Abstract: A non-volatile semiconductor memory device includes an interlayer dielectric film 9, 19 flattened by etching back an SOG film. In the non-volatile semiconductor memory device, a barrier film of a silicon nitride film 9D and 19D is formed to cover at least a memory cell composed of a floating gate 4, a control gate 6, etc. Because of such a structure, even if H or OH contained in the SOG is diffused, it will not be trapped by a tunneling film 3. This improves a “trap-up rate”. The barrier film may be formed in only an area covering the memory cell. This reduces its contact area with a tungsten silicide film, thereby suppressing film peeling-off. Thus, the operation life of the memory cell in the non-volatile semiconductor memory device can be improved.

Abstract: A nonvolatile semiconductor memory device of the present invention comprises: an isolation film formed on a semiconductor substrate of one conductivity type; a floating gate which is formed in an active region isolated by said isolation film so as to be disposed in a gap between adjacent isolation films and make each of end portions coincident with each end of said isolation film in a self-aligned manner; a tunnel oxide film which covers said floating gate; a control gate formed on said tunnel oxide film so as to comprise a region which overlaps said floating gate; a diffusion region of an opposite conductivity type and formed in a surface of the semiconductor substrate adjacent to said floating gate and the control gate.

Abstract: A method of forming a nonvolatile semiconductor memory device of the present invention comprises: an isolation film formed on a semiconductor substrate of one conductivity type; a floating gate which is formed in an active region isolated by said isolation film so as to be disposed in a gap between adjacent isolation films and make each of end portions coincident with each end of said isolation film in a self-aligned manner; a tunnel oxide film which covers said floating gate; a control gate formed on said tunnel oxide film so as to comprise a region which overlaps said floating gate; a diffusion region of an opposite conductivity type and formed in a surface of the semiconductor substrate adjacent to said floating gate and the control gate.