The Effect of Deep N+ Well on Single-Event Transient in 65 nm Triple-Well NMOSFET

Abstract

In a triple-well NMOSFET, a deep n+ well (DNW) is buried in the substrate to isolate the substrate noise. The presence of this deep n+ well leads to changes in single-event transient effects compared to bulk NMOSFET. In space, a single cosmic particle can deposit enough charge in the sensitive volume of a semiconductor device to cause a potential change in the transient state, that is, a single-event transient (SET). In this study, a quantitative characterization of the effect of a DNW on a SET in a 65 nm triple-well NMOSFET was performed using heavy ion experiments. Compared with a bulk NMOSFET, the experimental data show that the percentages of average increase of a SET pulse width are 22% (at linear energy transfer (LET) = 37.4 MeV·cm2/mg) and 23% (at LET = 22.2 MeV·cm2/mg) in a triple-well NMOSFET. This study indicates that a triple-well NMOSFET is more sensitive to a SET, which means that it may not be appropriate for radiation hardened integrated circuit design compared with a bulk NMOSFET.