Design optimization of high breakdown voltage vertical GaN junction barrier Schottky diode with high- K/low- K compound dielectric structure

A vertical junction barrier Schottky diode with a high- K/low- K compound dielectric structure is proposed and optimized to achieve a high breakdown voltage ( BV). There is a discontinuity of the electric field at the interface of high- K and low- K layers due to the different dielectric constants of high- K and low- K dielectric layers. A new electric field peak is introduced in the n-type drift region of junction barrier Schottky diode (JBS), so the distribution of electric field in JBS becomes more uniform. At the same time, the effect of electric-power line concentration at the p–n junction interface is suppressed due to the effects of the high- K dielectric layer and an enhancement of breakdown voltage can be achieved. Numerical simulations demonstrate that GaN JBS with a specific on-resistance ( R _on,sp) of 2.07 mΩ⋅cm ² and a BV of 4171 V which is 167% higher than the breakdown voltage of the common structure, resulting in a high figure-of-merit (FOM) of 8.6 GW/cm ², and a low turn-on voltage of 0.6 V.