Negative Bias-Induced Threshold Voltage Instability in GaN-on-Si Power HEMTs

• Published in: IEEE electron device letters Vol. 37; no. 4; pp. 474 - 477
• Main Authors: Meneghini, Matteo, Rossetto, Isabella, Bisi, Davide, Ruzzarin, Maria, Van Hove, Marleen, Stoffels, Steve, Tian-Li Wu, Marcon, Denis, Decoutere, Stefaan, Meneghesso, Gaudenzio, Zanoni, Enrico
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-04-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum gallium nitrides; degradation; gallium nitride; Gates; HEMT; High electron mobility transistors; Instability; Insulators; Logic gates; MIS; Semiconductor devices; Stability; Stress; Stress measurement; Temperature measurement; Threshold voltage; Time measurement; trapping; Voltage measurement; degradation; trapping; HEMT; Gallium nitride; MIS
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2016.2530693

This letter reports an in-depth study of the negative threshold voltage instability in GaN-on-Si metal-insulator-semiconductor high electron mobility transistors with partially recessed AlGaN. Based on a set of stress/recovery experiments carried out at several temperatures, we demonstrate that: 1) operation at high temperatures and negative gate bias (-10 V) may induce a significant negative threshold voltage shift, that is well correlated to a decrease in on-resistance; 2) this process has time constants in the range between 10-100 s, and is accelerated by temperature, with activation energy equal to 0.37 eV; and 3) the shift in threshold voltage is recoverable, with logarithmic kinetics. The negative shift in threshold voltage is ascribed to the depletion of trap states located at the SiN/AlGaN interface and/or in the gate insulator.