JPH0691241B2 - Transistor element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transistor device in the field of integrated circuits, and by using a biomaterial as a constituent material of a nuclear device, its size can be reduced to ultrafine particles at a biomolecule level. It is possible to approach a large size (several tens to several hundreds of Å) and to achieve high density and high speed.

[Conventional technology]

Conventionally, a field effect transistor (FET) shown in FIG. 6 has been used as a transistor element used in an integrated circuit. In the figure, 1 is an n-type silicon substrate, 2 is a channel region, 3 is a P + layer, 4 is a SiO ₂ film, 5 is a source electrode, 6 is a gate electrode, and 7 is a drain electrode. Alternatively, the switching operation is performed by controlling the gate voltage applied to the gate electrode. That is, if the number of current carriers in the surface layer between the source electrode 5 and the drain electrode 7 is changed by the gate voltage, the current is controlled by this.

[Problems to be solved by the invention]

Since the conventional transistor element is configured as described above, it can be microfabricated.Currently, a 256K-bit LSI is put to practical use as an LSI using the transistor element having the above structure or a rectifying element having a similar structure. ing.

By the way, in order to increase the memory capacity and operation speed of an integrated circuit, it is indispensable to miniaturize the element itself. However, in the element using Si, the average free path and the element size of the electron are reduced by an ultrafine pattern of about 0.2 μm. There is a limit that they become almost equal and the independence of elements cannot be maintained. In this way, silicon technology, which continues to develop day by day, is expected to eventually hit the wall in terms of miniaturization, and it is an electric circuit element based on a new principle.
What can break a 2 μm wall is required.

The present invention has been made in view of the above circumstances, and by using a biomaterial as a constituent material of an electric circuit element, an electric circuit element capable of approaching its size to an ultrafine size at a biomolecule level is provided. , Especially for the purpose of providing a transistor element of them.

[Means for solving problems]

Incidentally, during the lining of the mitochondrial biological membrane and higher organisms microorganisms, although each feature different, H _2, organic acid, NAD (P) H (Nicotineamide Adenine Dinucleotide
(Phosphate)) and an enzyme protein that withdraws an electron from a reducing chemical substance, as well as a protein (hereinafter referred to as an electron transfer protein) having an electron transfer ability to carry the extracted electron in a predetermined direction of a biological membrane. There are multiple types. These electron transfer proteins are embedded in the biological membrane with a certain orientation, and have a specific intermolecular arrangement so that electron transfer occurs between the molecules.

In this way, the electron transfer proteins are arranged in a chain in a biological membrane with a fine arrangement, so that electrons can flow along the protein chain, and the movement of electrons can be controlled at the molecular level. Conceivable.

FIG. 5 schematically shows an electron transfer system of the inner membrane of mitochondria as an example of a chain of electron transfer proteins (electron transfer system). In the figure, 8 is an inner membrane of mitochondria, 9 to 15 are electron transfer proteins, and NADH-Q reductase 9 and succinate are converted from reducing organic substances such as NADH (L in the figure) and succinic acid (M in the figure), respectively. The electrons extracted by the dehydrogenase 10 are
NADH-Q reductase 9, succinate dehydrogenase 10 → Chilechrome b (11) → cytochrome c1 (12) → cytochrome c
(13) → Cytochrome a (14) → Cytochrome a3 (15)
And is finally passed to oxygen on the outlet side N to produce water.

The electron transfer protein shown in FIG. 5 is accompanied by a redox reaction during electron transfer, and electrons can flow from the negative level of the redox potential of each electron transfer protein to the positive level.

According to recent findings, not only electron transfer proteins existing in the same living body but also electron transfer proteins existing in different living bodies are combined to form electron transfer protein complexes capable of electron transfer. Has been shown to be possible.

Therefore, if two kinds of electron transfer proteins (A and B) having an appropriate redox potential are used and these are accumulated in ABA and the three layers, the transistor characteristics or It is believed that junctions can be formed that produce switching characteristics. The inventors of the present invention pay attention to this fact and create the present invention.

That is, the transistor element according to the present invention has first, second, and different redox potentials between electron transfer proteins adjacent to each other.
The first, second, and third electron transfer protein membranes made of the third electron transfer protein are provided by sequentially adhering and joining, respectively, and
The second, third and third electron transfer protein membranes are provided with first, second and third electrodes.

