A robust and fast procedure for the determination of the small signal equivalent circuit of HEMTs

In this paper we present an analytical, fast, accurate and robust technique for the determination of the circuit model elements of HEMTs in the microwave range. By this method the values of the equivalent circuit parameters of the device under test are extracted using three measured scattering (S) parameter sets without any optimization. We also investigated the influence of the reverse transfer conductance Re(Y-12) on the modelling by means of a gate drain resistance R-dg. The validity of this method was verified upon a set of pseudomorphic HEMTs having different gate widths tested on wafer at several bias and temperature conditions. Very good agreement between the simulated and measured S-parameters has been obtained. The procedure has been implemented in Agilent VEE language as a fully automated tool to allow an accurate, fast and complete device characterization requiring no operator supervision. (C) 2004 Elsevier Ltd. All rights reserved.