Measurement of SET Injected Charge from a Californium-252 Source in 340 nm Straight and Enclosed Layout NMOS and PMOS Transistors

The amount of irradiation SET injected charge into both the straight and ELT 340nm NMOS and PMOS transistor of a 180 nm Mixed-Mode CMOS technology has been measured. The radiation source has been Californium-252 and the effective LET at the transistor level has been determined with SRIM to be 18.8 MeVcm²/mg at the start of the active area and reducing significantly with increasing depth. From the in situ injected charge distribution, the maximum injected charge and charge collection depth could be estimated and was found to vary significantly between the PMOS and NMOS devices. While between the straight and ELT NMOS only a small variation was detected, significant augmentation in collected charge has been measured with increasing bias voltages.