42results about How to "Reduce crystal defect density" patented technology

An AlGaInP layer is formed on a substrate made of GaAs, and an AlGaAs layer is formed on the AlGaInP layer via a buffer layer therebetween. The buffer layer has a thickness of about 1.1 nm and is made of AlGaInP whose Ga content is smaller than that of the AlGaInP layer. The buffer layer may alternatively be made of AlGaAs whose Al content is smaller than that of the AlGaAs layer.

Disclosed herein is a nitride semiconductor light emitting device, which is improved in luminance and reliability. The light emitting device, comprises an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer sequentially formed on a substrate, an n-side electrode formed on a portion of an upper surface of the n-type nitride semiconductor layer, and at least one intermediate layer formed between the substrate and the n-type nitride semiconductor layer. The intermediate layer has a multilayer structure of three or more layers having different band-gaps, and is positioned below the n-side electrode.

The present invention solves the problem of conventional group-III nitride semiconductor LED in that, since the LED driving current is supplied only from a pad electrode serving also as an ohmic electrode, the driving current cannot diffuse over a wide range of the light-emitting region and a group-III nitride semiconductor LED having high light emission intensity cannot be successfully provided. A group-III nitride semiconductor LED having high light emission intensity, which is fabricated using a stacked layer structure obtained by providing a surface ohmic electrode, a window layer including an electrically conducting transparent oxide crystal layer and a pad electrode on an electrically conducting substrate through a boron phosphide (BP)-based buffer layer to allow the driving current to diffuse over a wide range of the light-emitting region is provided.

The invention provides a vertical group III-nitride light emitting device improved in external extraction efficiency and a method for manufacturing the same. The method includes forming an undoped GaN layer and an insulating layer on a basic substrate. Then, the insulating layer is selectively etched to form an insulating pattern, and an n-doped Al_xGa_yIn_(1-x-y)N layer, an active layer and a p-doped Al_mGa_nIn_(1-m-n)N layer are sequentially formed on the insulating pattern. A conductive substrate is formed on the p-doped Al_mGa_nIn_(1-m-n)N layer. The basic substrate, the undoped gaN layer and the insulating pattern are removed, and an n-electrode is formed on a part of the exposed surface of the n-doped Al_xGa_yIn_(1-x-y)N layer.

A GaN-based semiconductor light-emitting element capable of suppressing the occurrence of piezoelectric spontaneous polarization in the thickness direction of an active layer and reducing the driving voltage of a light-emitting diode is provided. The GaN-based semiconductor light-emitting element has a structure with a first GaN-based compound semiconductor layer 21 having the top face parallel to the a-plane and having a first conductivity type, an active layer 22 having the top face parallel to the a-plane, a second GaN-based compound semiconductor layer 23 having the top face parallel to the a-plane and having a second conductivity type, and a contact layer 24 composed of a GaN-based compound semiconductor and having the top face parallel to the a-plane, stacked in that order. The GaN-based semiconductor light-emitting element further includes a first electrode 25 disposed on the first GaN-based compound semiconductor layer 21 and a second electrode 26 disposed on the contact layer 24.

A semiconductor device includes a semiconductor substrate that includes an IGBT region. A first lifetime control layer extending along a planar direction of the semiconductor substrate is provided in a range in a drift region that is closer to the rear surface than an intermediate portion of the semiconductor substrate in a thickness direction. A crystal defect density in the first lifetime control layer is higher than any of a crystal defect density in a region adjacent to the first lifetime control layer on the rear surface side and a crystal defect density in a region adjacent to the first lifetime control layer on a front surface side. A crystal defect density in a region between the first lifetime control layer and the rear surface is lower than a crystal defect density in a region between the first lifetime control layer and the front surface.

