Microwave Characteristics of SiGe HBT

Abstract

In this thesis, I described about the basic introduction to SiGe Hetero-junction bipolar transistors, evaluation of SiGe HBT, SiGe HBT advantages over Si BJT’s, the characteristics of Linearly Graded base doping and uniform base doping. Derived the S-parameters from the Complete Small Signal hybrid-pi Model of SiGe HBT. S-parameters of the Complete Small Signal hybrid-pi model of SiGe HBT calculated by using model equations of the Small Signal Model of intrinsic SiGe HBT within the frequency range of 0.2-50-GHz using parasitic effects. Intrinsic SiGe HBT model is having higher cutoff frequency than extrinsic SiGe HBT model because extrinsic SiGe HBT’s having parasitic effects. The linearly graded-base SiGe HBT doping has smaller base transit time and larger cutoff frequency than the uniformly-base HBT doping.
S-parameters of the intrinsic small signal SiGe HBT and complete Small Signal of SiGe HBT are calculated by using various base widths. S-parameters of the Complete small signal hybrid-pi model of SiGe HBT are calculated by using different Ge concentrations. Further SiGe HBT are used to MMIC (Millimeter Microwave Integrated Circuit) Technology.