80results about How to "Reduced ohmic contact resistance" patented technology

The present invention recites a new method for manufacturing Group III-N field-effect devices, such as HEMT, MOSHFET, MISHFET devices or MESFET devices, grown by Metal-Organic Vapor Phase Expitaxy, with higher performance (power), by covering the surface with a thin SiN layer on the top AlGaN layer, in the reactor where the growth takes place at high temperature, prior cooling down the structure and loading the sample out of the reactor, as well as a method to produce some HEMT transistors on those heterostructures, by depositing the contact on the surface without any removal of the SiN layer by MOCVD. The present invention recites also a device.

The objective of the present invention is to provide a semiconductor device of a hetero-junction field effect transistor that is capable of obtaining a high output and a high breakdown voltage and a manufacturing method of the same.

The present invention is a semiconductor device of a hetero-junction field effect transistor provided with an Al_xGa_1-xN channel layer with a composition ratio of Al being x (0<x<1) formed on a substrate, an Al_yGa_1-yN barrier layer with a composition of Al being y (0<y≦1) formed on the channel layer, and source/drain electrodes and a gate electrode formed on the barrier layer, wherein the composition ratio y is larger than the composition ratio x.

The invention discloses an aluminum paste for a solar energy battery. The aluminum paste for solar energy battery comprises an aluminum powder, a copper powder, a non-leaded glass powder and organic carriers, wherein the organic carriers are composed of organic solvents and organic addition agents, the aluminum powder is of sphere and /or of squamelliform, the aluminum powder has thick grains andthin grains; and the non-leaded glass powder adopts the glass system of lanthanum, boron and zinc. The preparation method includes uniformly mixing the raw materials of the non-leaded glass powder, subjecting the powder to heating and thermal insulation in a high temperature muffle furnace, then quenching the melted glass powder grains and grinding the grains; mixing and uniformly stirring the organic solvents and organic addition agents in proportion; weighing the aluminum powder, the copper powder, the non-leaded glass powder and the organic carriers, uniformly stirring the mixture in a container, then subjecting the mixture to grinding in a three-roll grinder and finally obtaining the uniform aluminum paste for the solar energy battery. On the premise of meeting the requirement of electrical properties of the solar energy battery, the requirement of non-leaded environmental protection can also be met.

A semiconductor structure having mesa structure comprising: a lower semiconductor layer; an upper semiconductor layer having a higher band gap than, and in direct contact with, the lower semiconductor layer to form a two-dimension electron gas (2DEG) region between the upper semiconductor layer. The 2DEG region has outer edges terminating at sidewalls of the mesa. An additional electron donor layer has a band gap higher than the band gap of the lower layer disposed on sidewall portions of the mesa structure and on the region of the 2DEG region terminating at sidewalls of the mesa. An ohmic contact material is disposed on the electron donor layer. In effect, a sideway HEMT is formed with the electron donor layer, the 2DEG region and the ohmic contact material increasing the concentration of electrons (i.e., lowering ohmic contact résistance) all along the contact between the lower semiconductor layer and the electron donor layer.

A semiconductor process for treating a metal gate includes the following steps. A metal gate including a main conductive material on a substrate is provided. A H₂/N₂ plasma treatment process is performed to reduce the main conductive material.

The invention discloses a GaN-based MS grid enhancement type high electron mobility transistor and a manufacture method thereof which mainly resolve the problems of low current density and poor reliability of a GaN-based enhancement type device. The structure of the device is that a transition layer (2) and a GaN main buffer layer (3) are sequentially arranged on a lining (1), a groove (4) is etched in the middle of the GaN main buffer layer, an AlGaN main barrier layer (5) is respectively arranged above the GaN mian buffer layer (3) on two sides of the groove, and a GaN auxiliary buffer layer (6) and an AlGaN auxiliary barrier layer (7) are sequentially arranged on the inner wall of the groove and the surface of the AlGaN main barrier layer (5) on two sides of the groove. A source electrode (8), a drain electrode (9), a grid electrode (11) and a medium layer (10) are arranged on the AlGaN secondary barrier layer (7). The source electrode (8) and the drain electrode (9) are respectively located on two sides above the AlGaN auxiliary barrier layer (7), the grid electrode (11) is located in the middle above the AlGaN auxiliary barrier layer (7), and the medium layer (10) is distributed on an area outside the source electrode, the drain electrode and the grid electrode. The transistor has the advantages of being good in enhancement type characteristic, high in current density, high in breakdown voltage, simple and mature in manufacture process and high in reliability, thereby being capable of being used in high temperature switch devices and digital circuits.