Provided are a high-quality non-polar/semi-polar semiconductor device with reduced defect density and improved internal quantum efficiency and light extraction efficiency, and a manufacturing method thereof. The manufacturing method is a method for manufacturing a semiconductor device, in which a template layer and a semiconductor device structure are formed on a sapphire substrate having a crystal plane for growing a non-polar or semi-polar nitride semiconductor layer. The sapphire substrate is etched to form uneven patterns, and the template layer including a nitride semiconductor layer and a GaN layer is formed on the sapphire substrate in which the uneven patterns are formed.

The invention provides a manufacture method of a GaN-based semiconductor light-emitting diode. The manufacture method includes the steps of forming of a GaN substrate and deposition of a p-type contact layer, an active layer, an n-type electronic barrier layer, an n-type transition layer and an n-type contact layer on the GaN substrate, wherein forming of the GaN substrate includes the steps: placing a GaN wafer into a high-temperature and high-pressure device at the normal temperature and under the normal pressure; heating and pressurizing the GaN wafer simultaneously for 10-15 minutes, wherein the heating temperature is 820-880 DEG C, and the pressurizing pressure is 4.1-4.6GPa; stopping heating to enable the GaN wafer to be cooled to the normal temperature; slowly releasing pressure to enable the GaN wafer to be recovered to the normal pressure; and taking the GaN wafer out after annealing in the high-temperature and high-pressure device for 20-30minutes. By the manufacture method, crystal defect density in a light-emitting diode substrate can be obviously reduced, the performance of the light-emitting diode is improved, and the service life of the light-emitting diode is prolonged.

Provided are a ZnO-based substrate having a surface suitable for crystal growth, and a method of manufacturing the ZnO-based substrate. The ZnO-based substrate is made in a way that almost no hydroxide groups exist on a crystal growth-side surface of a Mg_xZn_1-xO substrate (0≦x<1). To this end, as a method of treating the substrate, a final treatment to be applied on the crystal growth-side surface of the Mg_xZn_1-xO substrate (0≦x<1) is acidic wet etching at pH 3 or lower. Thereby, it is possible to prevent production of a hydroxide of Zn, and to reduce the density of crystal defects in a thin film formed on the ZnO-based substrate.

A method for manufacturing a single-crystal 4H-SiC substrate includes: preparing a flat 4H-SiC bulk single-crystal substrate; and epitaxially growing a first single-crystal 4H-SiC layer having recesses on the 4H-SiC bulk single-crystal substrate, wherein the first single-crystal 4H-SiC layer has a thickness of X (μm), the recesses have a diameter Y (μm) no smaller than 0.2*X (μm) and no larger than 2*X (μm), and a depth of Z (nm) no smaller than (0.95*X (μm) +0.5 (nm)) and no larger than 10*X (μm).

A substrate with a second semiconductor layer and a second mask film formed thereon is subjected to a heat treatment in an oxidizing atmosphere. Thus, second oxidized regions are formed through oxidization of the second semiconductor layer in regions of the second semiconductor layer that are not covered by the second mask film. At the same time, a second base layer is formed in each region that is interposed by the second oxidized regions. Then, the second mask film is removed, and a third semiconductor layer is selectively grown on the surface of the second base layer that is exposed between the second oxidized regions so as to cover the second oxidized regions, after which the first oxidized regions and the second oxidized regions covering the entire upper surface of the substrate are removed.

A semiconductor stacking structure according to the present invention comprises: a monocrystalline substrate which is disparate from a nitride semiconductor; an inorganic thin film which is formed on a substrate to define a cavity between the inorganic thin film and the substrate, wherein at least a portion of the inorganic thin film is crystallized with a crystal structure that is the same as the substrate; and a nitride semiconductor layer which is grown from a crystallized inorganic thin film above the cavity. The method and apparatus for separating a nitride semiconductor layer according the present invention mechanically separate between the substrate and the nitride semiconductor layer. The mechanical separation can be performed by a method of separation of applying a vertical force to the substrate and the nitride semiconductor layer, a method of separation of applying a horizontal force, a method of separation of applying a force of a relative circular motion, and a combination thereof.

