JP5082423B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a conductor in which a conductive path is formed by fine particles made of a conductor or a semiconductor and organic semiconductor molecules, a manufacturing method thereof, a semiconductor device using the conductor, and a manufacturing method thereof.

  Thin film transistors (hereinafter abbreviated as TFTs) are widely used as switching elements in electronic circuits, particularly active matrix circuits such as displays.

  Currently, most TFTs are silicon-based inorganic semiconductor transistors that use amorphous silicon or polycrystalline silicon as a semiconductor layer (channel layer). These manufacturing methods use a plasma CVD method (Chemical Vapor Deposition) or the like for forming a semiconductor layer, so that the process cost is high. In addition, since heat treatment at a high temperature of about 350 ° C. is necessary, the process cost is increased and the substrate is restricted.

  In recent years, organic semiconductors using organic semiconductor materials can be manufactured by low-cost processes at low temperatures such as spin coating and immersion, and can also be formed on flexible substrates without heat resistance such as plastics. Transistors are actively developed.

However, in organic semiconductor materials, the mobility, which is a characteristic index of TFT, is only 10 ^{−3 to 1} cm ² / Vs as a typical value (CDDimitrakopoulos et al., Adv. Mater., 14, 99). (2002)). This value is lower than the mobility of amorphous silicon of several cm ² / Vs and the mobility of polycrystalline silicon of about 100 cm ² / Vs, and the mobility required for display TFTs is 1 to 3 cm ² / Vs. Not reached. For this reason, improving the mobility is a major issue in the development of organic semiconductor materials.

  The mobility of an organic semiconductor material is determined by charge transfer within a molecule and charge transfer between molecules. Intramolecular charge transfer is made possible by the delocalization of electrons to form a conjugated system. Charge transfer between molecules is performed by intermolecular bonds, conduction due to overlapping of molecular orbitals by van der Waals force, or hopping conduction through trap levels between molecules.

In this case, the mobility in the molecule is μ-intra, the mobility due to the bond between molecules is μ-inter, and the mobility of hopping conduction between molecules is μ-hop.
μ-intra ≫ μ-inter ＞ μ-hop
There is a relationship. In organic semiconductor materials, charge mobility is low because slow intermolecular charge transfer limits mobility as a whole.

To improve mobility, for example, when forming a pentacene thin film of organic semiconductor material by vapor deposition, the deposition rate of vapor deposition is extremely suppressed, and the substrate temperature is reduced to room temperature, thereby improving molecular orientation. In some cases, the mobility is 0.6 cm ² / Vs (CDDimitrakopoulos et al., IBM J. Res. & Dev., 45, 11 (2001)).

  This aims to improve mobility by improving the crystallinity of the material and suppressing hopping conduction between molecules. Although there is some improvement, the movement between molecules limits the mobility as a whole, and a satisfactory mobility is not obtained.

  Apart from this, attempts have been made to improve electrical characteristics by combining organic semiconductor materials with other materials.

  For example, in Patent Document 1 described later, a network-type conductive path is formed by fine particles made of a conductor or a semiconductor and organic semiconductor molecules bonded to the fine particles, and the conductivity of the conductive path can be controlled by an electric field. A proposed semiconductor device and a method for manufacturing the same have been proposed.

  FIG. 12 is a cross-sectional view (a) and an enlarged view (b) of a main part of an insulated gate field effect transistor disclosed in Patent Document 1. In this field effect transistor, a channel layer 108 in which fine particles 109 such as gold and organic semiconductor molecules 112 such as 4,4′-biphenyldithiol are connected in a network between a source electrode 104 and a drain electrode 105 is provided. Thus, the carrier movement in the combined body is controlled by the gate voltage applied to the gate electrode 102.

  As shown in FIG. 12B, in the above conjugate, the organic semiconductor molecules 112 are bonded to the fine particles 109 by the functional groups at both ends, whereby the fine particles 109 and the organic semiconductor molecules 112 are alternately connected, and the fine particles A conductive path in which the conductive path in 109 and the conductive path in the organic semiconductor molecule 112 are connected is formed. Since a large number of organic semiconductor molecules 112 can be bonded to the fine particles 109, a network-type conductive path connected in a two-dimensional or three-dimensional network as a whole is formed.

  The above-mentioned conductive path does not include intermolecular electron transfer, which was the cause of the low mobility of conventional organic semiconductors, and the electron transfer in organic semiconductor molecules is a conjugated system formed along the molecular skeleton. High mobility is expected.

  13 and 14 are cross-sectional views showing a flow of manufacturing steps of the insulated gate field effect transistor shown in FIG. In the following description, it is assumed that gold fine particles are used as the fine particles 109 and 4,4′-biphenyldithiol is used as the organic semiconductor molecules 112.

Process 1
First, as shown in FIG. 13A, a gate electrode 102, a gate insulating film 103, a source electrode 104, and a drain electrode 105 are formed on a substrate 101 such as a plastic substrate. For example, the electrodes 102, 104, and 105 are formed by vapor deposition of gold, and the gate insulating film 103 is formed by applying a solution of polymethyl methacrylate (PMMA) by a spin coating method and then evaporating the solvent.

Process 2
Next, the surface of the region where the channel layer 108 is formed is immersed in, for example, a toluene solution or hexane solution of 3-aminopropyltrimethoxysilane (APTMS), which is the solder molecule 107, and washed with a solvent to replace the solution. Thereafter, the solvent is evaporated, and as shown in FIG. 13B, the molecular solder layer 106 is formed as an underlayer for fixing the gold fine particles 109 by one layer. APTMS can be bonded to the gate insulating film 103 by a silanol group at one end, and can be bonded to the gold fine particles 109 by an amino group at the other end. As described above, the solder molecule 107 is a molecule that can be bonded to the gate insulating film 103 at one end and can be bonded to the fine particle 109 at the other end, and has a function of fixing the fine particle 109 to the gate insulating film 103. is there.

Process 3
Next, the substrate 101 is immersed for several minutes to several hours in a dispersion (concentration of several mM) in which gold fine particles 109 are dispersed in a solvent such as toluene or chloroform, and then the solvent is evaporated. As a result, as shown in FIG. 13C, the gold fine particles 109 are fixed to the surface of the molecular solder layer 106 of the substrate 101, and a gold fine particle layer 109 a composed of the gold fine particles 109 is formed on the molecular solder layer 106. . Only one gold fine particle layer 109a bonded to an amino group is fixed to the molecular solder layer 106. Excess gold fine particles 109 not fixed to the molecular solder layer 106 are washed away.

