation wavelength.

The invention provides a method for forming a light emitting device. A first substrate is provided. A plurality of patterned masks is formed on the first substrate, or on a semiconductor epitaxial layer grown on the first substrate, or the first substrate is etched to form a plurality of trenches, followed by performing an epitaxial lateral overgrowth process to grow an epitaxy layer over the first substrate. A light emitting structure is formed on the epitaxy layer. A first electrode layer is formed on the light emitting structure. The light emitting structure is wafer bonded to a second substrate. A photoelectrochemical etching process is performed to lift off the first substrate from the epitaxy layer.

A method for forming a periodic structure is disclosed. A structural layer and an optical modulation element are provided. A light is emitted to pass through the optical modulation element to irradiate interference strips on the structural layer. A photoelectrochemical etching (PEC) is performed to form the periodic structure according the interference strips irradiated on the structural layer.

A method of performing a photoelectrochemical (PEC) etch on an exposed surface of a semipolar {20-2-1} III-nitride semiconductor, for improving light extraction from and for enhancing external efficiency of one or more active layers formed on or above the semipolar {20-2-1} III-nitride semiconductor.

The invention provides a single-flow micro-pore heat exchanger. A heat exchange core comprises a bottom plate, a top plate and at least one layer of cold medium sheet and at least one layer of thermal medium sheet which are clamped between the bottom plate and the top plate. The cold medium sheets and the thermal medium sheets are overlapped alternatively. A plurality of parallel cold medium flow channels are etched in the cold medium sheets, a plurality of parallel thermal medium flow channels are etched in the thermal medium sheets, and the flow directions of the thermal medium flow channel and the flow directions of the cold medium flow channels are vertical. By means of the heat exchanger, the heat transfer area density is high, a photoelectrochemical etching and atomic diffusion bonding technology is used, and accordingly, channel structures of various shapes can be formed, and leakage and vibration losses can be reduced effectively; the heat exchanger is stable in structure, good in safety, small in size, low in weight, convenient to mount and maintenance-free.

The invention discloses a preparation method of a novel InGaN-based photo-anode, which is specifically implemented according to the following steps of: 1, carrying out constant-voltage etching on a GaN multi-layer structure by adopting a photoelectrochemical etching technology in an acid solution to prepare a mesoporous GaN mirror; and 2, by taking a mesoporous GaN mirror as a substrate, firstly,epitaxially growing an InGaN/GaN layer by adopting an MOCVD technology, modulating an In component through energy band engineering, modulating a band gap of the In component, and then, evaporating anohmic contact electrode by adopting an electron beam evaporation technology to prepare an InGaN-based photo-anode. and the method provided by the invention can be used for preparing the photo-anode electrode with low starting voltage, high efficiency and strong stability.

The invention relates to an ultraviolet distributed Bragg mirror based on porous AlGaN and a preparation method thereof. The ultraviolet distributed Bragg mirror based on porous AlGaN includes a substrate, a nucleation layer, a buffer layer, a stress regulation layer, and Alx(Ga1-x)N layers and porous Aly(Ga1-y)N layers which are in a multi-cycle alternately stacking mode. The invention further provides the preparation method of the ultraviolet distributed Bragg mirror based on the porous AlGaN, the nucleation layer, the buffer layer, the stress regulation layer, and the Alx(Ga1-x)N layers andthe porous Aly(Ga1-y)N layers in a multi-cycle alternately stacking mode are stacked on the substrate, photoelectrochemical etching is then performed, the AlGaN layer is made porous by band gap selectivity of photoelectrochemical reaction, and the ultraviolet distributed Bragg mirror based on the porous AlGaN is formed.

The invention relates to the field of process processing, in particular to a method for forming a nanopillar array on a semiconductor substrate, which comprises the following steps of: providing the semiconductor substrate, coating photoresist on the semiconductor substrate, and photoetching on the photoresist to form a pattern; a mask layer is formed on the prepared pattern, and light propagation is stopped through the mask layer; according to the method, a semiconductor substrate containing a mask layer is subjected to electrochemical etching, patterns with different heights are obtained by controlling etching conditions, then the mask layer is removed, the semiconductor substrate comprises a silicon carbide substrate slice or a gallium nitride substrate slice, the length and width of the semiconductor substrate are 2-8 inches, the thickness of the semiconductor substrate is 200-500 micrometers, and the thickness of the semiconductor substrate is 1-10 micrometers. An electron beam direct writing technology is adopted in the photoetching mode, and the pattern is in a nanopillar array shape. By adopting the photoelectrochemical etching method, the large-scale preparation of the nano-pillar array with controllable diameter size and height can be realized on the surface of the wafer-level wide bandgap semiconductor substrate slice, the process is simple, and the yield is high.

The invention concerns a method for tuning at a targeted resonance wavelength at least one micro and/or nanophotonic resonator, the resonator having dimensions defining resonance wavelength of said resonator, the resonator being immersed in a fluid containing ions so that the resonator is surrounded by said fluid, wherein the method comprises a step of injecting light, having a light wavelength equal to the resonance wavelength, into the resonator, so that the injected light resonates within the resonator and triggers a photo-electrochemical etching process enabled by the surrounding fluid containing ions, said etching process being enhanced by the optical resonance which amplifies light intensity in the photonic resonator, the etching decreasing dimensions of the photonic resonator, hereby lowering and tuning the resonance wavelength of the photonic resonator.