Dynamic Gate Stress Induced $V_{\text {TH} Shift and Its Impact on Dynamic $R_{\mathrm {ON} in GaN MIS HEMTs
Very fast transients of VTH shift and their impact on RON under dynamic AC (1 k 1 MHz) positive gate stress in depletion mode (D mode) metal insulator semiconductor high electron mobility transistors (MIS HEMTs) are revealed. We achieve data acquisition within 120 ns right after each stress pulse throughout the entire stress time range from 10 7 up to 103 s, by virtue of a short stress to sense delay of ~100 ns and high sampling rate up to 50 MSa/s. Despite the considerable VTH shift, its impact on RON in D mode MIS HEMT is modest, if the device is under sufficient gate overdrive. Furthermore, VTH shift and the consequent RON increase under dynamic stress, which are more relevant to high frequency switching operation, exhibits frequency dependence within 1 k 1 MHz and is always smaller than that under conventionally used static (constant) stress.
IEEE Electron Device Letters