KR101798283B1 - Method of depositing catalyst for vertical growth of carbon nanotube - Google Patents
Method of depositing catalyst for vertical growth of carbon nanotube Download PDFInfo
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- KR101798283B1 KR101798283B1 KR1020150080883A KR20150080883A KR101798283B1 KR 101798283 B1 KR101798283 B1 KR 101798283B1 KR 1020150080883 A KR1020150080883 A KR 1020150080883A KR 20150080883 A KR20150080883 A KR 20150080883A KR 101798283 B1 KR101798283 B1 KR 101798283B1
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 154
- 238000000151 deposition Methods 0.000 title claims abstract description 56
- 239000002041 carbon nanotube Substances 0.000 title claims abstract description 55
- 229910021393 carbon nanotube Inorganic materials 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000003054 catalyst Substances 0.000 title description 18
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 108
- 239000007809 chemical reaction catalyst Substances 0.000 claims abstract description 106
- 239000000758 substrate Substances 0.000 claims abstract description 83
- 230000008021 deposition Effects 0.000 claims abstract description 26
- 239000002109 single walled nanotube Substances 0.000 claims abstract description 10
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 13
- 239000004065 semiconductor Substances 0.000 claims description 11
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 10
- 238000000992 sputter etching Methods 0.000 claims description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- 229910052763 palladium Inorganic materials 0.000 claims description 7
- 229910052786 argon Inorganic materials 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 5
- 229910017052 cobalt Inorganic materials 0.000 claims description 4
- 239000010941 cobalt Substances 0.000 claims description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 238000004544 sputter deposition Methods 0.000 claims description 4
- 238000002207 thermal evaporation Methods 0.000 claims description 4
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- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 3
- 238000010894 electron beam technology Methods 0.000 description 3
- 238000009713 electroplating Methods 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
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- 238000007743 anodising Methods 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 2
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/02587—Structure
- H01L21/0259—Microstructure
- H01L21/02606—Nanotubes
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- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
- H01L29/0657—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape of the body
- H01L29/0665—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape of the body the shape of the body defining a nanostructure
- H01L29/0669—Nanowires or nanotubes
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Abstract
The present invention relates to a method for depositing a carbon reaction catalyst for vertical growth of carbon nanotubes on a vertical pore bottom or side surface of a substrate having vertical voids, according to various embodiments of the present invention, The carbon reaction catalyst may be selectively deposited on the bottom surface or the bottom surface of the carbon reaction catalyst. Therefore, unlike the conventional carbon reaction catalyst deposition methods, the carbon reaction catalyst And the deposition thickness of the carbon reaction catalyst can be maintained in conjunction with the initial deposition, i.e., the thickness of the carbon reaction catalyst formed in the first deposition process, so that the thickness of the carbon reaction catalyst can be easily adjusted, It is possible to vertically grow the various single-wall carbon nanotubes, System may be usefully used for (e.g. electrical switches, electronic sensors).
Description
The present invention relates to a method for depositing a carbon reaction catalyst for vertical growth of carbon nanotubes on the vertical air gap bottom surface of a substrate having vertical voids.
Carbon nanotubes (hereinafter, CNTs) are attracting attention as a material applicable to various fields due to excellent physical and electrical characteristics due to a one-dimensional structure. In particular, Schottky device structures based on CNTs with semiconductor properties are being studied and analyzed to take full advantage of the excellent electrical properties of CNTs.
However, when the CNT is applied to a Schottky device, the CNT is horizontally contacted only. To solve the problem that the space is required between the electrodes connected in the horizontal alignment due to the surface density of the CNT, The results show that CNTs can realize a high-density device more than twice as much as an electron device in which vertically oriented electronic devices are oriented in a horizontal direction (Patent Document 1).
In order to vertically grow such CNTs, a conventional nano-scale vertical transistor using vertical chemical vapor deposition (CVD) has been disclosed. As a result of applying the vertical transistor to a semiconductor, an effect of achieving high density and high integration has been confirmed 2).
The vertical alignment of the CNTs can greatly increase the surface density of CNTs, so that the synthesis of vertically aligned CNTs can be expected to have improved properties and be utilized in various fields.
