Transient thermal characterization of AlGaN/GaN HEMTs grown on silicon

We studied a temperature increase and a heat transfer into a substrate in a pulsed operation of 0.5 length and 150 /spl mu/m gate width AlGaN/GaN HEMTs grown on silicon. A new transient electrical characterization method is described. In combination with an optical transient interferometric mapping technique and two-dimensional thermal modeling, these methods determine the device thermal resistance to be /spl sim/70 K/W after 400 ns from the start of a pulse. We also localized the high-electron mobility transistor heat source experimentally and we extracted a thermal boundary resistance at the silicon-nitride interface of about /spl sim/7/spl times/10/sup -8/ m/sup 2/K/W. Thermal coupling at this interface may substantially influence the device thermal resistance.