Influence of Rapid Thermal Annealing on the Characteristics of Sn-Doped Ga₂O₃ Films Fabricated Using Plasma-Enhanced Atomic Layer Deposition

In this work, Sn-doped Ga₂O₃ films fabricated using plasma-enhanced atomic layer deposition were treated by rapid thermal annealing (RTA). The RTA influence on the chemical state, surface morphology, energy band alignment, and electrical properties of Sn-doped Ga₂O₃ films were thoroughly investigated. The results of X-ray photoelectron spectroscopy (XPS) demonstrated that Sn atoms were successfully doped into these films. Moreover, energy band alignments were obtained by the energy-loss peak of the O 1s spectrum and valence band spectra and thoroughly discussed. X-ray reflectivity (XRR) and atomic force microscope (AFM) measurements indicated that the Sn-doping level affects the interfacial microstructure and surface morphology. As the Sn content increases, the film thickness decreases while the roughness increases. Finally, the leakage current-voltage (I-V) characteristics proved that the Sn-doped Ga₂O₃ films have a large breakdown field. In I-V tests, all metal oxide semiconductor (MOS) capacitors exhibited a hard breakdown. This research demonstrates a method for manufacturing high-performance optoelectronic devices with desired properties.