Fast electric field simulation of junction termination extension structure in vertical GaN power devices

We propose a fast simulation method for calculating the electric field strength under reverse bias in junction termination extension (JTE), a termination structure used in vertical power devices. In the conventional simulation method, the electrostatic potential, electron density, and hole density are solved simultaneously using three coupled equations. In contrast, the proposed method expresses electron and hole densities as functions of the potential, allowing the electric field strength to be determined by solving only the potential equation. We evaluate the proposed method for the termination structure of GaN vertical power devices and demonstrate that it achieves faster calculations than the conventional method. Furthermore, we demonstrate that the proposed method achieves sufficient accuracy for practical applications in calculating the electric field distribution by neglecting the computation of minority carriers, whose impact on the electric field strength is negligible.