Stress engineering and proton radiation influence on off-state leakage current in triple-gate SOI devices

In this work the influence of different stress techniques and proton irradiation on the off-state leakage current is investigated for p- and n-channel Multiple Gate MOSFETs (MuGFETs). Four different splits are evaluated: unstrained, uniaxially stressed, biaxially stressed and the combination of both types of stress. For nMuGFETs, the higher the stress effectiveness the higher is the GIDL due to band gap narrowing. However for p-channel devices, the gate leakage current is higher than band-to-band tunneling and it dominates the drain current in the off-state region. After proton irradiation all the n-channel devices present a worse behavior. Off-state leakage current for nMuGFETs was degraded by radiation due to the increase of the back gate leakage current generated by the increase of the interface charge density at the back interface. For p-channel devices, the radiation did not show any influence in off-state leakage current, since the gate oxide thickness is very thin and therefore the radiation has no influence on the gate current, which is the dominant effect in the pMuGFETs off-state region.