JP2011166070A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem with a semiconductor device which use properties of a semiconductor of nano-materials, wherein the semiconductor characteristics are degraded due to a metallic nano-material. <P>SOLUTION: In a method of manufacturing the semiconductor device, conductivity of a semiconductor nano-material among the semiconductor nano-material and metallic nano-material included in a plurality of nano-materials is lowered first. Then a cutting promoting material which promotes an action to cut the metallic nano-material is stuck on the metallic nano-material. Further, the metallic nano-material on which the cutting promoting material is cut. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device containing a nanomaterial.

  A carbon nanotube, which is a kind of nanomaterial and is a cylindrical material of carbon having a diameter of about nanometer, has excellent electrical characteristics and is expected to be applied to various electronic devices. Carbon nanotubes are known to have semiconducting properties due to chirality, and high mobility is expected. Therefore, application to a channel of a field effect transistor has been actively studied. There are two main types of channel structures containing carbon nanotubes. The first is a structure in which one carbon nanotube connects a source electrode and a drain electrode. The second is a structure in which a plurality of carbon nanotubes are continuously in contact with each other, and this network connects the source electrode and the drain electrode. In recent years, the latter structure has attracted attention. The reason is that the manufacturing method is easy because it can be manufactured using a printing technique, and the environmental load is low.

  When carbon nanotubes are synthesized, a semiconducting carbon nanotube that is a kind of semiconducting nanomaterial having semiconducting properties and a metallic carbon nanotube that is a kind of metallic nanomaterial having metallic properties are mixed. can get. Of these, semiconductor carbon nanotubes are used for transistor channels, and it is not desirable to use metallic carbon nanotubes for transistor channels. This is because when the metallic carbon nanotube is included in the channel, the on / off ratio of the current between the source and the drain is lowered, and variation in electrical characteristics between the transistors is increased.

  Therefore, in recent years, techniques for removing the influence of metallic carbon nanotubes have been studied. As an example, Patent Document 1 discloses a method of separating metallic carbon nanotubes and semiconducting nanotubes at a material level using centrifugation. However, the method disclosed in Patent Document 1 has a problem of low resolution and yield.

  As a method for solving this problem, Patent Document 2 discloses a method for removing the influence of metallic carbon nanotubes at the device level. In the method disclosed in Patent Document 2, first, a gate voltage is applied to a film of carbon nanotubes forming a channel to selectively deplete carriers of semiconductor carbon nanotubes. Then, a current is passed between the source electrode and the drain electrode to destroy the metallic carbon nanotubes that form the network between the source electrode and the drain electrode. If this method is applied to a field effect transistor including a carbon nanotube film as a channel, metallic carbon nanotubes contained in the film can be selectively destroyed. As a result, the short circuit of the channel caused by the metallic carbon nanotube can be reduced, and the on / off ratio of the current can be increased.

JP 2008-266112 A JP-T-2004-517489

  However, the method disclosed in Patent Document 2 has a problem that it can be applied only to a part of the metallic nanomaterials included in the film. In the method disclosed in Patent Document 2, an electric current is passed through a metallic nanomaterial that forms a network between a source electrode and a drain electrode in a state where carriers of the semiconductor nanomaterial are depleted, and the metallic nanomaterial is Disconnect. For this reason, it is not possible to cut a metallic nanomaterial that cannot pass a current in a state where carriers of the semiconductor nanomaterial are depleted. As a result, many metallic nanomaterials that are not cut remain in the channel of the semiconductor device, and these metallic nanomaterials cause deterioration of the semiconductor characteristics of the semiconductor device.

  An object of the present invention is to provide a method for manufacturing a semiconductor device that solves the problem that the semiconductor characteristics of the semiconductor device deteriorate due to the metallic nanomaterial in the semiconductor device using the semiconductor properties of the nanomaterial described above. is there.

  The semiconductor device manufacturing method of the present invention includes a first step of reducing the conductivity of a semiconductor nanomaterial among a semiconductor nanomaterial and a metal nanomaterial contained in a plurality of nanomaterials, and after the first step. A second step of attaching a cutting promoting substance for promoting the action of cutting the metallic nanomaterial to the metallic nanomaterial, and a third step of cutting the metallic nanomaterial to which the cutting promoting substance is attached. Have.

  ADVANTAGE OF THE INVENTION According to this invention, in the semiconductor device using the property of the semiconductor of a nanomaterial, the manufacturing method of the semiconductor device which can reduce deterioration of the semiconductor characteristic by a metallic nanomaterial can be provided.

