Increase of inverse beta of Si transistors due to low-temperature treatments

Transistors having diffused phosphorus emitters were treated at temperatures of 750° and 1100°C, At 1100°C, the direct and inverse beta both increase approximately as the square root of time. At 750°C, the inverse beta improves much more rapidly than the direct beta, and this is attributed primarily to a reduction of the concentration gradient in the base. This will decrease the inverse base transit time and allow i.i.l. transistors to operate at higher frequencies.