| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a semiconductor memory device that allows an increase in a coupling ratio.SOLUTION: A buried insulator 4 is buried in a trench 3 formed in a semiconductor substrate 2. An upper portion of the buried insulator 4 protrudes above a surface of the semiconductor substrate 2. On the surface of the semiconductor substrate 2, a tunnel oxide film 5 is formed. On the tunnel oxide film 5, a floating gate 6 is formed to a height over an upper portion of the buried insulator at a side of the buried insulator 4. The floating gate 6 includes a side portion protruding above the buried insulator 4 at a position spaced apart from the upper portion of the buried insulator. An ONO film 13 is formed on an upper portion and a side portion of the floating gate 6 so as to be in contact with the upper portion and the side portion of the floating gate 6. A control gate 14 is formed on the ONO film 13.</p> |
