Recent advancement and perspective of epitaxial growth and doping of <i>β</i>-Ga2O3 thin films for power electronics
Wenjing Xu, Yihong Chen, Xiaoqing Zhou, Xiangyu Xu, Xinyong Dong, Hao Long, Zhilai Fang, Zhenni Yang, Duanyang Chen, Hongji Qi, Kelvin H. L. Zhang
Abstract
Gallium oxide has gained significant attention due to its exceptional material properties, including an ultra-large bandgap of 4.9 eV, a high breakdown electric field of 8 MV/cm, and availability of large size bulk crystal grown by using the melt method. These merits enable Ga2O3 to be a promising material for high power electronics and solar blind UV optoelectronic applications. In recent years, substantial progress has been achieved in the single-crystal substrate growth, thin film epitaxy, and device fabrication. Thin film epitaxy is a particularly crucial step for harnessing the full potential of Ga2O3-based devices, as it enables precise control over carrier doping concentrations, interfaces, and defect minimization. This review presents recent advancements in the epitaxial growth of Ga2O3 thin films using molecular beam epitaxy, metal-organic chemical vapor deposition, hydride vapor phase epitaxy, and other growth techniques. We will first discuss the important material properties of Ga2O3 for electronic device applications, followed by a brief review on the status of bulk melt growth of single crystal substrate. Then, we will focus on the latest advancements on the thin film epitaxial growth technologies, with emphasis on the doping controlling over electrical properties, defect minimization and controlling, and progress in the development of (AlxGa1−x)2O3/Ga2O3 hetero-interface for two-dimensional electron gas.