The invention discloses a method for manufacturing a p-type GaAs-based laser diode. The method comprises the following steps: forming a GaAs substrate, and depositing a p-type coating layer, a p-type photoconductive layer, an active layer, an n-type barrier layer, an n-type photoconductive layer and an n-type coating layer in sequence. A method for forming the GaAs substrate comprises the following steps: putting a GaAs wafer in a high-temperature and high-pressure device; pressurizing while heating the GaAs wafer for 10-15 minutes at the heating temperature of 860-890 DEG C and the pressurizing pressure of 5.0-5.5GPa; ending heating and pressurizing so as to recover the GaAs wafer to the normal temperature and normal pressure; annealing for 20-30 minutes in the high-temperature and high-pressure device, and then, taking out the GaAs wafer. According to the method, the crystal defect density in the substrate of the light emitting diode can be obviously reduced, the performance of the laser diode is improved, and the service life of the laser diode is prolonged.

The invention discloses a manufacturing method for an N-shaped GaAs substrate laser diode. The manufacturing method comprises the steps that a GaAs substrate is formed, and an n-shaped coating layer, an n-shaped light guide layer, an active layer, a p-shaped barrier layer, a p-shaped light guide layer and a p-shaped coating layer are sequentially deposited. The forming method of the GaAs substrate comprises the steps that a GaAs wafer is placed in a high-temperature high-pressure device, the GaAs wafer is heated and pressurized, the heating temperature ranges from 860 DEG C to 890 DEG C, pressure ranging from 5.0 GPa to 5.5 GPa is exerted, and the GaAs wafer is heated and pressurized for 10 minutes to 15 minutes; heating and pressing are stopped, and the GaAs wafer returns to a normal temperature and pressure state; annealing is conducted for 20 minutes-30 minutes in the high-temperature high-pressure device, and the GaAs wafer is taken out. According to the method, crystal defect density of the substrate of the laser diode can be obviously reduced, performance of the laser diode is enhanced, and service life of the laser diode is prolonged.

The invention provides an organic photoelectric transistor, which belongs to the technical field of a semiconductor material. The organic photoelectric transistor successively comprises a silicon substrate layer, gold electrodes and a metal zinc phthalocyanine nano crystal active layer; wherein the metal zinc phthalocyanine nano crystal active layer covers the gold electrodes and an area between the gold electrodes. The metal zinc phthalocyanine nano crystal active layer in the transistor provided by the invention has excellent near-infrared spectral absorption characteristics, so that the response performance of the photosensitive transistor for near-infrared spectrum can be improved; the metal zinc phthalocyanine nano crystal is prepared by adopting an ultrasonic technology, and the crystal defect density is low, so that the adsorption of molecules such as O2, H2O and CO2 in the air in the photosensitive transistor active layer can be effectively reduced, and the stability of a device in an atmosphere environment can be improved; and meanwhile, the field effect carrier migration rate is excellent, so that the optical response of the photosensitive transistor can be effectively improved.

The invention discloses a manufacturing method of a GaN substrate laser diode. The manufacturing method comprises the following steps of: forming a GaN substrate, and sequentially depositing an n type coating layer, an n type light guide layer, an active layer, a p type barrier layer, a p type light guide layer and a p type coating layer, wherein the method for forming the GaN substrate comprises the steps of putting a GaN wafer into a high-temperature and high-pressure device, and pressurizing the GaN wafer when heating the GaN wafer, wherein the heating temperature is 820-880 DEG C, the pressurizing pressure is 4.1-4.6 GPa, and the pressurizing is kept for 10-15min; stopping heating and pressurizing to enable the GaN wafer to restore to constant temperature and constant pressure; and after annealing in the high-temperature and high-pressure device for 20-30min, taking out the GaN wafer. With the adoption of the method, the crystal defect density in the laser diode substrate can be obviously reduced, the performance of the laser diode is improved, and the service life of the laser diode is prolonged.