1. An oscillator for oscillating an electromagnetic wave, comprising:
a substrate; and
a resonant tunneling diode provided on the substrate,
wherein the resonant tunneling diode comprises at least two quantum well layers and plural barrier layers for separating the quantum well layers from each other,
wherein the two quantum well layers each has a lattice constant different from a lattice constant of the substrate and a film thickness smaller than a critical film thickness,
wherein the plural barrier layers include a first barrier layer sandwiched by the two quantum well layers;
wherein the first barrier layer has such a film thickness that carriers are able to be subjected to a photon assist tunnel between sub-bands of the two quantum well layers, and
wherein a strain of the first barrier layer and the two quantum well layers is compensated by a strain of a barrier layer among the plural barrier layers that is not sandwiched by the two quantum well layers.
2. An oscillator according to claim 1, wherein the substrate is an InP substrate;
wherein the quantum well layers are one of InGaAs and InAs each having an In composition of 60% or more and 100% or less; and
wherein the barrier layers include at least two layers of InAlAs whose In composition is 0% or more and 50% or less and of one of AlAs and AlAsSb.
3. An oscillator according to claim 1, wherein
the substrate is an InAs substrate; and
wherein the gain medium comprises at least an InAsSb well layer and one of an InAlAs barrier layer and an AlAsSb barrier layer.
4. An oscillator according to claim 1, wherein the substrate is a GaSb substrate; and
wherein the gain medium comprises at least one of an InAsSb well layer and an InGaSb well layer and one of an InAlAs barrier layer and an AlAsSb barrier layer.
5. An oscillator according to claim 1, wherein the substrate is a GaN substrate; and
wherein the gain medium comprises at least an InGaN well layer and an AlGaN barrier layer.
6. An oscillator according to claim 1, wherein the electromagnetic wave includes at least a part of a frequency region ranging from 30 GHz to 30 THz.
7. An oscillator according to claim 1, further comprising a resonator for oscillating a terahertz wave generated from the resonant tunneling diode, wherein the resonator comprises at least a transmission line and an antenna.
8. An oscillator according to claim 1, further comprising a resonator for oscillating a terahertz wave generated from the resonant tunneling diode, wherein the resonator comprises a stripe surface plasmon transmission line and a reflecting surface at an end portion of the transmission line.
9. An oscillator according to claim 8, wherein a propagation constant of the stripe surface plasmon transmission line is periodically changed along a propagation direction of the electromagnetic wave, thereby causing the electromagnetic wave to become a standing wave by Bragg reflection.
10. A sensing apparatus, comprising the oscillator according to claim 1, which is used as an oscillation source, wherein an interaction between an electromagnetic wave having a part of a frequency region ranging from 30 GHz to 30 THz and an object to be inspected is inspected.
11. An imaging apparatus, comprising the oscillator according to claim 1, which is used as an oscillation source, wherein
an interaction between an electromagnetic wave having a part of a frequency region ranging from 30 GHz to 30 THz and an object to be inspected is two-dimensionally inspected to obtain image data.
12. An oscillator according to claim 1, further comprising a carrier injecting unit for injecting carriers to the resonant tunneling diode.
13. An oscillator for oscillating an electromagnetic wave, comprising:
a substrate; and
a resonant tunneling diode provided on the substrate,
wherein the resonant tunneling diode comprises:
a first barrier layer that has a lattice constant different from a lattice constant of the substrate and has a film thickness smaller than a critical film thickness;
a first quantum well layer that is in contact with the first barrier layer, has a lattice constant different from the lattice constant of the substrate, and has a film thickness smaller than the critical film thickness;
a second barrier layer that is in contact with the first quantum well layer, has a film thickness smaller than the critical film thickness, and is so constructed that carriers in a sub-band of the first quantum well layer are able to be subjected to a photon assist tunnel;
a second quantum well layer that is in contact with the second barrier layer, is arranged on a side opposite to the first quantum well layer via the second barrier layer, has a lattice constant different from the lattice constant of the substrate, and has a film thickness smaller than the critical film thickness; and
a third barrier layer that is in contact with the second quantum well layer, has a lattice constant different from the lattice constant of the substrate, and has a film thickness smaller than the critical film thickness,
wherein a strain of the second barrier layer and the first and second quantum well layers is compensated by a strain of the first and third barrier layers.
14. An oscillator according to claim 13, wherein the second barrier layer has a lattice constant that is matched with a lattice constant of the substrate.
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. A magnetic memory, comprising:
a plurality of lead structures, disposed on a substrate, wherein the lead structures do not intersect each other;
a plurality of first magnetic metal structures, disposed on the substrate, wherein each of the first magnetic metal structures is disposed between adjacent two of the lead structures;
a second magnetic metal structure, disposed on the substrate, covering the lead structures and the first magnetic metal structures, and spanning over the lead structures, wherein a structure formed by the first magnetic metal structures and the second magnetic metal structure comprises a plurality of magnetic memory cells connected with each other, each of the magnetic memory cells has a magnetic domain and a domain wall adjacent to the magnetic domain, and the magnetic domain is suitable for storing a bit data; and
an insulation layer, disposed between the lead structures and the first magnetic metal structures and between the lead structures and the second magnetic metal structure.
