8. Metalorganic Chemical Vapor Deposition 1

This chapter is devoted to the growth of Ga₂O₃ and its alloys by metalorganic chemical vapor deposition (MOCVD) or, equivalently, metalorganic vapor phase epitaxy (MOVPE). MOCVD is a standard epitaxial growth technique used for nitride, III–V, and oxide-based power devices as well as LEDs and laser diodes. It would, therefore, seem that MOCVD would be the most appropriate growth method to accelerate the development and commercialization of Ga₂O₃. However, molecular beam epitaxy (MBE) and halide vapor phase epitaxy (HVPE) were commonly used in the earlier growth studies of Ga₂O₃ epitaxial films. Fortunately, the broad range of knowledge available on the hardware and control systems of the MOCVD tool for the growth of device quality epitaxial films makes it easily adaptable to the growth of epitaxial Ga₂O₃. Device quality films grown at ~10 µm/h were demonstrated [1, 2], evidencing the ability of MOCVD to achieve the high throughput Ga₂O₃ epitaxial layer growth needed for high voltage power device and deep ultraviolet solar-blind photodetector commercial applications. This chapter discusses the following topics: the selection of suitable metalorganic precursors and oxygen sources used for the growth of Ga₂O₃ and (Al, Ga)₂O₃ alloys; the need for the careful design of the MOCVD reactors, homoepitaxial and heteroepitaxial growth on c-plane sapphire and native Ga₂O₃ substrates, donor and acceptor doping; and the origin and methods for mitigating or reducing unintentional impurities.