基于k·p微扰理论框架,研究建立了单轴张/压应变Si,Si基双轴应变p型金属氧化物半导体(PMOS)反型层空穴量子化有效质量与空穴面内电导率有效质量模型.结果表明:对于单轴应力PMOS,选择单轴压应力可有效增强器件的性能;同等增强PMOS空穴迁移率,需要施加的单轴力强度小于双轴力的强度;在选择双轴应力增强器件性能时,应优先选择应变Si1-x Ge x作为沟道材料.所获得的量化理论结论可为Si基及其他应变器件的物理理解及设计提供重要理论参考.
通过合金化改性技术,Ge可由间接带隙半导体转变为直接带隙半导体.改性后的Ge半导体可同时应用于光子器件和电子器件,极具发展潜力.基于直接带隙Ge1-x Sn x半导体合金8带Kronig-Penny模型,重点研究了其导带有效状态密度、价带有效状态密度及本征载流子浓度,旨在为直接带隙改性Ge半导体物理的理解及相关器件的研究设计提供有价值的参考.研究结果表明:直接带隙Ge1-x Sn x合金导带有效状态密度随着Sn组分x的增加而明显减小,价带有效状态密度几乎不随Sn组分变化.与体Ge半导体相比,直接带隙Ge1-x Sn x合金导带有效状态密度、价带有效状态密度分别低两个和一个数量级;直接带隙Ge1-x Sn x合金本征载流子浓度随着Sn组分的增加而增加,比体Ge半导体高一个数量级以上.
Based on the Fermi's golden rule and the theory of Boltzmann collision term approximation, a physically-based model for hole scattering rate(SR) in strained Si1-x Gex/(100)Si was presented, which takes into account a variety of scattering mechanisms,including ionized impurity, acoustic phonon, non-polar optical phonon and alloy disorder scattering. It is indicated that the SRs of acoustic phonon and non-polar optical phonon decrease under the strain, and the total SR in strained Si1-x Gex/(100)Si also decreases obviously with increasing Ge fraction(x). Moreover, the total SR continues to show a constant tendency when x is less than 0.3. In comparison with bulk Si, the total SR of strained Si1-x Gex/(100) Si decreases by about 58%.
