7 results about "Threading dislocations" patented technology

This application provides an apparatus and method for reducing the density of through-type dislocation defects in silicon carbide crystals. The apparatus includes an insulation component formed by an upper insulation layer, a first outer insulation layer, and a lower insulation layer. The insulation component is provided with gas exchange channels. By placing a crucible containing a silicon carbide seed crystal and silicon carbide raw material into the insulation component and placing them together into a single crystal growth furnace, silicon carbide crystal is grown according to the parameters set for each growth stage to obtain an N-type silicon carbide crystal. When in the isothermal section, N2 is introduced into the single crystal growth furnace in a cycle of n periods according to a first flow rate state and a second flow rate state. Nitrogen is intentionally doped into the silicon carbide crystal during the growth process through the gas exchange channels to increase the conversion probability and ejection probability of through-type dislocations to basal plane dislocations and stacking faults in the N-type silicon carbide crystal. This solves the problem of high dislocation density in SiC single crystals grown by the current PVT method.

An embodiment of the present invention provides a semiconductor epitaxial structure and a method for preparing a semiconductor epitaxial structure, relating to the field of semiconductor epitaxial technology. The semiconductor epitaxial structure includes a substrate, a nucleation layer and a buffer layer. The present invention forms a nucleation layer on the substrate and then forms a buffer layer on the nucleation layer, wherein the nucleation layer includes multiple layers of periodically doped and repeatedly arranged semiconductor periodic stacks, so that the nucleation layer forms a doped superlattice structure with different doping types. The embodiment of the present invention uses doped superlattice structures with different doping types to improve the crystal quality of the nucleation layer. The embodiment of the present invention utilizes the formed doped superlattice to reduce epitaxial layer threading dislocations and obtain an epitaxial film with high crystal quality, and can simply and efficiently obtain a high-quality nucleation layer, reduce epitaxial layer threading dislocations, and thus obtain an epitaxial film with high crystal quality.

The present invention provides a semiconductor light-emitting element and a method for manufacturing the same. The epitaxial stack comprises an N-type semiconductor layer, an active region, a P-type semiconductor layer, and a V-shaped pit extending through the active region. Furthermore, a static charge collection layer is provided between the N-type semiconductor layer and the active region, with the tip of the V-shaped pit extending into the static charge collection layer. The N-type semiconductor layer has threading dislocations. Thus, the static charge collection layer collects static charge on the lower surface of the epitaxial stack (i.e., the N-type semiconductor layer side). The threading dislocations and the V-shaped pits then form a leakage path, transporting the static charge to the surface of the epitaxial stack (i.e., the P-type semiconductor layer side) to neutralize the accumulated positive charge. This prevents static charge from accumulating on the lower surface of the epitaxial stack, reduces the risk of electrostatic breakdown of the semiconductor light-emitting element, and improves the anti-static capability of the semiconductor light-emitting element.

A light emitting element includes an n-type semiconductor, a p-type semiconductor, and an active layer between the n-type semiconductor and the p-type semiconductor, threading dislocations are formed in the n-type semiconductor, and openings are formed on a surface of the n-type semiconductor based on the threading dislocations.

The application provides a method for identifying penetrating dislocations in silicon carbide, and the method comprises the following steps: performing preliminary etching on a silicon carbide sample to be identified; selecting a suitable diffraction vector; calculating relevant parameters corresponding to X-ray topography detection under the selected diffraction vector by using Bragg diffraction principle, the relevant parameters containing an incident angle; observing TSD and TED etch pits of the preliminary etched silicon carbide sample; recording an included angle between a line connecting the highest point and the lowest point of the selected etch pit and a horizontal line; obtaining an average value of the included angle of the selected etch pit; multiplying the average value of the included angle by a fixed coefficient to obtain a coefficient included angle; comparing the coefficient included angle with the incident angle of the selected diffraction vector; if the coefficient included angle is greater than the incident angle, directly performing X-ray topography detection; otherwise, etching again; and identifying by using an image of the X-ray topography detection. The application can effectively realize positioning and counting of different types of dislocations in silicon carbide.

The invention discloses a nitride semiconductor epitaxial structure for improving blue-green dual-wavelength luminous intensity and a growth method of the nitride semiconductor epitaxial structure. The epitaxial structure sequentially comprises a buffer layer, an undoped GaN layer, an undoped GaN layer, an N-type GaN layer, a stress release layer, a stress release layer, a green light multi-quantum well structure, a V-type defect filling layer, a low-temperature opening Pits layer, a defect blocking layer, a blue light multi-quantum well structure, an electron buffer layer, an electron blocking layer, a P-type GaN layer, an InGaN contact transition layer and a P-type contact layer. Wherein the green light multi-quantum well adopts a wide-well narrow-barrier design to relieve lattice strain and piezoelectric polarization effect; a three-layer defect regulation and control structure is arranged between the green light area and the blue light area, and through stress induction and dislocation conversion, dislocation is prevented from penetrating to extend to the blue light area, and the crystal quality is improved. According to the growth method, the epitaxy of each functional layer is controlled in stages under the conditions of different temperature zones and V / III ratios, and the construction of the high-quality multi-quantum well integrated structure is realized.

The invention discloses a preparation method of a nitride semiconductor laser. The method comprises the following steps: providing a gallium nitride substrate; sequentially growing a P-type waveguide layer, a quantum well layer and an N-type waveguide layer on the gallium surface of the gallium nitride substrate; wherein the doping concentration of the P-type waveguide layer is gradually changed along the growth direction; firstly removing the gallium nitride substrate, and then bonding a heat dissipation heat sink on one side, far away from the quantum well layer, of the P-type waveguide layer; or, a heat dissipation heat sink is bonded on the side, away from the quantum well layer, of the N-type waveguide layer, and then the gallium nitride substrate is removed. The gallium surface serves as a growth surface, heat scattering is facilitated, the high-power output performance is improved, the P-type waveguide layer is formed firstly, the crystal quality and the doping effect of the P-type waveguide layer can be improved, the hole transmission path is shortened, the non-radiative recombination loss is reduced, meanwhile, the doping concentration of the P-type waveguide layer is gradually changed, and the efficiency is improved. Lattice mismatch of the substrate and the epitaxial layer can be absorbed step by step through staged lattice matching, and penetration dislocation is reduced.