Forward transit delay in In0.53Ga0.47As heterojunction bipolar transistors with nonequilibrium electron transport

The existence of extreme nonequilibrium electron transport in abrupt Al₀.48ln₀_52As /In₀_53Ga₀.47As and InP /In₀_53Gao.₄₇As Heterojunction Bipolar Transistors (HBT's) has been previously demonstrated by studying static transistor characteristics [1]-[3]. Apart from con­ firming the existence of nonequilibrium base transport previous results demonstrate the fact that base and collec­ tor transport are interdependent quantities. In this situa­ tion the intrinsic collector delay 7 c depends on the base transit delay TB and, therefore, the relevant single physi­ cal quantity to be measured is the intrinsic (i.e., without parasitic charging times) emitter-collector delay TF. The TF is itself controlled by electron dynamics in the base and collector, so knowledge about electron scattering mech­ anisms leads to a more complete understanding of device operation.