Radiation-Hardened JFET Devices and CMOS Circuits Fabricated in SOI Films

The effects of total-dose radiation have been investigated for the first complementary JFETs fabricated in zone-melting-recrystallized (ZMR) Si films on SiO2-coated Si substrates. With a -5 V bias applied to the Si substrate during irradiation and device operation, both n- and p-channel devices show low threshold-voltage shift, low leakage currents and small transconductance degradation for total doses up to 108 rad(Si). Fully functional CMOS 1K static RAMs and 1.2K gate arrays have been fabricated in both ZMR and oxygen-implanted (SIMOX) SOI films. The ZMR circuits are superior in speed performance to the SIMOX circuits because parasitics are smaller for the ZMR structure. Excellent transient-radiation hardness has been demonstrated for both ZMR and SIMOX SRAMs, which showed no logic upset for dose rates up to 7 × 1010 rad(Si)/s.