NAND TYPE NONVOLATILE MEMORY

摘要

PROBLEM TO BE SOLVED: To provide a non-volatile semiconductor memory device, especially a NAND-type storage that is ideal for high integration. SOLUTION: An ion injection region 60 for increasing a cell current is formed only at the source and drain regions of a depletion-type transistor for string selection and the junction depth of the source and the drain of the depletion-type transistor for selecting a string is formed so that it is deeper than that of the source and the drain of other transistors, thus improving the current driving capability of a memory element.