1 is a schematic view showing a method for manufacturing a semiconductor device according to a first embodiment of the present invention. 1 is a schematic view showing a method for manufacturing a semiconductor device according to a first embodiment of the present invention. 1 is a schematic view showing a method for manufacturing a semiconductor device according to a first embodiment of the present invention. Schematic flowchart illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present invention. Schematic which shows the manufacturing method of the semiconductor device which concerns on the 2nd Embodiment of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
In the semiconductor device manufacturing method according to the first embodiment, the semiconductor device is a field effect transistor. In addition, carbon nanotubes are used as nanomaterials. In addition, as a cutting promoting substance, a catalyst for a reaction that oxidizes carbon nanotubes or a reactive substance that reacts with carbon nanotubes is used.

  A method of manufacturing a semiconductor device according to the first embodiment will be described with reference to FIGS. 1A to 1C are schematic views illustrating states of a semiconductor device in a predetermined process of the manufacturing method. FIG. 1A is a schematic view of a semiconductor device showing a state before a cutting promoting substance adheres to metallic carbon nanotubes. FIG. 1B is a schematic view of the semiconductor device showing a state after the cutting promoting substance is attached to the metallic carbon nanotube. FIG. 1C is a schematic view of a semiconductor device showing a state where metallic carbon nanotubes are cut by a cutting promoting substance. FIG. 2 is a schematic diagram showing a configuration for carrying out a method for reducing the conductivity of semiconducting carbon nanotubes and attaching a cutting promoting substance to metallic carbon nanotubes. FIG. 3 is a schematic view of the semiconductor device showing a state in which the cutting promoting substance is removed after the metallic carbon nanotube is cut.

  First, the semiconductor device illustrated in FIG. 1A is prepared. The semiconductor device illustrated in FIG. 1A includes contact electrodes 141 and 142 disposed on a substrate 150 and a carbon nanotube film disposed between the contact electrodes 141 and 142. In the present embodiment, this carbon nanotube film is referred to as a channel 110. The channel 110 includes metallic carbon nanotubes 121, 122, 123 and semiconducting carbon nanotubes 131, 132, 133, 134.

  Examples of materials that can be used for the substrate include inorganic materials such as glass and silicon, and plastic materials such as acrylic resins. In the case where the cutting promoting substance is migrated and attached to the metallic carbon nanotube in a later step, it is desirable to use a substrate in which a conductive film and an insulating film are formed on a substrate.

  As a method of forming the channel of the carbon nanotube, a direct growth method such as a chemical vapor deposition method can be used in addition to a solution process such as a spin coating method, a dip method, a dispenser method, and an ink jet method. It is not limited.

  A method for forming the contact electrode is not particularly limited, and an electrode formation process such as a vacuum deposition method, a sputtering method, an etching method, or a lift-off method can be used. In addition, when using an organic material such as a conductive polymer, or a dispersion containing silver paste or metal fine particles as an electrode, solution processes such as a spin coating method, a dip method, a dispenser method, and an ink jet method can also be used. It is not limited. Further, the position of the contact electrode may be above or below the channel.

  Examples of carbon nanotubes include single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes, but it is preferable to use single-walled carbon nanotubes.

  The carbon nanotube may have any thickness. For example, a thickness of about 0.4 nanometers to a thickness of about 10 nanometers can be used. The size of the band gap of the semiconducting carbon nanotube is inversely proportional to the thickness. Therefore, in order to more reliably obtain semiconducting carbon nanotubes, it is preferable to use carbon nanotubes having a thickness of 2 nanometers or less.

  Since the semiconductor characteristics of carbon nanotubes are considered not to change with the length of the carbon nanotubes, the carbon nanotubes can be of any length. For example, a length of about 10 nanometers to about 1 millimeter mail can be used. The carbon nanotubes are preferably of the same length as or less than the desired channel length depending on the size of the semiconductor device.

  Materials that can be used for contact electrodes include metals such as gold, silver, platinum, copper, palladium, titanium, indium, aluminum, and magnesium, and alloys thereof, as well as indium tin oxide alloys (ITO), zinc oxide, and tin oxide. In addition to metal oxides such as, organic materials such as conductive polymers can be mentioned, but are not limited thereto.

  Next, the conductivity of the semiconducting carbon nanotubes is lowered as the first step, and the cutting promoting substance 160 is attached to the metallic carbon nanotubes 121, 122, 123 as the second step. A method for doing this will be described below with reference to FIG.

