Radiation Hardened Silicon-on-Insulator Substrates for Advanced Electronics

SIMOX (Separation by Implanted Oxygen) technology achieves total dielectric 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 SOI BiCMOS for low power circuitry, and extreme (400 oC) 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 cost of the substrates for both military and commercial applications. recent device survivability studies have indicated that conventional hardening processes applied to SIMOX are not feasible unless the buried oxide density is near to that of thermal oxide. For the thin BOX experimental process, the hardening mechanisms will not work due to the 9% difference in BOX density as measured by spectroscopic ellipsometry. This Phase I proposal examines the feasibility of an innovative density reduction process for developing a hardened thin BOX SIMOX product. Buried oxide material quality and radiation hardness will be assessed via electrolytic tests and BOXCAP device performance. Commercialization of a radiation hardened thin BOX SIMOX product will be aggressively pursued. The nation may expect to benefit from the development of a low cost, radiation hardened semiconductor substrate process. Systems and components fabricated on hardened SIMOX will assist both military and commercial applications requiring high dose survivability. A wide scale production of advanced low power, low voltage SIMOX substrates with a United States manufacturing base is predicted.