Non-volatile memory and method for manufacturing the same

Claim 1

A non-volatile memory which comprises: a semiconductor substrate of a first conductive type, a source and drain impurity diffusion regions of a second conductive type, a channel region formed between the source and drain impurity diffusion regions, a gate insulating film formed on the channel region, a floating gate electrode formed on the gate insulating film, and a control gate electrode formed at least partially overlapped with the floating gate electrode through the intermediary of an insulating interlayer film, in which the source and drain impurity diffusion regions are formed with a constant distance in a main surface of a surface layer of the semiconductor substrate and at least a part of the either region is formed in a surface having a crystal face orientation different from the main surface of the substrate; the channel region is in contact with the drain impurity diffusion region and has an inclined region of which surface has a crystal face orientation different from the main surface of the semiconductor substrate; and the source impurity diffusion region is placed relatively upper than the drain impurity diffusion region.

Claim 6

A method for forming a non-volatile memory comprising the steps of: forming a device isolation oxide film in a predetermined region on a main surface of a semiconductor substrate having a first conductive type, forming a low concentration impurity diffusion region having a second conductive type in a region at least where the Fowler-Nordheim tunnel occurs in an active region, forming a gate insulating film in the active region in which the low concentration impurity diffusion region is formed, forming a floating gate electrode sandwiched by the low concentration impurity diffusion region and a control gate electrode and the area of the floating gate electrode being defined such that the capacity between the low concentration impurity diffusion region and the floating gate electrode and the capacity between the floating gate electrode and the control gate electrode are desirably adjusted, forming an interlayer film on the floating gate electrode, forming the control gate electrode patterned such that at least a part of the floating electrode is overlapped with the floating gate electrode, forming a source region and a drain region by implanting impurities having the second conductive type at a high concentration in the active region using the control gate electrode and the floating gate electrode as a mask.

Claim 8

A method for forming a non-volatile memory comprising the steps of: forming a device isolation oxide film in a predetermined region on a main surface of a semiconductor substrate having a first conductive type, forming an opening in the device isolation oxide film by etching a predetermined region of the device isolation oxide film using a film used for preventing formation of an insulating film at the time of forming the device isolation oxide film and a photoresist as a mask, removing the photoresist and the film used for preventing formation of an oxide film, forming a second insulating film having a different etching ratio from the device isolation oxide film, exposing a part of the semiconductor substrate which forms an active region by removing a thin region of the device isolation oxide film, forming a gate insulating film on an exposed region, forming a floating gate electrode material on the gate insulating film, forming a flat film on the whole surface such that the surface is flattened at least on the active region, etching such that the flat film remains on the inclined region and the floating gate electrode material and the surface of the floating gate electrode material other than the inclined region is exposed, forming a floating gate electrode by etching the floating gate electrode material using the flat film remaining on the inclined region as a mask.

Claim 9

A method for forming a non-volatile memory comprising the steps of: covering at least a part of the first electrode with an insulating film, forming a first interlayer film on the surface other than the region covered by the insulating film, removing the insulating film, forming on the region where the insulating film has been removed a second interlayer film which is thinner than the first interlayer film, forming a second electrode above the first electrode through the intermediary of the first and second interlayer films lying so that the second electrode at least covers all of the second interlayer film.