Inelastic-stress-induced threshold instability and mobility degradation in AlN/GaN MIS-HEMTs on Si

Inelastic-stress-induced threshold instability and mobility degradation in AlN/GaN MIS-HEMTs on Si

Applied Physics Letters

10.1063/5.0313481

https://doi.org/10.1063/5.0313481

Siyu Liu, Yihao Zhuang, Pengju Cui, Qingyun Xie, Hanlin Xie, Geok Ing Ng

10 March 2026

Liu, S., Zhuang, Y., Cui, P., Xie, Q., Xie, H., Ng, G. I. (2026). Inelastic-stress-induced threshold instability and mobility degradation in AlN/GaN MIS-HEMTs on Si. Applied Physics Letters, 128(10). https://doi.org/10.1063/5.0313481

This work investigates the impact of stress-induced effects on the stability of AlN/GaN MIS-HEMTs on Si employing PECVD-SiN as a passivation layer. DC and temperature-dependent C–V/I–V measurements together with technology computer-aided design simulations are used to correlate stress state, defect behavior, and channel transport. As-deposited PECVD-SiN introduces strong inelastic stress that compresses the 2DEG near the GaN surface and drives an anomalous reverse shift of the threshold voltage of ∼−0.3 V between 300 and 475 K, with room-temperature mobility limited to ∼700 cm2 V−1 s−1 by remote scattering. Arrhenius analysis of the drain current yields an activation energy Ea = 0.059 eV, attributed to thermally activated charging and restructuring of bulk and interface defects coupled to the stress field. Post-passivation annealing at 450 °C largely relaxes the inelastic component, broadens the potential well, and reduces Ea to 0.019 eV. The mobility increases to ∼1260 cm2 V−1 s−1 and exhibits a polar optical phonon-like temperature dependence, while the VTH–T behavior changes to a weak positive coefficient. These results offer insights on the temperature stability of stress-induced GaN MIS-HEMTs from a material perspective.

Publisher Copyright

This research / project is supported by the A*STAR - White Space Manufacturing, Trade, and Connectivity Funding
Grant Reference no. : M23WSNG001

This research / project is supported by the A*STAR - Manufacturing, Trade, and Connectivity Industry Alignment Fund Pre-Positioning (IAF-PP)
Grant Reference no. : M22L3a0112

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Liu, S., Zhuang, Y., Cui, P., Xie, Q., Xie, H., & Ng, G. I. (2026). Inelastic-stress-induced threshold instability and mobility degradation in AlN/GaN MIS-HEMTs on Si. Applied Physics Letters, 128(10). https://doi.org/10.1063/5.0313481 and may be found at https://doi.org/10.1063/5.0313481

https://oar.a-star.edu.sg/communities-collections/articles/23196

0003-6951
1077-3118

Institute of Microelectronics