Thermal mapping of defects in AlGaN∕GaN heterostructure field-effect transistors using micro-Raman spectroscopy

Abstract

We illustrate the use of micro-Raman mapping to study the local effect of defects on device temperature in active AlGaN∕GaN heterostructure field-effect transistors. Significant temperature rises in active devices, 50–100% above average device temperatures, were identified in the vicinity of defects. Measured temperature distributions were compared to finite difference simulations. Reduced thermal conductivity in the defect vicinity was found to be responsible for the local temperature rises in these devices, combined with possible changes in the current flow distribution.