2025 article

Process temperature dependence of sputtered MgO/n-type GaN metal–oxide–semiconductor capacitors

Shvilberg, L., Xue, H., Palmese, E. J., Heinrich, H. H., Kuan, J., Abad, G. C., … Ihlefeld, J. F. (2025, July 22). Journal of Applied Physics, Vol. 138.

By: L. Shvilberg *, H. Xue  n, E. Palmese  n, H. Heinrich *, J. Kuan*, G. Abad*, N. Shukla *, S. McDonnell *, J. Wierer n , J. Ihlefeld *

topics (OpenAlex): GaN-based semiconductor devices and materials; Semiconductor materials and devices; Ga2O3 and related materials
Source: ORCID
Added: July 22, 2025

The temperature dependence of epitaxial growth of MgO on n-type (0001)-oriented GaN by radio frequency magnetron sputtering is investigated. Epitaxial growth is obtained for growth temperatures of 550 °C and above, but polycrystalline films are observed for 500 °C and below. For all process temperatures, it is demonstrated that an interfacial phase is present that ranges from 2 to 3 nm in thickness and does not increase in thickness with temperature. The presence of the interfacial phase is shown to originate from ion bombardment during the initial growth. The electronic properties of metal–oxide–semiconductor capacitor devices are measured. Wider hysteresis is seen in capacitance–voltage measurements for devices fabricated at lower deposition temperatures. The less stable electrical performance of films grown at lower temperatures is shown to be related to both interface and bulk defects.