Nonvolatile semiconductor memory device and control method thereof

Abstract

A nonvolatile semiconductor memory device includes a memory array (101) in which a plurality of memory cells are arranged in a row direction and a column direction, each of the memory cells being formed by connecting one end of a variable resistive element for storing information according to a change in electric resistance caused by an electric stress and a drain of a selection transistor to each other on a semiconductor substrate, a voltage switch circuit (110) for switching among a program voltage, an erase voltage and a read voltage to be applied to the source line and the bit line connected to the memory cell, and a pulse voltage applying circuit (108). In the state where the program voltage or erase voltage corresponding to the bit line and the source line is applied to the bit line and the source line connected to a memory cell to be programmed or erased in the memory array via the voltage switch circuit (110), the pulse voltage applying circuit (108) applies a voltage pulse for programming or erasing to the word line connected to the gate electrode of the selection.

Description

technical field [0001] The present invention relates to a memory having a plurality of memory cells formed by connecting one end of a variable resistance element for storing information based on a change in resistance of a voltage application and a drain of a selection transistor, respectively arranged in a row direction and a column direction on a semiconductor substrate. An arrayed nonvolatile semiconductor memory device and a control method thereof, specifically, relate to a method of applying voltage to memory cells when writing or erasing. Background technique [0002] In recent years, we are entering an era where information can be obtained anytime, anywhere and freely carried. With the popularization of mobile devices represented by mobile phones and PDAs (portable information communication devices for personal use), various information can be accessed anytime and anywhere. However, the performance of mobile devices, such as battery life and access speed to informati...

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Problems solved by technology

That is, if there is a gap in the writing threshold voltage changing from the low resistance state (hereinafter referred to as RL) to the high resistance state (hereinafter referred to as RH) of the variable resistance element, or the erasing threshold voltage changing from the high resistance state to the low resistance state, When the same voltage is applied to the variable resistance element for writing or erasing, there will be a very large dispersion in the amount of current flowing through the variable resistance element, and the power consumption during writing or erasing will increase. Big

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