The invention provides a carbon nanotube composite thin film field emission cathode preparation method. The carbon nanotube composite thin film field emission cathode preparation method includes the following steps that: S1, nanotube/TiC/Ti composite materials are prepared; S2, the nanotube/TiC/Ti composite materials and nano filling particles are mixed according to at the mass ratio of 5:1 to 1:5, and the mixture is added to an organic solvent, and ultrasound is adopted to perform dispersion, and a first slurry can be formed; S3, the first slurry is transplanted on a silver electrode, and a nanotube composite film can be formed; S4, the nanotube composite film is put into a sintering furnace so as to be subjected to vacuum sintering or reducing atmosphere sintering for more than 15 minutes under temperature from 200 DEG C to 600 DEG C; S5, Ti on the surface of the sintered carbon nanotube composite film is corroded and removed through using a corrodent, and a carbon nanotube/TiC emission tip is exposed, and a carbon nanotube composite thin film field emission cathode can be formed. With the carbon nanotube composite thin film field emission cathode prepared by the invention adopted, adhesion and electrical contact between the emitter and the base of a carbon nanotube can be improved, and field emission performance can be improved.

The invention provides a solar cell and a manufacturing method thereof. The manufacturing method comprises the following steps of: providing a substrate, wherein the substrate comprises a body layer and a diffusion layer covering the front surface of the body layer; carrying out partial heavy doping on the diffusion layer to form a first secondary grid line; forming a refraction-reducing layer on the front surface of the substrate; forming a discontinuous second secondary grid line above the first secondary grid line; forming a continuous main grid line and a third secondary grid line above the second secondary grid line; and sintering the substrate. According to the solar cell and the manufacturing method thereof provided by the invention, the third secondary grid line does not contact the substrate, and the second secondary grid line and the substrate are in point contact, so that the compounding of current carriers on the surface of the substrate is reduce; in addition, the partial heavy doping is carried out on the diffusion layer to realize the partial heavy doping at a partial optical contact part of a front electrode and the substrate, so that ohmic contact resistance between the front electrode of the solar cell and the substrate is reduced as compared with that in the prior art, and the photoelectric conversion efficiency of the solar cell is improved.

The invention discloses a method of reducing GaN HEMT device ohm contact resistance. The method comprises the following steps of Si3N4 and SiO2 composite dielectric layer growing on a GaN heterojunction material; (2) ohm area thin layer Ni evaporating and stripping; (3) Ni metal nanocluster making and SiO2 dielectric layer etching; (4) photoresist mask layer making; (5) photoresist mask layer etching through oxygen plasma; (6) Si3N4 and SiO2 composite dielectric layer etching; (7) GaN heterojunction micropore making; (8) evaporating/stripping/annealing to form ohm contact. By means of the method, problems of high GaN ohm contact resistivity and a bad metal morphology are solved. The method has the following advantages that (1) the ohm alloy temperature can be lowered; the ohm metal surface and edge morphology can be improved; (2) the micro channel dimension can be controlled through nanodots; the dimension can reach a nanometer level; an electron beam technical preparation way is not required; the technical time consumption is low; (3) and low ohm contact resistance can be acquired.

The invention discloses a method for reducing the ohmic contact resistance of a wide band gap semiconductor device, wherein the material of the wide band gap semiconductor device is III- V-group wide-band gap semiconductor material that comprises a substrate, a buffer lay, a channel layer and an alloy barrier layer sequentially arranged from bottom to top. That method comprise the following steps:depositing a passivation layer; 2, coating photoresist and forming a photoresist window; 3, etching that passivation layer and for a window of the passivation layer; 4, coating a nano ball; 5, forming a nano groove; 6, coating photoresist and forming a photoresist window; 7, evaporating the electron beam or magnetron sputtering the multi-layer metal; Step 8, peeling off the multi-layer metal; Step 9: Rapidly carrying out thermal annealing to form ohmic contact. The method of the invention greatly increases the contact area between the electrode metal and the wide band gap semiconductor, reduces the ohmic contact resistance of the wide band gap semiconductor device, enhances the device performance, improves the process efficiency, and reduces the process cost.

