1. A method of manufacturing a semiconductor device comprising the steps of:
forming an oxide semiconductor film over a substrate by sputtering using a target, the oxide semiconductor film having a crystalline structure in which a c-axis is parallel to a normal vector of a surface of the substrate, wherein the target comprises a polycrystalline oxide semiconductor material in which a direction of a c-axis is parallel to a normal vector of a top surface of the target, the polycrystalline oxide semiconductor material comprising indium and zinc.
2. The method according to claim 1, wherein the polycrystalline oxide semiconductor material further comprises gallium.
3. The method according to claim 1, wherein the polycrystalline oxide semiconductor material further comprises at least one element selected from the group consisting of Sn, Hf, Al, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
4. The method according to claim 1, wherein the formation of the oxide semiconductor film is performed at a substrate temperature of 200\xb0 C. or higher.
5. The method according to claim 1, wherein the formation of the oxide semiconductor film is performed in a gas containing oxygen at 80 vol. % or greater.
6. The method according to claim 1, further comprising a step of etching the oxide semiconductor film to form an oxide semiconductor layer including a channel of a transistor.
7. The method according to claim 1, wherein the oxide semiconductor film has a crystal-amorphous mixed phase structure.
8. A method of manufacturing a semiconductor device comprising the steps of:
producing sputtered particles by cleaving a target along an a-b plane of crystals of the target, wherein the target comprises a polycrystalline oxide semiconductor material in which a direction of a c-axis is parallel to a normal vector of a top surface of the target, the polycrystalline oxide semiconductor material comprising indium and zinc;
depositing the sputtered particles onto a surface over a substrate to form an oxide semiconductor film including a crystalline structure,
wherein the crystalline structure of the oxide semiconductor film has a c-axis being parallel to a normal vector of the surface.
9. The method according to claim 8, wherein the sputtered particles maintain an original crystal state when the sputtered particles reach the surface over the substrate.
10. The method according to claim 8, wherein a crystal state of the target is transferred to the substrate by depositing the sputtered particles.
11. The method according to claim 8, wherein the oxide semiconductor film has a crystal-amorphous mixed phase structure.
12. The method according to claim 8, wherein the sputtered particles have a flat-plate-like shape.
13. The method according to claim 8, wherein the sputtered particles have a pellet-like shape.
14. The method according to claim 8, wherein the polycrystalline oxide semiconductor material further comprises gallium.
15. The method according to claim 8, wherein the polycrystalline oxide semiconductor material further comprises at least one element selected from the group consisting of Sn, Hf, Al, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
16. The method according to claim 8, wherein the oxide semiconductor film is formed at a substrate temperature of 200\xb0 C. or higher.
17. The method according to claim 8, wherein the oxide semiconductor film is formed in a gas containing oxygen at 80 vol. % or greater.
18. The method according to claim 8, further comprising a step of etching the oxide semiconductor film to form an oxide semiconductor layer including a channel of a transistor.
19. A method of manufacturing a semiconductor device comprising the steps of:
producing sputtered particles by cleaving a target along an a-b plane of crystals of the target, the target comprising a polycrystalline oxide semiconductor material comprising indium and zinc;
depositing the sputtered particles onto a surface over a substrate to form an oxide semiconductor film including a crystalline structure,
wherein the crystalline structure has a c-axis being parallel to a normal vector of the surface.
20. The method according to claim 19, wherein the sputtered particles maintain an original crystal state when the sputtered particles reach the surface over the substrate.
21. The method according to claim 19, wherein a crystal state of the target is transferred to the substrate by depositing the sputtered particles.
22. The method according to claim 19, wherein the oxide semiconductor film has a crystal-amorphous mixed phase structure.
23. The method according to claim 19, wherein the sputtered particles have a flat-plate-like shape.
24. The method according to claim 19, wherein the sputtered particles have a pellet-like shape.
25. The method according to claim 19, wherein the polycrystalline oxide semiconductor material further comprises gallium.
26. The method according to claim 19, wherein the polycrystalline oxide semiconductor material further comprises at least one element selected from the group consisting of Sn, Hf, Al, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
27. The method according to claim 19, wherein the oxide semiconductor film is formed at a substrate temperature of 200\xb0 C. or higher.
28. The method according to claim 19, wherein the oxide semiconductor film is formed in a gas containing oxygen at 80 vol. % or greater.
29. The method according to claim 19, further comprising a step of etching the oxide semiconductor film to form an oxide semiconductor layer including a channel of a transistor.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An X-ray computer tomography apparatus comprising:
at least one X-ray tube configured to generate X-rays;
a plurality of first detector elements of an energy integrating type, configured to detect an intensity of X-rays generated from the X-ray tube and transmitted through an object;
a plurality of second detector elements of a photon counting type, configured to detect a spectrum of X-rays generated from the X-ray tube and transmitted through the object;
at least one data acquisition circuit configured to acquire first projection data detected by the plurality of first detector elements and second projection data which is detected by the plurality of second detector elements and is smaller in data amount than the first projection data;
an arithmetic circuit configured to compute a minimum value of a predetermined cost function based upon the first projection data and the second projection data by executing an iterative reconstruction algorithm; and
a reconstruction circuit configured to reconstruct an image of the object based upon the first projection data and the second projection data, which correspond to the minimum value of the cost function.
2. The X-ray computer tomography apparatus according to claim 1, wherein the data acquisition circuit is configured to acquire the second projection data smaller in view count than the first projection data.
3. The X-ray computer tomography apparatus according to claim 1, wherein the plurality of second detector elements are detector elements arranged at a pitch larger than a pitch of the plurality of first detector elements.
4. The X-ray computer tomography apparatus according to claim 1, wherein an arrangement of the plurality of first detector elements includes a third-generation geometry.
5. The X-ray computer tomography apparatus according to claim 1, wherein an arrangement of the plurality of second detector elements includes one of a third-generation geometry and a fourth-generation geometry.
6. The X-ray computer tomography apparatus according to claim 1, wherein the cost function is based upon a total of a sum of square errors between the first projection data and first true values and a sum of square errors between the second projection data and second true values.
7. The X-ray computer tomography apparatus according to claim 1, wherein the iterative reconstruction algorithm is configured to minimize the cost function by using at least one of polar coordinates, system matrix, normalization, initialization, updating, positivity constraint, and penalty.
8. The X-ray computer tomography apparatus according to claim 1, wherein the second projection data includes a count number with respect to a predetermined number of energy bins.
9. The X-ray computer tomography apparatus according to claim 1, wherein the data acquisition circuit is configured to simultaneously acquire the first projection data and the second projection data.
10. The X-ray computer tomography apparatus according to claim 1, wherein the data acquisition circuit is configured to sequentially acquire the first projection data and the second projection data.
11. An image processing apparatus comprising:
a memory circuit configured to store first projection data detected by a plurality of first detector elements of an energy integrating type and second projection data which is detected by a plurality of second detector elements of a photon counting type and is smaller in data amount than the first projection data;
an arithmetic circuit configured to compute a minimum value of a predetermined cost function based upon the first projection data and the second projection data by executing an iterative reconstruction algorithm; and
a reconstruction circuit configured to reconstruct an image of an object based upon the first projection data and the second projection data, which correspond to the minimum value of the cost function.