[Action]

In the present invention, at least two kinds of three electron transfer proteins having different redox potentials exhibit transistor characteristics or switching characteristics. That is, A- shown in FIG.
The electron transfer protein complex will be described with reference to the schematic diagram of the B-A type electron transfer protein complex and the relationship between its redox potential.
In the complex composed of A, B, and A, the distribution of redox potential of A, B, and A proteins can be changed by controlling the applied voltage to each protein. It is possible to obtain an element exhibiting transistor characteristics or switching characteristics similar to a p-n-p junction formed by joining a type semiconductor.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional configuration diagram of an apparatus in which a transistor element according to an embodiment of the present invention is incorporated. In the figure, 16 is an insulating substrate such as a glass substrate, 17 is Ag, Au, Al, etc. A plurality of lines are formed in parallel on the substrate 16 by the metal electrodes. Reference numeral 18 denotes a first electron transfer protein film made of flavodoxin which is an electron transfer protein, and is formed on the electrodes 17 above the plurality of electrodes. Reference numeral 20 denotes a plurality of parallel electrodes formed in a direction perpendicular to the plurality of parallel electrodes 17 and is formed on the first electron transfer protein film 18. Reference numeral 19 denotes a second electron transfer protein film made of cytochrome c, which is an electron transfer protein, and is cumulatively adhesively bonded to the first electron transfer protein film 18 and bonded to the electrode 20. Reference numeral 21 is a third electron transfer protein film made of flavodoxin, which is an electron transfer protein, and is accumulated and adhesively bonded to the second electron transfer protein film 19. Reference numeral 22 is a plurality of parallel electrodes formed in a direction perpendicular to the plurality of parallel electrodes 20 and is formed on the third electron transfer protein film 21. FIG. 2 is an exploded perspective view showing the apparatus incorporating the formed transistor element in an exploded manner.

The transistor element thus configured has an electron transfer path in the vertical direction in the figure, and has the first and third electron transfer protein membranes 1
Electrodes 17 and 22 connected to 8 and 21 are connected to the surfaces that intersect with the electron transfer passage, respectively, and electrode 20 connected to the second electron transfer protein membrane 19 does not intersect with the electron transfer passage. Are connected to have an electrical effect on.

In this embodiment, a voltage is applied to the element formed as described above as shown in FIG. 3 (a). That is, the voltage V ₁ is applied between the first electron transfer protein film 18 and the second electron transfer protein film 19 via the electrodes 17 and 20, and the second electron transfer protein film 19 and the third electron transfer protein film are also applied. A voltage V ₂ is applied between the film 21 and the membrane 21 via electrodes 20 and 22, and the output voltage of each power source for applying the above voltages V ₁ and V ₂ can be controlled. ing.

Next, a method of manufacturing the above device will be described.

First, a metal thin film is formed on the substrate 16 by using an ion beam method, a molecular beam method, a vapor deposition method, or the like to form a metal electrode 17. Then, on the electrode 17, cytochrome c as an electron transfer protein and flavodoxin are used to form a monomolecular film and a cumulative film thereof. The LB (Langmuir-Blodgett) method is used to form these films. Can be used. For details of this LB method, see The Institute of Electrical Engineers of Japan, Vol. 55, 204.
Pp. 213, April 1952 (Iwing Langmuir), Journal of American Chemical Society (K. Bl)
odgett: Journal of American Chemical Society) Volume 57,
P1007, 1935, Michio Sugi et al., Solid State Physics, Vol 17, P744〜75
2,1982, Journal of Colloid and Interface Science
Interface Science) Vol 68, P471-477, 1979, etc.

To explain one example, a flavodoxin solution is dropped on the water surface of a water tank to form a flavodoxin monomolecular film on the water surface.
Then, the electrode 17 is placed in the water tank on which the flavodoxin film is formed.
The substrate 16 on which the electrodes are formed is vertically inserted and immersed,
The flavodoxin film is attached and bonded to the substrate 16 having 17 to form the first electron transfer protein film 18. At this time, the substrate 16
Although it was inserted into the water tank and dipped in it, the flavodoxin film may be formed on the substrate 16 by pulling it up vertically from below the water surface.

