GaInP/GaAs collector-up tunnelling-collector heterojunction bipolar transistors with underneath via-hole structure

Two types (one-finger and four-finger) GaInP/GaAs collector-up tunnelling-collector heterojunction bipolar transistors (C-up TC-HBTs) with a backside emitter structure have been developed. The four-finger C-up TC-HBT demonstrated thermally stable operation up to 0.9 mW/μm² without a ballast resistor. This performance shows that this C-up TC-HBT is promising for applications such as small monolithic-microwave ICs used in high-frequency high-power amplifiers.