Ricoh Company, Ltd.

Hiroaki Nakanishi

Masahiro Matsuo

Hirohisa Abe

Kunio Matsudaira

Minoru Fukuda

Masaaki Yoshida

Satoru Taji

Moriya Iwai

Yoichi Sakai

A reference voltage generating circuit for generating a reference voltage includes MOSFETs connected to each other. At least one of the MOSFETs includes a control gate and a floating gate that is made hole-rich or discharged by ultraviolet irradiation, and the reference voltage generating circuit is configured to output the difference between threshold voltages of a pair of the MOSFETs as the reference voltage.

Reference voltage generating circuit and power supply device using the same

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

A semiconductor device includes plural switching transistors configured to perform trimming for characteristic adjustment of the semiconductor device, and a nonvolatile memory connected to the plural switching transistors and configured to store data for determining ON and OFF of the plural switching transistors. When the semiconductor device is in operation, ON and OFF of the switching transistors are determined by the data.

Memory control circuit and semiconductor device

A non-volatile memory semiconductor device includes a first insulation layer, two diffusion regions, a memory gate oxide layer, a first control gate, a second insulation layer, a floating gate of polysilicon, a third insulation layer and a second control gate. The first insulation layer is formed on a semiconductor substrate. The two diffusion regions are formed on a surface of the substrate. The memory gate oxide layer is formed over the two diffusion regions on the substrate. The first control gate including a diffusion region is formed on the surface of the substrate. The second insulation layer is formed on the first control gate. The floating gate of polysilicon is formed over the memory gate oxide layer, the first insulation layer, and the second insulation layer. The third insulation layer is formed on the floating gate. The second control gate is disposed on the floating gate.

Semiconductor device of non-volatile memory

A semiconductor device is capable of being applied with both a positive and a negative voltage to its control gate, and writing to its memory requires a low voltage. A control gate is formed on a memory unit region of a field oxide film, and an inter-layer silicon oxide film is formed on its surface. A gate oxide film for a non-volatile memory is formed on a P substrate between N type diffusion layers. The floating gate is formed on the inter-layer silicon oxide film, the field oxide film, and the gate oxide film for the non-volatile memory. Since a large coupling ratio between the control gate and the floating gate is available on the field oxide film, memory rewriting requires only a low voltage. Further, since the control gate is formed by a poly silicon film, both a positive voltage and a negative voltage can be applied to the control gate.

Semiconductor device and its manufacturing method

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 non-volatile semiconductor memory device includes a substrate and a continuously formed drain diffusion layer and a continuously formed source diffusion layer which are alternately arranged within the substrate. Floating gates are disposed via a tunnel insulating film on the substrate so that they are adjacent to the drain diffusion layer. The floating gates are opposed to each other with the drain diffusion layer therebetween, and spaced away from the source diffusion layer. A control gate extends in a direction orthogonal with a direction in which the source and drain diffusion layers extend, the control gate being formed on the floating gates and the substrate via an insulating film. A select channel is provided between the floating gate closest to the source diffusion layer and the source diffusion layer. A thick insulating film is provided between the drain diffusion layer and the control gate between the floating gates which are opposed to each other with the drain diffusion layer therebetween.

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Kobe, Japan

Hiroaki Nakanishi