Renesas Technology Corp.

Other

Hitachi, Ltd.

Katsuhiko Kubota

Kousuke Okuyama

Shoji Shukuri

Kazuhiro Komori

Hiroyasu Ishizuka

Syoji Syukuri

A semiconductor integrated circuit device is provided on a semiconductor substrate, and includes a plurality of word lines, a plurality of data lines, and a plurality of electrically programmable and erasable non-volatile memory cells respectively coupled to the plurality of word lines and to the plurality of data lines. The erasable non-volatile memory cell each includes a MIS transistor having a floating gate having a first level polycrystalline silicon layer, a source, and a drain coupled to the corresponding data line, and a control gate formed of a semiconductor region in the semiconductor substrate, the control gate being coupled to the corresponding word line.

Semiconductor integrated circuit and nonvolatile memory element

0 Owing to the above, even with the single-layer gate process such as single-layer polysilicon gate process, it is possible to obtain a semiconductor integrated circuit such as system LSI in which a nonvolatile memory which is excellent in data retention capability is merged and packaged with a DRAM etc. Further, since the nonvolatile memory of high reliability can be formed without adding any step to a related art manufacturing process, such as a standard CMOS manufacturing process, the present invention may be readily applied to an LSI in which the nonvolatile memory and a logic LSI, or the nonvolatile memory and a DRAM are merged and packaged on an identical semiconductor substrate. Accordingly, a system LSI in which a flash memory is merged and packaged can be provided without increasing the cost of manufacture.

In order to eliminate the difference in ESD resistance caused by polarities of excessive voltages applied to an external terminal and enhance ESD resistance of a semiconductor integrated circuit device to both the positive and negative overvoltages, a protection element having a thyristor structure, for protecting an internal circuit from the positive overvoltage and a protection element made up of a diode D for protecting the internal circuit from the negative overvoltage are provided between the external terminal and a ground potential.

Semiconductor integrated circuit device and method of manufacturing the same

Owing to the above, even with the single-layer gate process such as single-layer polysilicon gate process, it is possible to obtain a semiconductor integrated circuit such as system LSI in which a nonvolatile memory which is excellent in data retention capability is merged and packaged with a DRAM etc. Further, since the nonvolatile memory of high reliability can be formed without adding any step to a related art manufacturing process, such as a standard CMOS manufacturing process, the present invention may be readily applied to an LSI in which the nonvolatile memory and a logic LSI, or the nonvolatile memory and a DRAM are merged and packaged on an identical semiconductor substrate. Accordingly, a system LSI in which a flash memory is merged and packaged can be provided without increasing the cost of manufacture.

An information retention capability based on a memory cell which includes pair of nonvolatile memory elements in a differential form is improved. A nonvolatile memory element ( ) constituting a flash memory is so constructed that its tunnel oxide film (GO ) and floating gate electrode (FGT) are respectively formed by utilizing the gate oxide film (GT ) and gate electrode (GT ) of a transistor for a circuit which is formed on the same semiconductor substrate as that of the element ( ). A memory cell is constructed in a 2-cells/1-bit scheme in which a pair of nonvolatile memory elements can be respectively connected to a pair of complementary data lines, and threshold voltage states different from each other are set for the nonvolatile memory elements so as to differentially read out data. A word line voltage in a readout mode is set to be substantially equal to a threshold voltage in a thermal equilibrium state (an initial threshold voltage), and also to be substantially equal to the average value of a low threshold voltage value and a high threshold voltage value. Thus, a data retention capability is enhanced to realize lowering in the rate of readout faults.

An information retention capability based on a memory cell which includes a pair of nonvolatile memory elements in a differential form is improved. A nonvolatile memory element ( ) constituting a flash memory is so constructed that its tunnel oxide film (G ) and floating gate electrode (FGT) are respectively formed by utilizing the gate oxide film (GT ) and gate electrode (GT ) of a transistor for a circuit which is formed on the same semiconductor substrate as that of the element ( ). A memory cell is constructed in a 2-cells/1-bit scheme in which a pair of nonvolatile memory elements can be respectively connected to a pair of complementary data lines, and threshold voltage states different from each other are set for the nonvolatile memory elements so as to differentially read out data. A word line voltage in a readout mode is set to be substantially equal to a threshold voltage in a thermal equilibrium state (an initial threshold voltage), and also to be substantially equal to the average value of a low threshold voltage value and a high threshold voltage value. Thus, a data retention capability is enhanced to realize lowering in the rate of readout faults.

An information retention capability based on a memory cell which includes a pair of nonvolatile memory elements in a differential form is improved. A nonvolatile memory element ( ) constituting a flash memory is so constructed that its tunnel oxide film (GO ) and floating gate electrode (FGT) are respectively formed by utilizing the gate oxide film (GT ) and gate electrode (GT ) of a transistor for a circuit which is formed on the same semiconductor substrate as that of the element ( ). A memory cell is constructed in a 2-cells/1-bit scheme in which a pair of nonvolatile memory elements can be respectively connected to a pair of complementary data lines, and threshold voltage states different from each other are set for the nonvolatile memory elements so as to differentially read out data. A word line voltage in a readout mode is set to be substantially equal to a threshold voltage in a thermal equilibrium state (an initial threshold voltage), and also to be substantially equal to the average value of a low threshold voltage value and a high threshold voltage value. Thus, a data retention capability is enhanced to realize lowering in the rate of readout faults.

In order to eliminate a difference in ESD resistance caused by the polarities of excessive voltages applied to an external terminal and enhance the ESD resistance of a semiconductor integrated circuit device to both positive and negative overvoltages, a protection element having a thyristor structure, for protecting an internal circuit from the positive overvoltage and a protection element made up of a diode D1 for protecting the internal circuit from the negative overvoltage are provided between the external terminal and a ground potential.

Growing community of inventors

Higashiyamato, Japan

Katsuhiko Kubota