The overall radiation response to X-ray exposure of metal-oxide-semiconductor (MOS) capacitors, subjected to two different post-deposition-annealing (PDA) processes in N 2 O or POCl 3 atmospheres, was investigated by capacitance-voltage (CV) analyses. The production rate and saturation density of electrically active defects, different for the two oxides, demonstrated an additional contribution to the defects formation coming from the annealing treatements. The higher susceptibility of the POCl 3-annealed oxide respect to the N 2 O annealed is discussed.