Time-resolved temperature measurement of AlGaN/GaN electronic devices using micro-Raman spectroscopy

We report on the development of time-resolved Raman thermography to measure transient temperatures in semiconductor devices with submicrometer spatial resolution. This new technique is illustrated for AlGaN/GaN HFETs and ungated devices grown on SiC and sapphire substrates. A temporal resolution of 200 ns is demonstrated. Temperature changes rapidly within sub-200 ns after switching the devices on or off, followed by a slower change in device temperature with a time constant of similar to 10 and similar to 140 mu s for AlGaN/GaN devices grown on SiC and sapphire substrates, respectively. Heat diffusion into the device substrate is also demonstrated.