Ricoh Company, Ltd.

Kunio Matsudaira

Masahiro Matsuo

Hirohisa Abe

Hiroaki Nakanishi

Minoru Fukuda

Keiji Fukumura

Motohiro Oishi

Shigemi Sasada

Yoichi Sakai

The present invention is related to a composite flash memory device comprises a plural sector flash memory array which is divided to plural sector that is a minimum erasing unit of the flash memory device, a flash memory array storing control commands which control a total system of the composite flash memory device and/or the only composite flash memory device in and sharing I/O line of the plural sector flash memory array, the read operation of the flash memory array is enable when the plural sector flash memory array is gained access.

Memory configuration of a composite memory device

An electrically alterable non-volatile memory device is disclosed. In the device architecture of the memory device, control gates are formed, divided corresponding to the blocks and interconnected independently within each block, to further be connected to a metal gate line through block select MOS transistors which are formed on a semiconductor substrate between the blocks. All gate electrodes of the block select MOS transistors which are connected to the control gates interconnected as above within each block are further connected each other. These block select transistors can be controlled by applying erase block signals such as, EBS0, EBS1 and so on, to respective transistors. In addition, the control gates are further connected to a decoder such that some of these control gates may be selected through metal control gate lines. With the block select transistors together with the metal control gate line provided as above, erasing can be achieved in the unit of memory cells which are connected to a metal control gate line within a block.

Electrically alterable non-volatile semiconductor memory device

A semiconductor memory device in which MOS transistors are used. The device has diffusion lines and polysilicon lines formed on a semiconductor substrate, first and second insulating films covering the diffusion lines and the polysilicon lines, respectively. The diffusion lines extend at intervals and parallel with each other, and constitute bit lines of the memory device. The polysilicon lines extend at intervals, intersect the diffusion lines, and constitute word lines of the memory device. Metal wiring lines are formed on the second insulating film are each positioned over every other diffusion line in such a manner as to extend along the corresponding diffusion line, each metal wiring line being electrically connected to the corresponding diffusion line through a contact hole. Two regions of two adjacent diffusion lines that are underneath the two intersections of these two adjacent diffusion lines and one polysilicon line constitute the source region and the drain region of one MOS transistor, and a portion of the polysilicon line which is between the source region and the drain region constitutes the gate of the MOS transistor. Thus, MOS transistors of the device can be disposed with an increased density, without involving any reduction in the operation speed of the device.

Semiconductor memory device using high-density and high-speed MOS

A sense circuit of a semiconductor memory transistor includes a bit line connected to a memory cell which stores '1' or '0'. The sense circuit includes a MOS transistor which has its gate connected to the bit line, its source connected to ground voltage and its drain connected to a supply voltage through a load MOS transistor. The sense circuit also includes a compensating circuit for compensating the voltage at the bit line when the ground voltage has fluctuated. For example, the compensating circuit includes a pull-up circuit for pulling up the voltage at the bit line when the ground voltage has shifted to the positive side and a pull-down circuit for pulling down the voltage at the bit line when the ground voltage has shifted to the negative side, thereby maintaining the relative voltage relationship between the voltage at the bit line and the ground voltage at a proper value.

Growing community of inventors

Kobe, Japan

Kunio Matsudaira