晶圆级硅基氧化镓单晶薄膜异质集成研究

β-Ga2O3 possesses a ultra-wide bandgap and high Baliga’s figure of merit of 3400, which has been identified as a promising candidate for the next generation power devices. However, the disadvantages of β-Ga2O3 are extremely low thermal conductivity and carrier mobility. These two factors are the most important bottleneck to limit the performance of the Ga2O3 devices. Therefore, it is urgent to develop the fabrication process for Si-based high-quality Ga2O3 thin film. Due to the lattice mismatch and crystal symmetry mismatch, it is difficult to directly grow the high qualityβ-Ga2O3 thin film on Si substrate via conventional heteroepitaxy. In order to solve these critical problems for the Ga2O3 device applications, this project purposes the method of ion-slicing and layer transferring. The investigations on ion-slicing of single crystalline β-Ga2O3 thin film, interface bonding between Si and Ga2O3 and the recovery of ion-induced defect and strain will pave the way for the wafer-scale fabrication of -Ga2O3-on-insulator substrate. The MOSFET devices will be demonstrated on this substrate. This project will understand the basic mechanisms of the ion-slicing and hetero-integration of the novel wide band gap semiconductor with a high lattice bonding strength and contribute to the development of theβ-Ga2O3 based high performance device technology.

β-Ga2O3材料具有超宽禁带宽度和高Baliga优值指数，在电力电子功率器件领域具有巨大的应用潜力。然而，β-Ga2O3极低的热导率和电子迁移率成为限制其器件性能的最关键的瓶颈。因此，亟需发展硅基β-Ga2O3薄膜异质集成材料制备技术。由于晶格失配等物理限制，采用传统的异质外延生长方法难以在硅基衬底上制备出高质量单晶β-Ga2O3薄膜。针对发展氧化镓材料制备和器件应用所面临的关键问题，本项目提出采用离子束剥离与衬底转移技术,通过研究离子束剥离氧化镓单晶薄膜的晶格裁剪“断键”机理、硅与β-Ga2O3异质界面融合“成键”机理、离子注入点缺陷修复三方面内容，实现高质量、晶圆级绝缘体上氧化镓衬底材料制备，并进行MOSFET器件验证。本项目的开展将为离子束剥离制备新型宽禁带半导体单晶薄膜及硅基异质集成提供理论基础，为超宽禁带氧化镓高性能器件技术的发展提供材料支撑。

极宽禁带半导体Ga2O3低的热导率（其热导率不到Si 的1/5，SiC 的1/20）限制了其功率器件的工作性能，导致器件工作中会产生严重的自热效应，降低其在功率和射频领域的竞争力，因而将Ga2O3薄膜异质集成到其他高导热衬底解决Ga2O3材料和器件的热耗散问题具有极其重要的意义。由于晶格失配、晶型失配等物理限制，传统的异质外延生长技术难以在高导热衬底（SiC、Si等）上生长出高质量的Ga2O单晶薄膜。为此，本项目提出了采用离子束剥离与转移的方法将Ga2O3 单晶薄膜转移到高导热衬底上，开展了离子束剥离Ga2O3单晶薄膜的物理机制、Ga2O3与硅基等高导热衬底键合工艺、晶圆级Ga2O3异质集成材料制备工艺、离子注入缺陷修复与热应力释放工艺、高性能Ga2O3功率器件制备工艺等研究，首次实现了晶圆级Ga2O3单晶薄膜与高导热Si、SiC衬底的异质集成，并制备器件验证其散热性能以及热稳定性能表征，这些工作充分表明了通过异质集成技术能够解决Ga2O3低热导率的瓶颈问题，从而大幅度推动Ga2O3功率器件的发展和应用。