  FIG. 2 shows a state in which a part of the semiconductor device is immersed in the dispersion 280 of the cutting promoting substance 260. The semiconductor device includes a substrate 250, a channel formed on the substrate 250, and contact electrodes 241 and 242. The channel is composed of carbon nanotubes including semiconducting carbon nanotubes and metallic carbon nanotubes 221. The substrate 250 includes an insulating film 251 and a substrate electrode 252. The dispersion 280 includes a cutting promoting substance 260. At least the electrode for electrophoresis 270 and the metallic carbon nanotube 221 are immersed in the dispersion 280. A substrate electrode voltage source 291 is connected to the substrate electrode 252. An electrophoresis voltage source 292 is connected to the electrophoresis electrode 270.

  In the first step, a voltage is applied between the contact electrode 241 and the substrate electrode 252 using the substrate electrode voltage source 291. Then, the semiconductor carbon nanotube carrier contained in the channel moves. As a result, the amount of carriers contained in the semiconducting carbon nanotube is reduced, and the conductivity of the semiconducting carbon nanotube is reduced.

  Note that the conductivity of the semiconducting carbon nanotube may be lowered by a method other than the method described above. For example, semiconductive carbon nanotubes may be cooled to reduce their conductivity. It is known that the electrical conductivity of metallic carbon nanotubes is relatively small with temperature, whereas the electrical conductivity of semiconducting carbon nanotubes is greatly varied with temperature, and the electrical conductivity decreases at low temperatures. Therefore, when the carbon nanotubes in which metallic and semiconducting materials are mixed are cooled, the conductivity of only the semiconducting carbon nanotubes can be reduced. As the temperature, any temperature below room temperature can be used, and −269 ° C. to 10 ° C. is particularly preferable. Furthermore, -196 degreeC-0 degreeC is preferable.

  In addition, the conductivity of the semiconducting carbon nanotubes may be reduced by adjusting the environment in which the semiconducting carbon nanotubes are present. The semiconducting carbon nanotube has a property that a p-type semiconductor or an n-type semiconductor and conductivity are lost depending on the environment in which it exists. For example, when many oxygen molecules are adsorbed on the semiconducting carbon nanotube, the semiconducting carbon nanotube becomes a p-type semiconductor. Further, when many potassium molecules are adsorbed on the semiconducting carbon nanotube, the semiconducting carbon nanotube becomes an n-type semiconductor. Therefore, using this property, the conductivity of semiconductor carbon nanotubes can be adjusted by adjusting the environment in which semiconducting carbon nanotubes exist, specifically, the type and concentration of solutions used in electrophoresis and electroplating described later. Can be reduced.

  In addition, the method of reducing the electroconductivity of the semiconductor carbon nanotube mentioned above can be used together. Therefore, a method of applying a voltage, a method of cooling the carbon nanotubes, and a method of adjusting the environment where the semiconducting carbon nanotubes may be used in combination.

  In the second step, a voltage is applied between the contact electrode 241 and the electrophoresis electrode 270 using the electrophoresis voltage source 292 to perform the electrophoresis of the cleavage promoting substance 260. At this time, since the conductivity of the semiconducting carbon nanotube is almost lost, the semiconducting carbon nanotube connected to the contact electrode 241 does not function as an electrode for electrophoresis. On the other hand, the metallic carbon nanotube 221 connected to the contact electrode 241 functions as an electrode for electrophoresis because it has conductivity. As a result, when electrophoresis is performed, the cleavage promoting substance 260 is selectively attached to the metallic carbon nanotube 221.

  Next, as shown in FIG. 1C, as a third step, the metallic carbon nanotubes 121, 122, 123 are cut with a cutting promoting substance 160. When the cleavage promoting substance 160 is a catalyst for the oxidation reaction, the oxidation temperature of the metallic carbon nanotube to which the catalyst is attached is lowered, so that only the metallic carbon nanotube can be oxidized and cut. When the cutting promoting substance 160 is a reactive substance that reacts with carbon nanotubes, only the metallic carbon nanotubes can be cut by reacting the cutting promoting substance with the metallic carbon nanotubes.

  As described above, the method for manufacturing a semiconductor device according to the first embodiment can selectively destroy metallic carbon nanotubes among semiconducting and metallic carbon nanotubes contained in the carbon nanotubes. Therefore, it is possible to obtain a semiconductor device that fully utilizes the semiconductor characteristics of semiconducting carbon nanotubes. Specifically, the on / off ratio of the current can be improved, and variations in drain current can be suppressed.

  The above effect will be described in detail with reference to FIG. A channel 110 of the semiconductor device shown in FIG. 1A includes metallic carbon nanotubes 121, 122, and 123, and the metallic carbon nanotubes 121 and 122 are short-circuited between the contact electrode 141 and the contact electrode 142. Yes. Therefore, the semiconductor device illustrated in FIG. 1A cannot be completely turned off. For example, the switching operation of the transistor is inhibited by the metallic carbon nanotubes 121 and 122. On the other hand, in the state of FIG. 1C in which the metallic carbon nanotubes 121 and 122 are cut, a short circuit due to these can be prevented. As a result, excellent semiconductor characteristics can be obtained in the semiconductor device illustrated in FIG.

