摘要
基于k·p微扰法研究单轴[110]应力作用下硅的导带结构,获得单轴[110]应力硅的导带底能量及电子有效质量.在此基础上,考虑电子谷间、谷内及电离杂质散射,采用弛豫时间近似计算单轴[110]应力硅沿不同晶向的电子迁移率.结果表明:单轴[110]应力作用下硅的电子迁移率具有明显的各向异性.在[001]、[110]及[110]输运晶向中,张应力作用下电子沿[110]晶向输运时迁移率有较大的增强,由未受应力时的1 450 cm2·Vs-1提高到2GPa应力作用下的2 500 cm^2·Vs^(-1).迁移率增强的主要原因是电子有效质量的减小,而应力作用下硅导带能谷分裂导致的谷间散射几率的减小对电子迁移率的影响并不显著.
Conduction band structure of silicon under uniaxial [ 110 ] stress is studied with two band k.p perturbation theory. Splitting energy of conduction band minima and electron effective mass as a function of stress and direction electron mobility in uniaxial stressed silicon are obtained with relax time approximate theory. Intervalley scattering, intravalley scattering, and ionized impurity scattering are considered in calculation. It is demonstrated that as uniaxial [ 110 ] stress is applied on silicon crystal, a significant anisotropy in electron mobility can be observed. Among crystal directions [001 ] , [ 110] , and [ 150] , electron mobility along [ 110] direction under uniaxial [ 110] tensile stress has a profound enhancement, which increase from 1 450 cm2 ·Vs-1 to 2 500 cm2 .Vs-1as stress change from 0 to 2 GPa. Electron mobility enhancement is mainly due to uniaxial stress induced conduction effective mass reduction, while suppression of intervalley scattering plays a minor role.
出处
《计算物理》
CSCD
北大核心
2017年第4期483-488,共6页
Chinese Journal of Computational Physics
基金
国家自然科学青年基金(51502005)
安徽理工大学青年教师科学研究基金资助项目
关键词
单轴应力硅
导带结构
散射
电子迁移率
uniaxial stressed silicon
conduction band structure
scattering
electron mobility
