Improved Electrical Characteristics of GaN-based HEMTs with Rationally Designed Compositionally Graded AlGaN Back Barrier and Passivation Schemes

GaN-based HEMTs are promising as next-generation power electronics and preliminarily implemented in many fields [1] . For the benefit of mass production, the mainstream HEMT is based on an AlGaN/GaN single heterojunction (SH) with fixed Al composition and layer thickness. However, further device tailoring such as band engineering and channel modulation are limited [2] . Besides, surface states in devices remain major challenges for device reliability [3] . In this regard, rational designs of heterojunctions and surface passivation are necessary to further boost GaN HEMTs. Herein, we propose a GaN-based HEMT with a rationally designed compositionally graded AlGaN back barrier (BB) with optimized surface passivation schemes to overall boost the device characteristics under complex operation conditions.