Thin Buried Oxide Densification for Radiation Hardened 80nm BOX SIMOX Substrates

SIMOX (Separation by IMplanted Oxygen) technology achieves total dielelectric isolation of active device regions from the substrate and reduces the collection path for ionized charges via the built-in buried oxide which restricts charge movement. Advances in SIMOX technology include radiation hardened memories and gate arrays for space applications, ULSI DRAMS for low voltage operation, thin film low power/low voltage circuitry, and extreme (400oC) temperature applications of SIMOX circuitry. A thin (~100 nm) buried oxide (BOX) SIMOX product is under development in order to significantly reduce the cost of the substrates for both military and commercial applications. However, the thin BOX SIMOX is too leaky for manufacturing. In addition, recent device survivability studies have shown that conventional hardening processes applied to SIMOX are not feasible unless the buried oxide density is near to that of thermal oxide. This Phase I proposal examines the feasibility of an innovative ramp rate process which indicates a singular window for densification of the thin BOX prior to the prolonged anneal. In addition, the application of an extreme anneal in combination with the singular ramp rate should further densify the thin buried oxide and reduce leakage in the thin BOX. Material quality and radiation hardness will be assessed for production of a rad hard substrate. Commercialization of that product is being aggressively pursued worldwide. The nation may expect to benefit from the development of a low cost, radiation hardened thin BOX SIMOX substrate process. Wide scale production and a source for advanced low power low voltage SIMOX substrate circuitry with a United States manufacturing base is predicted.