Improved on-resistance and breakdown voltage vertical GaN-based field effect transistors

Abstract

GaN-based vertical field effect transistors (VFETs) are very promising in various power switching applications owing to their high current density and small chip size. However, it is still challenging to obtain high breakdown voltage (BV) and low on-resistance (Ron) in the practical VFETs. Design and simulation of the device structures are necessary in shortening the device development progress. In this paper, the GaN-based VFETs with AlGaN barrier layer and slanted gate structures are proposed and demonstrated by TCAD simulations. The concentration of the key p-GaN blocking layer is optimized. Improved performances with Ron of 0.47 mΩ·cm2 and BV over 450V are achieved in the proposed devices with the help of 2DEG channel design to increase the current conductivity and the slanted gate structure to reduce the peak electric field and hence increase the BV of the devices.