A semiconductor integrated circuit device includes in a P-type well region containing a memory substrate a array section in which dynamic memory cells are arranged in a matrix. The P-type well region is fed with a back bias voltage whose absolute value is reduced so as to be the most suitable for the refresh characteristics. Also included is a P-well region wherein there are formed N-channel MOSFETs of a peripheral circuit this P-well region is fed with a back bias voltage whose absolute value is smaller than that of the potential fed to the P-type well of the memory array section, considering the high-speed operation. A P-type well section, wherein there is formed are N-channel MOSFETs of an input circuit or an output circuit connected with external terminals, is fed with a back bias voltage whose absolute value is made large considering an undershoot voltage. The P-type well region provided with the memory array section is fed with a requisite minimum back bias voltage. Accordingly, the P-type well region provided with the input circuit or the output circuit corresponding to the external terminals is fed with the back bias voltage to provide a measure of protection against undershoot, while the refresh characteristics are improved by reducing the leakage current between the source/drain region connected with a capacitor and the P-type well, to thereby raise the operation speed of the peripheral circuit can be raised.

A memory cell with a small surface area is fabricated by forming source lines and data lines above and below and by running the channels to face up and down. The local data lines for each vertically stacked memory cell are connected to a global data line by way of separate selection by a molecular oxide semiconductor, and use of a large surface area is avoided by making joint use of peripheral circuits such as global data lines and sensing amplifiers by performing read and write operations in a timed multiplex manner. Moreover, data lines in multi-layers and memory cells (floating electrode cell) which are non-destructive with respect to readout are utilized to allow placement of memory cells at all intersecting points of word lines and data lines while having a folded data line structure. An improved noise tolerance is attained by establishing a standard threshold voltage for identical dummy cells even in any of the read verify, write verify and erase verify operations. A register to temporarily hold write data in a memory cell during writing is also used as a register to hold a flag showing that writing has ended during write verify. Also, a circuit comprised of one nMOS transistor is utilized as a means to change values on the write-end flag.

A memory cell with a small surface area is fabricated by forming source lines and data lines above and below and by running the channels to face up and down. The local data lines for each vertically stacked memory cell are connected to a global data line by way of separate selection by a molecular oxide semiconductor, and use of a large surface area is avoided by making joint use of peripheral circuits such as global data lines and sensing amplifiers by performing read and write operations in a timed multiplex manner. Moreover, data lines in multi-layers and memory cells (floating electrode cell) which are non-destructive with respect to readout are utilized to allow placement of memory cells at all intersecting points of word lines and data lines while having a folded data line structure. An improved noise tolerance is attained by establishing a standard threshold voltage for identical dummy cells even in any of the read verify, write verify and erase verify operations. A register to temporarily hold write data in a memory cell during writing is also used as a register to hold a flag showing that writing has ended during write verify. Also, a circuit comprised of one nMOS transistor is utilized as a means to change values on the write-end flag.

A semiconductor device comprises select gates and control gates of a plurality of memory cells therebetween so that gate members on upper portions of stacked gates may cross element regions. A metal interconnection is disposed parallel to an upper layer of the element region. A source line SL is arranged at intervals of plural bit lines BL. The source line is led to a source line contact through a conductive member composed of a low-resistance metal in the same manner as a bit line contact.