The invention relates to a low-pressure diffusion process applied to polycrystalline black silicon solar cells, which comprises the following steps: (1) allowing a silicon wafer to entering a tube; (2) performing constant temperature processing; (3) performing low temperature oxidation, generating a thin oxide layer on a surface of the silicon wafer to make the subsequent phosphorus source deposition more uniform; (4) performing low temperature deposition, uniformly depositing a phosphorus source on the surface of the silicon wafer; (5) performing high temperature propulsion, allowing the phosphorus source to diffuse into the silicon wafer, wherein during high temperature propulsion, the temperature is 820-850 DEG C, the nitrogen flow rate is 1000-3000sccm, the dry oxygen is 0-1000sccm, the furnace pressure is 50-150mbar, and the time is 10-20 minutes; (6) performing secondary diffusion, wherein during the secondary diffusion, the temperature is 800-850 DEG C, the nitrogen flow rate is1000-3000sccm, the source nitrogen is 0-400sccm, the dry oxygen is 0-1000sccm, the furnace pressure is 50-150mbar, the time is 2-10 minutes; (7) performing cooling; (8) performing nitrogen filling, allowing the pressure inside the pipe to reach the atmospheric pressure so that a furnace door is opened; and (9) performing discharging. The present invention improves the uniformity of the square resistance after diffusion of polycrystalline black silicon.

The invention provides a GaN transistor and a manufacturing method thereof. The method comprises the steps of forming a non-doped GaN layer on a surface of a silicon substrate, and forming an AlGaN layer on a surface of the non-doped GaN layer; depositing a layer of silicon nitride on the surface of the AlGaN layer to form a dielectric layer; etching the dielectric layer, the AlGaN layer and the non-doped GaN layer to form a drain contact hole and a source contact hole; and growing N-type doped GaN layers in the drain contact hole and the source contact hole, forming a drain on the N-type doped GaN layer in the drain contact hole, and forming a source on the N-type doped GaN layer in the source contact hole. With the GaN transistor and a manufacturing method thereof, provided by the invention, the ohmic contact resistance can be reduced, the device current is increased, and the integral performance of the device is improved.

The invention discloses a manufacturing method of low-temperature ohmic contact of a III group nitride electronic device. The manufacturing method comprises the steps of: injecting N type impurities in a III group nitride ohmic contact region; depositing ohmic metal on the III group nitride ohmic contact region injected with the N type impurities; and adopting a microwave annealing technology to achieve ohmic contact at low temperature. After the N type impurities are injected to the III group nitride ohmic contact region, the manufacturing method further comprises the step of adopting the microwave annealing technology to activate the injected N type impurities. The microwave annealing technology utilizes the microwave annealing technology to achieve the low-temperature activation of the injected N type impurities in III group nitrides, so as to form an N type heavily-doped layer, increase electronic tunnelling probability, and reduce ohmic contact resistance; furthermore, the manufacturing method can enhance the interface reaction between the ohmic metal and the III group nitride semiconductor, reduce contact-potential barrier, improve ohmic contact area, and further reduce the contact resistance.

The invention provides a manufacturing method of an ohmic contact electrode based on an AlGaN/GaN HEMT. The method comprises the following stesp: successively depositing a silicon nitride passivation layer and a tetraethoxysilane oxide layer above an aluminum gallium nitride barrier layer; etching the silicon nitride passivation layer and the tetraethoxysilane oxide layer at a left-side area and a right-side area to form ohmic etching holes; performing cleaning processing on the aluminum gallium nitride barrier layer below the ohmic etching holes successively by use of a DHF solution, an SC1 solution and an SC2 solution; in the ohmic etching holes, depositing an ohmic electrode metal layer above the ohmic etching holes and the tetraethoxysilane oxide layer, and performing annealing processing on the AlGaN/GaN HEMT with the ohmic electrode metal layer deposited thereon; and performing photoethcing and etching on the ohmic electrode metal layer at an intermediate area above the tetraethoxysilane oxide layer so as to form the ohmic contact electrode. According to the invention, good ohmic contact is formed between the ohmic electrode contact layer and the aluminum gallium nitride barrier layer, and thus ohmic contact resistance of a device is effectively reduced.

The invention discloses a large-power vertical structure LED epitaxial structure. The large-power vertical structure LED epitaxial structure includes a pre-paved Al layer, an AlN buffer layer, an AlGaN buffer layer, a u-type GaN layer, a first graphene layer, an n-type GaN layer, a multi-quantum well, a p-type GaN layer, and a second graphene layer, wherein all the above layers and the multi-quantum well are grown on an Si substrate; and the first graphene layer and the second graphene layer are formed by vapor deposition. The large-power vertical structure LED epitaxial structure has better photoelectric performance and has wide application.