Nonvolatile memory element having a tantalum oxide variable resistance layer
View Patent ↗A nonvolatile memory apparatus includes a first electrode, a second electrode, a variable resistance layer, a resistance value of the variable resistance layer reversibly varying between a plurality of resistance states based on an electric signal applied between the electrodes. The variable resistance layer includes at least a tantalum oxide, and is configured to satisfy 0<x<2.5 when the tantalum oxide is represented by TaOx; and wherein when a resistance value between the electrodes is in the low-resistance state is RL, a resistance value between the electrodes is in the high-resistance state is RH, and a resistance value of a portion other than the variable resistance layer in a current path connecting a first terminal to a second terminal via the first electrode, the variable resistance layer and the second electrode, is R 0 , R 0 satisfies RL<R 0.
1. A nonvolatile memory element comprising:
a first electrode;
a second electrode; and
a variable resistance layer which is disposed between the first electrode and the second electrode, a resistance value of the variable resistance layer reversibly varying based on an electric signal applied between the first electrode and the second electrode;
the variable resistance layer comprising a tantalum oxide, and being configured to satisfy 0<x<2.5 when the tantalum oxide is represented by TaOx;
wherein a fixed resistance portion is provided in series with the variable resistance layer, and
when a resistance value of the variable resistance layer in a low-resistance state is RL, a resistance value of the variable resistance layer in a high-resistance state is RH, and a resistance value of the fixed resistance portion is R 0 , R 0 satisfies RL<R 0 .
2. The nonvolatile memory element according to claim 1 , wherein
the variable resistance layer and the fixed resistance portion are stacked together on the same substrate.
3. The nonvolatile memory element according to claim 1 , wherein
the variable resistance layer comprises at least a tantalum oxide, and is configured to satisfy 0<x≦1.9 when the tantalum oxide is represented by TaOx.
4. The nonvolatile memory element according to claim 1 , wherein
the variable resistance layer comprises at least a tantalum oxide, and is configured to satisfy 0.5≦x≦1.9 when the tantalum oxide is represented by TaOx.
5. The nonvolatile memory element according to claim 1 , wherein
the variable resistance layer comprises at least a tantalum oxide, and is configured to satisfy 0.8≦x≦1.9 when the tantalum oxide is represented by TaOx.