High-rate growth of gallium oxide films by plasma-enhanced thermal oxidation for solar-blind photodetectors

Abstract

Almost all reported high-performance β-Ga2O3 thin films are grown by molecular beam epitaxy, metal–organic chemical vapor deposition, and pulsed laser deposition at a very high cost and low throughput. To explore the fast growth method for β-Ga2O3 with high quality and low cost, a custom-made plasma-enhanced chemical vapor deposition is designed for innovative thermal oxidation of gallium nitride. It is shown that the growth rate of gallium oxide thin films prepared by the plasma-enhanced thermal oxidation (PETO) is 2 to 5 times higher than that of thermal oxidation process under similar growth conditions. For β-Ga2O3 thin films prepared by the PETO, the high-rate growth, low root-mean-square roughness, and growth with the orientation along (2¯ 01) lattice plane are achieved. The developed growth mechanism elucidates the role of the O2 and Ar + O2 plasma-surface interactions in the β-Ga2O3 growth process. Solar-blind photodetectors based on the β-Ga2O3 films grown by the PETO with a high solar blind-to-UV rejection ratio (R245 nm/R360 nm = 10.2), a low rise time of 0.17 s, and a low fall time of 0.2 s are demonstrated. The plasma-surface interaction effects are generic and are applicable to a broader range of materials systems and devices for diverse applications.