GALLIUM NITRIDE-BASED SEMICONDUCTOR STACKED STRUCTURE, METHOD FOR FABRICATION THEREOF, GALLIUM NITRIDE-BASED SEMICONDUCTOR DEVICE AND LAMP USING THE DEVICE

摘要

A gallium nitride-based semiconductor stacked structure includes a single crystal substrate, a low-temperature buffer layer grown at a low temperature in a region contiguous to the single crystal substrate and a gallium nitride-based semiconductor layer overlying the low-temperature buffer layer. The low-temperature buffer layer possesses therein a single crystal layer formed of a hexagonal A1XGaGN-based Group III nitride material containing gallium predominantly over aluminum, wherein 0.5 G = 1 and X + G = 1. The single crystal layer has crystal defects at a smaller density on a (1.0.-1.0.) crystal face than on a (1.1.-2.0.) crystal face. A method for the production of the gallium nitride-based semiconductor stacked structure includes forming on a single crystal substrate a low-temperature buffer layer grown at a low temperature falling in a range of 250°C to 500°C, forming a gallium nitride-based semiconductor layer on the low-temperature buffer layer and forming in the low-temperature buffer layer a single crystal layer made of a hexagonal AlXGaGN-based Group III nitride material containing gallium predominantly over aluminum, in which 0.5 G =1,X + G = 1, by causing gallium raw material to reach the surface of the substrate before aluminum raw material.