  The gold fine particles 109 are colloidal particles having a particle diameter of 10 nm or less. In order to stably disperse the gold fine particles 109 in a solvent such as toluene or chloroform, a protective film molecule that prevents the fine particles from aggregating and precipitating is attached and covered with the protective film 110. It is necessary to keep it on the molecular solder layer 106 in this state. The solder molecules 107 replace some of the protective film molecules and bind to the gold fine particles 109. However, as shown in FIG. 13C, most of the protective film molecules are still bonded to the gold fine particles 109. It is.

Process 4
Subsequently, the substrate 101 is immersed in a toluene solution (concentration of several mM or less) of 4,4′-biphenyldithiol 112, washed with a solvent to replace the solution, and then the solvent is evaporated. At this time, as shown in FIG. 13 (d), the 4,4′-biphenyldithiol 112 reacts with the gold fine particles 109 by the thiol group —SH at the end of the molecule to form the protective film 110. The molecules are replaced and bonded to the surface of the gold fine particles 109. A large number of 4,4′-biphenyldithiol molecules 112 are bonded to the surface of one gold fine particle 109 so as to enclose the gold fine particle 109. Some of them bind to other gold fine particles 109 using a thiol group at the other molecular end, and therefore, the gold fine particles 109 are connected in a two-dimensional network form by the 4,4′-biphenyldithiol molecule 112. The first channel layer 108a thus formed is formed.

  Since many unreacted thiol groups of 4,4′-biphenyldithiol 112 remain on the surface of the channel layer 108 a, the surface of the channel layer 108 a has a strong binding force to the gold fine particles 112. ing.

Process 5
Next, as shown in FIG. 14 (e), as in step 3, the substrate 101 is immersed for several minutes to several hours in a dispersion in which gold fine particles 109 are dispersed in a solvent such as toluene or chloroform. Evaporate. As a result, the gold fine particles 109 are bonded and fixed to the surface of the first channel layer 108a to form the second gold fine particle layer 109b. In this case, the gold fine particles 109 in the second layer are connected to the gold fine particles 109 in the first layer by 4,4′-biphenyldithiol 112, but the first gold fine particles 109 connected to the same second gold fine particle 109. 109 are indirectly connected through the second-layer gold fine particles 109, and the gold fine particles 109 are three-dimensionally connected. Excess gold fine particles 109 not fixed to the channel layer 108a are washed away.

  In step 5, as in step 3, in order to prevent the gold fine particles 109 from aggregating with each other, the gold fine particles 109 are introduced onto the channel layer 108a in a state of being covered with the protective film 110. The unreacted thiol group of 4,4′-biphenyldithiol 112 remaining on the surface of the channel layer 108a displaces the protective film molecule and binds to the gold fine particles 109, as shown in FIG. 14 (e). In addition, a significant portion of the protective film molecules still remain bound to the gold microparticles 109.

Step 6
Subsequently, as in step 4, the substrate 101 is immersed in a solution having a concentration of several mM or less in which 4,4′-biphenyldithiol 112 is dissolved in toluene, washed with a solvent to replace the solution, and then the solvent is evaporated. . As a result, as shown in FIG. 13 (f), a large number of 4,4′-biphenyldithiol 112 is bonded so as to enclose the gold fine particles 109, and the gold fine particles 109 are connected by the 4,4′-biphenyldithiol molecules 112. The second channel layer 108b thus formed is formed.

  Thereafter, Step 5 and Step 6 are repeated to form channel layers 108 each having a three-dimensional network-like conductive path as shown in FIG. 13G. Can do. By appropriately selecting the number of repetitions, the channel layer 108 having a desired thickness can be formed (for the formation method of the gold fine particle layer described here, MDMusick et al., Chem. Mater., 9, 1499 (1997); Chem. Mater., 12, 2869 (2000)).

  The conductive path disclosed in Patent Document 1 does not include electron transfer between molecules, and mobility is not limited by electron transfer between molecules. For this reason, the mobility of a conductive path (in the axial direction of the molecule) along the main chain in the organic semiconductor molecule, for example, high intramolecular mobility due to delocalized electrons can be utilized to the maximum.

  However, in order to prevent the fine particles 109 such as gold from aggregating and precipitating with each other in the process of forming the conductive path, a protective film molecule that prevents aggregation when forming the colloidal solution of the fine particles. It is necessary to coat the fine particles 109 with. For this reason, in the method of manufacturing a semiconductor device disclosed in Patent Document 1, as shown in FIGS. 13C and 14E, the fine particles 109 covered with the protective film 110 are dispersed in a solvent to form a substrate. After being introduced to the top and forming the fine particle layers 109a and 109b and fixing the fine particles 109 on the substrate, the fine particles 109 can be firmly bonded to both ends as shown in FIG. 13 (d) and FIG. 14 (f). The organic semiconductor molecule 112 having a functional group is allowed to act to replace the protective film molecule with the organic semiconductor molecule 112, and the organic semiconductor molecule 112 connects the fine particles 109 to form a network composed of the fine particles 109 and the organic semiconductor molecules 112. A conductive path of the mold is formed.

At this time, in order to achieve the networking between the fine particles that influence the performance of the semiconductor device with high efficiency, the following is required.
(1) The interval between the fine particles 109 in the fine particle layers 109a and 109b is set to be at least equal to or less than the maximum length of the organic semiconductor molecules 112 so that the proportion of the fine particles 109 connected by the organic semiconductor molecules 112 substituted with the protective film molecules is increased. Desirably, the length is easily adjusted by the organic semiconductor molecule 112, for example, the natural length of the organic semiconductor molecule 112 is adjusted.
(2) A protective film molecule having a smaller binding force to the fine particles 109 than the organic semiconductor molecule 112 is used so that the substitution reaction proceeds efficiently.

  However, it is difficult to accurately control the interval between the fine particles in the fine particle layers 109a and 109b. Further, if the binding force of the protective film molecules to the fine particles 109 becomes too weak, the protective effect on the fine particles 109 is not sufficient. Therefore, in order to have a sufficient protective action and satisfy the condition (2), the binding property of the protective film molecules to the fine particles 109 is greatly limited, and it is difficult to find an appropriate protective film molecule. As a result, it is difficult to achieve networking between the fine particles with high efficiency by the method of Patent Document 1.

  Further, in order to effectively obtain the gate field effect in the semiconductor device described above, a structure in which the electric field generated by the gate electrode is sufficiently applied to the organic semiconductor molecules 112 is required. For example, when the length of the organic semiconductor molecule 112 is about 1 to 2 nm or less, when the metal fine particles 109 come close to the length of the organic semiconductor molecule 112, the electric field due to the gate electrode is shielded by the metal fine particles 109, and the organic semiconductor It does not sufficiently act on the molecules 112 and the gate field effect cannot be obtained effectively.

