Single event gate rupture in thin gate oxides

Abstract

The dependence of single event gate rupture (SEGR) critical field on oxide thickness is examined for gate oxides from 6 to 18 nm. Capacitor data are compared to SEGR data from full integrated circuits. A 1/E/sub CR/ dependence is found for critical field to rupture as a function of ion linear energy transfer (LET), consistent with earlier work for power MOSFETS with oxide thicknesses from 30 to 150 nm. More importantly, critical field to rupture increases with decreasing oxide thickness, consistent with increasing oxide breakdown field prior to heavy-ion exposure. This suggests that SEGR need not be a limiting factor as future technologies scale into the deep submicron region. However, there is a great deal of uncertainty in how voltage may scale with decreasing oxide thickness, and SEGR may continue to be a concern for devices that operate at electric fields significantly higher than 5 MV/cm.