Based on the direct tunneling model, the complete solution is obtained for the charge‐transport equation for MIS memory transistors. It is shown that the time dependence is linear in the microsecond range, roughly logarithmic in the millisecond range, and eventually saturates to a value determined by the physical characteristics of the device. For an oxide layer 20 Å thick, the theory predicts a switching time of about 45 &mgr;sec and saturation in about 150 sec.