  Therefore, in order to prevent the gate electric field from being shielded by the metal fine particles 109, the organic semiconductor molecules 112 connecting the fine particles 109 need to have a length of, for example, about 5 nm or more. In order to fabricate the semiconductor device using the long organic semiconductor molecules 112 by the method of Patent Document 1, first, the fine particles 109 are coated with a protective film molecule having a length about half that of the organic semiconductor molecules 112. It is necessary to adjust the distance between the fine particles 109. However, if this is done, the protective film covering the fine particles 109 becomes too thick, and the process of replacing the protective film molecules with the organic semiconductor molecules 112 becomes difficult to occur. As a result, there arises a problem that the fine particle layers 109a and 109b cannot be networked with high efficiency.

  Therefore, the present inventor disclosed in Patent Document 2 described later, an organic semiconductor molecule that forms a bond between a protective film molecule bonded to a fine particle and another protective film molecule bonded to an adjacent fine particle, thereby connecting the fine particles. And a protective film molecule serving as an organic semiconductor molecule is bonded to the fine particles, and then a plurality of fine particles are arranged, and a bond between the protective film molecules is formed between these fine particles. We have proposed a method of manufacturing a semiconductor device that generates organic semiconductor molecules that connect each other.

JP 2004-88090 A (pages 11-14, FIGS. 1 and 2) JP 2006-100519 A (page 11-16, FIGS. 1-4)

  FIG. 15 is an explanatory diagram showing a comparison between the main points of the method of manufacturing a semiconductor device according to the method of Patent Document 1 and the method of manufacturing a semiconductor device according to the method of Patent Document 2. In the method of Patent Document 1, as described above, first, a fine particle layer is formed on a substrate using fine particles covered with a protective film, and then has functional groups that form strong bonds with the fine particles at both ends. It is necessary to replace the protective film with organic semiconductor molecules, and this process becomes difficult when the length of the organic semiconductor molecules is increased. Further, in order to achieve networking with high efficiency, it is necessary to make the interval between the fine particles substantially coincide with the length of the organic semiconductor molecule before the replacement with the organic semiconductor molecule.

  On the other hand, in the method of Patent Document 2, a semiconductor device can be manufactured without going through the step of replacing the protective film with organic semiconductor molecules as shown in FIG. Regardless of the length, the fine particles can be connected.

  However, in the method of Patent Document 2, since the protective film molecules are required to have two functions of protecting the fine particles and generating semiconductor molecules, it is difficult to select the protective film molecules. In particular, when the semiconductor molecule is long chain and the protective film molecule is also long chain, there arises a problem that it is difficult to find a protective film molecule having sufficient electric conductivity.

For example, when a voltage is applied, the current flowing in a semiconductor molecule is generally dominated by a non-resonant tunneling current. In this case, the electrical conductivity is an index of the length of the semiconductor molecule. The electrical conductivity decreases in inverse proportion to the function. That is, when the distance between the fine particles is L and the length of the semiconductor molecule is L, the conductivity when the distance L is zero is σ ₀ , and the attenuation constant is β, the molecules are connected by long-chain organic semiconductor molecules. The electrical conductivity σ between the fine particles is approximately expressed by the formula σ = σ ₀ exp (−βL) (MA Ratner, B. Davis, M. Kemp, V. Mujica, A. Roitberg, S. Yaliraki, (See Ann. NY Acad. Sci., 852, p.22-p.37 (1998), p.31).

  Therefore, in order to maintain realistic electrical conductivity that can be operated as an electronic device, it is necessary to decrease β in inverse proportion to L as it increases. In general, the β value is small if the molecule is conjugated, and the β value is relatively large if the molecule is non-conjugated. Therefore, it is necessary to select a molecule group having a conjugated system and a small β, that is, a long chain molecule exhibiting a molecular wire-like behavior, as a semiconductor molecule that bonds fine particles. In addition, since such long-chain organic semiconductor molecules are generally synthesized by a multi-step organic synthesis reaction, in order to make them easier to use, a synthesis method that allows them to be synthesized more easily There is also a problem that development of is indispensable.

  In addition to the above problems, there is a problem that the longer the molecules used, the more difficult it is to bind molecules synthesized in advance over the entire surface of the fine particles.

  The present invention has been made in view of such a situation, and an object of the present invention is to form a conductive path by fine particles and organic semiconductor molecules bonded to the fine particles, and to control the conductivity by an electric field. It is an object of the present invention to provide a semiconductor device configured as described above and a method for manufacturing the same, and a semiconductor device in which the electrical conductivity does not decrease even when the organic semiconductor molecules are in a long chain shape and an easy manufacturing method therefor.

That is, the present invention relates to a semiconductor device in which a conductive path is formed by fine particles made of a conductor or a semiconductor and organic semiconductor molecules bonded to the fine particles, and the conductivity of the conductive path is controlled by an electric field. ,
The precursor molecules bonded to the fine particles and the other precursor molecules bonded to the adjacent fine particles form a bond to constitute the organic semiconductor molecules that connect the fine particles,
The precursor molecule relates to a semiconductor device, wherein the precursor molecule is a molecule generated by polymerization of a first molecule bonded to the fine particle and one or more kinds of second molecules.

Also, a method of manufacturing the semiconductor device,
Forming the fine particles in a state where the surface is coated with a protective film molecule for preventing aggregation; and
Causing the first molecule having a functional group capable of binding to the fine particles to act on the fine particles, substituting the protective film molecules, and binding to the fine particles;
Polymerizing the first molecules bound to the fine particles and one or more types of the second molecules to generate the precursor molecules;
Disposing the fine particles to which the precursor molecules are bonded in a region where the conductive path is formed;
A step of bonding the precursor molecules bonded to the fine particles and the other precursor molecules bonded to the adjacent fine particles to generate the organic semiconductor molecules that connect the fine particles. This relates to the manufacturing method.

  The first molecule and the second molecule are generally different types of molecules, but if possible, they may be the same type of molecules.

