Design and thermal analysis of SiGe HBT with segmented emitter fingers and non-uniform segment spacing

A novel multi-finger power SiGe heterojunction bipolar transistor (HBT) with segmented emitter fingers and nonuniform segment spacing was proposed to improve the thermal stability. Thermal simulation for a ten-finger power SiGe HBT with novel structure was conducted with ANSYS software. Three-dimensional temperature distribution on emitter fingers was obtained. Compared with traditional emitter structure, the maximum junction temperature of novel structure reduce significantly from 427.465 K to 417.03 K, the thermal resistance reduce from 170 K/W to 156 K/W, temperature distribution were significantly improved. Thermal stability was effective enhanced.