103results about How to "Raise the barrier height" patented technology

The invention discloses a GaN-based LED structure and a formation method thereof. The GaN-based LED structure comprises a substrate; a GaN buffer layer formed on the substrate; a first-doping-type GaN layer arranged on the GaN buffer layer; a quantum well luminous layer arranged on the first-doping-type GaN layer; a second-doping-type GaN layer arranged on the quantum well luminous layer; an electronic barrier layer arranged between the quantum well luminous layer and a P-doping-type GaN layer, wherein the electronic barrier layer comprises a block structure layer and a superlattice structure layer, the forbidden band width of the block structure layer being larger than that of the GaN, and the superlattice structure layer is used for adjusting the energy band inclination degree between the P-doping-type GaN layer and the block structure layer so as to reduce hole barrier height; and a P electrode and an N electrode. The GaN-based LED structure adopts a composite structure of the block structure layer and the superlattice structure layer, so that composite luminescence efficiency of electron holes in the quantum well luminous layer is greatly improved; and the GaN-based LED structure has the advantage of simple structure and the like.

The invention discloses a method for manufacturing a medium / nitride composite structure enhanced field effect transistor, which comprises the steps of: sequentially growing a AlGaN buffer layer, a GaN channel layer, a AlN inserting layer, a AlGaN barrier layer and a AlInN cap layer on a substrate; and forming a AlInN / AlGaN / AlN composite front barrier and a GaN / AlGaN back barrier into a high electronic air tightness external channel well limited by strong electrons. The thick AlInN cap layer with lattice match remarkably improves the electronic air tightness of an external channel, and the high and wide barriers provided by the AlInN cap layer strengthen the quantum restriction of the channel well, thus the serial resistance of the external channel is lowered and the ohmic contact resistance is reduced. After the AlInN layer is corroded by using a dry method channeling process and the AlGaN barrier layer is thinned, a Si3N4 medium layer with set thickness is deposited by using an atom layer deposition (ALD) process, thus the quantum restriction of an internal channel well is strengthened, and the ON state current of the element is improved by band distortion of a heterojunction, caused in a way that an electron wave function does not permeate into the barrier layer, under the condition that a large grid voltage change is ensured. A negative space charge is introduced on the surface of the Si3N4 medium layer by using a fluorine plasma process, thus the barrier height is increased, electron air in the internal channel well is consumed fully to ensure that the inner channel is pinched off under zero grid voltage. An ideal module enhancing work is realized.

The invention discloses a CNTs@alpha-Fe2O3 heterojunction composite material-based acetone gas sensor and a preparation method thereof, and belongs to the technical field of gas sensors. The acetone gas sensor comprises an insulating alumina ceramic tube substrate with two parallel and separate annular gold electrodes on the outer surface, a semiconductor metal oxide gas sensitive material coated on the outer surface of the insulating alumina ceramic tube substrate and the gold electrodes, and a nichrome heating coil arranged in the insulating alumina ceramic tube, wherein each gold electrode is provided with a platinum wire; the sensitive material is a CNTs and alpha-Fe2O3 nano-rod-compounded heterojunction hierarchical structure nanomaterial. The sensor has the advantages of being simple in structure, low in price, relatively small in volume, solid and durable, is suitable for massive production; and the gas-sensitivity characteristic testing result shows that the sensor can detect low-concentration acetone, has excellent long-term stability and has an important application prospect in detection and alarming of acetone leakage in industrial production and medical detection.

The invention discloses a lateral epitaxial technique based longitudinal structure AlGaN / GaN HEMT device and a manufacture method thereof. The device comprises a substrate, a current blocking layer and an epitaxial layer, wherein the current blocking layer is formed on the substrate; the epitaxial layer laterally epitaxially grows on the current blocking layer; a current conducting through hole is formed in the current blocking layer. According to the invention, the current blocking layer acts as an insulation layer, so that the problems that the two-dimensional electron gas concentration, self-diffusion, high electricity leakage and the like are caused by ion implantation damage due to Mg doping, barrier height improvement by Mg ion implantation and formation of a similar insulation layer by Al ion implantation in a traditional technology can be solved; meanwhile, the defects of high cost, long time consumption, technology complexity and the like due to secondary epitaxial growth are also prevented; in addition, a clearance region formed by incomplete healing is isolated via F ion implantation, so that the clearance region is not involved in the device structure, and the problems of electric leakage and the like caused by the clearance region are relieved effectively.

The present invention provides a technology for improving the barrier height of an electrode layer and a semiconductor layer. The semiconductor device comprises a semiconductor layer which is formed by semiconductors, and an electrode layer, wherein at least one part of the semiconductor layer is in Schottky connection with the electrode layer; the electrode layer comprises a first layer and a second layer successively from the semiconductor layer side; the first layer is mainly formed by nickel, and the film thickness is 50-200nm; the second layer is mainly formed by at least one metal of palladium, platinum and iridium; and the film thickness of the second layer is greater than the film thickness of the first layer.

The present invention is method of raising the coercive force of multilayer magnetic metal film with antiferromagnetic material. Multilayer Pt / [CoCr / Pt]5 / FeMn / Pt film is formed through depositing on cleaned glass substrate by means of using one magnetically controlled sputtering instrument. The multilayer magnetic metal film has the advantages of small thickness, excellent vertical magnetic anisotropy and high coercive force, and is suitable for use in ultrahigh density vertical magnetic record. In addition, the deposited film needs no annealing treatment, so that the present invention has also the advantages of low cost, simple preparation, etc and is suitable for future application.

The invention relates to a SiC MOS capacitor of an Al2O3 / LaAlO3 / SiO2 stacking gate medium layer and a manufacturing method. According to the capacitor, a SiC substrate is a heavy-doped SiC substrate layer, and a light-doped SiC epitaxial layer is arranged on the SiC substrate layer. The stacking gate medium layer comprises a lower SiO2 transition layer, an LaAlO3 layer and an Al2O3 covering layer. The lower SiO2 transition layer is arranged on the SiC epitaxial layer, the LaAlO3 layer is arranged on the lower SiO2 transition layer and provided with the Al2O3 covering layer, and a positive electrode and a negative electrode are connected with the surface of the Al2O3 covering layer and the back surface of the SiC substrate respectively. According to the SiC MOS capacitor of the stacking gate medium layer, the interface state density and boundary trap density are lowered, the MOS channel mobility is increased, gate leakage current is reduced, the voltage endurance capability of the medium layer is improved, and the quality and reliability of the SiC MOS capacitor are improved.

The invention belongs to the technical field of a semiconductor and relates to a gate-ballast structure RF AlGaN / GaN HEMTs device and a preparation method thereof. The device includes a AlGaN / GaN substrate on SiC, a gate, a source and a drain, wherein the gate is a doped polysilicon, and square resistance is in a range of 20-40omega / sq. The doped polysilicon is taken as a gate, barrier potential height is high, a gate leakage is smaller compared with a conventional Ni / Au schottky gate, power consumption of a radio frequency power device is reduced, efficiency is improved, and the doped polysilicon has relatively low Rg and has the ballast resistor function. The device can be applied to a multi-finger gate device AlGaN / GaN HEMTs, through adjusting Lg length, the purpose of optimizing Wg length is achieved, heat radiation of the device is effectively improved, the device can be further applied to AlGaN / GaN HEMTs, and the polysilicon gate can be biased by wider Vgs swing.