Semi-empirical equations for electron velocity in silicon: Part II—MOS inversion layer

We present a simple model of inversion layer and accumulation layer mobilities in Si MOSFET´s. The use of an effective normal field and a simple approximation for the temperature dependent quantum mechanically broadened channel layer width Permits the development of a versatile semi-empirical equation. This equation provides good agreement with electron mobility data in the literature as a function of normal electric field, temperature, substrate doping, and fixed charge density. Screening effects have considerable influence in the model. Subthreshold behavior is predicted with reasonable accuracy. The model is also applicable at high tangential fields where mobility is reduced due to hot-carrier effects.