Al2O3 AS A RADIATION-TOLERANT CMOS DIELECTRIC.

Complementary-symmetry MOS circuits with their high noise immunity and low power consumption are excellent candidates for many stringent military and aerospace applications. However, their sensitivity to high-energy ionizing radiation often restricts their use. By employing Al//2O//3 as the gate dielectric, CMOS circuits that withstand up to 10**8 rads (Si) of ionizing radiation can be made. Al//2O//3 has been applied to bulk CMOS circuits with aluminum gates and to CMOS in silicon-on-sapphire with both aluminum gates and self-aligned polysilicon gates. In this paper the fabrication, characterization, and limitations of Al//2O//3 as a gate dielectric are presented. Also presented is an evaluation of Al//2O//3 as a radiation-hard dielectric as compared to other hardening approaches, which are based on improving the standard SiO//2 gate dielectric.