Abstract: A semiconductor device includes: a first read/write amplifier; a second read/write amplifier; a first group of bit lines belonging to the first read/write amplifier; a second group of bit lines belonging to the second read/write amplifier and mixed with the first group of bit lines. One of the first group of bit lines and one of the second group of bit lines are selected in parallel. A reference potential is supplied to at least one of the first non-selected bit lines adjacent to the first selected bit line selected from the first group of bit lines, and to at least one of the second non-selected bit lines adjacent to the second selected bit line selected from the first group of bit lines. At least one of remaining ones of the first and second non-selected bit lines is set into a floating state.

Abstract: A phase change memory device comprises: a phase change element for rewritably storing data by changing a resistance state; a memory cell arranged at an intersection of a word line and a bit line and formed of the phase change element and a diode connected in series; a select transistor formed in a diffusion layer below the memory cell, for selectively controlling electric connection between an anode of the diode and a ground line in response to a potential of the word line connected to a gate; and a precharge circuit for precharging the diffusion layer below the memory cell corresponding to a non-selected word line to a predetermined voltage and for disconnecting the diffusion layer below the memory cell corresponding to a selected word line from the predetermined voltage.

Abstract: Disclosed is a semiconductor memory device which includes a read data latch that holds read data from a phase change memory and latches write data entered from outside and holds write data entered from outside, a write data latch that holds the write data for a cell for the time duration of a preset number of cycles until start of data write, a transfer switch that controls whether or not an output of the read data latch is to be transferred to the write data latch, a comparator circuit that decides whether or not data transferred to the write data latch via the transfer switch and held in the write data latch and data in the read data latch are coincident with each other, and a write flag latch that latches an output of the comparator circuit. Data is written only in case there is a write request and the result of comparison of the comparator circuit indicates non-coincidence, that is, only in bits in need of data writing.

Abstract: To provide a plurality of write amplifiers that perform a data write operation upon memory cells and a write control circuit that controls a timing of a data write operation performed by the write amplifiers. When a data write operation using another write amplifier is requested while a data write operation using a predetermined write amplifier is performed, the write control circuit suspends the data write operation using the predetermined write amplifier. The suspended data write operation is performed again simultaneously with the data write operation using the other write amplifier. Accordingly, random column access like that of a DRAM can be realized by simple control.

Abstract: A semiconductor memory device is provided that has a storage unit that includes an interlayer insulation film, a lower electrode layer embedded in the interlayer insulation film, and a recording layer and an upper electrode layer provided on the interlayer insulation film. When a predetermined current is passed to the storage unit, the recording layer is heated by substantially exceeding a melting point, and a cavity is formed near the interface between the recording layer and the lower electrode layer. As a result, the recording layer is physically separated from the lower electrode layer, and no current flows through the storage unit. When the recording layer is physically separated from the lower electrode layer, these layers cannot be returned to the contact state again. Therefore, information can be stored irreversibly.

Abstract: A semiconductor memory device includes: a plurality of write control circuits; a plurality of memory cells grouped in the write control circuits; a plurality of write drivers that write data to a corresponding memory cell when the write control circuit is activated; and a main control circuit that causes the write control circuits to become active in response to presence of a data writing request to the memory cells belonging to a predetermined group and subsequent absence of the data writing request to the memory cells belonging to the same group within a predetermined period.

Abstract: A semiconductor memory device includes: first and second wiring layers extending in substantially parallel to each other in a first direction; a first semiconductor region formed in a part of a portion between the first and second wiring layers; a second semiconductor region formed on an opposite side to the first semiconductor region with respect to the second wiring layer and making a pair with the first semiconductor region; a third semiconductor region formed in another part of the portion between the first and second wiring layers; a fourth semiconductor region formed on an opposite side to the third semiconductor region with respect to the first wiring layer and making a pair with the third semiconductor region; a third wiring layer extending in a second direction that crosses the first direction and having an electrical contact with the first semiconductor region; a fourth wiring layer extending in the second direction and having an electrical contact with the fourth semiconductor region; a fifth wirin

Abstract: A phase change memory device has a memory cell that uses a phase change film as a storage element, and includes: a first phase change region formed on a side of one face of the phase change film; and a second phase change region formed on a side of another face of the phase change film in a position that corresponds to the first phase change region, wherein the phase change memory stores two-bit data using combinations of a high resistance state due to amorphization and a low resistance state due to crystallization in the first phase change region with the high resistance state and the low resistance state in the second phase change region, the resistance value of the low resistance state being lower than that of the high resistance state.

Abstract: A semiconductor device includes: a first read/write amplifier; a second read/write amplifier; a first group of bit lines belonging to the first read/write amplifier; a second group of bit lines belonging to the second read/write amplifier and mixed with the first group of bit lines. One of the first group of bit lines and one of the second group of bit lines are selected in parallel. A reference potential is supplied to at least one of the first non-selected bit lines adjacent to the first selected bit line selected from the first group of bit lines, and to at least one of the second non-selected bit lines adjacent to the second selected bit line selected from the first group of bit lines. At least one of remaining ones of the first and second non-selected bit lines is set into a floating state.

Abstract: A write amplifier for driving a bit line connected to a selected phase change memory cell drives the bit line with a first current driving capability and then drives the bit line with a second current driving capability lower than the first current driving capability.

