Vertical leakage/breakdown mechanisms in AlGaN/GaN-on-Si structures

In this paper, we studied the vertical leakage/breakdown mechanisms in AlGaN/GaN structures grown on low resistivity p-type (111) Si substrate by temperature-dependent current-voltage measurements. We suggested that the top-to-substrate vertical leakage/breakdown is dominated by the space-charge-limited current (SCLC) conduction mechanism involving both acceptor and donor traps in buffer/transition layer. Based on temperature-dependent transient backgating measurements, the acceptor level and donor level were determined to be at E_V+543 meV and E_C-616 meV, respectively.