| 摘要 |
PURPOSE:To prevent the electric characteristics from being deteriorated by radiation, by a method wherein the titled device is provided with an Si dioxide film of 10nm-50nm thickness formed on a channel region and an Si nitride film or PSG film formed on this Si dioxide film. CONSTITUTION:The Si dioxide film 5 of 10nm-50nm thickness is formed on the channel region by dry oxidation at a temperature below 1,000 deg.C e.g. 900 deg.C, and the Si nitride film 6 or the PSG film 7 is formed on this Si dioxide film 5. The variation in characteristics of the interface between Si and Si dioxide becomes smaller with the decrease in thickness of the Si dioxide film by irradiation with radioactive rays. Since a thickness of the Si dioxide film of 50nm or less increases the input capacitance and decreases the gate dielectric strength, the Si nitride film 6 or the P silicide film 7 is used. Polarization occurs if the phosphorus concentration of the PSG film is too high, and resistance to radiation cannot be obtained if too low; therefore, a range of 2mol% to 10mol% is effective. |
