Effect of the detailed growth conditions on the injection efficiency of (N)AlGaAs‐(p+)GaAs heterojunctions produced by molecular‐beam epitaxy

摘要

Abrupt (N)AlGaAs‐(p+)GaAs heterojunction diodes were grown by molecular‐beam epitaxy. It was found that the position with respect to the heterointerface at which the substrate temperature was changed from that for the growth of (p+)GaAs to that for the growth of (N)AlGaAs had a significant effect on the injection efficiency of the devices. By initiating the substrate temperature rise right at the start of the (N)AlGaAs growth, heterojunction bipolar transistors with an abrupt (N)Al0.18Ga0.82As‐(p+)GaAs emitter‐base junction having current gains of between 60 and 70 were fabricated. These relatively high‐current gains are argued to be due to the effects of hot‐electron injection into the base.