Meanwhile, as a method of precisely controlling the CNT size up to now, there is known a method of synthesizing CNT using an aluminum anodic oxide (AAO) nanotemplate. Using AAO nanotemplate deposited with a carbon reaction catalyst, When CNT is synthesized, a carbon reaction catalyst such as a transition metal such as cobalt, nickel and iron is present as an ion. Since the ion itself can not act as a catalyst, it can be used as a catalyst nanoparticle in the form of thermal deposition, sputtering, A method of depositing by a vapor deposition method is known.
In particular, CNTs can be synthesized by using a tip growth mechanism by depositing a carbon reaction catalyst on the bottom of the pores of the AAO nanotemplate. The carbon reaction catalyst is contacted with the AAO nanotemplate It is difficult to control the exact thickness, that is, the thickness of the nanometer. Since the deposition of the carbon reaction catalyst is performed in all parts, it is impossible to perform the selective deposition, that is, the position selective deposition, and the aspect ratio (length: width) of the catalyst is generally about 10: 1 or more, there is a restriction that the incident angle of the carbon reaction catalyst deposited on the AAO is maintained to be exactly perpendicular in order to deposit the catalyst on the bottom of the pore.
In addition, when electrochemical plating is used, it is difficult to control the thickness of the nanometer, and there is an additional restriction that the catalytic material must be electrochemically plated.
An aspect of the present invention is to provide a carbon reaction catalyst deposition method for solving the problem caused when a carbon reaction catalyst is deposited by metal deposition (thermal deposition, electron beam deposition) for the vertical growth of carbon nanotubes in a porous aluminum oxide film.
The present invention also provides a method for producing carbon nanotubes grown on a substrate.
The present invention also provides carbon nanotubes grown vertically by the above method.
The present invention also provides a Schottky diode.
A first aspect of the present invention is a method for manufacturing a carbon-based catalyst, comprising the steps of: (1) adjusting a substrate having a vertical gap to a first angle with respect to a flow direction of a carbon reaction catalyst (step 1);
(2) firstly depositing a carbon reaction catalyst to a first thickness on the upper sidewall of the vertical space of the substrate of the
(3) adjusting the substrate on which the first deposition is completed in the step 2 to a second angle (step 3); And
(4) The carbon reaction catalyst is sputtered on the upper sidewall of the vertical gap and the upper surface of the substrate in the angle-adjusted substrate of step 3, and the carbon reaction catalyst is sputtered on the bottom surface and the lower sidewall of the vertical gap of the substrate, (Step 4) of depositing carbon nanotubes on the surface of the carbon nanotubes.
A second aspect of the present invention is a method for manufacturing a carbon-based catalyst, comprising the steps of: (1) adjusting a substrate having vertical voids to a first angle with respect to the direction of introduction of a carbon reaction catalyst (step 1);
(2) firstly depositing a carbon reaction catalyst to a first thickness on the upper sidewall of the vertical space of the substrate of the
(3) adjusting the substrate on which the first deposition is completed in the step 2 to a second angle (step 3);
(4) The carbon reaction catalyst is sputtered on the upper sidewall of the vertical gap and the upper surface of the substrate in the angle-adjusted substrate of step 3, and the carbon reaction catalyst is sputtered on the bottom surface and the lower sidewall of the vertical gap of the substrate, Depositing (step 4); And
(5) a step of vertically growing carbon nanotubes by supplying C 2 H 4 , Ar and H 2 to the deposited carbon reaction catalyst layer (step 6) ≪ / RTI >
On the other hand, the first angle of the
Also, in the step 2, the first deposition of the carbon reaction catalyst may be performed by an electron beam deposition method or a thermal deposition method.
Also, the second angle of step 3 of the present invention may be equal to or less than a first angle so that the first deposited catalyst material of the sidewall may be sputtered in its entirety, and the sputtering of the carbon reaction catalyst in step 4 may be performed by ion milling ≪ / RTI > method.
The aluminum oxide film having the vertical voids of the present invention is preferably continuously rotated, and the carbon reaction catalyst may be one kind selected from iron, cobalt, nickel, and palladium (Pd) May be one selected from a porous aluminum oxide film or a template in which a vertical cavity is formed through a semiconductor process.
The third aspect of the present invention provides a vertically grown carbon nanotube by the above method, and the vertically grown carbon nanotube may be a single wall carbon nanotube having a semiconductor property.
A fourth aspect of the present invention provides a semiconductor device comprising: a substrate; An oxide film having vertical voids disposed on the substrate; A carbon reaction catalyst deposited at the lower end of the oxide film vertical gap; Two electrodes disposed on the oxide film; And a channel formed of vertically grown carbon nanotubes on the carbon reaction catalyst connecting the two electrodes.
