Resistance-change non-volatile memory device

Abstract

A resistance-change non-volatile memory device (100) is provided with memory cells (M11, M12,...), each comprising a resistance-change element (R11, R12,...) and a current control element (D11, D12,...) connected in series. The resistance-change elements constitute a resistance-change layer interposed between a first electrode and a second electrode and provided so as to contact both electrodes. The current control elements constitute a current control layer interposed between a third electrode and a fourth electrode and provided so as to contact both electrodes. To decrease the resistance of the resistance-change elements, said elements are driven by a first LR drive circuit (105a1), via a current control circuit (105b). To increase the resistance of the resistance-change elements, the elements are driven by a second HR drive circuit (105a2). The current control circuit (105b) makes the current lower when decreasing the resistance of the resistance-change elements than when increasing the resistance thereof.

Description

technical field [0001] The present invention relates to a variable resistance nonvolatile memory device including a memory cell including a variable resistance element whose resistance value changes reversibly based on an electric signal, and a current control element. Background technique [0002] In recent years, research and development of a nonvolatile memory device having a memory cell constituted by a variable resistance element has progressed. The variable resistance element refers to an element that has a property that its resistance value changes reversibly according to an electrical signal, and can store data corresponding to the resistance value in a non-volatile manner. [0003] As a nonvolatile memory device using variable resistance elements, it is generally known that transistors and variable resistance elements connected in series, so-called A non-volatile memory device called a memory cell of the 1T1R type. In addition, it is known that diode elements and ...

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Problems solved by technology

However, since the writing resistance value is different from the desired resistance value, the reading performance cannot be made uniform, and as a result, there is a problem that a product with stable performance cannot be provided.

In addition, since a high voltage is required, there is also a problem of hindering the reduction of voltage, or a second problem described later.

[0049] In addition, it is conceivable that both the A mode and the B mode may appear, and both the LR driving circuit and the HR driving circuit are prepared as both the word line driving circuit and the bit line driving circuit. The method of switching according to the appearance state of the B mode, but there are problems related to the complexity of switching settings according to the state, or the increase of the chip area.

[0050] The second problem is related to the reliability of the memory cell, especially the current control element

[0052] When the A-mode and B-mode are contrary to assumptions, as described in the first problem, by applying a high voltage and supplying more current during the high-resistance high-resistance operation, the high-resistance operation can be performed, but there are Possibility of deteriorating diode characteristics

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