Polarity Inversion-Driven Band Structure Modulation, Strain Engineering, and Electrical Property Analysis on...

The 4H-SiC/GaN heterojunction, with its excellent electrical properties, is highly promising for advanced semiconductor devices. This study delves into four heterojunction structures (01-C-Si-Ga-N, 02-C-Si-N-Ga, 03-Si-C-Ga-N, and 04-Si-C-N-Ga) with varying polarity configurations, analyzing their electronic and electrical characteristics. The results reveal notable differences in the band structures of the four designs: structures 01 and 03 exhibit direct band gaps, while structures 02 and 04 display indirect band gaps. In structures 01 and 04, the valence bands become degenerate, resulting in the overlap of the valence band in the heterojunction. Structures 02 and 03 represent typical type-II heterojunction band structures. Structure 03 displays a symmetric electron distribution, which may lead to a smaller deformation potential and enhanced electron mobility, reaching 18 527.2 cm²·V^-1·s^-1. Structure 04 contains an electron depletion region approximately 2 Å in width, which could improve hole mobility. Furthermore, the study finds that the effective mass in the 4H-SiC/GaN heterojunction exhibits anisotropy, with these variations closely tied to the type of band structure.