High-Performance E-Mode AlGaN/GaN MIS-HEMT with Dual Gate Insulator Employing SiON and HfON

Abstract

A high-performance E-mode AlGaN/GaN MIS-HEMTs is fabricated with atomic layer deposited 5nm SiON/16nm HfON and with atomic layer deposited 22nm HfON gate insulator and their characteristics are compared. Plasma nitridation is employed in every atomic layer deposition cycle to deposit SiON and HfON dielectrics. SiON is used as an interfacial layer to ensure a high-quality AlGaN/dielectric interface, and high-k HfON is employed to realize a large transconductance, a high on-state current, and a high on/off current ratio. The E-mode AlGaN/GaN MIS-HEMT with 5nm SiON/16nm HfON exhibited more excellent DC and dynamic characteristics than that with 22nm HfON. The fabricated MIS-HEMT with dual gate insulator showed a high on/off ratio of approximate to 1.2x10(11), a low off-state drain leakage current less than 10(-11)Amm(-1), a threshold voltage of 1.1V, a subthreshold slope of 77mVdec(-1), a specific on-resistance of 1.34mcm(2), and a breakdown voltage of 800V.