Fujitsu Corporation

A. Aoki & Associates

Shigeki Nozaki

Yoshihiro Takemae

Katsuhiko Kabashima

Seiji Enomoto

Tsutomu Mezawa

Tomio Nakano

Masao Nakano

Kimiaki Sato

Tsuyoshi Ohira

Nobumi Kodama

Hatsuo Miyahara

Makoto Yanagisawa

Kiyoshi Miyasaka

Jun-ichi Mogi

Yasuhiro Takada

Satoshi Momozono

Masaru Satoh

Masakazu Kanai

A dynamic random access memory comprises a substrate, a transfer transistor provided on the substrate, a memory cell capacitor provided on the substrate in contact with a first diffusion region formed in the substrate, a first conductor pattern provided on the substrate to extend in a first direction as a word line, a first insulator layer provided on the substrate to bury the memory cell capacitor and the first conductor pattern, a first contact hole provided on the first insulator layer to expose a second diffusion region formed in the substrate, a second conductor pattern provided on the first insulator layer to extend in a second direction, passing above the memory cell capacitor and making a contact with the second diffusion region at the first contact hole, a second insulator layer provided on the second conductor pattern, a second contact hole provided on the second insulator layer at a part thereof that locates above the memory cell capacitor to expose the upper major surface of the second conductor pattern, and a third conductor pattern provided on the second insulator layer to extend in the second direction substantially coincident with the first conductor pattern as a bit line of the dynamic random access memory, wherein the third conductor pattern makes a contact with the second conductor pattern at the second contact hole.

Dynamic semiconductor memory device

A semiconductor memory device including a pair of bit lines, a memory cell provided between the pair of bit lines, and a potential difference control device connected to the pair of bit lines. The bit lines include a potential difference therebetween when information stored in the memory cell is read out. The potential difference control device has a transistor control for receiving a first control signal and for responding thereto; thereby, increasing the potential difference between the pair of bit lines up to a predetermined level so as to provide a high speed read-operation and to reliably discriminate a 'good' or a 'no good' reading when subjected to a screening test.

Semiconductor static memory device

A semiconductor memory device is connected to a power source and includes a reference potential line connected to receive a reference potential from the power source. An input circuit is connected to the reference potential line and receives an external input signal having a logic level defined in reference to the reference potential to be supplied to the source potential line. The output circuit has an external output terminal which is connected to the reference potential line. The output circuit is for generating an output to the external output terminal. An inhibiting circuit inhibits a response to the external input signal of the input circuit for a predetermined period during which the output of the output circuit changes.

Semiconductor memory device with internal control signal based upon

In a semiconductor integrated circuit having first and second power supply lines for receiving a power supply voltage, an external input terminal for receiving an input signal, and a high voltage detection circuit for detecting at the external input terminal a high voltage higher than a predetermined voltage which is higher than the power supply voltage, the high voltage detection circuit comprises an input circuit connected to the external input terminal for generating circuit for generating a reference voltage; and a differential voltage amplifier connected to receive the detection voltage and the reference voltage for amplifying the difference between the detection voltage and the reference voltage, to thereby determine whether the high voltage is applied, the input circuit comprising; a level shift element connected to the external input terminal for providing the detection voltage; an impedance element connected between the level shift element and the second power supply line; and a leak current compensating element connected between the first power supply line and the level shift element for allowing a current to flow from the first power supply line through the leak current compensating element and the impedance element to the second power supply line when the high voltage is not applied to the external input terminal.

Semiconductor integrated circuit having function for switching

In a semiconductor integrated circuit comprising an internal circuit, a device for receiving a chip select signal from the outside, a device for receiving an input signal from the outside, and a voltage detecting circuit for detecting whether or not the potential of the input signal is higher than a reference potential; the voltage detecting circuit comprises a first device for differentially comparing the potential of the input signal with the reference potential and generating an output potential in accordance with the results of the comparison, a second device for detecting a predetermined edge of the chip select signal so as to trigger the first device, and a third device for latching the output potential of the first device to the third device when the first device is triggered by the second device, the internal circuit being switched from a first mode to a second mode, or vice versa, in accordance with the output potential of the third device.

A clock signal generating circuit for a dynamic type semiconductor memory device including an input voltage level control unit for converting a transistor-transistor-logic (TTL) drive level to a metal-oxide-semiconductor (MOS) drive level during transmission of an address strobe signal; an address buffer control unit for generating an address signal and an inverted address signal in response to a trailing edge of the address strobe signal, a clock signal generating unit for generating a clock signal used for a word line selection and an input signal for a next stage in response to a low level of the address strobe signal, and an inhibiting unit for inhibiting a drive of the word line by the clock signal when the address strobe signal is at high level in the timing of a leading edge of the clock signal.

