A direct extraction method to determine the extrinsic resistances for an InP HBT device based on S-parameter measurement up to 110GHz

A direct extraction method to determine the small-signal equivalent circuit model for III-V compound heterojunction bipolar transistor device is proposed in this paper. The advantage of this method is that the extrinsic resistances can be determined directly from a cut-off S-parameters measurement at the millimetre-wave frequencies (30-110 GHz) based on the T-π transformation method. After de-embedding the extrinsic elements, all intrinsic elements of the π-type model can be obtained utilizing a set of closed-form expressions. Good agreement between modeled and measured data is achieved up to 110 GHz to verify the accuracy.