Avalanche leakage current mechanism in vertical GaN devices on foreign substrates
Abstract
Avalanche breakdown, the most desirable breakdown mode in power devices, is typically characterized by a positive temperature coefficient (PTC) of breakdown voltage (BV) extracted from leakage current-voltage (I-V) characteristics. Here, we report a suppression and reversal of this PTC in avalanche-capable gallium nitride (GaN) p-n diodes with high dislocation densities grown on foreign substrates and elucidate the underlying mechanism. Vertical GaN p-n diodes with optimized edge termination are fabricated on GaN, patterned sapphire, and sapphire substrates, providing a controlled increase in dislocation density. Although all devices exhibit robust avalanche behavior in circuit-based tests, their breakdown I-V characteristics show distinct temperature dependences, evolving from a clear PTC to a negative temperature coefficient (NTC) with increasing dislocation density. This behavior arises from the …
Zineng Yang
M.Sc. RWTH Aachen University
B.Eng. (Hons) University of Nottingham Ningbo/University of Nottingham
Hehe Gong
Ph.D Nanjing University
B.S.Northwestern Polytechnical University
Xin Yang
M.S. Xi'an Jiaotong University
B.S. Chongqing University
