Comparison of Two DC Extraction Methods for Mobility and Parasitic Resistances in a HEMT

This is the authors' abstract. We don't add key points for this paper.

The channel mobility, μ0, parasitic source/ drain resistances, RS/RD, and virtual gate length, A, due to surface traps, at low drain-source bias, VDS, are important parameters of high-electron mobility transistors (HEMT's). DC methods are available to extract these parameters from drain-current, ID, versus gate-source voltage, VGS, measurements. We report a comparative study of two such methods based on the linear ID-VGSapproximation, from the viewpoint of device modeling, process monitoring, and physical understanding. One method yields constant values of μ0and RS+ RDaveraged over the VGSrange, while the other yields variations of μ0, RS, RD, and A with VGS. The study reveals some new details of these methods, and discusses their results on a range of GaAs and GaN HEMTs.