NONVOLATILE SEMICONDUCTOR MEMORY DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device with an improved operational reliability, and also to provide a method for manufacturing the nonvolatile semiconductor device. SOLUTION: This nonvolatile semiconductor memory is provided with a first MOS transistor and a second MOS transistor. The first MOS transistor is formed on a first device area enclosed by a first device separation area via a first gate insulting film and has a gate width direction edge on the above first device separation area. The second MOS transistor is provided with the second gate electrode which is formed on a secondary device area enclosed by a secondary device separation area via a second gate insulating film whose thickness is double the film thickness of the above first gate insulating film and has a gate width direction edge on the above second device separation area. In addition, the width from the contact position of the above first device separation area and the above first gate insulating film to the edge of the top of the above first element separation area is equal to that from the contact position of the above second device separation area and the above second gate insulating film to the edge of the top of the above second device separation area. COPYRIGHT: (C)2005,JPO&NCIPI