Highly preferred orientation of Ga2O3 films sputtered on SiC substrates for deep UV photodetector application

Abstract

As a wide-bandgap semiconductor oxide material, Ga2O3 has great application prospects in various optoelectronic fields. At present, much attention has been paid to Ga2O3 deep ultraviolet (DUV) detectors, in which Ga2O3 films are often poor-quality poly-crystalline or expensive mono-crystalline. In this paper, Ga2O3 films with highly preferred orientation were deposited on hexagonal SiC (6H-SiC) substrate by magnetron sputtering, and the as-prepared Ga2O3 films were then annealed. The influences of sputtering and annealing parameters on Ga2O3 films were analyzed. Finally, DUV photo-detectors based on the as-obtained Ga2O3 films were fabricated. The experimental results show, when choosing optimal sputtering parameters (RF power: 120 W, gas pressure: 1.5 Pa, film thickness: 400 nm), the sputtered Ga2O3 films with (2¯01) highly preferred orientation after annealing at 800 °C, have good crystalline quality (FWHM = 0.108°) between single-crystal and polycrystal, showing good compromise between optoelectronic characteristics and preparation cost. The fabricated metal-semiconductor-metal (MSM) DUV photodetector operated at a bias voltage of 10 V can achieve excellent comprehensive photo-detection properties for 254 nm ultraviolet light: the responsivity, detectivity and quantum efficiency are high as 2.6 A/W, 1.6 × 1012 Jones and 1265%, respectively, along with short response time of 0.26 s.