2. The magnetic memory according to claim 1, wherein the lead structures receive an alternating current (AC) signal during a shift period.
3. The magnetic memory according to claim 2, wherein the bit data is shifted into or out of the magnetic domain during the shift period according to a low current pulse received by the second magnetic metal structure.
4. The magnetic memory according to claim 1, wherein the magnetic domain in each of the magnetic memory cells is connected with the domain wall in the adjacent magnetic memory cell.
5. The magnetic memory according to claim 1, wherein the first magnetic metal structures present a linear arrangement.
6. The magnetic memory according to claim 1, wherein the first magnetic metal structures and the second magnetic metal structure belong to a same layer.
7. The magnetic memory according to claim 6, wherein the magnetic domain is located between adjacent two of the lead structures.
8. The magnetic memory according to claim 6, wherein a material of the first magnetic metal structures and the second magnetic metal structure comprise at least one of a horizontal ferromagnetic material and a vertical ferromagnetic material.
9. The magnetic memory according to claim 8, wherein the horizontal ferromagnetic material comprises CoFe, NiFe, or CoFeB.
10. The magnetic memory according to claim 8, wherein the vertical ferromagnetic material comprises Fe\u2014Pt, Co\u2014Pt, or Co\u2014Ni multilayer.
11. The magnetic memory according to claim 1, wherein the first magnetic metal structures and the second magnetic metal structure belong to different layers.
12. The magnetic memory according to claim 11, wherein each of the first magnetic metal structures has a specific magnetic coupling force.
13. The magnetic memory according to claim 12, wherein the domain wall is located between adjacent two of the lead structures and has a magnetic coupling force direction produced by the specific magnetic coupling force.
14. The magnetic memory according to claim 11, wherein a material of the first magnetic metal structures comprises at least one of an antiferromagnetic material and a ferromagnetic material.
15. The magnetic memory according to claim 14, wherein the antiferromagnetic material comprises PtMn or IrMn.
16. The magnetic memory according to claim 14, wherein the ferromagnetic material comprises at least one of a horizontal ferromagnetic material and a vertical ferromagnetic material.
17. The magnetic memory according to claim 16, wherein the horizontal ferromagnetic material comprises CoFe, NiFe, or CoFeB.
18. The magnetic memory according to claim 16, wherein the vertical ferromagnetic material comprises Fe\u2014Pt, Co\u2014Pt, or Co\u2014Ni multilayer.
19. The magnetic memory according to claim 11, wherein a material of the second magnetic metal structure comprises a ferromagnetic material.
20. The magnetic memory according to claim 19, wherein the ferromagnetic material comprises at least one of a horizontal ferromagnetic material and a vertical ferromagnetic material.
21. The magnetic memory according to claim 20, wherein the horizontal ferromagnetic material comprises CoFe, NiFe, or CoFeB.
22. The magnetic memory according to claim 21, wherein the vertical ferromagnetic material comprises Fe\u2014Pt, Co\u2014Pt, or Co\u2014Ni multilayer.
23. The magnetic memory according to claim 1, wherein a thickness of each of the lead structures is substantially between 10 nm and 50 nm.
24. The magnetic memory according to claim 1, wherein a width of each of the lead structures is substantially between 50 nm and 500 nm.
25. The magnetic memory according to claim 1, wherein a width of the magnetic domain is about 65 nm.
26. The magnetic memory according to claim 1, wherein a width of the domain wall is about 65 nm.
27. The magnetic memory according to claim 1, wherein the bit data in one of the magnetic domains is updated by the corresponding lead structure during a readwrite period.
28. The magnetic memory according to claim 27, wherein the bit data in the magnetic domain is updated by two of the lead structures adjacent to the magnetic domain.
29. The magnetic memory according to claim 27, wherein the bit data in the magnetic domain is updated by the lead structure under the magnetic domain.
30. The magnetic memory according to claim 1, further comprising:
a read device, disposed below one of the first magnetic metal structures, for reading the bit data in the corresponding magnetic domain during a readwrite period.
31. The magnetic memory according to claim 1, further comprising:
a read device, disposed above the second magnetic metal structure, for reading the bit data in the corresponding magnetic domain during a readwrite period.
32. A driving method of the magnetic memory according to claim 1, comprising:
providing an AC signal to the lead structures during an shift period; and
providing a low current pulse to the second magnetic metal structure during the shift period to shift the bit data in each of the magnetic memory cells out of or into the magnetic domain.
33. The driving method according to claim 32, further comprising:
providing a data pulse to one of the lead structures during a readwrite period to update the bit data in the corresponding magnetic domain.
34. The driving method according to claim 32, further comprising:
providing a data pulse to adjacent two lead structures among the lead structures during a readwrite period to update the bit data in the corresponding magnetic domain.
35. The driving method according to claim 32, further comprising:
reading the bit data in one of the magnetic domains during a readwrite period by using a read device.
