Single event gate rupture in 130-nm CMOS transistor arrays subjected to X-ray irradiation

We present new experimental results on heavy ion-induced gate rupture on deep submicron CMOS transistor arrays. Through the use of dedicated test structures, composed by a large number of 130-nm MOSFETs connected in parallel, we show the response to heavy ion irradiation under high stress voltages of devices previously irradiated with X-rays. We found only a slight impact on gate rupture critical voltage at a LET of 32 MeV cm² mg^-1 for devices previously irradiated up to 3 Mrad(SiO₂), and practically no change for 100 Mrad(SiO₂) irradiation, dose of interest for the future Super Large Hadron Collider (SLHC). We attribute this effect to the interplay between the damages produced by X rays, heavy ions, and electrical stress.