Transient Radiation Response of Complementary-Symmetry MOS Integrated Circuits

Complementary-symmetry MOS (CMOS) integrated circuits were subjected to a sub-microsecond burst of high intensity ionizing radiation using 10-MeV electrons from a LINAC. The results show that, at peak doserate values of less than 8 × 108 rads (Si)/s, the transient change in output voltage of a CMOS inverter is small and can be attributed simply to the net junction photocurrent flowing at the output node. At dose rates in excess of 8 × 108 rads (Si)/s, however, a new type of response comes into play and the transient change in output voltage becomes very large, approaching the operating voltage. In some instances, this change can result in a non-destructive temporary latch-up condition. The results suggest that this condition is caused by a parasitic effect, namely the interaction of the P-well, the source-drain diffusions, and the protection diodes that constitute a four layer structure.