DC and RF techniques for computing access resistances in microwave FET´s

In order to estimate the access resistances of PHEMTs two different techniques based on I(V) and RF measurements were investigated. An improved cold-FET technique is presented. The main difference between the classical and the proposed cold-FET techniques lies on the open circuit condition in drain-source instead of short circuit condition (V/sub DS/=0 V). A good agreement is observed between the values of parasitic resistances computed from DC I(V) and RF measurements.