Abstract: To provide a nonvolatile memory including a word-line drive circuit that supplies a selective voltage to a selective transistor connected in series to a nonvolatile memory device. The word-line drive circuit applies a first selective voltage VDD to a control electrode of the selective transistor in a first period, and applies a second selective voltage VPP higher than the first selective voltage VDD to the control electrode of the selective transistor in a second period that follows the first period. Thereby, a current drive capability of the selective transistor is gradually changed. Thus, it becomes possible to limit the current drive capability of the selective transistor at timing at which snap-back is caused. As a result, an excessive current caused by the snap-back is suppressed, thereby reducing damage inflicted on the nonvolatile memory device.

Abstract: A phase change memory device, comprising a phase change memory device; a semiconductor substrate; a MOS transistor disposed at each intersection of a plurality of word lines and a plurality of bit lines arranged in a matrix form; a plurality of phase change memory elements for storing data of a plurality of bits, each formed on an upper area opposite to a diffusion layer of the MOS transistor in a phase change layer made of phase change material; a lower electrode structure for electrically connecting each of the plurality of phase change memory elements to the diffusion layer of the MOS transistor.

Abstract: Semiconductor storage device of reduced layout area having memory cell rows accessed selectively. Memory cells, each including a programmable resistive element, are connected by a bit line to form a memory cell row. Selecting circuit for selecting a memory cell row includes a first NMOS transistor having first end connected to write amplifier, second end connected to the bit line, and a gate, and controlled such that, if the write amplifier outputs a voltage level on power-supply side after the block-select activating signal has been activated, a voltage of the same polarity as that of the power-supply voltage and exceeding the voltage level of the power supply is applied to the gate. A second NMOS transistor has first end to which the block-select activating signal is applied, a gate connected to the power supply, and second end connected to the gate of the first NMOS transistor.

Abstract: A memory device in which both DRAM and phase-change memory (PCRAM) are mounted is provided with a DRAM bit line, a PCRAM bit line or a PCRAM source line formed on an conductive layer shared with the DRAM bit line, and a sense amplifier connected between the DRAM bit line and the PCRAM bit line. The memory device further has a capacitive element disposed on the upper layer of the DRAM bit line, and a phase-change element disposed on the upper layer of the PCRAM bit line. The lower electrode of the capacitive element and the lower electrode of the phase-change memory element are formed on the shared conductive layer.

Abstract: A non-volatile semiconductor memory device includes a plurality of lower electrodes arranged in a matrix manner, a plurality of recording layer patterns, each being arranged on the lower electrode, that contain a phase change material, and an interlayer insulation film that is provided between the lower electrode and the recording layer pattern and that has a plurality of apertures for exposing one portion of the lower electrode. The lower electrode and the recording layer pattern are connected in each aperture. The apertures extend in the X direction in parallel to one another. The recording layer patterns extend in the Y direction in parallel to one another. Thus the aperture can be formed with higher accuracy as compared to forming an independent aperture. Accordingly, high heating efficiency can be obtained while effectively preventing occurrence of poor connection or the like.

Abstract: Disclosed is a semiconductor storage apparatus in which two sorts of memories, that is, a volatile memory and a non-volatile memory, are mounted on one chip. Data of a DRAM memory array are saved in a corresponding area of a non-volatile memory before entry to a data retention mode or before power down and data is transferred from the area of the non-volatile memory to the DRAM memory array in exiting from the data retention mode or power up. Normal read/write access is made to the DRAM memory array, while data retention is in an area of the non-volatile memory.

Abstract: For the purpose of providing a phase change memory device advantageous in layout and operation control by obtaining sufficient write current for high integrated phase change memory devices, the nonvolatile semiconductor memory device of the invention in which word lines and bit lines are arranged in a matrix-shape comprises a select transistor formed at each cross point of the word lines and the bit lines, and a plurality of memory elements commonly connected to the select transistor at one end and connected to a different element select line at an other end and which is capable of writing and reading data. Write and read operations for the selected memory element are controlled by supplying a predetermined current through the select transistor and through the element select line connected to the selected memory element, and the element select lines are arranged in parallel with the bit lines.

Abstract: A semiconductor memory device includes: first and second wiring layers extending in substantially parallel to each other in a first direction; a first semiconductor region formed in a part of a portion between the first and second wiring layers; a second semiconductor region formed on an opposite side to the first semiconductor region with respect to the second wiring layer and making a pair with the first semiconductor region; a third semiconductor region formed in another part of the portion between the first and second wiring layers; a fourth semiconductor region formed on an opposite side to the third semiconductor region with respect to the first wiring layer and making a pair with the third semiconductor region; a third wiring layer extending in a second direction that crosses the first direction and having an electrical contact with the first semiconductor region; a fourth wiring layer extending in the second direction and having an electrical contact with the fourth semiconductor region; a fifth wirin

Abstract: A semiconductor memory device includes: a plurality of write control circuits; a plurality of memory cells grouped in the write control circuits; a plurality of write drivers that write data to a corresponding memory cell when the write control circuit is activated; and a main control circuit that causes the write control circuits to become active in response to presence of a data writing request to the memory cells belonging to a predetermined group and subsequent absence of the data writing request to the memory cells belonging to the same group within a predetermined period.

Abstract: A semiconductor memory device includes a plurality of active regions, and a gate electrode in a fish bone shape arranged on each active region. In each active region, a plurality of source regions and a plurality of drain regions are arranged in a matrix manner. The source regions are commonly connected to a source line, and the drain regions are each connected to a lower electrode of a different memory element. According to the present invention, it is possible to assign three cell transistors connected in parallel to one memory element, so that an effective gate width is further increased.