Next, in the same manner as described above, the first electron transfer protein film 18
Create the electrode 20 on top. At this time, it is necessary to prepare at a low temperature so that the electron transfer protein is not destroyed. Subsequently, a cytochrome c solution is dropped on several surfaces of the water tank to form a monomolecular film of cytochrome c on the water surface. Then, the substrate 16 on which the first electron transfer protein 18 and the electrode 20 are formed is vertically inserted into a water tank having a cytochrome c membrane and immersed therein.
The cytochrome c film is adhered and joined onto the first electron transfer protein film 18, and the second electron transfer protein film 19 joined to the electrode 20 is prepared. Similarly, a flavodoxin film is adhered and bonded onto the second electron transfer protein film 19 of the substrate 16 to form a third electron transfer protein film 21, and further an electrode 22 is formed thereon.

The electron transfer protein membrane may be a monomolecular film,
Further, a film of another electron transfer protein may be laminated on this. For example, when the first electron transfer protein is formed by accumulating two layers, the redox potential difference between these two electron transfer protein membranes is selected to be smaller than the redox potential difference between the first and second electron transfer proteins. . The redox potentials of various electron transfer proteins are described in "Takahiro Takano; Protein Nucleic Acid Enzymes, 27, P1543, 1982", and the redox potential difference between cytochrome c and flavodoxin is about 665 mV.
Is.

Further, in the above-mentioned production method, either the lipid or the fatty acid is mixed in advance with the electron transfer protein solution to be dropped on the water surface, and the mixed solution is dropped on the water surface to form a film on the water surface, which is then attached to a substrate for bonding. According to this, the lipid or fatty acid acts as a support for the molecule of the electron transfer protein, and the orientation of the electron transfer protein is adjusted.

Further, in order to improve the transfer of electrons between the metal electrode and the electron transfer protein membrane, the metal electrode should be 4,4′-bipyridyl (bipyridine).
ridyl), 2,2'-bipyridyl or the like.

Next, the function and effect will be described.

In FIG. 1, the first electron transfer protein film 18 is interposed between the electrode 17 and the electrode 20. However, if only the first electron transfer protein film 18 acts as a dielectric, it is between the electrodes 17 and 20. Insulation is maintained. However, as described above, when the first, second and third electron transfer protein films are aligned, accumulated, and adhesively bonded, electrons can be transferred between the electrodes 17 and 22. That is, the electrode 20 is insulative to the second electron transfer protein film 19, but by applying a voltage to this electrode 20, the second electron transfer protein film 19 can be electrically affected. it can. That is, the electrode 20 corresponds to the gate electrode of the conventional FET, and the electrodes 17 and 22 correspond to the source electrode and the drain electrode, respectively.

FIG. 3 (a) is a schematic diagram showing the voltage application state of the transistor element of this example, and FIG. 3 (b) is a diagram showing the redox potential state of each electron transfer protein membrane at this time. In FIG. 7B, the broken line shows the state before voltage application, that is, the OFF state, and V _O is the difference in redox potential between cytochrome c and flavodoxin (about 665 mV). In such a state, the voltage V ₁ is set between the electrodes 17 and 20 with the electrode 17 side being positive.
Voltage is applied between the electrodes 20 and 22 with the electrode 20 side being positive.
When V ₂ is applied, the redox potential state changes as shown by the solid line in FIG. 3 (b). That is, the redox potential of the first electron transfer protein 18 is positive by V ₁ ', the redox potential of the second electron transfer protein 19 is negative by vo', and the redox potential of the third electron transfer protein 21 is negative. It is increased by V2 ′, and electrons flow between the electrodes 22 and 17 to turn on.

If the distribution of the redox potential of each electron transfer protein is changed by controlling the above voltages V ₂ and V ₂ , the electrodes 17, 2
The current flowing between the two can be changed.

The change in the redox potential due to the above configuration and voltage application is
It is considered to be similar to the conventional semiconductor transistor (pnp junction type), and the transistor element can be realized as an element having an ultrafine size at the molecular level by the above configuration, and the device can be used for high density and high speed. An integrated circuit that can be realized is obtained.

An enzyme may be used to supply electrons to the electron transfer protein in the above examples.