Clock signal generating circuit for dynamic type semiconductor memory

A semiconductor memory device capable of compensating for variation in a discriminating voltage of a memory cell comprising a memory cell and a gate circuit for coupling the memory cell to a bit line. The device has a precharge circuit for precharging the bit line pair to a predetermined resultant precharge voltage in a reset state. The precharge circuit precharges a bit line pair with the resultant precharge voltage obtained by adding a compensating voltage to a precharge voltage in the reset state. The compensating voltage is adapted to compensate for variation in a memory cell discriminating voltage based on variation in a memory cell voltage caused by capacitive coupling of a word line to a memory capacitor due to a parasitic capacitance of a gate circuit in the active state, and the precharge voltage is adapted to optimize the memory cell discriminating voltage when it is assumed that the parasitic capacitance is not present.

Semiconductor memory device having a circuit for compensating for

A semiconductor memory device operates under a so-called address multiplex access method. A row part of the device is enabled by receiving a row address strobe (RAS) signal. A column part of the device is enabled by simultaneously receiving both a column address strobe (CAS) signal and a timing control signal supplied from the row part during its enable state. A column address buffer in the column part is enabled by simultaneously receiving both the CAS signal and a timing control signal. The timing control signal is produced from a circuit when it detects and holds the RAS signal.

Semiconductor memory device

A dynamic semiconductor memory device includes data output lines (D, D), a data output buffer (12), a column enable buffer (9), and an output enable buffer (11) for generating an output enable signal (OE) to enable the transmission of data from the data output lines to the data buffer. The output enable buffer is driven by the clock signals of the column enable buffer. An output disabling circuit (13) is provided to stop the generation of an output enable signal by the output enable buffer when the output enable buffer is not being driven by the column enable buffer. As a result, the data output buffer assumes a high-impedance state when a power supply is turned on.

A semiconductor device, provided with a buffer, which comprises a first transistor for pulling up the output terminal voltage, a second transistor for pulling down the output terminal voltage, and a charge-pumping circuit for maintaining the output terminal voltage at a level higher than the power source voltage by charge pumping when the output terminal voltage is at a high level. The semiconductor device further comprises a circuit for pulling down the output terminal voltage during the period from when power is supplied to when an input signal is supplied to the buffer.

Semiconductor device for pulling down output terminal voltage

A semiconductor integrated circuit (IC) device includes therein a test circuit. The test circuit operates to distinguish the power source level during the testing or ground level occurring at an internal node located inside the semiconductor chip. The test circuit includes a series-connected MIS transistor and an MIS diode. The gate of the MIS transistor is connected to the internal node. The MIS diode is connected to an external input/output (I/O) pin. The level at the internal node, i.e., the power source level or the ground level, can be distinguished by a first voltage level or a second voltage level applied to the external I/O pin, whichever enables a current to be drawn from the external I/O pin.

Semiconductor integrated circuit device

A metal-insulator semiconductor dynamic memory device comprising sense amplifiers arrayed on a semiconductor substrate and column decoders. Each of the column decode being provided for a plurality of sense amplifiers and selecting one or more sense amplifiers from the plurality of sense amplifiers, the column decoders being dispersed on both sides of the arrayed sense amplifiers. A plurality of control signal lines which, in order to select the sense amplifiers, control gate elements connected between bit lines connected to the sense amplifiers and data bus lines and which are disposed on both sides of the arrayed sense amplifiers. Conducting lines are also disposed between the sense amplifiers and deliver signals from the control signal lines, for selecting sense amplifiers to the gate elements on the opposite side of the control signal lines with regard to the arrayed sense amplifiers.

A semiconductor memory device which includes a plurality of memory cells each having a capacitor, and peripheral circuits of the memory cells, integrated on a semiconductor substrate. Each capacitor has a storage electrode and an electrode opposite to the storage electrode, the opposite electrode being connected to a ground line, wherein, the ground line connected to the opposite electrode of each capacitor is separated from the other ground lines connected to the peripheral circuits. All of the ground lines are connected to a common portion having an impedance lower than the impedance of each ground line, whereby data stored in the capacitors is prevented from being destroyed.

A metal-insulator semiconductor dynamic memory device including sense amplifiers arrayed on a semiconductor substrate and divided into a plurality of sense amplifier groups. Column decoders are provided, one decoder for each sense amplifier group, each sense amplifier group being selected by the column decoder. One or more control signal lines for simultaneously selecting the output signals of at least two sense amplifiers in the sense amplifier group selected by the column decoder, a plurality of data buses for transferring the output signals of at least two sense amplifiers selected by one or more control signal lines, are included in the memory device. All of the sense amplifiers have the control signal lines and the data buses in common.

A semiconductor circuit for driving a clock signal line comprising a first circuit for pulling up the potential of the clock signal line to the source voltage and a second circuit for pulling down the potential of the clock signal line to a lower voltage. A capacitor is connected to the clock signal line for receiving a potential push signal and pushing the potential of the clock signal line higher than the source voltage. The capacitor performs the function of capacitance only after the potential of the clock signal line is raised to the source voltage. The operational speed of a dynamic memory device associated with the semiconductor device is then enhanced.

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Kawasaki, Japan

Shigeki Nozaki