Study of single event transient induced by heavy-ion in NMOS transistor and CMOS inverter

SET has become the main concern of radiation effect researchers as technology scales down and increasing sensitivity of modern integrated circuits. Transient response induced by heavy-ion, especially the impact of parasitic bipolar amplification in both the NMOS transistor and the CMOS inverter, is investigated in this paper. The bipolar effect of the bulk NMOS transistor has been studied through transient current measurements by using 3-D simulation. The simulation of a 3-D structure has confirmed the enhancement effect due to the bipolar-like structure inherent to the NMOS transistor. With regard to the CMOS inverter, waveforms of transient voltage pulse are fully measured via 2-D mixed-mode simulation. In addition, the impact of LET on transient voltage pulse amplitude and width is analyzed; also, the effect of load capacitance on voltage pulse amplitude is discussed as well. The 2-D mixed-mode simulation results indicate that SET pulse amplitude increases with the value of LET due to enhancement of drift, while SET pulse width increases with the LET for the reason of more significant parasitic bipolar amplification effect. In addition, SET pulse amplitude increases monotonically with the load capacitance. This paper further investigates the bipolar amplification mechanism in bulk MOSFET and analyzes the variation of transient voltage pulse in different conditions in deep submicron device.