Method of horizontally growing carbon nanotubes and field effect transistor using the carbon nanotubes grown by the method

• US 20020014667A1
• Filed: 07/18/2001
• Published: 02/07/2002
• Est. Priority Date: 07/18/2000
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Kyu Tae, Han, Young Soo, Lee, Jae Eun, Shin, Jin Koog, Yoon, Sang Soo, Jung, Min Jae
• Granted Patent: US 6,515,339 B2
• Time in Patent Office: Days
• US Class Current: 257/368
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 2202/08 Aligned nanotubes
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: G11C 13/025 using fullerenes, e.g. C60, or nanotubes, e.g. carbon or silicon nanotubes
• CPC Class Codes: G11C 2213/17 Memory cell being a nanowire transistor
• CPC Class Codes: H10K 10/00 Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having potential barriers integrated devices or assemblies of multiple devices H10K19/00
• CPC Class Codes: H10K 10/46 Field-effect transistors, e.g. organic thin-film transistors [OTFT] H10K10/43 takes precedence
• CPC Class Codes: H10K 10/462 Insulated gate field-effect transistors [IGFETs]
• CPC Class Codes: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 10/491 Vertical transistors, e.g. vertical carbon nanotube field effect transistors [CNT-FETs]
• CPC Class Codes: H10K 19/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic element specially adapted for rectifying, amplifying, oscillating or switching, covered by group H10K10/00
• CPC Class Codes: H10K 71/10 Deposition of organic active material
• CPC Class Codes: H10K 85/221 Carbon nanotubes
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/843 Gas phase catalytic growth, i.e. chemical vapor deposition
• CPC Class Codes: Y10S 977/844 Growth by vaporization or dissociation of carbon source using a high-energy heat source, e.g. electric arc, laser, plasma, e-beam
• CPC Class Codes: Y10S 977/89 Deposition of materials, e.g. coating, cvd, or ald
• CPC Class Codes: Y10S 977/896 Chemical synthesis, e.g. chemical bonding or breaking
• CPC Class Codes: Y10S 977/90 : having step or means utilizing mechanical or thermal property, e.g. pressure, heat
• CPC Class Codes: Y10S 977/936 : in a transistor or 3-terminal device
• CPC Class Codes: Y10S 977/938 : Field effect transistors, FETS, with nanowire- or nanotube-channel region

Abstract

Disclosed is a method of horizontally growing carbon nanotubes, in which the carbon nanotubes can be selectively grown in a horizontal direction at specific locations of a substrate having catalyst formed thereat, so that the method can be usefully utilized in fabricating nano-devices. The method includes the steps of: (a) forming a predetermined catalyst pattern on a first substrate; (b) forming a vertical growth preventing layer on the first substrate, which prevents carbon nanotubes from growing in a vertical direction; (c) forming apertures through the vertical growth preventing layer and the first substrate to expose the catalyst pattern through the apertures; and (d) synthesizing carbon nanotubes at exposed surfaces of the catalyst pattern in order to grow the carbon nanotubes in the horizontal direction.

Claims

1. A method of horizontally growing carbon nanotubes, the method comprising the steps of:

(a) forming a predetermined catalyst pattern on a first substrate;

(b) forming a vertical growth preventing layer on the first substrate, which prevents carbon nanotubes from growing in a vertical direction;

(c) forming apertures through the vertical growth preventing layer and the first substrate to expose the catalyst pattern through the apertures; and

(d) synthesizing carbon nanotubes at exposed surfaces of the catalyst pattern in order to grow the carbon nanotubes in the horizontal direction.

2. A method as claimed in claim 1, wherein the apertures formed in step c are of a hole-type, in which the apertures extend entirely through the vertical growth preventing layer and the first substrate.

3. A method as claimed in claim 1, wherein the apertures formed in step c are of a well-type, in which the first substrate is partially etched, so that the apertures extend through the vertical growth preventing layer and a portion of the first substrate.

4. A method as claimed in claim 1, wherein the catalyst pattern has one of a straight-line shape, an intersection shape, a radial shape, a circular shape, and a rectangular shape, while the apertures are formed at intersecting areas of the catalyst pattern of a straight line shape, an intersection shape, and a radial shape, at an interior of a circle, and at an interior of a rectangle of the pattern.

5. A method as claimed in claim 4, wherein the carbon nanotubes formed respectively from the catalyst pattern and the apertures are grown to make a junction between them.

6. A method as claimed in claim 5, wherein the junction between the carbon nanotubes intersecting each other is formed by means of a phenomenon of thermal contraction of material, which is generated in a cooling stage after the carbon nanotubes are grown.

7. A method as claimed in claim 4, wherein the carbon nanotubes formed from the catalyst pattern and the apertures, respectively, are grown while intersecting each other.

8. A method as claimed in claim 1, wherein the carbon nanotubes grown in step d forms a bridge construction, by which exposed surfaces of the catalyst pattern opposing each other are connected with each other.

9. A method as claimed in claim 1, wherein the carbon nanotubes grown in step d forms a free-hang construction, in which the carbon nanotubes from the exposed surfaces of the catalyst pattern opposing each other are separated from each other.

10. A method as claimed in claim 1, wherein the carbon nanotubes grown in step d are a plurality of carbon nanotubes grown at a single catalyst pattern.

11. A method as claimed in claim 1, wherein the carbon nanotubes grown in step d forms a mesh construction, in which a plurality of carbon nanotubes are grown from each of the exposed surfaces of catalyst pattern opposing each other, to be connected with each other.

12. A method as claimed in claim 1, the method further comprising a step of patterning a metal on a grown carbon nanotubes, so as to selectively form a junction between the carbon nanotube and the metal at a specific location, after step d.

