Chemical Vapor Deposition of Nitrides by Carbon-Free Brominated Precursors

The epitaxial growth of group 13-nitride semiconductors (GaN, AlN, and AlGaN alloys) for the mass production and fabrication of high-frequency and high-power devices relies on metal-organic chemical vapor deposition (CVD) using metal-organic molecules, also called precursors. While this growth method ensures high productivity and low operation costs compared to other methods, its most significant disadvantage lies in the presence of carbon atoms in the precursors, which are unavoidably incorporated into the epitaxial layers and hamper the performance of most types of fabricated devices. Carbon-free precursors for the CVD process could enhance the performance of high-frequency and high-power nitride-based devices while maintaining growth capability in industrial equipment. In this article, we implement gallium- and aluminum-brominated precursors, which contain no carbon atoms, to grow GaN and AlN layers in an industrial CVD system. We compare the results of this alternative CVD process with the conventional method using trimethyl precursors through several characterization techniques, indicating a clear reduction in optically active carbon-related defects.