不同晶系应变Si状态密度研究

应变Si技术是当前微电子领域研究发展重点,态密度是其材料的重要物理参量.本文基于应力相关KP理论,建立了(001),(101)和(111)晶面施加双轴应力形成的四方、单斜及三角晶系应变Si导带、价带态密度模型.结果表明,除单斜和三角晶系导带底态密度外,应力对其余各态密度均有显著影响.本文所得模型数据量化,可为应变Si材料物理的理解及其他物理参数模型的建立奠定重要理论基础. 关键词： 应变Si KP 态密度

Densities of states of strained Si in different crystal systems

There has been aroused a lot of interest in the strained Si technology in the microelectronic field. Density of states (DOS) is an important physical parameter in strained Si materials. Based on the Kleinerts Variational perturbation (KP) theory related to stress, DOSs of electrons and holes near the bottom of conduction band and the top of valence band are obtained in tetragonal, rhombohedral and monoclinic strained Si grown from (001), (101) and (111) substrates respectively. It is found that their DOSs are obviously different from the ones of cubic unstrained Si, except DOSs of electrons near the bottom of conduction band in rhombohedral and monoclinic strained Si. The quantized model obtained can provide valuable references for understanding the strained Si material physics and developing the theoretical model of the other important physical parameters.