Generation lifetime and surface generation velocity were measured by capacitance transient analysis of metal‐oxide‐semiconductor capacitors to study the effect of high‐energy neutron irradiation in the fluence range 1012–1014cm−2. Thirty‐minute isochronal anneals show that the generation lifetime and surface generation velocity recover their preirradiation values at 470 °C, which is close to the temperature for annealing of recombination lifetime decreases produced by electron irradiation. The relatively low value of annealing temperature for the recovery of lifetime after neutron irradiation is in sharp contrast with the improved thermal stability of lifetime effects produced by ion implantation into silicon when compared to the case of electron irradiation.