A Novel High-Voltage GaN Current Aperture Vertical Electron Transistor with Polarization-Doped Current Blocking Layer

A novel structure of GaN current aperture vertical electron transistor (CAVET) with polarization-doped current blocking layer (PD-CBL) is proposed and simulated in this paper. Comparing with the conventional p-GaN CBL, the p-type dopant activation efficiency in the AlGaN PD-CBL is enhanced significantly by graded Al mole fraction from 0 to r ₁. High hole concentration, combined with the increased electron barrier height in the PD-CBL, lead to a decrease of the subthreshold leakage current and a drastic improvement of the breakdown voltage. Moreover, due to the suppression of the depletion region in the n-GaN buffer by the 2DEG formed at the PD-CBL/buffer interface, negligible negative impact on the ON-state resistance is observed for the PD-CAVETs with r ₁ varying from 0 to 0.5.