Transit Time Model Analysis Through the Basis in the Case of Drift Transistors HBT

Abstract

The manufacturing technology for heterojunction bipolar transistor (HBT) is different from the one used for bipolar silicon junction transistor (BJT). The base in case of BJT is manufactured by using diffusion and the diffusion laws determine a Gaussian type of profile in the base. HBT devices are manufactured using molecular epitaxy which gives a contact doping profile. In case of HBT, producing an internal field by using uniform doping is no more possible. This is the reason why was used in the gradation of the molar composition. The Analysis using Octave soft was made for the transit time through the base of the drift HBT transistors type GaAs/AlxGa1-xAs.