14. A method as claimed in claim 13, wherein the catalyst pattern has one of a straight line shape, an intersection shape, a radial shape, a circular shape, and a rectangular shape, while the apertures are formed at intersecting areas of the catalyst pattern of a straight line shape, an intersection shape, and a radial shape, at an interior of a circle, and at an interior of a rectangle of the pattern.

15. A method as claimed in claim 14, wherein the carbon nanotubes formed respectively from the catalyst pattern and the apertures are grown to make a junction between them.

16. A method as claimed in claim 14, wherein the carbon nanotubes formed respectively from the catalyst pattern and the apertures are grown while intersecting each other.

17. A method as claimed in claim 13, wherein the carbon nanotubes grown in step m forms a bridge construction, by which exposed surfaces of the catalyst pattern opposing each other are connected with each other.

18. A method as claimed in claim 1, wherein the carbon nanotubes grown in step m forms a free-hang construction, in which the carbon nanotubes from the exposed surfaces of the catalyst pattern opposing each other are separated from each other.

19. A method as claimed in claim 13, the method further comprising a step of patterning a metal on a grown carbon nanotubes in order to selectively form a junction between the carbon nanotube and the metal at a specific location, after step m.

13. A method of horizontally growing carbon nanotubes, the method comprising the steps of:

(i) forming masks at predetermined locations on a first substrates

(j) forming a catalyst pattern on the first substrate and the masks formed on the first substrate;

(k) forming a vertical growth preventing layer on the first substrate, which prevents the carbon nanotubes from growing in a vertical direction;

(l) eliminating the masks from the vertical growth preventing layer and the first substrate to form apertures and expose the catalyst pattern; and

(m) synthesizing the carbon nanotubes at exposed locations of the catalyst pattern in order to grow the carbon nanotubes in the horizontal direction.

20. A method of horizontally growing carbon nanotubes, the method comprising the steps of:

forming a catalyst pattern in a predetermined two-dimensional arrangement on a first substrate;

fabricating a second substrate for preventing vertical growth of the carbon nanotubes having holes in a predetermined arrangement;

placing the second substrate for preventing vertical growth of the carbon nanotubes over the first substrate having the catalyst pattern with a predetermined gap; and

synthesizing the carbon nanotubes at the catalyst pattern, so as to horizontally grow the carbon nanotubes.

21. A method of horizontally growing carbon nanotubes, the method comprising the steps of:

forming a catalyst in a shape of nanodots or nanowires on a substrate;

patterning a growth preventing layer on the catalyst in the shape of nanodots or nanowires, so as to prevent the nanodots or nanowires from growing in a vertical direction; and

selectively growing the carbon nanotubes in a horizontal direction at the nanodots or nanowires.

22. A method as claimed in claim 21, wherein the catalyst in the shape of the nanodots or nanowires are patterned by an imprint method.

23. A method as claimed in claim 21, wherein the catalyst in the shape of the nanodots or nanowires are patterned by a self-assembly method.

24. A method as claimed in claim 21, wherein the growth preventing layer is formed of an insulator film made from a compound selected from the group consists of silicon nitride (SiN) and silicon oxide (SiO₂).

25. A method as claimed in claim 21, wherein the growth preventing layer is formed from a metal selected from the group consists of Palladium (Pd), Niobium (Nb), and Molybdenum (Mo).

27. A method as claimed in claim 26, wherein the catalyst in the shape of nanowires are patterned by an imprint method.

28. A method as claimed in claim 26, wherein the catalyst in the shape of nanowires are patterned by a self-assembly method.

30. A field effect transistor as claimed in claim 29, wherein the carbon nanotube bridge formed between the source and the drain comprises carbon nanotubes having a characteristic of semiconductor.

31. A field effect transistor as claimed in claim 29, wherein, on the carbon nanotube bridge formed between the source and the drain, a plurality of gate carbon nanotubes are formed intersecting the carbon nanotube bridge between the source and the drain at, so as to produce an energy barrier to form a quantum point and to control the flow of the electric current.

32. A field effect transistor as claimed in claim 31, wherein the quantum point has a size, which is controlled by using a common terminal, when the gate carbon nanotube bridges form gates.

33. A field effect transistor as claimed in claim 29, the field effect transistor further comprising first and second wires, through which electric current can pass, and which are provided on the source and the drain, so as to magnetize catalysts being in contact with the source and the drain in a desired direction.

34. A field effect transistor as claimed in claim 33, wherein the first wire disposed on the source and the second wire disposed on the drain are arranged in parallel with each other.

35. A field effect transistor as claimed in claim 29, wherein a guide groove is formed at a substrate of the field effect transistor to allow the carbon nanotubes to be grown in a horizontal direction between the source and the drain, thereby the carbon nanotube bridge is formed in the horizontal direction between the source and the drain.

26. A method of horizontally growing carbon nanotubes, the method comprising the steps of:

forming catalysts in a shape of nanowires an a substrate;

forming a growth preventing layer on the catalysts having the shape of nanowires by a semiconductor process including a lithography process, the growth preventing layer being spaced from the substrate with a, predetermined gap;

eliminating a portion of the catalysts having the shape of nanowires in an area at which the growth preventing layer is not formed, by means of a wet etching; and

growing the carbon nanotubes in a horizontal direction between the catalysts formed under the growth preventing layer spaced from the substrate with a predetermined gap, by means of a chemical vapor deposition method.

29. A field effect transistor comprising a source, a drain, and a carbon nanotube bridge between the source and the drain, the carbon nanotube bridge being formed by carbon nanotubes grown in a horizontal direction between the source and the drain, so that the field effect transistor can control the flow of electrons.