Influence of SiH4 treatment time on the properties of GaN films grown on in-situ SiNx patterned sapphire substrate

Abstract

Sapphire substrate was treated by SiH 4 under NH 3 atmosphere and nano-size islands SiN x mask was formed on the surface. GaN films were grown on the SiN x patterned sapphire substrates to form GaN/SiN x /Al 2 O 3 structure. The influence of SiH 4 treatment time on crystalline quality and luminance properities of GaN films were studied. The lowest density of screw and edge type dislocations of 1.3×108 cm−2 and 5.0×109cm−2 was got by SiH 4 treatment time of 120s, together with the lowest FWHM of GaN PL spectra of 5.4nm. The result indicated that SiH 4 treatment time could affect the size and density of SiN x islands. The SiN x mask with modified SiH 4 treatment time increased 3D to 2D growth time of high temperature GaN, which was the major factor improving the crystalline quality of GaN films.