  Moreover, the semiconductor device manufacturing method according to the present embodiment can prevent the length of the current path formed by the semiconducting carbon nanotube from being shortened. In the case where metallic carbon nanotubes and semiconducting carbon nanotubes are mixed, as shown in FIG. 1A, the length of the current path formed by the semiconducting carbon nanotubes 131 and 132 is shortened by the metallic carbon nanotube 123. Become. However, with the method for manufacturing a semiconductor device according to the present embodiment, it is possible to prevent the current path length from being shortened by cutting the metallic carbon nanotube 123 as shown in FIG.

  By preventing the length of the current path formed by the semiconducting carbon nanotube from being shortened, the following effects can be obtained. First, semiconductor characteristics can be improved. As a result, for example, the off-state current in the case of manufacturing a field effect transistor can be reduced, so that the on / off ratio can be increased. Furthermore, performance variations among semiconductor devices can be reduced. When a channel of a semiconductor device is formed using a material in which semiconducting carbon nanotubes and metallic carbon nanotubes are mixed, it is possible to produce one with a large number and a few short paths of metallic carbon nanotubes contained in the channel. As a result, a semiconductor device with a high off current and a semiconductor device with a low off current are manufactured. On the other hand, the manufacturing method of the semiconductor device according to the present embodiment can remove the short-circuit path caused by the metallic carbon nanotube, so that the performance variation between the semiconductor devices can be reduced.

  By using the manufacturing method of the semiconductor device shown in this embodiment, more metallic carbon nanotubes can be cut than the method described in Patent Document 2. The reason will be described below. In the method described in Patent Document 2, an electric current is applied to the metallic carbon nanotube to destroy the metallic carbon nanotube. However, current can be passed only to the metallic carbon nanotubes that are electrically connected to the plurality of electrodes in a state where the conductivity of the semiconducting carbon nanotubes is lost. Therefore, for example, the metallic carbon nanotube 123 shown in FIG. 1A cannot be cut using the method described in Patent Document 2. On the other hand, in the manufacturing method of the semiconductor device of this embodiment, a reactive substance or a catalyst can be attached to the metallic carbon nanotube 123 connected to only one electrode as shown in FIG. As shown in (C), this metallic carbon nanotube 123 can be destroyed. As a result, the manufacturing method of the semiconductor device of the present embodiment can cut more metallic carbon nanotubes than the method described in Patent Document 2, and can eliminate much influence of metallic carbon nanotubes.

  In the method for manufacturing a semiconductor device of this embodiment, the metallic carbon nanotubes are cut using a chemical reaction by a cutting promoting substance, so that this cutting operation can be performed on a plurality of semiconductor devices at once.

Furthermore, the semiconductor device manufacturing method of the present embodiment eliminates the need for a large current when cutting the metallic carbon nanotubes, thereby increasing the degree of freedom in circuit design and process of the semiconductor device. In the method described in Patent Document 2, since a current is passed through the metallic carbon nanotubes to burn out the metallic carbon nanotubes, a current density exceeding the current density tolerance of the carbon nanotubes is required. It is known that the current density tolerance of carbon nanotubes is generally 10 ⁹ A / cm ² or more. Therefore, for example, in order to cut a carbon nanotube having a diameter of 1 nm using a current, a current of 10 uA or more is required. This is because the current density resistance of copper, which is a general material of circuit wiring of a semiconductor device, is about 10 ⁶ A / cm ² , and the current required to cut copper having a diameter of 1 nm is about 10 nA. Considering this, it can be said that the current is large. On the other hand, in the present invention, for example, the number of gold fine particles to be attached to one CNT using an electroplating method is one, the particle size of the gold fine particles is 100 nm, and the number of gold atoms to be attached is 10 ⁷ to 10 ^8. In this case, the electric charge to be supplied is about 10 ⁻¹² to 10 ⁻¹¹ coulombs, and the current supplied for 1 second is 0.001 to 0.01 nA. The magnitude of this current varies depending on the amount of substance to be deposited and the time during which the current is applied, but can be made smaller than the current required to burn off the carbon nanotubes. Therefore, the semiconductor device manufacturing method according to the present embodiment eliminates the need for consideration of resistance to a large current, and thus increases the degree of freedom in circuit design and process of the semiconductor device.

