Self Aligned Radiation Hard CMOS/SOS

This paper reports the results of extending previously reported radiation hardening methods to a self-aligned CMOS/SOS process. Over 20 lots of CMOS/SOS circuits have been fabricated with this process. Threshold shifts, after 1 Mrad (Si) Co60 irradiation are ¿ 1.2V for the n-channel devices and ¿ 2.7V for the p-channel devices under worst case bias conditions. Several lots of devices have been fabricated with ¿ 0.7V n-channel shifts and ¿ 1.2V p-channel shifts under the above radiation and bias conditions. Post-irradiation n-channel back leakage is in the range of .05 to 5 ¿A per mil of channel width, the specific value dependent to a considerable extent on quality of the starting SOS material. Electrical parameters and life-test stability are excellent and equal to those obtained with similar, non-radiation-hard processes.