The electron transfer proteins include non-heme-iron / sulfur proteins, cytochrome c type proteins, cytochrome b type proteins, cytochrome a, flavodoxin, plastocyanin, thioredoxin, etc., and each electron transfer protein is selected from these. At this time, the orientation between the molecules and the orientation with respect to the substrate on which the electrode is formed are selected to be suitable for electron transfer.

Further, in the above-mentioned embodiment, the case where the transistor element is composed of the cumulative film of two kinds of proteins has been described.
It may be configured as a cumulative film of more than one kind of protein.

Further, each electron transfer protein utilizes the property that electrons flow only in a certain direction between heterogeneous electron transfer proteins, so that electrons flow in the direction perpendicular to the cumulative film and are adjacent to each other in the direction parallel to the cumulative film. It is desirable that the electron transfer protein molecules be oriented by the LB method or the like so as to have a predetermined molecular arrangement so that electrons are not transferred between the molecules.

〔The invention's effect〕

As described above, according to the present invention, electron transfer proteins having different redox potentials form the first, second, and third electron transfer protein membranes, and the difference in the redox potential of each electron transfer protein is utilized. Since the transistor operation or the switching operation is performed by using the device, the transistor element size can be made close to the ultra-fine size at the biomolecule level, and the integrated circuit using the element can have higher density and higher speed. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a schematic sectional configuration diagram of a device incorporating a transistor element according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the device, and FIG. 3 (a) is a voltage application state of the transistor element. FIG. 3 (b) is a diagram showing the retox potential state of each electron transfer protein membrane, FIG. 4 is a schematic diagram of the electron transfer protein complex and its redox potential, and FIG. 5 is FIG. 6 is a schematic view showing the electron transfer system of the inner membrane of mitochondria, and FIG. 6 is a sectional view showing a conventional field effect transistor device. 17,20,22 ... Electrode, 18 ... First electron transfer protein membrane, 19 ... Second
Electron transfer protein membrane, 21 ... Third electron transfer protein membrane. The same reference numerals in the drawings indicate the same or corresponding parts.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 21/368 L 9277-4M 29/804

Claims (11)

[Claims] 1. A first electron transfer protein membrane made of a first electron transfer protein capable of transferring electrons in a certain direction, and a second electron transfer protein having a redox potential different from the redox potential of the first electron transfer protein. And a second electron transfer protein film that is cumulatively adhered and bonded on the first electron transfer protein film and a third electron transfer protein having a redox potential different from the redox potential of the second electron transfer protein. And a third electron transfer protein film accumulated and adhered on the second electron transfer protein film, and a third electron transfer protein film connected to the first and third electron transfer protein films, respectively.
1, a third electrode, and a second electrode for electrically affecting the second electron transfer protein membrane, and using the difference in redox potential of each electron transfer protein, transistor characteristics or switching characteristics A transistor element characterized by exhibiting: 2. The electron transfer protein is a non-heme-iron / sulfur protein, a cytochrome c type protein, a cytochrome b type protein, a cytochrome a, a flavodoxin, a plastocyanin, or a thioredoxin. The transistor element according to item 1. 3. The transistor device according to claim 1 or 2, wherein the electron transfer protein film is a monomolecular film. 4. The transistor device according to claim 1, wherein an enzyme is used to supply electrons to the electron transfer protein. 5. The transistor element according to claim 1, wherein each of the electrodes is a metal electrode or a chemically modified electrode obtained by chemically modifying the metal electrode with an organic molecule. . 6. The electron transfer protein membrane of each of the above-mentioned electron transfer proteins, in which electrons flow in a direction perpendicular to a membrane surface, which is a direction in which the respective membranes are accumulated, and between adjacent electron transfer protein molecules in a horizontal direction. The transistor element according to any one of claims 1 to 5, which is oriented so that electrons are not transferred. 7. The transistor device according to claim 1, wherein a lipid or a fatty acid is used as a support for orienting the electron transfer protein. 8. The transistor element according to claim 1, wherein the first electrode and the second electrode are arranged at right angles to each other. 9. The transistor element according to claim 8, wherein each of the first and second electrodes is a group of a plurality of parallel linear electrodes. 10. The transistor element according to claim 1, wherein the second electrode and the third electrode are arranged at right angles to each other. 11. The transistor element according to claim 10, wherein each of the second and third electrodes is a group of a plurality of parallel linear electrodes.