| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device having a stack gate structure comprising a floating gate electrode and a control gate electrode that are laminated, which is improved in tunnel insulating film and inter-electrode insulating film. SOLUTION: The nonvolatile semiconductor memory device includes: a floating gate electrode 12 which is selectively formed above a main surface of a first conduction type semiconductor substrate 10 via a tunnel insulating film 11; a control electrode 14 formed above the floating gate electrode 12 via an inter-electrode insulating film 13; and a second conduction type source/drain region 15 formed on the main surface of the substrate 10 in correspondence with respective gate electrodes 12, 14, wherein the tunnel insulating film 11 is a dielectric film containing at least two kinds of metallic elements (Al, Hf) and oxygen, with the composition of the metallic elements continuously varying with respect to the direction of the film thickness and having a symmetrical distribution. COPYRIGHT: (C)2009,JPO&INPIT
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