A Ti film may be arranged in the first region on the oxide film and Pd may be arranged in the second region on the oxide film and the Ti film must be separated from the Pd because it is connected to the upper and lower electrodes.
Preferably, the two electrodes are a source electrode and a drain electrode, the source electrode is Ti / Au, and the drain electrode is Pd / Mo or Pd / W. At this time, although the electrodes are made of two metal materials, the CNTs directly contacted with each other may be Ti and Pd.
Meanwhile, the vertically grown carbon nanotube is a single walled carbon nanotube having a semiconductor property.
According to the present invention, when the first deposition process and the second deposition process of the carbon reaction catalyst are performed on the angle-controlled substrate, the carbon reaction catalyst can be deposited together on the bottom surface or the bottom side wall. Thus, unlike conventional carbon reaction catalyst deposition methods, position selective deposition of a carbon reaction catalyst is possible. Also, since the deposition thickness of the carbon reaction catalyst can be maintained in conjunction with the initial deposition, that is, the thickness of the carbon reaction catalyst formed in the first deposition process, the thickness of the carbon reaction catalyst can be easily controlled, The carbon nanotubes can be grown vertically. And can be usefully used in various electronic systems (for example, electric switches, electronic sensors) that can use vertically grown carbon nanotubes.
1 is a view illustrating a process of depositing a catalyst material of a carbon nanotube on a porous aluminum oxide film according to an embodiment of the present invention.
FIG. 2 illustrates a process for fabricating a Schottky diode using vertically grown semiconducting carbon nanotubes according to an embodiment of the present invention. Referring to FIG.
3 illustrates a Schottky device including a vertical Schottky diode according to one embodiment of the present invention.
4 is a view showing a scanning electron microscope (SEM) measurement result for confirming the yield of carbon nanotubes synthesized in the AAO substrate according to one aspect of the present invention.
5 is a graph showing Schottky device IV characteristics of a semiconducting carbon nanotube having a vertical path according to an aspect of the present invention.
Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.
The present invention discloses a method for depositing a carbon reaction catalyst for vertical growth of carbon nanotubes on a vertical pore bottom or bottom side of a substrate having vertical voids, comprising the steps of:
(1) adjusting a substrate having a vertical gap to a first angle with respect to the direction of introduction of the carbon reaction catalyst (step 1);
(2) firstly depositing a carbon reaction catalyst on the upper sidewalls of the vertical pores and the upper surface of the substrate to a first thickness (step 2) by introducing a carbon reaction catalyst into the substrate of
(3) adjusting the substrate on which the first deposition of the carbon reaction catalyst is completed in the step 2 to a second angle (step 3); And
(4) The carbon reaction catalyst is sputtered on the upper sidewall of the vertical gap and the upper surface of the substrate in the angle-adjusted substrate of step 3, and the carbon reaction catalyst is sputtered on the bottom surface and the lower sidewall of the vertical gap of the substrate, (Step 4).
The carbon reaction catalyst is uniformly deposited on the sidewalls of the vertical pores of the substrate and the upper surface of the substrate through the first deposition process by introducing the carbon reaction catalyst onto the substrate having the angle adjusted as described above, The carbon reaction catalyst on the upper sidewall and the upper surface of the substrate may be removed through a secondary deposition process and the carbon reaction catalyst may be re-deposited only on the bottom surface.
Therefore, it is possible to perform position selective deposition of the carbon reaction catalyst differently from the conventional carbon reaction catalyst deposition methods, and the thickness of the carbon reaction catalyst formed in the initial deposition, i.e., the first deposition process, It is possible to control the thickness of the carbon reaction catalyst so that the catalyst metal layer having a thickness of less than nanometer can be realized and the single wall carbon nanotube can be vertically grown. Therefore, And can be usefully used in various electronic systems (for example, electric switches, electronic sensors).
Hereinafter, a carbon reaction catalyst deposition method for vertical growth of carbon nanotubes will be described in detail.
First,
It is important to adjust the inclination of the substrate so that the carbon reaction catalyst is deposited in a state in which the substrate having the vertical air gap is inclined at a first angle not perpendicular to the direction of introduction of the carbon reaction catalyst and maintained at an oblique angle, The carbon reaction catalyst can be selectively deposited at desired positions on the upper sidewall of the vertical cavity and the upper surface of the substrate.
