Channel temperature measurements of InxAl1−xN/GaN high electron mobility transistors on Si(111) using optical spectroscopy

The temperature profiles of InxAl1-xN/GaN high electron mobility transistors (HEMTs) were investigated using nondestructive optical spectroscopic techniques. In this study, HEMT structures were epitaxially grown on a Si(111) substrate with a diameter of 200mm. In particular, the channel temperature underneath the gate was able to be accurately probed by using a RuOx-based semitransparent Schottky contact in the ultraviolet photoluminescence (PL) and visible Raman excitation modes. A maximum channel temperature as high as similar to 475K was probed near the gate edge using the PL technique at a power dissipation of similar to 11.6 W/mm, thus leading to a minimum thermal conductance of about 64.7Wm(-1) K-1 in such a HEMT structure. Furthermore, the temperature profiles at the GaN buffer and AlN/Si(111) interface were determined using micro-Raman measurements. (C) 2015 American Vacuum Society.