GaN heteroepitaxy with an in-situ amorphous BN interlayer

Abstract

The fabrication of micro-optoelectronic devices based on inorganic semiconductors has been increasing interest for future applications, with significant improvements in device efficiency and size reduction still required. One promising method to enhance device performance is by improving semiconductor crystallinity through epitaxial lateral overgrowth (ELOG). This research facilitates the in-situ ELOG of GaN films through the introduction of an amorphous boron nitride (a-BN) layer. Using the metal- organic chemical vapor deposition (MOCVD) process, an a-BN layer can be monolithically deposited onto the initially grown GaN film, eliminating the need for external manufacturing processes typically required for forming a mask layer for ELOG. The a-BN layer, during the high-temperature growth of flat and smooth GaN overlays, forms stably on the GaN film and serves as a growth mask. The laterally grown GaN layer, epitaxially related to the initial GaN film, benefits from the a-BN effectively blocking dislocations caused by residual strains in the initial GaN film grown on heterogeneous c-Al2O3 substrates. In comparison to typical heteroepitaxy of GaN films grown on c-Al2O3, the laterally grown GaN films demonstrate markedly enhanced crystalline alignment and internal quantum efficiency. The application of a-BN enables in-situ mask formation, thus fully capitalizing on the benefits of ELOG through an immediate monolithic approach.