At this time, the first angle may be 10 ° to 80 ° with respect to the flow direction of the carbon reaction catalyst.
According to an embodiment of the present invention, when the substrate is inclined to less than 10 degrees with respect to the flow direction of the carbon reaction catalyst, the carbon reaction catalyst is deeply deposited to the inside of the vertical gap, And when the substrate is inclined by more than 80 ° with respect to the direction of the carbon reaction catalyst, the carbon reaction catalyst is not deposited on the vertical voids, and the yield of vertically grown carbon nanotubes is lowered have.
Meanwhile, the thickness of the carbon reaction catalyst deposited in the step 2 is preferably 1 to 15 Å in order to synthesize a single walled carbon nanotube.
According to an embodiment of the present invention, the deposition thickness of the carbon reaction catalyst may be determined by setting the tilt angle of the substrate having vertical voids and the nominal thickness of the carbon reaction catalyst to predict the thickness of the carbon reaction catalyst deposited from
[Equation 1]
Thickness of the deposited carbon reaction catalyst (Å) = sin α × nominal thickness (Å)
In Equation (1),? Represents a tilted angle of the substrate having vertical voids, and represents the tilted angle of the substrate with respect to the direction in which the carbon reaction catalyst is introduced, as shown in FIG.
As noted above, the thickness of the carbon reaction catalyst deposited on the vertical cavity sidewalls and surfaces by performing
The carbon nanotubes thus prepared may have a thickness of 1 Å to 15 Å.
In the steps 3 and 4, ion milling is performed on the substrate having the vertical gap completed by performing the
In the meantime, it is important to tilt the substrate having been subjected to the first vapor deposition at the second angle in the
When ion milling is performed by tilting the substrate at a second angle smaller than the first angle, the carbon reaction catalyst that has been first deposited is etched and simultaneously redeposited on the bottom surface of the vertical gap.
In this case, since the speed of the aluminum oxide layer is generally slower than the sputtering speed of the catalyst metal in the step 4, the metal oxide is selectively sputtered to the oxide layer.
According to an embodiment of the present invention, in order to uniformly deposit a carbon reaction catalyst, the aluminum oxide film having vertical pores of the present invention preferably continuously rotates the substrate on which the aluminum oxide film is mounted using a rotation motor .
The carbon reaction catalyst may be in the form of a metal capable of producing carbon nanotubes, and may be at least one selected from iron, cobalt, nickel and palladium.
In addition, the substrate having the vertical voids may be a porous aluminum oxide film, but is not limited thereto.
The present invention also discloses a method for producing carbon nanotubes grown vertically on a substrate comprising the steps of:
(1) adjusting a substrate having a vertical gap to a first angle with respect to the direction of introduction of the carbon reaction catalyst (step 1);
(2) firstly depositing a carbon reaction catalyst to a first thickness on the upper sidewall of the vertical space of the substrate of the
(3) adjusting the substrate on which the first deposition is completed in the step 2 to a second angle (step 3);
(4) The carbon reaction catalyst is sputtered on the upper sidewall of the vertical gap and the upper surface of the substrate in the angle-adjusted substrate of step 3, and the carbon reaction catalyst is sputtered on the bottom surface and the lower sidewall of the vertical gap of the substrate, Depositing (step 4); And
(5) a step of vertically growing carbon nanotubes by supplying C 2 H 4 , Ar and H 2 to the deposited carbon reaction catalyst layer (step 5).
The
The present invention also provides carbon nanotubes grown vertically by the method according to the present invention.
The vertically grown carbon nanotube is preferably a single-walled carbon nanotube having a semiconductor property in order to serve as a diode and an electrical switch.
In addition, the present invention provides a semiconductor device comprising a substrate; An oxide film having vertical voids disposed on the substrate; A carbon reaction catalyst deposited at the lower end of the oxide film vertical gap; Two electrodes disposed on the oxide film; And a channel formed of vertically grown carbon nanotubes on the carbon reaction catalyst connecting the two electrodes.
The Ti film may be disposed in the first region on the oxide film, the Pd film may be disposed in the second region on the oxide film, and the Ti film is preferably spaced apart from the Pd film.
The two electrodes are preferably a source electrode and a drain electrode, respectively, and the drain electrode is preferably Mo or W.