According to the method for manufacturing a semiconductor device of the present invention,
Causing the first molecule having a functional group capable of binding to the fine particles to act on the fine particles, substituting the protective film molecules, and binding to the fine particles;
Polymerizing the first molecules bonded to the fine particles and one or more kinds of the second molecules to generate the precursor molecules. In the polymerization step, the second molecules can be polymerized one by one, and the polymer molecules bonded to the fine particles and the unreacted second molecules can be easily separated. The precursor molecule can be easily and reliably synthesized while accurately controlling the length of the precursor molecule. Further, in the conventional method, the longer the semiconductor molecules used, the more difficult it is to bond the long-chain molecules synthesized in advance over the entire surface of the fine particles, but according to the present invention, The short first molecules are bonded to the surface of the fine particles in advance, and the first molecules are grown on the precursor molecules by the polymerization step. Therefore, the precursor molecules are very long long chain molecules. However, regardless of the length, the precursor molecules can be closely bonded over the entire surface of the fine particles.

A step of arranging the fine particles to which the precursor molecules are bonded in a region where the conductive path is formed;
A step of bonding the precursor molecules bonded to the fine particles and the other precursor molecules bonded to the adjacent fine particles to generate the organic semiconductor molecules connecting the fine particles. For this reason, as in the method of Patent Document 2 described above, after the step of disposing the fine particles in the conductive path formation region, the fine particles have already been obtained without going through the step of replacing the protective film molecules with organic semiconductor molecules. Since the organic semiconductor molecules are generated by the bonds between the precursor molecules bonded to the particles, the fine particles are reliably connected regardless of the distance between the fine particles and the length of the organic semiconductor molecules. Thus, the semiconductor device can be manufactured.

  In addition, since the second molecule is polymerized after the protective film molecule bonded to the fine particles is replaced with the first molecule, the degree of freedom in selecting the first molecule and the second molecule is great. . For this reason, a molecule having a skeletal structure excellent in electrical conductivity can be selected as the first molecule and / or the second molecule, and the organic semiconductor molecule having a long chain shape is formed, and the fine particles are formed between the fine particles. Even if the distance increases, the electrical conductivity of the conductive path is hardly lowered. As a result, in the semiconductor device of the present invention, it becomes possible to use the long-chain organic semiconductor molecules, and the distance between the fine particles can be increased, so that the electric field is shielded by the fine particles. As a result, the electric field effect on the organic semiconductor molecules can be more effectively extracted, and the conductivity of the conductive path can be controlled more effectively by the electric field.

  The semiconductor device of the present invention is a semiconductor device manufactured by the method for manufacturing a semiconductor device of the present invention, and as described above, is constituted by the organic semiconductor molecules having a characteristic structure corresponding to the manufacturing method. As a result, a semiconductor device having high mobility by the highly networked conductive path and having the above-described characteristics can be easily obtained.

  In the semiconductor device and the manufacturing method thereof of the present invention, the bond between the precursor molecule and the other precursor molecule is a complex formation reaction, a condensation reaction, a substitution reaction, a coupling reaction, an addition reaction, a hydrogen bond formation reaction, And at least one reaction selected from the group consisting of π-π stacking formation reactions.

  In this case, the reaction may be caused by at least one means selected from the group consisting of heating, light irradiation, introduction of a reaction initiator and metal ions into the system, and removal of the solvent. When using a chemical reaction by light, by optically narrowing the area to which light is applied, only the fine particles present in a specific area can be reacted, and if necessary, the unreacted fine particles are washed away thereafter. You can also. In addition, a linking group that forms the bond may be introduced into the precursor molecule in the polymerization.

  The network type conductive path may be formed by alternately bonding the organic semiconductor molecules and the fine particles, and bonding the single or plural organic semiconductor molecules to the fine particles.

  In addition, it is preferable that a long-chain conductive portion having a conjugated system in the molecular skeleton of the precursor molecule is formed by the polymerization of the first molecule and the second molecule. At this time, it is preferable that the main part of the conductive part is composed of the same structural unit. Such a structure can be generated by polymerizing the first molecule and / or the second molecule having the same structural unit.

  The natural length of the organic semiconductor molecule is preferably 5 nm or more. In this way, the problem that the gate electric field is shielded by the fine particles and does not effectively act on the organic semiconductor molecules can be avoided. For this reason, the length of the precursor molecule is 2.5 to 3 nm or more.

  The combined body of the fine particles and the organic semiconductor molecules may form a single layer or a plurality of layers to form the conductive path. At this time, the step of arranging the fine particles to which the precursor molecules are bonded as a single layer in the conductive path forming region, and the step of subsequently forming the bonds between the precursor molecules and the other precursor molecules. Are performed once, the conductive path composed of a single layer of the combined body can be formed. Further, by repeating these steps a plurality of times, the conductive path composed of a plurality of layers of the combined body can be formed.

  Alternatively, the step of forming the bond after forming a plurality of layers of the fine particles may be performed to form the conductive path including the plurality of layers of the combined body. For example, when the reaction for forming the bond is activated by heating, a plurality of the fine particle layers are formed before the bond is formed, and the bond is formed by heating over the entire region of the plurality of layers. In addition, the fine particles can be networked together. This facilitates the formation of the semiconductor device on a substrate having a large unevenness or a curved substrate.

  The fine particles are fine particles made of gold, silver or platinum as the conductor, or cadmium sulfide, cadmium selenide or silicon as the semiconductor, and the particle diameter is preferably 10 nm or less.

The first molecule may be bonded to the fine particles by a thiol group —SH, amino group —NH ₂ , isocyano group —NC, thioacetoxyl group —SCOCH ₃ , or carboxyl group —COOH.

  It is preferable to form an insulated gate field effect transistor by forming a channel region having the conductive path, providing source and drain electrodes on both sides of the channel region, and providing a gate electrode between these electrodes. This structure can also operate as an optical sensor or the like by using a dye that absorbs light near the visible region as an organic semiconductor molecule having a conjugated system.

  At this time, it is preferable that a base molecular layer is formed on the surface of the source electrode and / or the drain electrode by a base molecule that can be bonded to the precursor molecule to form a conductive path. By doing in this way, the favorable electrical connection of the said source electrode and / or the said drain electrode, and the said conductive path can be obtained easily.

  Next, a preferred embodiment of the present invention will be described specifically and in detail with reference to the drawings.

  FIG. 1A is a schematic cross-sectional view showing an example of an insulated gate field effect transistor based on this embodiment, and shows a bottom gate type device structure often used as a TFT. In this field effect transistor, a gate electrode 2 and a gate insulating film 3 are stacked on a substrate 1, and a source electrode 4 and a drain electrode 5 are patterned on the surface of the gate insulating film 3. A channel layer 9 is formed between the source electrode 4 and the drain electrode 5. The channel layer 9 is formed of a combined body in which fine particles 6 such as gold and organic semiconductor molecules 7 are bonded in a network. A current flowing between the source electrode 4 and the drain electrode 5 through the channel layer 9 is modulated by the potential of the gate electrode 2 and operates as a field effect transistor.

