The deviation from the ohmic low-field mobility is modeled as a function of the carrier temperature, , after

denotes the energy relaxation times and are the saturation velocities calculated respectively in (3.138) and in (3.134).

For some III-V semiconductor materials a multi-valley mobility model can be
used. In the following model a weighted mean is calculated from the low-field
mobilities of the - and -electrons [181].

denotes the ratio of the and -valley populations
[86]. The valley mobilities
and
account for impurity scattering after
(3.97), and are constant with respect to the lattice
temperature.

(3.133) |

For calculation of the high field mobilities no additional parameters need to be
specified for the model. The respective interpolations between the *basic materials* are carried out in the models for the saturation velocities and, in the case
of HD simulation, of the energy relaxation times.

2001-02-28