Design and Development of p-GaN Gate HEMT with Schottky Source Extension for Improved Short-Circuit Reliability

This study investigates the p-GaN gate HEMT with Schottky source extension (SSE) for improved short-circuit (SC) reliability. Under higher drain bias, the SSE pinches off and functions as a current source, resulting in reduced saturation current
$(I_{\text{D,sat}})$
that is expected to enhance the short-circuit reliability. According to TCAD simulation, compared to other approaches (i.e. reducing
$V_{\text{GS}}$
or using a larger
$L_{\mathrm{G}}$
), the adoption of SSE only slightly sacrifices its
$R$
ON
for a targeted
$I_{\text{D,sat}}$
. Fabricated devices with and without SSE are evaluated for SC reliability. The high-voltage pulse
$I_{\mathrm{D}}-V_{\text{DS}}$
test mimics the SC stress, and the new device with SSE can endure an SC pulse with much higher
$V_{\text{DS}}$
. The progressive SC-stress/
$I_{\text{OFF}}$
characterization monitors the accumulative SC degradation of devices, confirming that the new device with SSE is much more rugged against SC-stress. Therefore, the proposed p-GaN gate HEMT with SSE offers a promising approach for developing SC-rugged GaN power transistors for industrial applications.