Oxide semiconductor device comprising oxygen vacancies
Disclosed is a semiconductor device comprising an oxide semiconductor layer on a substrate and including a first part and a pair of second parts that are spaced apart from each other across the first part, a gate electrode on the first part of the oxide semiconductor layer, and a pair of electrodes on corresponding second parts of the oxide semiconductor layer. A first thickness of the first part of the oxide semiconductor layer is less than a second thickness of each second part of the oxide semiconductor layer. A number of oxygen vacancies in the first part of the oxide semiconductor layer is less than a number of oxygen vacancies in each second part of the oxide semiconductor layer.
1. A semiconductor device, comprising:
an oxide semiconductor layer on a substrate, the oxide semiconductor layer including
a first part and a pair of second parts, and
each of the second parts of the pair of second parts are spaced apart from each other across the first part;
a gate electrode on the first part of the oxide semiconductor layer; and
a pair of electrodes on corresponding second parts of the pair of second parts,
wherein a first thickness of the first part of the oxide semiconductor layer is less than a second thickness of each of the second parts, and
a concentration of oxygen vacancies in the first part of the oxide semiconductor layer is less than a concentration of oxygen vacancies in each of the second parts,
wherein a bottom surface of the first part is at a same height as that of a bottom surface of each of the second parts, and
wherein the oxide semiconductor layer is a single layer including of one or more of amorphous oxide semiconductor, crystalline oxide semiconductor and polycrystalline oxide semiconductor.
2. The semiconductor device of claim 1 , further comprising:
a gate dielectric pattern between the gate electrode and the first part of the oxide semiconductor layer.
3. The semiconductor device of claim 1 , further comprising:
an oxygen supply layer on the substrate and adjacent to the oxide semiconductor layer,
wherein, in each of the second parts, a concentration of oxygen vacancies in a portion distant from the oxygen supply layer is greater than a concentration of oxygen vacancies in another portion adjacent to the oxygen supply layer.
4. The semiconductor device of claim 3 , wherein the oxygen supply layer includes an oxygen-containing dielectric material.
5. The semiconductor device of claim 1 , wherein
each of the second parts are spaced apart from each other along a first direction parallel to a top surface of the substrate,
each electrode of the pair of electrodes are contact electrodes on the corresponding second parts, and
the first thickness and the second thickness are measured along a second direction perpendicular to the top surface of the substrate.
6. The semiconductor device of claim 5 , wherein a top surface of the first part of the oxide semiconductor layer is at a height lower than a height of a top surface of each of the second parts.
7. The semiconductor device of claim 5 , further comprising:
an oxygen supply layer between the substrate and the oxide semiconductor layer,
wherein each of the second parts includes a lower portion adjacent to the oxygen supply layer and an upper portion distant from the oxygen supply layer,
a concentration of oxygen vacancies in the lower portion of each of the second parts is less than a concentration of oxygen vacancies in the upper portion of each of the second parts.
8. The semiconductor device of claim 7 , wherein the concentration of oxygen vacancies in the first part of the oxide semiconductor layer is less than the concentration of oxygen vacancies in the upper portion of each of the second parts.
9. The semiconductor device of claim 7 , wherein each of the contact electrodes is on the upper portion of each of the second parts.
10. A semiconductor device, comprising:
an oxide semiconductor layer on a substrate, the oxide semiconductor layer including
a first part and a pair of second parts, and
each of the second parts of the pair of second parts are spaced apart from each other across the first part;
a gate electrode on the first part of the oxide semiconductor layer; and
a pair of electrodes on corresponding second parts of the pair of second parts,
wherein a first thickness of the first part of the oxide semiconductor layer is less than a second thickness of each of the second parts, and
a concentration of oxygen vacancies in the first part of the oxide semiconductor layer is less than a concentration of oxygen vacancies in each of the second parts,
wherein each of the second parts are spaced apart from each other along a second direction perpendicular to a top surface of the substrate,
each electrode of the pair of electrodes include a lower electrode and an upper electrode that are correspondingly adjacent to each of the second parts, and
the first thickness and the second thickness are measured along a first direction parallel to the top surface of the substrate.
11. The semiconductor device of claim 10 , wherein
each of the second parts are horizontal parts that extend in the first direction, and
the first part of the oxide semiconductor layer is a vertical part that extends in the second direction between each of the second parts.
12. The semiconductor device of claim 10 , wherein
the oxide semiconductor layer has an inner surface and an outer surface that are opposite to each other in the first direction,
the gate electrode is on the inner surface of the oxide semiconductor layer, and
the semiconductor device further comprises an oxygen supply layer that covers the outer surface of the oxide semiconductor layer.
13. The semiconductor device of claim 12 , wherein each of the second parts protrude along the first direction from the outer surface of the first part of the oxide semiconductor layer.
14. The semiconductor device of claim 13 , wherein outer surfaces of each of the second parts are offset along the first direction from the outer surface of the first part of the oxide semiconductor layer.
15. The semiconductor device of claim 12 , wherein each of the second parts includes an outer portion adjacent to the oxygen supply layer and an inner portion distant from the oxygen supply layer,
wherein a concentration of oxygen vacancies in the outer portion of each of the second parts is less than a concentration of oxygen vacancies in the inner portion of each of the second parts.
16. The semiconductor device of claim 15 , wherein the concentration of oxygen vacancies in the first part of the oxide semiconductor layer is less than the concentration of oxygen vacancies in the inner portion of each of the second parts.
17. The semiconductor device of claim 12 , further comprising:
a gate dielectric pattern between the gate electrode and the inner surface of the oxide semiconductor layer.
18. The semiconductor device of claim 10 , further comprising:
a gate dielectric pattern between the gate electrode and the first part of the oxide semiconductor layer.
19. The semiconductor device of claim 10 , further comprising:
an oxygen supply layer on the substrate and adjacent to the oxide semiconductor layer,
wherein, in each of the second parts, a concentration of oxygen vacancies in a portion distant from the oxygen supply layer is greater than a concentration of oxygen vacancies in another portion adjacent to the oxygen supply layer.
20. The semiconductor device of claim 19 , wherein
the oxygen supply layer includes an oxygen-containing dielectric material.