This paper describes the physical origin of VTH instabilities in β-Ga2O3 finFETs, based on electro-optical measurements. In particular, (i) we investigated the VTH instability by means of pulsed ID–VGs, demonstrating the existence of an electron trapping process involving border states in the dielectric; then, (ii) we analyzed the charge trapping kinetics at high temperatures, identifying a temperature-dependent mechanism having activation energy of 0.44 ± 0.08 eV; and finally, (iii) we describe a new experimental methodology to investigate the optically stimulated emission of the trapped carriers. The results were employed to develop a quantitative model that identifies, as a root cause for trapping, the presence of a defect band located ∼3.3 eV below the conduction band edge of the dielectric layer.
Fregolent et al. (2026) studied this question.