  The semiconductor device manufacturing method of this embodiment can use a nanomaterial having a property that can be semiconductive or metallic. Nanomaterials include, for example, nanotubes such as carbon nanotubes that have the property of becoming semiconducting or metallic due to chirality, as described above. In addition, the nanomaterial includes graphene and the like in which semiconductivity and metallicity may be mixed depending on the width and the number of layers. Nanotubes include both single-walled nanotubes (SWNT) and multi-walled nanotubes (MWNT). Nanomaterials include boron nitride nanotubes (BN nanotubes) and metal dichalcogenide nanostructures.

  It is particularly preferable to use single-walled carbon nanotubes as the nanomaterial.

  The manufacturing method of the semiconductor device according to the present embodiment can be applied to a manufacturing method of a transistor, a diode, a resistor, or the like that uses the characteristics of a semiconducting nanomaterial.

  In addition, although many metallic carbon nanotubes are drawn in the semiconductor device of FIG. 1, it is preferable that there are many semiconducting carbon nanotubes as a semiconductor device.

  As a method for attaching a catalyst or a reactive substance to the metallic carbon nanotube, electrolytic plating can be used instead of electrophoresis. And electroplating is performed using the structure shown in FIG. For example, when electrolytic plating is performed using metal fine particles as a catalyst, a solution containing metal ions may be used instead of the dispersion 280.

  The temperature when oxidizing and cutting metallic carbon nanotubes is higher than the oxidation temperature when the catalyst adheres to the carbon nanotubes and lower than the oxidation temperature when the catalyst does not adhere to the carbon nanotubes. It is desirable to choose. Thereby, the selectivity of the carbon nanotube to cut | disconnect can be improved.

  The temperature is preferably 200 ° C. to 600 ° C., and particularly preferably 300 ° C. to 500 ° C. By heating at 200 ° C. or higher, the metallic carbon nanotube can be sufficiently oxidized. Moreover, it can prevent that a semiconductor carbon nanotube is oxidized by heating at 600 degrees C or less.

  It is desirable that an oxidizing agent be present in the environment in which metallic carbon nanotubes are oxidized. For example, the metallic carbon nanotube can be easily oxidized by heating the metallic carbon nanotube in an atmosphere containing oxygen.

  The catalyst is not particularly limited as long as it promotes oxidation. For example, a metal colloid can be used as a catalyst. Metal fine particles such as gold, silver, copper, platinum, and palladium can be used, but the type of metal is not limited to these. Electrophoresis can be performed by using metal colloids or charging of fine particles.

  The material that can be used for the reactive substance is not particularly limited as long as it reacts with the carbon nanotube and destroys the structure of the carbon nanotube. For example, a metal that forms an alloy with carbon, such as cobalt, chromium, iron, molybdenum, tantalum, titanium, thorium, uranium, manganese, niobium, vanadium, tungsten, yttrium, and zirconium, can be used as the reactive substance. It is preferable to use cobalt, iron, titanium, or manganese.

  It is desirable that the reaction promoting substance has a non-conductive property. By using a non-conductive reaction promoting substance, the reaction promoting substance that has moved after being cut can be prevented from being electrically connected to the cut metallic carbon nanotubes.

  The size of the cutting promoting substance is preferably about 1 nanometer to 100 nanometers.

  The number of cutting promoting substances to be attached to the metallic carbon nanotubes is preferably 1 or more per metallic carbon nanotube. By controlling the number of cutting promoting substances to be attached in this manner, the metallic carbon nanotubes can be sufficiently broken and cut.

  The concentration of the cleavage promoting substance contained in the solution used when performing electrophoresis or electroplating is preferably selected in accordance with the type of the cleavage promoting substance, the range of the concentration in which the cleavage promoting substance is stably dispersed, It is not limited to this.

  The voltage of electrophoresis or electrolytic plating can be set to, for example, 0 to 1000 V, but is not limited thereto. When water is used as a solvent, it is preferable to use a voltage of 0 to 150 V in order to suppress water electrolysis.

The current of electrophoresis or electrolytic plating is not limited to 0.001 to 10 mA / cm ² , for example.

  The time for electrophoresis or electrolytic plating can be, for example, 0.01 to 1000 minutes, but is not limited thereto.

  The amount of the cutting promoting substance attached to the metallic carbon nanotube is determined by the voltage, current, time of electrophoresis or electroplating, and the concentration of the cutting promoting substance contained in the dispersion or plating solution. Therefore, it is desirable to determine these conditions according to the density of carbon nanotubes contained in the channel.

  Water or an organic solvent can be used as a solvent for the dispersion or plating solution.

  The dispersion liquid or the plating solution may be removed from the semiconductor device after the cutting promoting substance is attached to the metallic carbon nanotube.

