New method for determining parasitic access inductances of high frequency on-wafer coplanar heterojunction bipolar transistors

摘要

New analytical extraction procedure is developed for determining independently the parasitic inductances of high frequency on-wafer coplanar Heterojunction Bipolar Transistor. It takes into account the influence of inductive effect due to other device parameters which can not be neglected for these transistors and it does not require any numerical optimizations or special test structures. In particular the analytical expressions demonstrate that base resistance and intrinsic and extrinsic base-collector capacitances have a significant effect on the accurate determination of the HBT parasitic inductances. Our theoretical investigations are validated using two types of transistors: A on-wafer coplanar GalnP/GaAs HBT and a microstrip mounted GalnP/GaAs which have a unity current gain cutoff frequency of 80 GHz respectively.