NOR type flash memory and manufacturing method thereof

Abstract

The present invention provides a NOR type flash memory including memory cells with three-dimensional structure and its manufacturing method. The flash memory (100) of the present invention includes: a plurality of columnar parts (120) extending vertically from the surface of the silicon substrate (110) and including active regions; a plurality of charge accumulation parts (130) surrounding each columnar part (120); and a plurality of control gates (140) formed so as to surround the side part of each charge accumulating part (130). One end of the columnar part (120) is electrically connected to the bit line (150) through a contact hole, and the other end of the columnar part (120) is electrically connected to a conductive region formed on the surface of the silicon substrate (110). The invention can form the active area of ​​the storage unit without being restricted by the two-dimensional scale, and realize the integration and high operating current of the storage unit at the same time.

Description

technical field [0001] The present invention relates to a kind of NOR type flash memory (flashmemory), especially relates to a kind of memory unit (memory cell) structure. Background technique [0002] Flash memories roughly exist in a NAND type and a NOR type. The NAND flash memory can realize a highly integrated memory cell array by reducing the occupied area by configuring a memory cell array including NAND strings. On the other hand, the NOR flash memory has a structure in which a memory cell is arranged between a bit line and a source line, although high-speed random access (random access) can be performed on a memory cell , but needs to be in contact with each memory cell, therefore, compared with the NAND type, the occupied area of ​​the memory cell increases. [0003] The NOR flash memory adopts a virtual ground method or a multi-valued method in order to increase the degree of integration. In a typical virtual ground method, the source / drain of a memory cell is s...

AI Technical Summary

Problems solved by technology

If the channel length of the memory cell is shortened, the distance between the source / drain is shortened, or if the design rule is reduced, the distance between the gate electrode and the source / drain is shortened, Memory cells are randomly turned on due to accidental breakdown, which causes read errors, write errors, etc.

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