Work

Substrate Off-Cut Effect on the Performance of Enhancement-Mode β-Ga 2 O 3 Metal-Oxide-Semiconductor Field-Effect Transistors

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide This study examines the effect of a 6° off-cut toward the a -plane (A-6°) and m -plane (M-6°) of the c -plane sapphire ( c -plane) substrates on the performance of enhancement-mode β-Ga 2 O 3 metal-oxide-semiconductor field-effect transistors (MOSFETs). All epitaxial layers were grown simultaneously by metal–organic chemical vapor deposition, and the devices were fabricated using the same process, so that substrate orientation was the only experimental variable. Hall measurements at room temperature showed an improvement in mobility from 13.7 cm 2 /V·s ( c -plane) to 20.5 cm 2 /V·s (A-6°) and 18.9 cm 2 /V·s (M-6°). In addition, density functional theory simulations were performed to evaluate the lattice mismatch between β-Ga 2 O 3 and differently oriented sapphire substrates. The study confirms that off-cut substrates improve the crystalline quality and translate these improvements into fully fabricated, normally off transistors. In the fabricated MOSFETs, the on-resistance decreases from 1.85 kΩ mm ( c -plane) to 0.45 kΩ mm (A-6°) and 0.70 kΩ mm (M-6°). Electrical benchmarking of c -plane, A-6°, and M-6° devices showed that devices grown on A-6° substrate achieve the best overall performance among the three substrates, indicating that substrate engineering is an effective method for advancing β-Ga 2 O 3 power devices.

Source: ACS Applied Electronic Materials

DOI: 10.1021/acsaelm.5c02198