Investigation of TID and DD Effects on FD SOI Nanowire FET Induced by Proton Irradiation

In this study, radiation-induced degradation, which is caused by total ionizing dose (TID) and displacement defect (DD) effect, is investigated in fully depleted silicon-on-insulator (FD SOI) nanowire field-effect transistors (NWFETs) under 25-MeV proton irradiation. The combined effect of TID and DD degraded the subthreshold swing (SS) and OFF-state current (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>off</roman></sub>) of n-type FD SOI NWFETs, while it degraded the threshold voltage (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>th</roman></sub>) and ON-state current (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>on</roman></sub>) of p-type FD SOI NWFETs. This degradation was sensitive to increases in proton fluence. Additionally, as the gate length (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>g</i></sub>) decreased, the degradation due to DD effect increased, aggravating the degradation due to the combined effects of TID and DD. However, narrow devices with improved side gate control mitigated the effects of the interface traps, oxide traps, positive charge trapped in the spacer, and DD.