Analytical modelling of Early voltage and Current Gain of Si1−yGey Heterojunction Bipolar Transistor

Analytical modelling of Early Voltage (V
A
) and Common Emitter Current Gain (β) of Heterojunction Bipolar Transistor (HBT) are derived considering field dependent mobility, doping dependent mobility, Band Gap Narrowing (BGN), changes in density of state (DOS) and velocity saturation effect. BGN was considered due to heavy doping and presence of Germanium. The effect of various base doping profiles (Gaussian, exponential and uniform) and germanium profile (trapezoidal/triangular/box) on V
A
and β are addressed. The results of the analysis are compared with the data available in the previous research work.