New SiGe power bipolar transistors with the optimum base and emitter structures

We have newly developed SiGe power-bipolar-transistors with optimum base and emitter structures. The presented SiGe transistor allows fast switching operation of less than 100 ns, while the low on-state voltage drop of 0.2 V has been achieved at a current density of 113 A/cm². The optimized transistor with poly-Si emitter, minimized SiGe layer, and interconnect structure, enables very high current gain of ∼200 at a high current region exceeding 100 A/cm². The presented SiGe transistors are effective in lower power dissipation in switching circuits.