High‐frequency small‐signal capacitances of semiconductor junction vs temperature, from the initial conditions of filled and emptied traps in the junction depletion region, are used to determine the trap concentration and the thermal activation energies of trapped electrons and holes. Illustrations are given for siliconN+Pdiodes doped with gold impurity or irradiated with 1‐MeV electrons, showing the room‐temperature annealing for the latter.