  The mobility of electrons and holes in silicon depends on many parameters.
Two of them are the electric field and the temperature. It has been observed
previously that the mobility in the transition region between ohmic transport
and saturation velocities is a function of the orientation of the crystal
lattice.
  This paper presents a new set of parameters for the mobility as function of
temperature and electric field for <111> and <100> crystal orientation. These
parameters are derived from time of flight measurements of drifting charge
carriers in planar p^+nn^+ diodes in the temperature range between -30{\deg}C
and 50{\deg}C and electric fields of 2x10^3 V/cm to 2x10^4 V/cm.
