Abstract: A switching device according to an embodiment includes a switching layer disposed between a first electrode and a second electrode. The switching layer contains a material containing a first cation element Z, Te, and N. This material contains at least 5 atomic % or more of each of Z, Te, and N, and when an atomic ratio of Te is X, an atomic ratio of N is Y, an atomic ratio of Z is W, a ratio of Z2Te3 to ZN on a straight line connecting a compound of the first cation element Z with tellurium and nitride of the first cation element Z in a ternary phase diagram of Z, Te, and N is A, and a change in an N content from the Z2Te3—ZN line is B, the material has a composition satisfying X=1.2 (1?A) (0.5+B), Y=A (0.5+B), and W=1?X?Y, where ?0.06?B?0.06 is satisfied when ?>A and ¾<A, and ?0.06?B and Y?0.45 are satisfied when ??A?¾.

Abstract: A semiconductor memory device includes a first wiring extending in a first direction; a second wiring extending in a second direction and spaced from the first wiring in a third direction; a stacked body disposed between the first and second wirings and including conductive layers and insulating layers alternately stacked on top of one another in the third direction; a columnar body extending through the stacked body and including: (a) an electrode disposed between the first wiring and the second wiring, (b) a memory layer disposed between the electrode and the conductive layers, and (c) a selection layer disposed between the electrode and the first wiring; and a diode disposed between the electrode and the second wiring.

Abstract: A semiconductor storage device including a phase change memory film having a composition containing at least Ge, Sb, Te, and Se, and containing Se as a design composition ratio to Te in a composition ratio showing a phase change memory property with at least three elements Ge, Sb, and Te. The composition ratio of Se is 33.6 atom % or less.

Abstract: A switching device according to an embodiment includes a switching layer disposed between a first electrode and a second electrode. The switching layer contains a material containing a first cation element Z, Te, and N. This material contains at least 5 atomic % or more of each of Z, Te, and N, and when an atomic ratio of Te is X, an atomic ratio of N is Y, an atomic ratio of Z is W, a ratio of Z2Te3 to ZN on a straight line connecting a compound of the first cation element Z with tellurium and nitride of the first cation element Z in a ternary phase diagram of Z, Te, and N is A, and a change in an N content from the Z2Te3-ZN line is B, the material has a composition satisfying X=1.2 (1?A) (0.5+B), Y=A (0.5+B), and W=1?X?Y, where ?0.06?B?0.06 is satisfied when ?>A and ¾<A, and ?0.06?B and Y?0.45 are satisfied when ??A?¾.