ANALYTICAL PARAMETER EXTRACTION OF THE HBT EQUIVALENT-CIRCUIT WITH T-LIKE TOPOLOGY FROM MEASURED S-PARAMETERS

A pure analytical method for extraction of the small-signal equivalent circuit parameters from measured data is presented and successfully a pplied to heterojunction bipolar transistors (HBT's). The T-like equiv alent circuit is cut into three shells accounting for the connection, and the extrinsic and intrinsic parts of the transistor. The equivalen t circuit elements are evaluated in a straightforward manner from impe dance and admittance representation of the measured S-parameters. The measured data are stripped during the extraction process yielding, ste p by step, a full set of circuit elements, without using fit methods, No additional knowledge of the transistor is needed to start the extra ction process with its self-consistent iteration loop for the connecti on shell, The extrinsic and intrinsic equivalent circuit elements are evaluated using their bias and frequency dependencies, This method yie lds a deviation of less then 4% between measured and modeled S-paramet ers.