Current Transport Characteristics of Quasi-Al_xGa_1-xN/SiC Heterojunction Bipolar Transistors with Various Band Discontinuities

Abstract

The current transport characteristics of quasi-Al x Ga1-x N/SiC heterojunction bipolar transistors (HBTs) with various band discontinuities were investigated in a low-current range using a Gummel plot. In the low-current range, the base currents of the HBTs were dominated by recombination currents. The collector current characteristics of the HBTs in the low-current range were almost the same in spite of the various band discontinuities, and the ideality factor n was 1.0. The band discontinuities at the heterojunction had no effect on electron injection in the low-current range. This is because the collector currents were dominated by diffusion process in the base region rather than by injection process at the AlGaN/SiC interface.

Beta-Gallium Oxide/SiC Heterojunction Diodes with High Rectification Ratios

“…Although studies of HBT based on SiC have tried using GaN or Al x Ga 1-x N with SiC, there are problems of large leak current and a difficulty of growth Al x Ga 1-x N with high Al composition. 28 HBT structure might be constructed when emitter of n-type β-Ga 2 O 3 will be formed on base of p-type SiC on collector of n-type SiC. When the low resistance base region with high p-type doping density is constructed, holes in the base (p-type SiC) hardly get over the barrier to the emitter region (β-Ga 2 O 3 ).…”