Bit line controlling decoder circuit, semiconductor storage device and data reading method thereof

Abstract

There is provided a virtual ground type nonvolatile semiconductor storage device capable of effectively suppressing a leak current to the adjacent cell and thereby achieving high-speed read. During read operation, a ground potential GND is applied to a bit line SBL5 connected to the source region of one memory cell transistor MC04 subjected to read. Moreover, a read drain bias potential Vread is applied to a bit line SBL4 connected to the drain region of the memory cell transistor MC04. A bit line SBL3 connected to the drain region of a first adjacent memory cell transistor MC03 is put into a floating state. A potential Vdb equal to the read drain bias potential Vread is applied to a bit line SBL2 connected to the drain region of a second adjacent memory cell transistor MC02.

Description

technical field [0001] The present invention relates to a bit line control decoder circuit, a virtual ground type nonvolatile semiconductor storage device equipped with the decoder circuit, and a data readout method of the virtual ground type nonvolatile semiconductor storage device. Background technique [0002] In recent years, with the development of functions of portable telephones and the expansion of the memory card and file markets, flash memory capacity is increasing, and devices with small effective cell areas are being continuously developed, (such as multi-valued systems and virtual ground array systems ) in order to solve the problem of cost reduction. Specifically, the virtual ground array system can achieve a small unit area by designing its circuits, thereby allowing the development of devices with a small chip area through the same process. However, due to the virtual ground structure, it cannot be ignored that the memory cell to be rea...

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Problems solved by technology

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Moreover, there is a problem that high-speed readout is prevented by leakage current flowing to adjacent cells even before misread occurs.

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