Temperature-dependent dose rate effects in CMOS/SOS devices

The measured photocurrent output by the 3392-/spl mu/m p-channel and 1992-/spl mu/m n-channel transistors in the output buffer of the Harris 05131A Octal Latch manufactured in the TSOS4 1.25-/spl mu/m CMOS/SOS process are used to extract the field and temperature-dependent conductivity of the sapphire substrate. The bulk conductivity was found to vary from 2.15/spl times/10/sup -15/ /spl Omega//sup -1//cm/rad(Si)/s at -55/spl deg/C to 4.16/spl times/10/sup -15/ /spl Omega//sup -1//cm/rad(Si)/s at +125/spl deg/C. Parasitic transistor action contributed significant photocurrents with the gain of the n-channel increasing from 1.3/spl plusmn/0.3 at -55/spl deg/C to 5.7/spl plusmn/3.3 at +125/spl deg/C. The gain of the p-channel followed the same temperature variation, with 1.6/spl plusmn/0.5 at -55/spl deg/C to 7.0/spl plusmn/2.0 at +125/spl deg/C. The temperature-dependence of both the substrate and parasitic transistor action appeared due to an Arrenhius variation of the carrier lifetime or mobility controlled by a trap 0.05 eV above the quasi-Fermi level.<
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