A Bandgap-Engineered Silicon-Germanium Biristor for Low-Voltage Operation

A bandgap-engineered silicon-germanium biristor for low-voltage operation is investigated through numerical simulations. A reduced latch-up voltage is achieved using germanium as a base, and improved hysteresis is attained by adopting a hetero-bandgap structure which harnesses the silicon-germanium composite at the collector/emitter. The geometric parameters of the base length and base diameter are optimized. The proposed device shows a much lower latch-up voltage than a pure-silicon biristor and larger hysteresis than a pure-germanium biristor. Thus, the proposed bandgap-engineered silicon-germanium biristor is preferable for low-voltage operations.