Thin amorphous gallium nitride films formed by ion beam synthesis

Abstract

Ion implantation and plasma enhanced chemical vapour deposition (PECVD) have been used to synthesise an amorphous gallium nitride compound (a-GaN) within an amorphous silicon nitride (a-SiN x :H y ) matrix by implanting Ga + into a-SiN x substrates. This route may enable the synthesis of large area a-GaN substrates for the use as possible seed layers for the growth of crystalline GaN as well as an amorphous semiconductor in its own right. A study of an entire range of a-SiN x with different compositions ‘ x’ has enabled the choice of the most suitable type of target substrate. It has been shown that nitrogen-rich a-SiN x has a high stress as well as a steady incorporation of N. X-ray Photoelectron Spectroscopy (XPS) and Rutherford Backscattering Spectroscopy (RBS) studies yield information on the chemistry and elemental depth profiles of the material synthesised. Low temperature annealing, compatible with large area glass substrates is then used to increase the thickness of the a-GaN layer and transform more of the nitrogen rich a-SiN x .