Hole Scattering And Mobility Of Compressive Strained Ge/（001）Si_1-xGe_x

Strained Ge materials attract for its high mobility and compatibility with Si technology. It has become the focus of the silicon CMOS research development.Based on the K?P energy band theory, the influence of stress to the energy level splitting of strained Ge/(001)Si1-x Gex under Γ point were established in this paper. Then, models of average effective mass of hole, conductivity effective mass of hole and state density effective mass of hole were established. On this basis, the valence band structure model of compressive strained Ge/(001)Si1-x Gex were established. The relationship between hole scattering and stress were established in this paper, including ionized impurity, acoustic phonon, non-polar optical phonon and total scattering rates. And the influence of stress intensity to the hole isotropy and anisotropy mobility were analyzed. The hole scattering model and mobility model were established, and the simulations were carried on. It revealed the evolution that, the influence of stress to the valence band structure, scattering probability and the hole isotropy and anisotropy mobility: With the increase of stress, acoustic phonon and non-polar optical phonon of compressive strained Ge/(001)Si1-x Gex reduced significantly, especially the acoustic phonon, reduced by about one order of magnitude. With the increase of stress, the total scattering rates of compressive strained Ge/(001)Si1-x Gex also reduced significantly. Under the effect of stress, hole isotropy and anisotropy mobility of compressive strained Ge/(001)Si1-x Gex enhanced significantly, when stress continues to increase, the in-plane anisotropy mobility of compressive strained Ge/(001)Si1-x Gex is no longer apparent.Our quantitative data from the models can provide valuable references to the research of modified Ge materials physics and the design of the related devices.