Preferably, the source electrode is fabricated by further depositing Au on a previously deposited Ti film and the drain electrode is fabricated by electroplating Pd on the bottom Mo or W, the source electrode may be Ti / Au, The electrode may be Pd / Mo or Pd / W.
Meanwhile, the vertically grown carbon nanotube is a single walled carbon nanotube having a semiconductor property.
Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It is natural that it belongs to the claims.
Production Example 1
Porous aluminum oxide (AAO) was fabricated by anodizing a thin Al layer. First, the drain electrode was formed by depositing 20 nm of Mo on the silicon substrate using e-beam and then depositing Ti to 50 nm. 2 탆 of aluminum was deposited on the substrate and anodic oxidation treatment was performed by applying a potential difference to form vertical pores.
At this time, 0.3 M of Moxalic acid solution maintained at 15 캜 was used for the anodic oxidation. Anodizing is anodized at 1/3 of the aluminum layer to improve the uniformity of the arrangement of the pores, the anodized portion is removed using chromic acid, anodic treatment of the remaining half of the aluminum layer, And then the remaining aluminum layer was completely anodized by using chromic acid.
Through these three anodic oxidation processes, the pores were increased in uniformity of spacing and size.
On the other hand, in the last stage of the third anodic oxidation process, in order to introduce a larger surface area at the bottom of the vertical pores, the input voltage is reduced to 2V every 20 seconds to form several small pores, The pores of the anodized layer were expanded using phosphoric acid.
At the time of enlarging the pores, the oxide remaining on the bottom of the vertical pores was etched to expose the lower part of the Mo layer. At this time, the diameter of the pores was confirmed to be about 100 nm, the thickness of the AAO layer obtained above was about 1 μm, and the pore aspect ratio was 1:10.
The anodized AAO layer tends to shrink and stabilize when the temperature is substantially raised. Therefore, when the temperature rises, thermal stress occurs between the catalyst metal layer that is about to expand and the AAO layer to be shrunk. If the thermal stress is large, there is a problem that the AAO layer may be cracked due to cracking. Therefore, in order to minimize the thermal stress of the AAO layer, which may occur during the synthesis of the high-temperature CNT, The AAO layer was previously annealed at 820 캜.
As a result, after the synthesis of s-SWCNT, it was confirmed that the previously annealed AAO layer was preserved, whereas when the CNT synthesis was performed in the non-annealed state, the AAO layer was seriously cracked.
Example 1
As shown in FIG. 1A, electron-beam (e-beam) deposition of a carbon reaction catalyst was performed on a substrate inclined at 30 degrees with respect to the carbon reaction catalyst inlet direction. At this time, iron (Fe) was used as a carbon reaction catalyst and spun using an electric motor to uniformly deposit a carbon reaction catalyst on the substrate (see FIG. 1A).
Based on the tilted angle and the expected thickness, the electron beam (e-beam) system was set to 10 Å and the carbon reaction catalyst thickness was found to be about 5 Å (= sin 30 ° × 10 Å) on the top sidewall.
Then, as shown in FIG. 1B, after the substrate on which the carbon reaction catalyst was deposited was set to 5 ° (smaller angle than that in the initial deposition), ion milling was performed to sputter the catalyst from the top sidewall , The catalyst on the upper surface of the template was etched by ion milling and redeposited with the catalyst sputtered on the bottom surface of the void. At this time, the final thickness of the iron on the lower side of the vertical pore after re-deposition is expected to be similar to the thickness of the iron deposited by the electron beam by the first deposition angle (about 10 Å).
The ion milling process for re-deposition uses argon ions at a pressure of 10 -5 Torr, which is set low enough to prevent backscattering at the bottom of the vertical cavity, where the substrate is uniformly uniform during ion milling .
Example 2
CNTs were grown using Chemical Vapor Deposition. After catalyst deposition in Example 1 above, CNT synthesis was performed. The AAO template was placed in a reaction chamber, and chemical gas was supplied. First, the template was heated to 500 DEG C with oxygen supplied for 5 minutes and then heated to 820 DEG C by further heating with argon carrier gas. The pressure was set at 820 DEG C at 10 < 5 > Pa, and carbon nanotubes were synthesized by supplying CH 2 H 4 20 ccm, CH 4 1000 ccm and H 2 500 ccm into the chamber for 3 minutes.
