IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

372 / 2018-03-29 22:55:34

Reliability investigation of AlGaN/GaN HEMTs under reverse-bias stress at 77K

low temperature; trap; reverse-bias step stress; ALGaN/GaN; HEMT; reliability

Plenary track > Harsh environment (e.g. high temperature) operation and reliability

The degradation phenomenon and mechanism of AlGaN/GaN HEMTs working at cryogenic temperature have been rarely reported. In this paper, degradation of AlGaN/GaN HEMTs under reverse-bias step stress at 300K and 77K was investigated. The electrons tunneling from gate electrode trapped at the SiN/AlGaN interface and in the AlGaN barrier were more difficult to escape at 77K compared with 300K. The trapping and detrapping behavior had a more serious affect on the properties of devices after reverse bias stress at low temperature than at room temperature. The trapped electrons reduced the electric field peak on the gate edge and few thermal phonons existed at the lower temperature resulting in the higher “critical voltage” for inverse piezoelectric effect at 77K.