US Patent 7804128 Nonvolatile semiconductor memory device

A nonvolatile semiconductor memory device according to an example of the present invention includes a semiconductor region, source/drain areas arranged separately in the semiconductor region, a tunnel insulating film arranged on a channel region between the source/drain areas, a floating gate electrode arranged on the tunnel insulating film, an inter-electrode insulating film arranged on the floating gate electrode, and a control gate electrode arranged on the inter-electrode insulating film. The inter-electrode insulating film includes La, Al and Si.