  The number of contact electrodes used for electrophoresis is not particularly limited, and may be one, for example. However, it is desirable to use a plurality of contact electrodes. For example, it is desirable to use both contact electrodes 241 and 242 as shown in FIG. Thus, a catalyst can be made to adhere to more metallic carbon nanotubes by using a some electrode.

  The cutting promoting substance is preferably removed from the semiconductor device after cutting the metallic carbon nanotube. By removing the cutting promoting substance, the metallic carbon nanotube can be more reliably electrically cut. The cutting promoting substance adhering to the metallic carbon nanotube may move away from the metallic carbon nanotube after the metallic carbon nanotube is cut. For this reason, the cutting promoting substance is buried in the cut portions of the metallic carbon nanotubes, and the cut metallic carbon nanotubes may be electrically connected again. Therefore, in order to reliably cut the metallic carbon nanotube, it is more desirable to remove the cutting promoting substance after cutting the metallic carbon nanotube.

  When gold fine particles or the like are used as the cutting promoting substance, the cutting promoting substance can be dissolved by exposing the carbon nanotubes to aqua regia. As a result, as shown in FIG. 3, the cutting promoting substance adhering to the metallic carbon nanotubes 121, 122, 123 can be removed.

  The transistor obtained by the method for manufacturing a semiconductor device according to the present embodiment can be used for a sensor device such as a bolometer or a gas sensor, thereby increasing the sensitivity of the sensor device. For example, when a transistor obtained by the method for manufacturing a semiconductor device according to this embodiment is used in a bolometer, a change in electrical resistance with respect to a temperature change can be increased. Further, when used in a gas sensor, it is possible to increase the electrical resistance change with respect to the gas concentration change. In these sensor devices, the electrical resistance of the carbon nanotube film is measured, and its temperature change or gas concentration change is detected. Therefore, the sensitivity of the sensor can be increased by reducing the number of metallic carbon nanotubes whose resistance change due to temperature or gas concentration is smaller than that of semiconducting carbon nanotubes.

[Second Embodiment]
Next, an example of manufacturing a diode using the method for manufacturing a semiconductor device according to this embodiment will be described with reference to FIGS.

  In the method of manufacturing a semiconductor device according to the present embodiment, as shown in FIG. 4, first, the conductivity of the semiconductor nanomaterial is reduced among the semiconductor nanomaterial and the metal nanomaterial contained in the plurality of nanomaterials ( S101). Next, a cutting promoting substance that promotes the action of cutting the metallic nanomaterial is attached to the metallic nanomaterial (S102). Next, the metallic nanomaterial to which the cutting promoting substance is attached is cut (S103).

  Next, the cutting promoting substance is removed.

  Through the above steps, a semiconductor device in a state similar to the semiconductor device in the state shown in FIG.

  Next, as shown in FIG. 5, the electrode 341 side of the film composed of a plurality of nanomaterials 310 is coated with an electron-withdrawing substance such as a carboxyl compound to form a p-type region 311. As the carboxyl compound, for example, poly (acrylic acid) (PAA) can be used.

  Further, as shown in FIG. 5, the electrode 342 side of the film composed of a plurality of nanomaterials 310 is coated with an electron donating substance such as an amine compound to form an n-type region 312. As the amine compound, for example, polyethylenimine (PEI) can be used.

  In this manner, by coating the electron-withdrawing substance and the electron-donating substance on different regions of the plurality of nanomaterials 310, the nanomaterial in the p-type region 311 is converted into a p-type semiconductor, and the n-type region 312 is formed. The nanomaterial can be an n-type semiconductor. Accordingly, different polarities can be provided in the plurality of nanomaterials 310. As a result, the semiconductor device shown in FIG. 5 can be used as a diode.

  By manufacturing the diode using the manufacturing method according to the present embodiment, the current path caused by the metallic nanomaterial can be reduced, so that the rectification of the diode can be improved.

  The polarity of the plurality of nanomaterials 310 can also be controlled by doping the plurality of nanomaterials 310 with a dopant. For example, semiconducting carbon nanotubes used as the material of the plurality of nanomaterials 310 are usually p-type semiconductors. Therefore, by doping this with potassium, the p-type semiconductor carbon nanotubes can be changed to n-type.

