Study On Scattering Mechanism And Characteristics For Strained Si Carriers

Strained Si has the broad prospects in high-speed / high-performance devices and circuits for its advantages of high mobility, adjustable band structure and been compatible with Si process. It's an important research area of concern at home and abroad. The scattering mechanism and characteristic of strained silicon is the theoretical basis for the in-depth study of strained Si carrier mobility enhancement. Till now, there are little papers about it. Base on the Physical mechanism of strained Si, this thesis mainly study the scattering mechanism and characteristic of strained silicon.This thesis first analyzes the formation mechanism of Si strain, thus parameters, necessary to get scattering probability,are obtained. Then, with the analysis of the quantum mechanics fundament of scattering mechanism, this thesis studies the main scattering mechanisms in Si strain, such as ionized impurity scattering , acoustical phonon scattering, optic phonon scattering and inter-valley phonon scattering, and builds the corresponding scattering models. Finally, using these corresponding scattering models, the relationship between energy E, Ge concentration and the probabilities is obtained. The models have been simulated by Matlab and all results are presented. The results show that compared with non-strained silicon, the total scattering probabilities about electronics and hole of strained silicon were significantly reduced. In addition, with the same Ge concentration, the total scattering probability about electronics of strained silicon decreases with increasing energy, while the total scattering probability about the hole of strained silicon increases with increasing energy.The scattering mechanism probability models obtained in this thesis could provide important theoretical bases for both the understanding of the Si strain physical properties and the device performance improvements.