Efficient physical-thermal model for thermal effects in AlGaN/GaN high electron mobility transistors

This letter describes the thermal behavior of AlGaN/GaN high electron mobility transistors on different substrates thanks to a fully consistent physical-thermal model. Self-heating explains the drastic reduction in the current flowing from drain to source. It is shown that, in order to keep the material from significantly degrading at the gate exit, the maximum dissipated power must be limited to 7 W/mm, 13 W/mm, and 38 W/mm for silicon, silicon carbide, and diamond substrates, respectively. These results have been validated from experimental thermal measurements.