36. The driving method according to claim 32, wherein a frequency of the AC signal is substantially between 106 Hz and 109 Hz.
37. The driving method according to claim 32, wherein a current density of the low current pulse is substantially between 106 ampcm2 and 107 ampcm2.
38. A manufacturing method of a magnetic memory, comprising:
forming a plurality of lead structures on a substrate, wherein the lead structures do not intersect each other;
forming an insulation layer on the substrate, wherein the insulation layer covers the lead structures;
forming a plurality of first magnetic metal structures on the insulation layer, wherein each of the first magnetic metal structures is respectively disposed between adjacent two of the lead structures;
performing a magnetization process to the first magnetic metal structures so that a magnetic coupling force direction is produced by each of the first magnetic metal structures; and
forming a second magnetic metal structure on the insulation layer, wherein the second magnetic metal structure covers the first magnetic metal structures and spans over the lead structures, and an extension direction of the second magnetic metal structure is different from the magnetic coupling force direction;
wherein a structure formed by the first magnetic metal structures and the second magnetic metal structure is divided into a plurality of magnetic memory cells connected with each other by dispositions of the lead structures, and each of the magnetic memory cells has a magnetic domain and a domain wall adjacent to the magnetic domain.
39. The manufacturing method according to claim 38, wherein the step of forming the first magnetic metal structures on the substrate comprises:
aligning top surfaces of the first magnetic metal structures with a top surface of the insulation layer so that the top surfaces of the first magnetic metal structures and the top surface of the insulation layer form a flat top surface.
40. The manufacturing method according to claim 39, wherein the step of forming the second magnetic metal structure on the substrate comprises:
forming the second magnetic metal structure on the flat top surface.
41. The manufacturing method according to claim 38, wherein the domain wall is located between adjacent two of the lead structures.
42. The manufacturing method according to claim 38, wherein the magnetic domain in each of the magnetic memory cells is connected with the domain wall in the adjacent magnetic memory cell.
43. The manufacturing method according to claim 38, wherein the extension direction of the second magnetic metal structure is perpendicular to the magnetic coupling force direction.
44. The manufacturing method according to claim 38, wherein the first magnetic metal structures present a linear arrangement.
45. The manufacturing method according to claim 38, wherein a material of the first magnetic metal structures comprises at least one of an antiferromagnetic material and a ferromagnetic material.
46. The manufacturing method according to claim 45, wherein the antiferromagnetic material comprises PtMn or IrMn.
47. The manufacturing method according to claim 45, wherein the ferromagnetic material comprises at least one of a horizontal ferromagnetic material and a vertical ferromagnetic material.
48. The manufacturing method according to claim 47, wherein the horizontal ferromagnetic material comprises CoFe, NiFe, or CoFeB.
49. The manufacturing method according to claim 47, wherein the vertical ferromagnetic material comprises Fe\u2014Pt, Co\u2014Pt, or Co\u2014Ni multilayer.
50. The manufacturing method according to claim 38, wherein a material of the second magnetic metal structure comprises a ferromagnetic material.
51. The manufacturing method according to claim 50, wherein the ferromagnetic material comprises at least one of a horizontal ferromagnetic material and a vertical ferromagnetic material.
52. The manufacturing method according to claim 51, wherein the horizontal ferromagnetic material comprises CoFe, NiFe, or CoFeB.
53. The manufacturing method according to claim 51, wherein the vertical ferromagnetic material comprises Fe\u2014Pt, Co\u2014Pt, or Co\u2014Ni multilayer.
54. A manufacturing method of a magnetic memory, comprising:
forming a plurality of lead structures on a substrate, wherein the lead structures do not intersect each other;
forming an insulation layer on the substrate, wherein the insulation layer covers the lead structures; and
forming a magnetic metal structure on the insulation layer, wherein the magnetic metal structure spans over the lead structures,
wherein the magnetic metal structure is divided into a plurality of magnetic memory cells connected with each other by dispositions of the lead structures, and each of the magnetic memory cells has a magnetic domain and a domain wall adjacent to the magnetic domain.
55. The manufacturing method according to claim 54, wherein the magnetic domain is located between adjacent two of the lead structures.
56. The manufacturing method according to claim 54, wherein the magnetic domain in each of the magnetic memory cells is connected with the domain wall in the adjacent magnetic memory cell.
57. The manufacturing method according to claim 54, wherein the magnetic metal structure presents a linear arrangement.
58. The manufacturing method according to claim 54, wherein a material of the magnetic metal structure comprises a ferromagnetic material.
59. The manufacturing method according to claim 54, wherein the ferromagnetic material comprises at least one of a horizontal ferromagnetic material and a vertical ferromagnetic material.
60. The manufacturing method according to claim 59, wherein the horizontal ferromagnetic material comprises CoFe, NiFe, or CoFeB.
61. The manufacturing method according to claim 59, wherein the vertical ferromagnetic material comprises Fe\u2014Pt, Co\u2014Pt, or Co\u2014Ni multilayer.