摘要
采用分子束外延(MBE)技术在GaAs衬底上生长Al_(0.26)Ga_(0.74)As外延层,并在相同的退火条件下,分别退火0,10,20,40 min。利用扫描隧道显微镜对不同退火时间下Al_(0.26)Ga_(0.74)As/GaAs样品表面进行了扫描,得出不同退火时间Al_(0.26)Ga_(0.74)As/GaAs表面形貌特点。在40 min的热退火后,Al_(0.26)Ga_(0.74)As/GaAs表面完全熟化。本文采用基于热力学理论的半平台扩散理论模型估测获得平坦Al_(0.26)Ga_(0.74)As/GaAs薄膜表面所需退火时间,根据理论模型计算得到Al_(0.26)Ga_(0.74)As/GaAs平坦表面的退火时间和实验获得平坦表面所需退火时间一致。
The impact of the annealing conditions on the formation of the surface microstructures of the Al_（0.26）Ga_（0.74）As layers,grown by molecular beam epitaxy（MBE） on GaAs（001） substrate and in-situ monitored with reflection high-energy electron diffraction（RHEED）,was phenomenologically formulated as the half-terrace diffusion model,theoretically analyzed in thermodynamics,and experimentally characterized with scanning tunneling microscopy（STM）.The temperature-dependent surface effective diffusion velocity and diffusion length of the adsorbed atoms were estimated to be 0.0252 nm/s and 59 nm,respectively.The STM surface images show that the annealing time significantly reduces the surface roughness via formation of terraced islands.For example,annealed at 560℃for 40 min,the well-defined,stepped surfaces were observed on the Al_（0.26）Ga_（0.74）As layers.The optimized annealingtime was calculated to be 39 min,agreeing well with the experimental result.
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2016年第4期477-481,共5页
Chinese Journal of Vacuum Science and Technology
基金
贵州省自然科学基金(黔科合J字[2013]2114号
黔科合J字[2014]2046号)
贵州省教育厅自然科学研究项目(黔教合KY字[2014]265号)
贵州大学研究生创新基金资助项目(研理工2015082)