  FIG. 1B is an explanatory diagram showing a unit structure of the conductive path 10 in the channel layer 9. In the channel layer 9, the organic semiconductor molecules 7 are bonded to the fine particles 6 by the coupling portions 12 at both ends, whereby the fine particles 6 and the organic semiconductor molecules 7 are alternately connected, and the conductive path in the fine particles 6 and the organic semiconductor molecules 7 are connected. A conductive path 10 connected to the inner conductive path is formed. As shown in FIG. 1A, since a large number of organic semiconductor molecules 7 can be bonded to the fine particles 6, a network type conductive path connected in a two-dimensional or three-dimensional network as a whole is formed. Electron conduction in the channel layer 9 is performed through the network-type conductive path 10, and the conductivity is controlled by a voltage applied to the gate electrode 2.

  The organic semiconductor molecule 7 is formed by bonding a precursor molecule 11 bonded to one fine particle 6 and another precursor molecule 11 bonded to an adjacent fine particle 6 at a connecting portion 13. A long-chain conductive portion 14 having a conjugated system in the molecular skeleton generated by polymerization of the first molecule and the second molecule is disposed between the coupling portion 12 and the coupling portion 13. Yes. The main part of the conductive part 14 is usually formed by repeating the same structural unit 15.

  In the above-described insulated gate field effect transistor, the conductive path 10 does not include intermolecular electron transfer that has been the cause of the low mobility of conventional organic semiconductors, and the electron transfer in the organic semiconductor molecules is long chain. Since it is performed through the conjugated system formed in the conductive part 14, the high mobility and high electrical conductivity can be obtained. Further, since the conductive portion 14 is formed to have a sufficient length by the polymerization of the second molecule, the gate electric field is hardly shielded by the fine particles 6, and the source electrode 4 and the drain electrode 5 are passed through the channel layer 9. Is effectively modulated by the potential of the gate electrode 2.

  This will be described in more detail below.

  As the substrate 1, a silicon substrate, a plastic substrate such as polyimide, polycarbonate, or polyethylene terephthalate (PET), a glass substrate, a quartz substrate, or the like can be used. When a plastic substrate is used, a flexible semiconductor device such as a display having a curved surface can be manufactured.

  The transistor formed on the substrate 1 may be used as a monolithic integrated circuit in which a large number of transistors are integrated together with the substrate 1 as in the case of application as a display device. It may be used as a part.

  Examples of the material of the gate electrode 2 include gold Au, silver Ag, platinum Pt, chromium Cr, copper Cu, palladium Pd, aluminum Al, titanium Ti, impurities doped silicon, graphite, and, for example, poly (3 , 4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), or a combination thereof. The upper surface of the substrate 1 and the lower surface of the gate insulating film 3 are in close contact with the gate electrode 2.

Examples of the material of the gate insulating film 3 include silicon oxide SiO ₂ , silicon nitride Si ₃ N ₄ , aluminum oxide Al ₂ O ₃ , metal oxide high dielectric, mica, polyethylene terephthalate (PET), polymethyl Organic polymers such as methacrylate (PMMA) and polyvinylphenol (PVP) can be mentioned.

  As the material for the source electrode 4 and the drain electrode 5, the conductive materials mentioned as the material for the gate electrode 2 can be used. Each electrode is not necessarily made of the same material.

  According to this embodiment mode, since the processing temperature in the manufacturing process can be suppressed to 200 ° C. or lower, all of the above materials can be composed of organic compounds.

The fine particle 6 is, for example, a fine particle having a particle diameter of 10 nm or less. Examples of the material include a metal such as gold Au, silver Ag, platinum Pt, copper Cu, palladium Pd, iron Fe, or a conductor made of these alloys. Semiconductors such as silicon Si, titanium oxide TiO ₂ , gallium arsenide GaAs, and cadmium selenide CdSe can be used.

The organic semiconductor molecule 7 is an organic semiconductor molecule having a conjugated system in the molecular skeleton, and functional groups that can be chemically bonded to the fine particles 6 at both ends of the molecule include, for example, a thiol group —SH, a disulfide group —S—S—, It has an amino group —NH ₂ , an isocyano group —NC, a thioacetoxyl group —SCOCH ₃ , a cashboxyl group —COOH, or a phosphono group —PO (OH) ₂ . The functional group that can be used as the bonding portion 12 varies depending on the constituent material of the fine particles 6, and the thiol group, amino group, isocyano group, and thioacetoxyl group are functional groups that bond to conductive fine particles such as gold, A functional group that binds to semiconductor fine particles.

Examples of combinations of fine particles made of metal or semiconductor and functional groups suitable as the bonding portion 12 are as follows.
For Au fine ... -SH, -S-S -, - NH 2, -CN, -NC
In the case of Ag fine particles: -SH, -SS-, -COOH
In the case of Pt fine particles ... -SH, -SS-
In the case of Cu fine particles: -SH, -SS-
In the case of TiO ₂ fine particles: -PO (OH) ₂ , -COOH, -NH ₂

  Next, a manufacturing method will be described.

<Synthesis of precursor molecules bound to fine particles>
FIG. 2 is an explanatory view showing a synthesis route of the precursor molecules 11 bonded to the fine particles 6.

  First, the fine particles 6 are synthesized by a known method in a state where the surface is covered with a protective film for preventing fusion of the fine particles. Into the solution in which the fine particles 6 are dispersed, the reactive molecule 21 corresponding to the first molecule is introduced to replace the protective film molecule (reaction 1). The reactive molecule 21 has a structural unit 15 having a high electrical conductivity such as a conjugated system, and has a binding portion (functional group capable of binding to the fine particle 6) 12 that is bonded to the fine particle 6 at one end thereof. At the other end, a molecule having a reaction site a that acts as a reaction site with the reaction site b of the reaction molecule 22 in the polymerization with the reaction molecule 22 described later. As a result of the reaction 1, the reactive molecule 21 is physically and electrically bonded to the fine particle 6. Thereafter, the molecules 21 not bound to the fine particles 6 are removed from the solution by methods such as ultrafiltration, solvent extraction, size exclusion chromatography, and electrophoresis.

  Next, a reaction molecule 22 having a structural unit 15 and having a reaction site a and a reaction site b at both ends thereof, in which the reaction site a is inactivated by a protecting group c, is introduced. The reaction molecule 22 reacts with the reaction site a of the reaction molecule 21 through the reaction site b, and the reaction molecule 22 and the reaction molecule 21 are polymerized (reaction 2). Thereafter, unreacted molecules 22 are removed from the solution by methods such as ultrafiltration, solvent extraction, size exclusion chromatography, and electrophoresis.

