Performance limitations of silicon bipolar transistors

The author considers some performance limitations of silicon bipolar transistors, assuming our ability to fabricate small geometric devices, by device analysis using an accurate two-dimensional numerical solution of classic semiconductor transport equations. The applicability of mathematical equations used to represent carrier transport in small geometric bipolar transistors and silicon-material parameters, such as bandgap narrowing with doping, ionization coefficients, and lifetime, used in the model has also been considered. The terminal characteristics, the internal behaviour, and performance limitations due to voltage and current operating levels of bipolar transistors with emitter depths and basewidths ranging from 0.4 μm to 30 nm have been analyzed.