Hot-electron hardened Si-gate MOSFET utilizing F implantation

A technique is presented for incorporating fluorine (F) into the gate-oxide film, and the subsequent improvement of channel-hot-electron hardness of the resulting MOSFET is reported. This technique uses low-energy F implantation onto the surface of the polysilicon 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 hot-electron hardness is explained by a model involving a strain relaxation near the SiO/sub 2//Si interface by fluorine incorporation that results from Si-F bond formation.<>