Radiation hardened micron and submicron MOSFETs containing fluorinated oxides

The generation of interface traps and oxide trapped charge in fluorinated MOSFETs and MOS capacitors has been found to depend strongly on the amount of fluorine introduced. In this study, the fluorine is introduced by low-energy F implantation into the surface layer of the polycrystalline silicon gate electrode, followed by annealing at 950 degrees C to diffuse F into the gate SiO/sub 2/, toward the SiO/sub 2//Si interface The improved interface radiation hardness is attributed to the strain relaxation near the SiO/sub 2//Si interface due to fluorine incorporation. An optimum F implant dose has been found to exist for a given technology; in the present case the optimum dose appears to be 2*10/sup 15/ cm/sup -2/. The results demonstrate the potential of the technique for producing radiation hard micron and submicron MOS devices.<
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