77 K OPERATION OF AMORPHOUS SI SI HETEROJUNCTION BIPOLAR-TRANSISTORS/

The low-temperature characteristics of current gain H(FE) in amorphous emitter silicon heterojuntion bipolar transistors are studied. Curren t gain H(FE) falls with decreasing temperature and increasing base con centration N(B) at both room temperature and low temperatures. H(FE) i ncreases with increasing applied voltage V(BC) at low-temperatures due to the low-temperature avalanche multiplication effect in the collect or-base junction. It is concluded finally that the values of H(FE) of this device at low temperatures are adequate for most digital applicat ions.