  Next, the protecting group c linked to the reaction site a of the reaction molecule 22 is removed, and the reaction site a is brought into a reaction active state (reaction 3).

  Thereafter, the reaction 2 and the reaction 3 are repeated, and the conductive unit 14 forms polymer molecules having a predetermined length by repeating the structural unit 15.

  Next, the reaction molecule 23 having the reaction site b and the linking group 16 that forms the linking part 13 at both ends of the molecule is polymerized to introduce the linking group 16 into the polymer molecule (Reaction 4). Thus, the synthesis of the precursor molecules 11 bonded to the fine particles 6 is completed. Although FIG. 2 shows an example in which the reactive molecule 23 is composed only of the reactive site b and the linking group 16, a structural unit 15 or the like may be included in the middle.

  FIG. 3 is an explanatory diagram showing an example of a precursor molecule synthesis reaction. The reactive molecule 21 has a phenylene ethynylene group as the structural unit 15 having high electrical conductivity, and has a thiol as a bonding portion (functional group capable of binding to the fine particle 6) 12 bonded to the fine particle 6 such as gold at one end. And ≡C—H as a reactive site a at the other end. The reactive molecule 22 has a phenylene ethynylene group as the structural unit 15 having high electrical conductivity, an iodine group bonded to the benzene ring as a reactive site b at one end, and a protective group c at the other end. And a reaction site a masked by a trialkylsilyl group such as a trimethylsilyl (TMS) group or a tributylsilyl group. The reaction molecule 23 has an iodine group bonded to the benzene ring as a reaction site b at one end, and a terpyridyl group as the linking group 16 at the other end.

  Reaction 1 to reaction 4 are as shown in FIG. Reactions 2 and 4 are reactions that occur with high efficiency in the presence of Pd (II) and Cu (I) catalysts (DL Peason, JM Tour, J. Org. Chem., 62, 1376-1387 (1997). In particular; see compounds 11 and 23 on page 1379.) Reaction 4 is a reaction in which a linking group 16 is introduced. As the linking group 16, a pyridyl group, a bipyridyl group, a terpyridyl group, a phenanthroline, a quinolinol, a quinoline, or the like that can be a ligand of a metal complex can be used.

  As the structural unit 15 having a high electrical conductivity, for example, a phenylene group, a phenyleneethynylene group, a thiophene skeleton, or the like that is configured by a conjugated system having a small β value and a high electrical conductivity is preferable. Various types of protecting groups c are known depending on the functional group, and it is desirable to select those that can be protected and deprotected with high yield under mild reaction conditions (Theodora W. Greene and Peter GM (See Wuts, in “Protective groups in organic synthesis,” 3rd edition, Wiley-Interscience, New York, 1999.) For example, when the phenylene ethynylene group is the structural unit 15, the above trimethylsilyl group can be used for the purpose of protecting ≡C—H.

  FIG. 4 is an explanatory view showing another example of the synthesis reaction of precursor molecules. The reactive molecule 21 has a phenylene group as the structural unit 15 having high electrical conductivity, has a thiol group as a bonding portion 12 that bonds to the fine particles 6 such as gold at one end, and a reactive site at the other end. a has a carboxyl group; The reactive molecule 22 has a phenylene group as the structural unit 15 having high electrical conductivity, has a carboxyl group coordinated to a copper ion as a reactive site b at one end, and is esterified at the other end by esterification. It has a carboxyl group which is a reaction site a masked by an alkyl group as the protecting group c. Reaction 1 to Reaction 4 are as shown in FIG. 4 (however, other ligands coordinated to copper ions in FIG. 4 are not shown). As in this example, it is also possible to use a structural unit 15 including an organometallic complex part as the structural unit 15 having high electrical conductivity. In this case, the ligand includes terephthalate, chloroanil, oxalate, 9,10-bis (3,3) having a carboxyl group or a hydroxyl group (hydroxyl group) capable of introducing a protecting group at both ends of the molecule. And 5-dihydroxyphenyl) anthracene. The functional groups at both ends may be different. As the metal ion, one capable of forming a complex with the above ligand is selected.

FIG. 5 is a structural formula showing examples of the reactive molecule 21 and the reactive molecule 22. In the table, the example shown in the column A is the example shown in FIG. 3 if X is a phenylene group, and the others are modified examples. X is a divalent atomic group, and examples can be given by enclosing with a dotted frame below the table. Z _{1 to} Z ₄ in the formula are examples further enclosing with a dotted frame below And so on. M and n are integers of 1 or more. In the table, the example shown in column B is the example shown in FIG. 4 if X is a phenylene group, and the others are modified examples. X and Z _{1 to} Z ₄ are the same as described above.

FIG. 6 is an explanatory view showing still another example of the precursor molecule synthesis reaction. The reactive molecule 21 has X which is a phenylene group or the like as the structural unit 15 having high electrical conductivity, has a thiol group as the bonding portion 12 at one end, and a terpyridyl group as the reactive site a at the other end. Have. The reactive molecule 22 has X, which is a phenylene group, as the structural unit 15 having high electrical conductivity, and has terpyridyl groups as reactive sites b and a, respectively, at both ends of the molecule. X and Z _{1 to} Z ₄ are the same as described above. Reaction 1 to reaction 3 are as shown in FIG. Since the terpyridyl group is easily coordinated to the ruthenium (III) ion Ru ³⁺ , as shown in Reactions 2 and 3, the reactive molecules can be linked to each other by a complex formation reaction with Ru ³⁺ . This complex formation reaction with Ru ³⁺ is also used when precursor molecules described later are linked to form organic semiconductor molecules. In the figure, DMF is dimethylformamide. Since the reaction molecule 22 has the linking group 16, the reaction 4 for introducing the linking group 16 is not necessary.

  FIG. 7 is an explanatory diagram showing another synthesis route of the precursor molecules 11 bonded to the fine particles 6. In the synthetic route shown in FIG. 7, the reactive molecule 31 has an active site a, and the reactive site b is protected by a protecting group d among the active site a and the reactive site b of the reactive molecule 32. This is different from the synthesis route shown in FIG.

<Fabrication of semiconductor device>
8 and 9 are flow charts showing manufacturing steps of the insulated gate field effect transistor shown in FIG.

