Work

Impact of Defects on the Low-Field Electron Mobility in GaN-on-Si HEMTs

Year: 2025

Type: article

Abstract: In this work, we investigate the field and temperature dependence of the electron mobility in aluminum-gallium-nitride/gallium-nitride (AlGaN/GaN) high electron mobility transistors (HEMTs) realized on GaN-on-silicon (Si) substrates. For this purpose we employ an extraction method to eliminate parasitic and fringing effects. Our results show that especially at low fields the temperature dependence of the mobility, and consequently that of the specific on-resistance, is strongly affected by stress-induced charged dislocation scattering. For explaining the mobility behaviour at low fields, the subthreshold operation regime of the HEMTs has also been analyzed. An interface trap density at the AlGaN/GaN interface (Nit) of 6.9 × 1010 cm-2 has been extracted independent of the temperature which is close to the extracted dislocation density from mobility measurements. This suggests that the relatively high dislocation density in the GaN layer, which is a consequence of the still imperfect buffer layer in the GaN-on-Si substrate that is used to accommodate the strain difference, has an impact on Nit, thus subthreshold swing, in addition to the mobility reduction.

Source: IEEE Journal of the Electron Devices Society

DOI: 10.1109/jeds.2025.3577260

Authors: Ran Zhou, D. J. Gravesteijn, R. J. E. Hueting

Institution: University of Twente

Language: English

Topic: GaN-based semiconductor devices and materials

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,350

Funder: Nederlandse Organisatie voor Wetenschappelijk Onderzoek