Degradation of deep submicron partially depleted soi CMOS transistors under MeV proton or gamma irradiation

The performance degradation of CMOS transistors, fabricated in a 0.13 μm Partially Depleted (PD) Silicon-on-Insulator (SOI) technology and subjected to high-energy proton and γ-irradiation is described. The devices have been fabricated on UNIBOND wafers with a final film thickness of 100 nm, while the NO gate oxide thickness was 2.5 nm. Splits with and without halo implantation have been studied. It has been shown that the n-channel transistors develop a subthreshold edge channel leakage with increasing total ionising dose, which is related to radiation-induced hole trapping in the 400 nm thick buried oxide. This effect is absent in the p-MOSFETs. At the same time, the static parameters (threshold voltage, transconductance) exhibit a length dependent change. The latter is different for the halo and no halo split and is also a function of the type of irradiation. Finally, some new radiation damage mechanisms are described which are related to the so-called Linear Kink Effect (LKE), which is a gate tunneling induced floating body effect.