The Study On Enhancement Mechanism And Model Of Strained Si Carrier Mobility

Strained Si has the advantage of high-mobility and adjustable energy structure, moreover, its processing technology can also be compatible with that of traditional silicon. In the current semiconductor industry, many kinds of heterojuction devices and circuits of strained Si have been in practical use. Simultaneously,theoretically study the mechanism of mobility enhancement, has been developed. From the theoretical study of strained silicon to enhance mobility mechanism can be clearly strained silicon material performance reasons, as well as the guidance of new strained silicon devices and circuit design.The main work was focused on enhancement mechanism and model of strained Si mobility.By solving the Schr?dinger equtation,we got the energy band ,split energy of energy band and density-of-state,intrinsical carrier density .Based on the scattering theory ,we got the scattering matrix elements and got the expression of Relaxtion Time.The subband energies and the envelop function can be calculated by solving the Schr?dinger equtation and Poission equation self-consistently.Then,we calculate the phonon scattering mobility .First,calculate the screened scattering potential induced by a point charge and the scattering rate given by the entire distribution of scattering centers,include dopants and possible fixed charges.Then,the momentum relaxtion time and the remote Coulomb scattering limited mobility are calculated ,similarly to other scattering mechanisms.At last ,the expression of mobility can be got.At last,I simulated the relation between strained silicon mobility and effective electric field, temperature , doping concentration and the stress .We compared this mobility models and the semi-empirical model.