Example 3
After synthesis, the bottom of the s-CNT was coated with Pd to form Ohmic contact, and the top was coated with Ti for Schottky contact. First, Pd was plated directly on the bottom end of the s-CNT. The electroplating is Pd (NH 3) 4 in a solution consisting of Cl 2 -NH 4 Cl, was performed at a current density of 50 mA / cm 2 for 10 minutes. It was confirmed that Pd filling the bottom of the pores by electroplating was sufficient to connect with the bottom edge of the grown s-CNT and the bottom surface electrode (Mo) of the pore (see FIG.
Thereafter, Pd on the top of the s-CNT is removed by ion milling so that Ti can be directly deposited on the top of the s-CNT (see FIG. 2B) Thereby forming a Schottky contact (see FIG. 2C).
The Schottky diode thus manufactured can be designed as a device, as shown in Fig.
Experimental Example 1
The yield of the carbon nanotubes prepared in Example 2 was examined using a scanning electron microscope (SEM).
As a result, it was confirmed that carbon nanotubes were grown on the upper surface of the AAO substrate as shown in FIG.
Experimental Example 2
I-V characteristics were evaluated to confirm that the semiconductor single-walled carbon nanotube device having the vertical path prepared in Example 3 performs the function of a Schottky diode.
As a result, as shown in FIG. 5, it was confirmed that the Schottky diode including the carbon nanotubes manufactured according to the present invention performs a function as a Schottky diode.
Claims (17)
(2) firstly depositing a carbon reaction catalyst on the upper sidewall of the vertical gap of the substrate of step 1 and the upper surface of the substrate (step 2);
(3) adjusting the substrate on which the first deposition is completed in the step 2 to a second angle (step 3); And
(4) The carbon reaction catalyst is sputtered on the upper sidewall of the vertical gap and the upper surface of the substrate in the angle-adjusted substrate of step 3, and the carbon reaction catalyst is sputtered on the bottom surface and the lower sidewall of the vertical gap of the substrate, (Step 4). ≪ Desc / Clms Page number 20 >
Wherein the first angle of the step 1 is in the range of 10 ° to 80 °.
Wherein the first deposition of the carbon reaction catalyst is performed by an electron beam deposition method or a thermal deposition method in the step 2.
Wherein the second angle of step 3 is equal to or less than the first angle (Carbon - Reaction Catalyst Deposition Method for Vertical Growth of Carbon Nanotubes).
Wherein the sputtering of the carbon reaction catalyst in the step 4 is performed by an ion milling method.
Wherein the substrate having the vertical gap is continuously rotated. ≪ RTI ID = 0.0 > 11. < / RTI >
Wherein the carbon reaction catalyst is at least one selected from iron, cobalt, nickel, and palladium.
Wherein the substrate having the vertical voids is a porous aluminum oxide film.
(2) firstly depositing a carbon reaction catalyst to a first thickness on the upper sidewall of the vertical space of the substrate of the step 1 and the upper surface of the substrate (step 2);
(3) adjusting the substrate on which the first deposition is completed in the step 2 to a second angle (step 3);
(4) The carbon reaction catalyst is sputtered on the upper sidewall of the vertical gap and the upper surface of the substrate in the angle-adjusted substrate of step 3, and the carbon reaction catalyst is sputtered on the bottom surface and the lower sidewall of the vertical gap of the substrate, Depositing (step 4);
(5) a step of vertically growing carbon nanotubes by supplying C 2 H 4 , Ar, and H 2 to the deposited carbon reaction catalyst layer (step 5), thereby producing a vertically grown carbon nanotube on the substrate Way.
A first electrode disposed on the substrate;
An oxide film having a vertical gap disposed on the first electrode;
A carbon reaction catalyst deposited at the lower end of the vertical gap of the oxide film;
A channel formed of vertically grown carbon nanotubes on the carbon reaction catalyst; And
A second electrode disposed on the top of the oxide film;
The Schottky diode comprising:
And the channel connects the first electrode and the second electrode.
A Ti film is deposited on the first region on the oxide film and Pd is electroplated on the second region on the oxide film.
And the Ti film is spaced apart from the Pd.
Wherein the first electrode and the second electrode are a drain electrode and a source electrode, respectively.
The source electrode is Ti / Au,
Wherein the drain electrode is Pd / Mo or Pd / W.
Wherein the vertically grown carbon nanotube is a single-walled carbon nanotube having a semiconductor property.
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