Large SET Duration Broadening in a Fully-Depleted SOI Technology—Mitigation With Body Contacts

Abstract

Significant floating body effects were measured in 0.2 μm fully-depleted SOI resulting in large amounts of single event transient (SET) broadening, i.e., SET duration stretching. The transient response of single transistors and the propagation of single-event transients (SET) in chains of logic gate (inverters and NOR gates) were investigated by using either heavy ion irradiation or focused laser pulses. Single transistors displayed a particularly slow recovery after an ion strike (> 100 ns). In logic chains, large amounts of SET duration broadening, up to 30 ps/gate, were measured when the unattenuated rail-to-rail SET propagates to the output of the chain. These floating body effects occur mainly at low frequency. They are induced by the accumulation of majority carriers in the body region which contribute to reduce the threshold voltage of OFF-state transistors. This is a slow phenomenon which takes up to several tenths of a second to build-up. It is demonstrated that floating body effects are reduced when designed with body contacts or when the chain operates at high frequency.