Patent ID: 7939878

Claim:
A nonvolatile semiconductor memory comprising: a semiconductor substrate; first and second isolation insulating layers provided in the semiconductor substrate; a channel region between the first and second isolation insulating layers; a gate insulating film on the channel region; a floating gate electrode on the gate insulating film; anti-oxide films covering whole side surfaces of the floating gate electrode in a channel width direction, the anti-oxide film being continuous on the side surface of the floating gate electrode; an inter-gate insulating film on a top surface of the floating gate electrode and on the anti-oxide film; and a control gate electrode on the inter-gate insulating film, wherein the first and second isolation insulating layers is made of a thermal oxide film provided on a bottom surface and a side surface of a concave portion of the semiconductor substrate and an insulating film which is provided on the thermal oxide film and fills the concave portion, a dimension of the floating gate electrode in a channel width direction is wider than a dimension of the channel width, a dimension of the gate insulating film in the channel width direction is wider than maximum dimension of the floating gate electrode in a channel width direction, and the dimension of the gate insulating film in the channel width direction is wider than the dimension of the channel width.