  First, as shown in FIG. 8A, a gate electrode 2, a gate insulating film 3, a source electrode 4 and a drain electrode 5 are formed on a substrate 1 using a known method.

  As the substrate 1, a silicon substrate, a plastic substrate such as polyimide or polycarbonate, a glass substrate, a quartz substrate, or the like is used.

  A gate electrode 2 is formed on the substrate 1 by vapor deposition of gold. As a material of the gate electrode 2, in addition to gold, for example, a conductive polymer, a conductive substance such as platinum, aluminum, nickel, titanium, or a combination thereof can be used. The lift-off method, the shadow mask method It is formed by a screen printing method, an ink jet printing method or the like. For example, when the substrate is a highly doped silicon substrate and the substrate itself has sufficient conductivity, the substrate itself can be used as a gate electrode without performing the above gold deposition. .

  Subsequently, the gate insulating film 3 is formed by a thermal oxidation method, a CVD method, a spin coating method, a sputtering method, a dipping method, a casting method, or the like. As the material of the gate insulating film 3, for example, silicon oxide, polymethyl methacrylate, spin-on glass, silicon nitride, metal oxide high dielectric insulating film, or a combination thereof can be used.

  On the gate insulating film 3, gold is deposited while masking other portions to form the source electrode 4 and the drain electrode 5. As a material of the source electrode 4 and the drain electrode 5, in addition to gold, for example, a conductive material such as palladium, platinum, chromium, nickel, a conductive polymer, or a combination thereof can be used. It is formed by a shadow mask method, a screen printing method, an ink jet printing method or the like.

  Next, as shown in FIG. 8B, a base molecule layer is formed on the surface of the source electrode 4 and the drain electrode 5 by the base molecule 17 that can be bonded to the precursor molecule 11 to form a conductive path. To do. By doing so, a good electrical connection can be easily obtained between the source electrode 4 and the drain electrode 5 and the conductive path 10 of the channel layer 9. As the base molecule 17, a molecule having the structural unit 15 and having functional groups capable of binding to the source electrode 4 or the drain electrode 5 and linking groups 16 capable of forming the precursor molecules 11 and the linking portions 15 at both ends thereof. Is good.

  Next, as shown in FIG. 8C, a single particle film 8a composed of fine particles 6 to which precursor molecules 11 are bonded is applied to a dipping method, a casting method, a Langmuir Blodget (LB) method, an inkjet method, or a stamp. The source electrode 4 and the drain electrode 5 are fixed to the surface of the substrate 1 on which the source electrode 4 and the drain electrode 5 are patterned. At this time, it is desirable that the fine particles 6 form a two-dimensional regular array based on hexagonal close-packing.

  In the dipping method, the substrate 1 is dipped for several minutes to several hours in a dispersion (concentration of several mM) in which fine particles 6 are dispersed in a suitable solvent such as toluene or chloroform, and then the solvent is evaporated. Thereby, the fine particle layer 6 a is formed on the substrate 1. Excess fine particles 6 are washed away.

  In the casting method, a dispersion liquid in which fine particles 6 are dispersed is dropped onto a substrate, and the solvent is gradually evaporated. Thereby, the fine particle layer 6 a is formed on the surface of the substrate 1. The concentration of the dispersion is adjusted in advance so that only one fine particle layer is formed.

  In the LB method, a dispersion liquid in which fine particles 6 are dispersed on a water surface that has been allowed to stand is developed to form a fine particle layer 6a. Next, the fine particle layer 6 a is transferred onto the substrate 1 by a water surface descending method or the like, and the fine particle layer 6 a is formed on the substrate 1.

  In the stamp method, a fine particle layer 6a formed on a solid surface or a water surface by a casting method or an LB method is once transferred onto a surface such as polydimethylsiloxane, and then pressed onto the substrate 1 like a stamp. The gold fine particle layer 6a is transferred to the surface.

  Next, as shown in FIG. 8D, the organic semiconductor that bonds the precursor molecules 11 bonded to the fine particles 6 and the precursor molecules 11 bonded to other adjacent fine particles 6 to connect the fine particles 6. In addition to generating molecules 7, a conductive path 10 that connects the fine particles 6 in a network is formed.

  FIG. 10 is an explanatory view for explaining the connecting step. The method reported to patent document 2 can be used for this connection process. For example, in the case where the linking group 16 is composed of an atomic group that can be a ligand of a metal complex, the substrate 1 on which the fine particle layer is formed is immersed in a solution containing metal ions. As shown in a), a metal ion is introduced between the linking groups 16 and the precursor molecules 11 are linked by a complex formation reaction (J. Park, AN Pasupathy, JI Goldsmith, C. Chang, Y. Yaish, JR). (See Petta, M. Rinkoski, JP Sethna, HD Abruna, PL McEuen, and DC Ralph, Nature (2002), 417, 722-725). On the other hand, when the linking groups 16 can react with each other to form a bond, as shown in FIG. 10B, the reaction is performed by heating, light irradiation, introduction of a reaction initiator or a catalyst, and the like. Are connected. When the linking group 16 interacts with the adjacent linking group 16 by electrostatic attraction, van der Waals force, hydrogen bond, π-π stacking, etc., the precursor molecules 11 are linked by these actions. Is also possible.

  Thereafter, the step (c) and the step (d) are repeated a predetermined number of times to form an insulated gate field effect transistor.

  FIG. 11 is a cross-sectional view showing various device structures of an insulated gate field effect transistor, and any device structure can be used for the insulated gate field effect transistor according to the present invention. FIG. 11A shows a bottom gate type device structure whose schematic cross-sectional view has already been shown in FIG. 1, in which the gate electrode 2, the gate insulating film 3, the source electrode 4 and the drain electrode 5 are formed in advance. A channel layer 9 is formed on the gate insulating film 3 in a region between the source electrode 4 and the drain electrode 5. FIG. 11B is a cross-sectional view showing a top gate type device structure, in which a source electrode 4 and a drain electrode 5 are formed first, a channel layer 9 is formed in a region therebetween, and vapor deposition is performed thereon. Thus, the gate insulating film 3 and the gate electrode 2 are formed. FIG. 11C is a cross-sectional view showing a dual gate type device structure, which includes a first gate electrode 2a and a first gate insulating film 3a, and a second gate electrode 2b and a second gate insulating film 3b. By providing this, the conductivity of the channel layer 9 can be controlled more effectively.

