Temperature dependence of breakdown voltage in InAlAs/InGaAs HEMTs: theory and experiments

We present results of an experimental and theoretical study of the temperature dependence of the off-state breakdown voltage of InAlAs/InGaAs high electron mobility transistors (HEMTs). We find that the breakdown voltage (BV) has a negative temperature coefficient that is more prominent for lower values of the extrinsic sheet carrier concentration (n/sub s/). Structural parameters such as the insulator thickness and top-to-bottom delta doping ratio have little effect on BV if n/sub s/ is held constant. These results are consistent with an extension of a new tunneling model for breakdown in HEMTs to include thermionic-field emission.