Study of self-heating in GaAs pHEMTs using pulsed I-V Analysis

Abstract

A pulsed I-V thermal resistance R th measurement method is formulated and applied on-wafer to a GaAs MMIC pHEMT. An investigation of device dispersion phenomena assesses their impact on the measurement. It is found that performing the R th measurement using two quiescent bias points in close proximity (situated beyond the knee voltage yet prior to drain voltages that result in significant levels of gate leakage due to impact ionization) improves the accuracy of the method. Extraction of thermal coefficients characterizes the drain current reduction due to heating, allowing for an efficient calculation of R th with improved precision.

An Accurately Scalable Small-Signal Model for Millimeter-Wave Hemts Based on Electromagnetic Simulation

“…Because the self-heating [9] is inevitable during the static IV measurement, it makes the device IV characteristics difficult to scale precisely. There are also some dispersive errors [10] caused by the lowfrequency dispersion between the simulated and measured AC conductances.…”