The influence of impact-ionized holes accumulating in the device was studied for InP-based InAlAs/InGaAs HEMTs using light irradiation experiments. Two parasitic phenomena arise from the generation of electron-hole pairs and subsequent accumulation of holes in the body of the device: The hole accumulation in the source region causes the decrease in the source resistance, which eliminates the kink effect. The hole accumulation in the gate region shifts the threshold voltage. This could be a positive feedback that increases the drain current at the on-state breakdown of the device.
- Impact ionization
- Light irradiation