A Comprehensive Negative Bias Temperature Instability Model for Gallium-nitride Metal-insulator-semiconductor High Electron Mobility Transistors From 77K to 393K

This work studies the degradation mechanisms behind negative bias temperature instability (NBTI) in galliumnitride metal-insulator semiconductor high electron mobility transistors (GaN MIS-HEMT) under a wide range of temperature conditions (77K to 393K). The positive shift of threshold voltage increases with temperature from 77K to 303K, owing to the trapping of electrons in the silicon nitride (Si
3
N
4
) bulk layer and at the Si
3
N
4
/aluminum gallium nitride (AlGaN) interface. Anomalously, the threshold voltage shift substantially reduces from 303K to 393K. Such an abnormal phenomenon could be attributed to additional hole trapping in Si
3
N
4
due to impact ionization. The occurrence of impact ionization can be further evidenced by the recovery behavior if the test devices. Accordingly, a comprehensive model is proposed to clarify the degradation behavior of NBTI for GaN MIS-HEMT under different temperature conditions.