  In addition, the polarity of the plurality of nanomaterials 310 can be controlled by applying a voltage to the electrodes connected to the plurality of nanomaterials 310. In this case, an electrode connected to a part of the plurality of nanomaterials 310 through an insulating film is further provided in the structure shown in FIG. 5, and this electrode is used as a gate electrode. When there are two gate electrodes, by applying different voltages to these electrodes, a p-type region and an n-type region are formed in the plurality of nanomaterials 310, and a pn junction is formed in the plurality of nanomaterials 310. Can be formed. When there is only one gate electrode, a voltage is applied to the gate electrode so that the polarity of the region near the gate electrode of the plurality of nanomaterials 310 is opposite to the polarity of the region away from the gate electrode. Adjust so that In addition, when the voltage is applied to the gate electrode and the polarity is provided to the plurality of nanomaterials 310 in this way, in order to maintain the function as a diode, the voltage is continuously applied to the gate electrode to maintain the polarity. It is desirable to continue.

  Note that when carbon nanotubes are used as the nanomaterial, the carbon nanotubes are usually p-type in the atmosphere, and therefore it is possible to manufacture a diode without coating the p-type region.

  In addition, a resistor can be manufactured using a method similar to that in the above-described example of manufacturing a diode. The resistance value of the resistor is adjusted by selecting a material for coating a plurality of nanomaterials 310 or a dopant material. In addition, a film having a desired resistance can be obtained by controlling the voltage applied to the plurality of nanomaterials 310.

  Furthermore, by changing the number of carbon nanotubes contained in the plurality of nanomaterials 310 and the length or width of the plurality of nanomaterials, a resistor having a desired resistance value can be manufactured.

  By manufacturing a resistor using the manufacturing method according to the present embodiment, a high-resistance film can be easily manufactured, and resistance controllability can be improved.

  Next, the manufacturing method of this invention is demonstrated using an Example.

  First, a dispersion liquid in which a mixture of semiconducting carbon nanotubes and metallic carbon nanotubes was dispersed was dropped on a silicon substrate to form carbon nanotube channels.

  Next, gold was electron beam evaporated to form a pair of contact electrodes on the silicon substrate.

Subsequently, the substrate was immersed in a solution having a concentration of colloidal gold of about 10 ¹⁰ pieces / cm ³ , and electrophoresis was performed using the configuration shown in FIG. During electrophoresis, a voltage of 15 V was applied between the channel and the substrate electrode to reduce the conductivity of the semiconducting carbon nanotubes. In order to perform electrophoresis, a voltage of 10 V was applied between the electrophoresis electrode and the channel. The magnitude of the current was 0.01 mA / cm ² or less, and the applied time was 1 minute. A silicon oxide film was used as the insulating film, and doped silicon was used as the substrate electrode. An aqueous citric acid solution was used for the dispersion.

  Finally, heating was performed at 500 degrees in a dry air atmosphere to oxidize and cut the metallic carbon nanotubes.

  About the channel of the carbon nanotube obtained by said method, the characteristic as a field effect transistor was evaluated. As a result, the on / off ratio at the same on-current was improved by 16 to 25% as compared with the case of using the method for destroying metallic carbon nanotubes by current disclosed in Patent Document 2. Also, the variation in on-current decreased by 10 to 13%.

(Additional remark 1) The 1st process of reducing the electroconductivity of the said semiconducting nanomaterial among the semiconducting nanomaterial and metallic nanomaterial contained in several nanomaterial,
After the first step, a second step of attaching a cutting promoting substance that promotes an action of cutting the metallic nanomaterial to the metallic nanomaterial;
A third step of cutting the metallic nanomaterial to which the cutting promoting substance is attached;
A method for manufacturing a semiconductor device comprising:

    (Supplementary note 2) The method of manufacturing a semiconductor device according to supplementary note 1, further comprising a fourth step of removing the cleavage promoting substance after the metallic nanomaterial is cut.

(Additional remark 3) The said 2nd process contains the said cutting | disconnection acceleration | stimulation substance for the said several nanomaterial and the electrode for an application electrically connected to the 1st electrode connected to the said several nanomaterial. Soak in the solution
A step of applying the voltage between the first electrode and the application electrode to perform electrophoresis or electroplating to attach the cutting promoting substance to the metallic nanomaterial. The method for manufacturing a semiconductor device according to any one of Appendix 1 or 2.

    (Additional remark 4) The said 1st process includes the process of applying a voltage to the board | substrate electrode arrange | positioned through the insulating film to these nanomaterials, and reducing the carrier of the said semiconductor nanomaterial, It is characterized by the above-mentioned. The method for manufacturing a semiconductor device according to any one of appendices 1 to 3.

    (Supplementary Note 5) The semiconductor device manufacturing according to any one of Supplementary notes 1 to 4, wherein the third step includes a step of heating the plurality of nanomaterials to which the cutting promoting substance is attached. Method.

    (Additional remark 6) The said 3rd process is performed in the atmosphere where an oxidizing agent exists, The manufacturing method of the semiconductor device as described in any one of Additional remark 1 to 5 characterized by the above-mentioned.

