Experimental Validation of Buffer Traps-Driven Electric Field Dynamics Governing Breakdown and Leakage Trends in AlGaN/GaN Heterostructures

This work experimentally validates the impact of buffer carbon (C) induced acceptor traps on electric field redistribution, affecting breakdown and leakage behavior. Using electroluminescence microscopy and stress testing on the ONstate characteristics of anode-recessed AlGaN/GaN lateral Schottky barrier diodes (SBDs), we found that devices with low acceptor trap concentrations exhibit higher leakage, with breakdown hotspots located at the anode and field plate edge. In contrast, higher acceptor trap concentrations increase buffer trapping, reduce leakage, and redistribute the electric field toward the cathode, thereby shifting the breakdown hotspot to the cathode. This buffer trap concentration-dependent electric field dynamics necessitates device design modifications to optimize breakdown voltage. Specifically, devices with low trap concentrations improve breakdown voltage with longer field plates, while those with high trap concentrations benefit from larger anode-cathode distances and reduced passivation thickness. These experimental findings corroborate well with earlier computational predictions.