On reverse gate leakage current of GaN high electron mobility transistors on silicon substrate

摘要

Reverse leakage current characteristics of Ni Schottky contacts to GaN grown on Si is experimentally studied using high electron mobility transistors (HEMT). The temperature in this study is between 273 K and 428 K. The reverse gate leakage current is found to be dominated by Frenkel-Poole emission, a trap-assisted process, when the reverse electric field is smaller than 1.4MV/cm. For electric field larger than 1.6MV/cm, the underlying mechanism is mainly Fowler-Nordheim tunneling, an electric-field-dominated process. As a result, properly engineering electric field is considered critical for reducing reverse leakage current in GaN-on-Si HEMT for high-voltage applications.