Method for improving electrical properties and optical properties of gallium nitride through laser irradiation on gallium nitride epitaxial wafer

Abstract

The invention discloses a method for improving the electrical properties and the optical properties of gallium nitride through laser irradiation on a gallium nitride epitaxial wafer and belongs to the field of preparation of materials. According to the method, first, the GaN epitaxial wafer is preprocessed, contaminated attachments, organic residue and the like on the surface of the GaN epitaxial wafer are removed, surface lattice defects are overcome, a 248-nm excimer laser is adopted for irradiating the GaN epitaxial wafer, the single pulse energy density ranges from 0.15 J / cm<2> to 0.6 J / cm<2>, through test, the photoluminescence of the irradiated sample changes remarkably, the defect luminescence peak strength in the position of 455 nm (2.72 eV) is the highest and increased obviously compared with that of the GaN epitaxial wafer before irradiation, the defect luminescence peak strength can be six times that of the GaN epitaxial wafer before irradiation to the maximum extent, and all those can be attributed to the counterdiffusion phenomenon and the surface recystallization effect of surface atoms of the sample. A magnetron sputtering method is adopted for deposition of Ni(30 nm) / Au (100 nm) metal electrodes on the surface of the sample, then, the carrier concentration, the surface resistivity and the like are tested, and the result shows that the ohmic contact of the sample is improved to a certain extent after irradiation.

Description

technical field [0001] The invention belongs to the field of material preparation. Background technique [0002] As an emerging material with rich physical properties, wide bandgap semiconductors represented by materials such as gallium nitride and silicon carbide are playing an increasingly important role in current production and life. Especially in recent years, blue LEDs based on GaN have developed rapidly. [0003] The bandgap of GaN material is direct bandgap type, and its bandgap width is 3.39eV at room temperature, which belongs to the category of wide bandgap semiconductors, and generally has a high quantum efficiency during carrier recombination. The GaN material has a direct band gap, which means that it has a wide band gap, and is very suitable for making blue, green and ultraviolet light-emitting devices (such as LEDs) and ultraviolet light detection devices. Its electron saturation rate, breakdown electric field, thermal conductivity, and band gap are higher ...

AI Technical Summary

Problems solved by technology

However, the lattice mismatch between the sapphire substrate and the GaN material is large, resulting in a large dislocation density in the epitaxially grown GaN material, which affects the crystal quality and many electrical and optical properties of the material.

It is precisely because of this that the epitaxial growth of high-quality GaN materials is very difficult, and the development of its growth technology is also very slow

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