Forming method for resistance-change non-volatile memory element, and resistance-change non-volatile memory device

Abstract

An optimum forming method of performing a forming for a variable resistance element to maximize an operation window of the variable resistance element is provided. The forming method is used to initialize a variable resistance element (100). The forming method includes: a determination step (S35) of determining whether or not a current resistance value of the variable resistance element (100) is lower than a resistance value in a high resistance state; and a voltage application step (S36) of applying a voltage pulse having a voltage not exceeding a sum of a forming voltage and a forming margin when the determination is made that the current resistance value is not lower than the resistance value in the high resistance state (No at S35). The determination step (S35) and the voltage application step (S36) are repeated to process all memory cells in a memory array (202) (S34 to S37).

Description

Technical field [0001] The present invention relates to a forming (initialization) method for stably changing the resistance of a variable resistance nonvolatile memory element whose resistance value changes reversibly in accordance with an electrical signal, and a variable resistance nonvolatile memory having that function Device. Background technique [0002] In recent years, a resistance variable nonvolatile memory device (hereinafter also simply referred to as a variable resistance nonvolatile memory device) having a memory cell composed of a variable resistance nonvolatile memory element (hereinafter also simply referred to as a "Non-volatile storage devices".) Research and development. The so-called variable resistance element refers to an element that has a property that the resistance value changes reversibly in accordance with an electrical signal, and can further store data corresponding to the resistance value in a nonvolatile manner. [0003] As a non-volatile memory ...

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Problems solved by technology

When this phenomenon is used to configure a resistance variable memory device using a resistance variable memory element, it is important to set the window defined by the minimum value of the high-resistance state HR and the maximum value of the low-resistance state LR in the read operation (window )C is maximized, but when a plurality of variable resistance memory elements are integrated and constituted, the conventionally known manufacturing variation factor of each bit increases

As a result, since the window C is further narrowed, misreading and a drop in readout speed have been found to be a major problem for stable operation.

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