Drain Current Decrease in MOSFETs After Heavy Ion Irradiation

heavy ion irradiation on MOSFETs with ultra-thin gate oxide, even after electrical stresses subsequent to irradiation. We found that a single ion can generate a physically damaged region (PDR) localized in the Si/SiO2 interface, which may hamper the surface channel formation. In order to generate a PDR the ion hit must be close enough to MOSFET borders, i.e., in correspondence with the STI or the LDD spacer. Consequently, if both MOSFET W and L are large enough only few ion hits may give place to a PDR, mitigating the radiation damage. Finally we have developed an original model to describe the impact of the PDR on channel conductance in the ohmic linear region. On the basis of this model we predicte a PDR size around 0.2 – 1