Semiconductor device
A semiconductor device of an embodiment includes an oxide semiconductor layer. The oxide semiconductor layer includes a metal oxide containing at least one first metal element selected from the group consisting of indium and tin and at least one second metal element selected from the group consisting of zinc, gallium, aluminum, tungsten, and silicon. The oxide semiconductor layer includes a first region in which at least one anion element selected from the group consisting of fluorine and chlorine is contained within a range of 1 atomic % or more and less than 8 atomic % in the metal oxide.
1. A semiconductor device comprising:
an oxide semiconductor layer extending in a first direction, and including a first end portion and a second end portion opposite the first end portion;
a first electrode surrounding an outer peripheral surface of the oxide semiconductor layer;
an insulation film between the first electrode and the outer peripheral surface of the oxide semiconductor layer;
a second electrode electrically connected to the first end portion of the oxide semiconductor layer; and
a third electrode electrically connected to the second end portion of the oxide semiconductor layer, wherein
the oxide semiconductor layer comprises a metal oxide containing at least one first element selected from the group consisting of indium and tin and at least one second element selected from the group consisting of zinc, gallium, aluminum, tungsten, and silicon, and
the oxide semiconductor layer includes a first region in which at least one third element selected from the group consisting of fluorine and chlorine is contained within a range of 1 atomic % or more and less than 8 atomic % in the metal oxide;
an insulator which extends in the first direction, and is surrounded by the oxide semiconductor layer, wherein
the insulator contains at least one element selected from the group consisting of fluorine and chlorine.
2. The semiconductor device according to claim 1 , wherein the oxide semiconductor layer has an amorphous structure.
3. The semiconductor device according to claim 1 , wherein the oxide semiconductor layer includes a second region in which the third element is contained within a range of less than 1 atomic % in the metal oxide.
4. The semiconductor device according to claim 1 ,
wherein, when a composition of the first region is represented by
a composition formula: M 2 i M 3 j M 4 k M 6 l (O, F, Cl) n ,
where M 2 represents Zn, M 3 represents at least one of In, Ga, or Al, M 4 represents at least one of Sn or Si, M 6 represents W, i represents an atomic ratio of M 2 , j represents an atomic ratio of M 3 , k represents an atomic ratio of M 4 , l represents an atomic ratio of M 6 , and n represents a total atomic ratio of O, F, and Cl,
the composition of the first region satisfies a relation of
(2 i+ 3 j+ 4 k+ 6 l )/2×0.95< n <(2 i+ 3 j+ 4 k+ 6 l )/2×1.05.
5. The semiconductor device according to claim 1 , wherein the oxide semiconductor layer includes the first region facing the first electrode across the insulation film and at least one of a second region which is electrically connected to the second electrode and in which a content of the third element is less than 1 atomic % in the metal oxide and a third region which is electrically connected to the third electrode and in which a content of the third element is less than 1 atomic % in the metal oxide.
6. The semiconductor device according to claim 1 , further comprising a capacitor electrically connected to the second electrode or the third electrode.