Analysis of Insulator Breakdown Induced by Body-Grounded-Coupling Effect in GaN-Based MIS-HEMT

Abstract

This study focuses on abnormal breakdown issues observed during the practical operation of D-mode GaN-based metal insulator semiconductor high electron mobility transistor (MIS-HEMT). The measurement statistics show that the breakdown voltage ( ${V}_{\text {BD}}\text {)}$ of the body-floating device reaches 1653 V; however, the body-grounded device experiences early breakdown at 1161 V. Through high-temperature reverse bias (HTRBs) degradation mechanisms, a discrepancy in the energy band of the channel layer due to body contact is identified. The experimental results indicate that the phenomenon corresponds to drain-induced barrier lowering (DIBL), causing the channel to turn on early. TCAD simulations indicate that the body-grounded state causes larger energy band bending and generates a higher electric field within the insulator compared to the body-floating state, which is called the body-grounded coupling effect. Furthermore, the gate and drain lag dynamic measurement confirms that the effect originates from the buffer, while the electric field beneath the gate does not immediately affect the quality of the dielectric layer. This mechanism of this study is proposed to describe the insulator breakdown behavior that occurs in the D-mode body-grounded MIS-HEMTs.