【Device Papers】Impact of Deep-Level Traps on Carrier Mobility in β-Ga₂O₃ MOSFETs

      Researchers from the George Mason University have published a dissertation titled "Impact of Deep-Level Traps on Carrier Mobility in β-Ga₂O₃ MOSFETs" in IEEE Transactions on Electron Devices.

Abstract

      Beta-phase gallium oxide (β-Ga₂O₃ is a promising semiconductor for high-power and high-frequency electronics due to its ultra-wide bandgap (UWBG) and high breakdown field. However, the carrier mobility in β-Ga₂O₃-based metal-oxide-semiconductor field-effect transistors (MOSFETs) remains significantly lower than its theoretical limit, often attributed to the presence of deep-level traps. In this work, an electro-optical measurement technique is used to study ionized impurity scattering by deep-level traps in lateral depletion-mode β-Ga₂O₃ field-effect transistors (FETs). Using the conductance method and photo-assisted capacitance-voltage (PCV) measurements with sub-bandgap illumination from 730 nm (1.7 eV) to 280 nm (4.4 eV), the density of interface trap states (D_it β-Ga₂O₃ FETs was determined between 0.4 and 4.4 eV below the conduction band (E_C) of β-Ga₂O₃ Dit peaks near the band edges, similar to conventional material systems. Based on the results, traps located between E_C–4.0 eV and E_C–3.4 eV are primarily responsible for carrier scattering, reducing the mobility by 50%–75% in these devices with increasing distance from the interface. The increased mobility degradation further from the interface is attributed to traps located in the bulk.

DOI：

https://doi.org/10.1109/TED.2026.3678479