High-Performance MIM/p-GaN Gate HEMTs With a 3-nm Insulator for Power Conversion

Abstract

Schottky-type p-GaN gate HEMTs with a low forward bias gate breakdown voltage ${V}_{\text {G- {BD}}}$ are vulnerable to failures during switching. In this work, high-performance MIM/p-GaN gate HEMTs with a TiN/Al2O3/TiN (30/3/40 nm) MIM structure on top of p-GaN layer are proposed. Compared to the conventional Schottky-type reference, the MIM/p-GaN gate structure successfully promotes the ${V}_{\text {G- {BD}}}$ from 11.4 to 14.1 V and the maximum applicable gate voltage ${V}_{\text {G- {max}}}$ from 5.1 to 7.0 V corresponding to a lifetime of 10 years at the failure of 1%. Benefiting from the 3-nm ultra-thin Al2O3 layer and the MIM structure, trapping effect is avoided. Neither significant degradation of static nor dynamic characteristics of the proposed devices are observed. The developed MIM/p-GaN gate HEMTs present great potentials for future power conversion applications.