Analysis of High-Performance β-Ga2O3 Solar-Blind Ultraviolet Interdigital Photodetectors Fabricated via High-Temperature Thermal Oxidation of GaN and Their Geometric Topology Optimization

This paper reports a metal-semiconductor-metal (MSM) photodetector formed by the surface thermal oxidation of a GaN thin film on a silicon (Si) substrate. A high-temperature treatment of 4 h was used to synthesize a high-quality gallium oxide (Ga2O3) thin film on top of the GaN layer, which was followed by the deposition of titanium-gold (Ti/Au) interdigitated electrodes to complete the photodetector fabrication. A physics-driven optimization model based on a multiphysical function, F(W, S), was used to design the geometric topology of the photodetector. Theoretical simulations unveil a global performance peak at the symmetric topology of the electrode width W = 50 μm and interdigital spacing S = 50 μm. To validate this framework, eight sets of electrodes of varying geometric dimensions (D1–D8) were constructed on the empirical Ga2O3 surface. The experimental results are in excellent agreement with the trends predicted by the physical model, with Sample D4 yielding the apex performance indices (F-score = 4.5 and F-intrinsic = 29.6). Furthermore, multidimensional performance radar profiles reveal that Sample D4 possesses the largest optimized envelope area, establishing a synergistic balance of carrier transport, signal-to-noise ratio, and spatial photon collection. This work provides theoretical foundations and practical design guidelines for the topological integration of high-performance Ga2O3-based MSM photodetectors developed via annealing oxidation processes.