Development of GaN trench MOSFET process technologies

Abstract GaN holds great promise as a next-generation power device material. While lateral GaN power devices have already been commercialized and are finding expanding applications, vertical GaN power devices remain at the developmental stage. This paper systematically describes the fabrication process technologies for vertical GaN trench MOSFETs that we have developed over many years. The established elemental technologies include low-doped epitaxial growth, precise trench-shape control, etching-damage removal, p-type ion implantation, formation of high-concentration n-type sputtered layers, and high-quality AlSiO gate dielectrics. Highly reliable and reproducible process technologies are indispensable for the practical realization of vertical GaN power devices. Moreover, the technologies developed in this study are broadly applicable to various vertical GaN device architectures. Consequently, the set of elemental process technologies established here constitutes a fundamental process platform and is expected to play a crucial role in enabling the future practical application of vertical GaN power electronics.