Study On Neutron Radiation Effect Of FinFET SRAM

The integrated circuit technology has been advanced to 14 nm,and the structure of the device has been changed into the triple-gate FinFET.Considering the difference of device structure between FinFET and traditional planar MOSFET,it is necessary to study the neutron radiation effects based on FinFET SRAM which is an important part of electronic system.This paper based on the mechanism of radiation effects,neutron transient dose rate effect and neutron single event upset effect are carried out by building a simulation platform.The main simulation results obtained in the following five aspects:1.A simulation platform including particle transport,device level and circuit level is built to study neutron transient dose rate effect of SOI and Bulk FinFET.In this paper,two kinds of 3D FinFET device models are established in Geant4 and Sentaurus TCAD to obtain the energy deposition of the device's sensitive regions and the current pulse caused by the large number of neutrons.The FinFET SRAM standard cell is built in Hspice,and the current pulse is added in the form of transient current source.The simulation result shows that: the charges in substrate can't be collected by drain due to the buried oxide layer in the SOI device,so SOI FinFET present a better ability to anti-neutron transient dose rate effect than Bulk FinFET.The number of incident neutron threshold of SOI FinFET and Bulk FinFET are 3×106 and 3×105 respectively.2.The neutron transient dose rate effect of the planar 65 nm MOSFET SRAM is studied based on the simulation platform,and the simulation result is compared with that of FinFET SRAM.The simulation result shows that,the voltage of the MOSFET SRAM's sensitive node has been reversed and the value of the voltage drop is larger when the number of neutrons is 3×105.It proves that the planar devices has larger sensitive surface and volume compared with the triple-gate FinFET,so it's more susceptible to neutron transient dose rate effect.3.The DICE and 10T unit circuit based on FinFET are constructed by Hspice.It is verified that these two circuit-level reinforcement methods are suitable for FinFET SRAM and DICE is better than 10T unit.4.A simulation platform including secondary particle energy spectrum and TCAD device level is built to study neutron single event upset effect of SOI FinFET SRAM.The species and energy of the reaction products of neutrons with oxygen atoms and silicon atoms are compared by Talys.It shows that the secondary particles produced by the interaction between oxygen atoms and neutrons can obtain more energy,it's about 1.6 times of that of silicon.5.FinFET SRAM device structure is produced by TCAD directly to obtain the effect of the logic state by secondary particles with different type and energy.The simulation result shows that secondary particles produced by oxygen atoms have more energy,but the relative atomic mass is small.The nuclear reaction between neutron and silicon atoms plays a major role in SEU induced by neutron,and that 25 Mg produced by 14 Me V can make a flip of the circuit logic.