10 kV E-mode GaN HEMT: Physics for breakdown voltage upscaling
Abstract
High-voltage GaN high electron mobility transistors (HEMTs) have recently reached the 10 kV milestone; however, prior reports relied on unconventional epitaxial structures—such as multi-channel, Si delta-doping, or unintentional p-GaN doping—which pose challenges in the realization of enhancement-mode (E-mode) gate control. Here, we demonstrate a 10 kV E-mode GaN HEMT with a standard highly doped p-GaN gate. This p-GaN layer also forms a reduced-surface-field (RESURF) structure. By analyzing devices with varying RESURF thickness (t R), we identify the key physical mechanism that enables the breakdown voltage (BV) upscaling with device length. We find the BV upscaling is only viable when t R is below 21 nm and reaches peak effectiveness at a t R of 17 nm—deviating from predictions based on ideal polarization superjunction theory. This suggests the presence of donor trap states that …
