| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a semiconductor storage device where high reliability and high-performance characteristics of a memory transistor can be obtained. SOLUTION: In this manufacturing method for a semiconductor storage device which has a cell array in which non-volatile memory transistors are arranged, and a peripheral circuit including a high-voltage system MISFET and a low-voltage system MISFET, a first gate oxide film 6 which is used for the high-voltage system MISFET is formed first on a silicon substrate 1. The first gate oxide film 6 is eliminated in the region of the cell array, and a second gate oxide film 8 turning, which serves as a tunnel insulating film of the memory transistors, is formed. A first polycrystalline silicon film 9 is deposited on the first and the second gate oxide films. In a region of the low- voltage system MISFET, the first polycrystalline silicon film and the first gate oxide film 6 are removed, and a third gate oxide film 13 of a low-voltage system MISFET is formed.
|
