Charge trapping versus buried oxide thickness for SIMOX structures

Radiation induced charge trapping versus Buried-Oxide (BOX) thickness on various Separation-by-IMplantation-of-OXygen (SIMOX) buried oxides has been determined. An inflection point has been observed in the voltage shift versus buried oxide thickness relationship. As such, the radiation-induced voltage shifts for thin buried-oxides are greater than what could be expected from a simple square-law relationship. However, for irradiation applied fields higher than that of typical buried-oxide fringing fields the thickness relationship obeys a square-law. These results can be explained by the location and magnitude of the radiation induced oxide charge centroid and its relationship to the BOX thickness. The location of the centroid for trapped positive charge is dependent on the radiation-induced hole mobility, which is related to SIMOX processing, as well as on geometry and charge saturation