The demonstration of recessed anodes AlGaN/GaN Schottky barrier diodes using microwave cyclic plasma oxidation/wet etching techniques

This paper presents the recessed anodes AlGaN/GaN Schottky barrier diodes (SBDs) using cyclic microwave plasma oxidation and wet etching techniques which were investigated to reduce the damage and contamination on the recessed GaN-based surface. A wide bandgap Ga-doped MgZnO (GMZO) sidewall layer structure was also conducted to suppress the hard breakdown mechanism at high reserve voltage. The SBD with recessed anodes and GMZO sidewall structure had specific on-resistance (R _ON-SP) of 1.99 mΩ cm², turn-on voltage (V _ON) of 0.40 V, and breakdown voltage of 465 V. The SBDs in this study realized higher R _{ON_SP} and lower V _ON than that of the conventional device. In addition, the reverse recovery and low frequency noise characteristics of a SBD with recessed anode and GMZO sidewall structure were lower than those in the conventional structure because the anode metals are close to a high-density 2DEG by using recessed structure and the leakage current from the etching damages is declined by using a GMZO sidewall structure.