Radiation damage studies of a custom-designed VLSI readout chip

Two structurally similar versions of an NMOS custom VLSI circuit, fabricated by different manufacturers, have been irradiated with a /sup 60/Co source up to doses of 100 krad. Large differences in their behavior after irradiation have been seen and are thought to be due to the fabrication processes. These differences are observed in test structure measurements and overall chip performance. An increase in circuit noise causes one version of the chip to be unusable after radiation doses of 20 krad.<
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