Nonvolatile semiconductor memory device and manufacturing method thereof

Abstract

Provided is a nonvolatile semiconductor memory device including a variable resistance element with reduced parasitic resistance between a lower electrode constituting the variable resistance element and a variable resistance layer. The non-volatile semiconductor storage device includes: a substrate (201); and a variable resistance element (208) formed on the substrate (201); the variable resistance element (208) has: a lower electrode layer (202), formed on the substrate ( 201); the variable resistance layer (203) is formed on the lower electrode layer (202); and the upper electrode layer (204) is formed on the variable resistance layer (203); the lower electrode layer (202) at least includes: the first a conductive layer (202a); and a second conductive layer (202c), formed on the first conductive layer (202a) and in contact with the variable resistance layer (203); a second conductive layer (202c) is formed on the upper surface of the first conductive layer (202a) 1 A conductive layer (202a) is oxidized, that is, an oxidatively degraded layer (202b).

Description

technical field [0001] The present invention relates to a nonvolatile semiconductor memory device including a variable resistance element, and more particularly to a configuration of a nonvolatile semiconductor memory device excellent in operational stability and a method of manufacturing the same. Background technique [0002] In recent years, with the advancement of digital technology in electronic equipment, large-capacity nonvolatile semiconductor memory devices have been actively developed to store data such as music, images, and information. For example, nonvolatile semiconductor memory devices using ferroelectrics as capacitive elements have been used in many fields. In addition, unlike nonvolatile semiconductor memory devices using such ferroelectric capacitors, variable resistance nonvolatile semiconductor memory devices (hereinafter also referred to as ReRAMs) equipped with variable resistance elements are easily available and compatible with ordinary semiconductor...

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Problems solved by technology

However, in the variable resistance element having the above-mentioned oxidatively degraded layer, due to the resistance value of the parasitic resistance component included in the oxidatively degraded layer, a sufficient voltage may not be applied to the variable resistance element, and the molding process for starting oxidation and reduction reactions may not be sufficient. sufficient, stable resistance changes may not be possible

In addition, due to repeated rewriting operations, insufficient oxygen removal in the lower electrode may occur, and the oxygen concentration in the variable resistance layer may be increased to stop the phenomenon of resistance change, and the durability characteristics may be deteriorated.

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