    (Additional remark 7) The said cutting | disconnection acceleration | stimulation substance is a catalyst of the reaction which oxidizes the said metallic nanomaterial, The manufacturing method of the semiconductor device as described in any one of additional remark 1-6 characterized by the above-mentioned.

    (Additional remark 8) The said catalyst is gold, silver, copper, platinum, or palladium, The manufacturing method of the semiconductor device of Additional remark 7 characterized by the above-mentioned.

    (Additional remark 9) The said cutting | disconnection acceleration | stimulation substance is a reactive substance which reacts directly with the said metallic nanomaterial, The manufacturing method of the semiconductor device as described in any one of additional remark 1-6 characterized by the above-mentioned.

    (Supplementary note 10) The supplementary note 9, wherein the reactive substance is cobalt, chromium, iron, molybdenum, tantalum, titanium, thorium, uranium, manganese, niobium, vanadium, tungsten, yttrium, or zirconium. A method for manufacturing a semiconductor device.

    (Additional remark 11) The said 4th process removes the said reaction promoting substance using aqua regia, The manufacturing method of the semiconductor device of Additional remark 2 characterized by the above-mentioned.

    (Supplementary note 12) The method of manufacturing a semiconductor device according to supplementary notes 1 to 11, wherein the first step includes a step of cooling the plurality of nanomaterials to reduce carriers of the semiconducting nanomaterial.

    (Supplementary note 13) The method for manufacturing a semiconductor device according to any one of Supplementary notes 1 to 12, wherein a second electrode connected to the plurality of nanomaterials is disposed.

(Appendix 14)
14. The method of manufacturing a semiconductor device according to any one of appendices 1 to 13, wherein the nanomaterial is a carbon nanotube.

110 Channels 121, 122, 123, 221 Metallic carbon nanotubes 131, 132, 133, 134 Semiconductor carbon nanotubes 141, 142, 241, 242 Contact electrodes 150, 250, 350 Substrate 160, 260 Cutting promoting substance 251 Insulating film 252 Substrate Electrode 270 Electrophoresis electrode 280 Dispersion liquid 291 Substrate electrode voltage source 292 Electrophoresis voltage source 310 Multiple nanomaterials 311 p-type region 312 n-type region 321 322 323 Metallic nanomaterial 331 332 333 334 Semiconductor nanomaterials 341, 342 Electrodes

Claims (10)

A first step of reducing conductivity of the semiconducting nanomaterial among the semiconducting nanomaterial and the metallic nanomaterial included in the plurality of nanomaterials;
After the first step, a second step of attaching a cutting promoting substance that promotes an action of cutting the metallic nanomaterial to the metallic nanomaterial;
A third step of cutting the metallic nanomaterial to which the cutting promoting substance is attached;
A method for manufacturing a semiconductor device comprising: The method of manufacturing a semiconductor device according to claim 1, further comprising a fourth step of removing the cutting promoting substance after the metallic nanomaterial is cut. The second step includes immersing the plurality of nanomaterials and an application electrode electrically connected to the first electrode connected to the plurality of nanomaterials in a solution containing the cutting promoting substance. ,
A step of applying the voltage between the first electrode and the application electrode to perform electrophoresis or electroplating to attach the cutting promoting substance to the metallic nanomaterial. The manufacturing method of the semiconductor device as described in any one of Claim 1 or 2. 2. The method according to claim 1, wherein the first step includes a step of reducing a carrier of the semiconducting nanomaterial by applying a voltage to a substrate electrode disposed on the plurality of nanomaterials through an insulating film. 4. A method for manufacturing a semiconductor device according to claim 3. 5. The method of manufacturing a semiconductor device according to claim 1, wherein the third step includes a step of heating the plurality of nanomaterials to which the cutting promoting substance is attached. The method for manufacturing a semiconductor device according to claim 1, wherein the third step is performed in an atmosphere in which an oxidizing agent is present. The method for manufacturing a semiconductor device according to claim 1, wherein the cleavage promoting substance is a catalyst for a reaction that oxidizes the metallic nanomaterial. The method for manufacturing a semiconductor device according to claim 7, wherein the catalyst is gold, silver, copper, platinum, or palladium. The method of manufacturing a semiconductor device according to claim 1, wherein the cutting promoting substance is a reactive substance that directly reacts with the metallic nanomaterial. The semiconductor device according to claim 9, wherein the reactive substance is cobalt, chromium, iron, molybdenum, tantalum, titanium, thorium, uranium, manganese, niobium, vanadium, tungsten, yttrium, or zirconium. Production method.

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