γ—Radiation effects on MOSFET´s fabricated with NMOS Submicrometer technology

In this letter, we report γ-radiation effects on MOSFET´s fabricated with NMOS submicrometer technology. We have investigated the radiation sensitivity of n-channel MOSFET´s with Leffvarying from 6 to 0.3 µm and with a gate oxide thickness of 250 Å. We observed that, for radiation doses ≤ 10⁴rad´s, the threshold voltage shift is less than 75 mV and this shift is independent of the device geometry (even for Leff= 0.3 µm). A comparision has also been made between TaSi2gate MOSFET´s and poly-gate MOSFET´s. The deposition of TaSi2on poly/oxide/silicon structure does not decrease the radiation sensitivity of these MOSFET´s. We have also compared MOSFET´s fabricated with X-ray lithography and optical lithography. The X-ray lithography does not have a significant effect on the radiation sensitivity of these MOSFET´s.