Study of total ionizing dose radiation effects on enclosed gate transistors in a commercial CMOS technology

This paper studies the total ionizing dose radiation effects on MOS(metal-oxide-semiconductor) transistors with normal and enclosed gatelayout in a standard commercial CMOS (compensate MOS) bulk process.The leakage current, threshold voltage shift, and transconductance ofthe devices were monitored before and after $gamma $-rayirradiation. The parameters of the devices with different layoutunder different bias condition during irradiation at different totaldose are investigated. The results show that the enclosed layout notonly effectively eliminates the leakage but also improves theperformance of threshold voltage and transconductance for NMOS(n-type channel MOS) transistors. The experimental results alsoindicate that analogue bias during irradiation is the worst case forenclosed gate NMOS. There is no evident different behaviour observedbetween normal PMOS (p-type channel MOS) transistors and enclosedgate PMOS transistors.