Electric-stress reliability and current collapse of different thickness SiN_x passivated AlGaN/GaN high electron mobility transistors

This paper investigates the impact of electrical degradation and current collapse on different thickness SiN_x passivated AlGaN/GaN high electron mobility transistors. It finds that higher thickness SiN_x passivation can significantly improve the high-electric-field reliability of a device. The degradation mechanism of the SiN_x passivation layer under ON-state stress has also been discussed in detail. Under the ON-state stress, the strong electric-field led to degradation of SiN_x passivation located in the gate-drain region. As the thickness of SiN_x passivation increases, the density of the surface state will be increased to some extent. Meanwhile, it is found that the high NH₃ flow in the plasma enhanced chemical vapour deposition process could reduce the surface state and suppress the current collapse.