Study of Layout Dependent Radiation Hardness of FinFET SRAM using Full Domain 3D TCAD Simulation

Due to the emerging of novel technologies, such as stacked horizontal nanowires, and novel 3D integration schemes, such as stacking PMOS on top of NMOS, multiple transistors in a SRAM cell might be struck simultaneously by a single Alpha particle. This may result in worse radiation hardness of SRAM. We show that if the access transistor (A-NMOS) and pull-down transistor (PD-NMOS) are struck at the same time, bulk MOSFET SRAM (L _g,eff = 25nm) will be ~20% more susceptible to Single Event Upset (SEU). Full domain 3D TCAD simulation of L _g =25nm FinFET SRAM cell is then performed to confirm that such scenario is possible even in a standard SRAM layout and the radiation hardness is reduced by as much as 50%. Therefore, DTCO of 3D integration should take radiation effect into account for critical mission applications.