  According to the embodiment of the present invention, since the electrical conductivity of the repeating structural unit 15 in the organic semiconductor molecule 7 is high, even if the distance between the fine particles is increased by using the long-chain organic semiconductor molecule 7, it is networked. It is possible to avoid a decrease in the conductivity of the fine particle layer. The increase in the distance between the fine particles makes it difficult for the electric field generated by the gate electrode to be shielded by the fine particles, so that the electric field effect can be more efficiently extracted to the organic semiconductor molecule 7.

  In the synthesis of the precursor molecule 11 composed of repeating structural units 15, the structural units 15 are polymerized one by one, so that the chain length can be easily controlled. In this case, generally, when molecules having different chain lengths are prepared by organic synthesis, an operation capable of separation with high accuracy such as chromatography is required for separation / removal of unreacted molecules in the system. On the other hand, when the structure is repeatedly extended one structural unit at a time with one end of the organic molecule bonded to the surface of the fine particle 6 as in the present invention, the fine particle 6 having the organic molecule bonded to the surface. And the unreacted reaction molecules 21 to 23 and 31 to 33 can be separated, so that there is an advantage that a relatively less troublesome method such as ultrafiltration or solvent extraction can be used.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to these examples at all, and can be suitably changed in the range which does not deviate from the main point of invention.

  The semiconductor device and the manufacturing method thereof according to the present invention are used as a semiconductor device such as a thin film transistor (TFT) widely used as a switching element for various electronic circuits, particularly an active matrix circuit of a display, and a manufacturing method thereof. It can contribute to the development of new applications such as cost reduction and application to flexible substrates without heat resistance such as plastic.

It is the schematic sectional drawing (a) which shows an example of the insulated gate field effect transistor based on embodiment of this invention, and a principal part schematic diagram (b). It is explanatory drawing which shows the synthesis | combining method of a precursor molecule | numerator similarly. It is explanatory drawing which shows an example of the synthesis reaction of a precursor molecule | numerator similarly. It is explanatory drawing which shows another example of the synthesis reaction of a precursor molecule | numerator similarly. It is a structural formula showing an example of a reactive molecule. It is explanatory drawing which shows another example of the synthesis reaction of a precursor molecule | numerator similarly. It is explanatory drawing which shows another synthesis method of a precursor molecule | numerator similarly. It is a flowchart which shows the manufacturing process of an insulated gate field effect transistor equally. It is a flowchart which shows the manufacturing process of an insulated gate field effect transistor equally. It is explanatory drawing which shows the example of the connection process of a precursor molecule | numerator similarly. It is sectional drawing which shows the various device structure of an insulated gate field effect transistor similarly. They are sectional drawing (a) of the insulated gate field effect transistor currently disclosed by patent document 1, and the principal part enlarged view (b). It is a flowchart which shows the manufacturing process of an insulated gate field effect transistor equally. It is a flowchart which shows the manufacturing process of an insulated gate field effect transistor equally. FIG. 10 is an explanatory diagram showing a comparison between the main points of a semiconductor device manufacturing method according to the method of Patent Document 1 and a semiconductor device manufacturing method according to the method of Patent Document 2;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Gate electrode, 3 ... Gate insulating film, 4 ... Source electrode, 5 ... Drain electrode,
6 ... fine particles (such as gold), 7 ... organic semiconductor molecules, 8a ... first fine particle layer,
8b ... second fine particle layer, 9 ... channel layer, 9a ... first channel layer,
9b ... second channel layer, 10 ... conductive path, 11 ... precursor molecule, 12 ... bonding part,
13 ... connecting part, 14 ... conductive part (preferably long chain conductive part), 15 ... structural unit of conductive part,
16 ... Linking group, 17 ... Base molecule, 21-23, 31-33 ... Reactive molecule, 101 ... Substrate,
102 ... Gate electrode, 103 ... Gate insulating film, 104 ... Source electrode,
105 ... Drain electrode, 106 ... Molecular solder layer, 107 ... Solder molecule,
108 ... channel layer, 108a ... first channel layer, 108b ... second channel layer,
109 ... fine particles such as gold, 109a ... first fine particle layer, 109b ... second fine particle layer,
110 ... protective film, 111 ... protective film molecule,
112 ... Organic semiconductor molecules such as 4,4'-biphenyldithiol, a, b ... reaction sites

Claims (12)

In a semiconductor device configured such that a conductive path is formed by fine particles made of a conductor or a semiconductor and organic semiconductor molecules bonded to the fine particles, and the conductivity of the conductive path is controlled by an electric field.
The precursor molecules bonded to the fine particles and the other precursor molecules bonded to the adjacent fine particles form a bond to constitute the organic semiconductor molecules that connect the fine particles,
The semiconductor device, wherein the precursor molecule is a molecule generated by polymerization of a first molecule bonded to the fine particle and one or more kinds of second molecules.   The bond between the precursor molecule and the other precursor molecule is a group consisting of a complex formation reaction, a condensation reaction, a substitution reaction, a coupling reaction, an addition reaction, a hydrogen bond formation reaction, and a π-π stacking formation reaction. The semiconductor device according to claim 1, wherein the semiconductor device is formed by at least one selected reaction.   The semiconductor device according to claim 2, wherein a linking group that forms the bond is introduced into the precursor molecule in the polymerization.   2. The network-type conductive path is formed by alternately bonding the organic semiconductor molecules and the fine particles, and bonding one or more organic semiconductor molecules to the fine particles. The semiconductor device described.   2. The semiconductor device according to claim 1, wherein a long-chain conductive portion having a conjugated system in a molecular skeleton is formed by the polymerization of the first molecule and the second molecule.   The semiconductor device according to claim 5, wherein a main part of the conductive part is formed by repetition of the same structural unit.   The semiconductor device according to claim 1, wherein a natural length of the organic semiconductor molecule is 5 nm or more.   The semiconductor device according to claim 1, wherein the fine particles are made of gold, silver, or platinum as the conductor, or cadmium sulfide, cadmium selenide, silicon, or titanium oxide as the semiconductor.   The semiconductor device according to claim 1, wherein the fine particles are fine particles having a particle diameter of 10 nm or less. The first molecule is bound to the fine particles by a thiol group —SH, amino group —NH ₂ , isocyano group —NC, thioacetoxyl group —SCOCH ₃ , carboxyl group —COOH, or phosphono group —PO (OH) ₂ . The semiconductor device according to claim 1.   A channel region having the conductive path is formed, a source electrode and a drain electrode are provided on both sides of the channel region, and a gate electrode is provided between the two electrodes. The semiconductor device according to claim 1.   12. The semiconductor device according to claim 11, wherein a base molecule layer is formed on a surface of the source electrode and / or the drain electrode by a base molecule capable of forming a conductive path by being bonded to the precursor molecule. .

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