Comparison of Radiation Hardness of Stacked Transmission-Gate Flip Flop and Stacked Tristate-Inverter Flip Flop in a 65 nm Thin BOX FDSOI Process

We examined radiation hardness of a stacked transmission-gate flip flop and a stacked tristate-inverter flip flop, which are called STACKEDTGFF and STACKEDTIFF respectively. Stacked flip flops fabricated in FDSOI are stronger against soft errors than in bulk because all transistor channels are isolated by a BOX layer. We evaluated soft-error tolerance by neutron and heavy-ion irradiation. STACKEDTIFF is faster than STACKEDTGFF because of the difference of the number of gates along the data path. Those FFs did not flip by neutrons and the normal incidence of heavy ions with LET of less than 40 MeV-cm2mg. They are stronger against soft errors than a standard TGFF by two order of magnitude. We also investigated incident angle dependence of those FFs by heavy ions.