Variable resistance nonvolatile memory element and method for manufacturing the same
AssigneePanasonic Intellectual Property Management Co., Ltd.
InventorsTakeki Ninomiya, Takumi Mikawa, Yukio Hayakawa
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Abstract
A nonvolatile memory element which inhibits deterioration of an oxygen concentration profile of a variable resistance layer due to a thermal budget and is able to stably operate at low voltages, and a method for manufacturing the nonvolatile memory element are provided. The nonvolatile memory element includes a first electrode layer formed above a substrate, a variable resistance layer disposed on the first electrode layer, and a second electrode layer disposed on the variable resistance layer, and the variable resistance layer has a two-layer structure in which an oxygen- and/or nitrogen-deficient tantalum oxynitride layer and a tantalum oxide layer are stacked.
Claims7
A nonvolatile memory element comprising:
- a first electrode layer formed above a substrate;
- a variable resistance layer disposed directly on said first electrode layer;
- and
- a second electrode layer disposed directly on said variable resistance layer,
- wherein said variable resistance layer:
- consists of a two-layer structure in which an oxygen- and/or nitrogen-deficient tantalum oxynitride layer and a tantalum oxide layer are stacked;
- changes to a low resistance state due to oxygen ions moving from said tantalum oxide layer to said oxygen- and/or nitrogen-deficient tantalum oxynitride layer;
- and
- changes to a high resistance state due to the oxygen ions moving from said oxygen- and/or nitrogen-deficient tantalum oxynitride layer to said tantalum oxide layer;
- wherein a thickness of said oxygen- and/or nitrogen-deficient tantalum oxynitride layer is greater than a thickness of said tantalum oxide layer;
- wherein, when a composition of said oxygen- and/or nitrogen-deficient tantalum oxynitride layer is represented by TaOxNy, x and y satisfy:
- 0.8≦x+y≦1.9 and
- 0<y≦0.5
- and
- wherein, when a composition of said tantalum oxide layer is represented by TaOz, z satisfies:
- x+y<z.
Dependencies are inferred from the claim text.