氧化镓同质外延及二维“台阶流”生长研究  

Research on Gallium Oxide Homoepitaxy and Two-Dimensional Step-Flow Growth

作　　者：李悌涛 卢耀平 陈端阳[2] 齐红基[2] 张海忠 LI Titao;LU Yaoping;CHEN Duanyang;QI Hongji;ZHANG Haizhong(College of Physics and Information Engineering,Fuzhou University,Fuzhou 350108,China;Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]福州大学物理与信息工程学院,福州350100 [2]中国科学院上海光学精密机械研究所,上海201800

出　　处：《人工晶体学报》2025年第2期219-226,共8页Journal of Synthetic Crystals

基　　金：国家自然科学基金(62204270);福建省科技重大专项(2022HZ027006);福建省自然科学基金(2024J01251)。

摘　　要：如何同质外延生长出具有原子级平整的氧化镓(Ga_(2)O_(3))单晶薄膜,是制备高性能Ga_(2)O_(3)基功率电子器件或紫外光电器件的基础。本文通过金属有机气相外延(MOVPE)技术综合调控外延生长的热力学条件与动力学参数,在Ga_(2)O_(3)衬底上制备了厚度为1.0μm的器件级Ga_(2)O_(3)单晶薄膜(非故意掺杂),对薄膜样品进行了物相、表面形貌、晶体质量和电学性能的研究。该薄膜具有单一β相,呈现出与衬底相同的(100)面择优取向。对Ga_(2)O_(3)薄膜表面形貌进行AFM表征,呈现出典型的台阶流形貌,表面粗糙度0.166 nm,且台阶高度0.6 nm(a/2),表明薄膜具有原子级平整。进一步通过HRXRD双晶摇摆曲线评估Ga_(2)O_(3)薄膜结晶质量,外延膜的FWHM低于单晶衬底,表明外延在晶格匹配衬底上的Ga_(2)O_(3)薄膜质量优于衬底。霍尔效应测试结果表明,Ga_(2)O_(3)薄膜的电子迁移率为92.1 cm^(2)/(V·s),载流子浓度为2.65×10^(16) cm^(-3)。本文的研究结果表明只要通过精细化调控温度、压力、Ⅵ/Ⅲ比等关键热力学条件,使核心动力学参数中的横向扩散速率充分大于纵向沉积速率,就有可能在通用的非刻意斜切衬底上实现高长速二维“台阶流”生长。本研究所制备的具有优异晶体质量与电学特性的(100)面同质外延单晶薄膜,在制造高性能Ga_(2)O_(3)功率电子器件具有重要的应用潜力。The achievement of single crystalline gallium oxide(Ga_(2)O_(3))homoepitaxial layers with atomic-level smoothness is fundamental for the fabrication of high-performance Ga_(2)O_(3)-based power electronics or ultraviolet photodetectors.In this study,metal organic vapor phase epitaxy(MOVPE)technique was employed to comprehensively control the thermodynamic conditions and kinetic factors of epitaxial growth,resulting in the production of unintentionally doped,device-grade Ga_(2)O_(3)single crystal films with a thickness of 1.0μm on Ga_(2)O_(3)substrates.Characterizations of the Ga_(2)O_(3)samples were performed to investigate phase composition,surface morphology,crystal quality,and electrical properties.The Ga_(2)O_(3)homoepilayer exhibits a singleβphase with a preferential orientation matching the(100)plane of the substrate.Atomic force microscopy(AFM)analysis reveals a typical step-flow morphology,with a surface roughness of 0.166 nm and a step height of 0.6 nm(a/2),indicating atomic-level smoothness.High-resolution X-ray diffraction(HRXRD)rocking curve analysis was conducted to further evaluate the crystallinity of the Ga_(2)O_(3)epilayers.The full width at half maximum(FWHM)of the epilayers is lower than that of the single crystal substrate,indicating superior quality of the Ga_(2)O_(3)epilayers grown on the lattice-matched substrate.Hall effect measurements indicate an electron mobility of 92.1 cm^(2)/(V·s)and a carrier concentration of 2.65×10^(16) cm^(-3).Our results demonstrate that high-growth-rate 2D step-flow growth on commonly used non-intentionally miscut substrates can be achieved as long as the critical thermodynamic conditions,such as temperature,pressure,and the Ⅵ/Ⅲ ratio—are finely tuned to ensure that the lateral diffusion rate of the core kinetic parameters is sufficiently greater than the vertical deposition rate.The exceptional crystal quality and electrical properties highlight the significant potential of these(100)-oriented homoepitaxial films in the development of high-performance

关 键 词：氧化镓 同质外延 二维“台阶流”生长 MOVPE 单晶薄膜 原子级平整 

分 类 号：TN304.2[电子电信—物理电子学] O78[理学—晶体学]