JPH0940934A - Material for electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material for a minute electronic device which is used in an in-vivo environment and does not allow the adsorption and flocculation of bioprotein on its surface by installing a silicon crystal having a low electric resistance on the surface to control the electric charge on it. SOLUTION: This material is used for a minute electronic device (e.g. a micromachine or a nanomachine) used in an in-vivo environment, and the electric charge of the surface of the material is controlled according to the net charge of a biopolymer or a biotissue (specifically protein) so that the adsorption and flocculation of bioprotein on the surface are inhibited. A minute machine made by using a silicon substrate causes a specific adsorption reaction (electrostatic interaction) with a polymer in a living body; however, the adsorption reaction can be inhibited by using a silicon crystal having its surface doped with a group V element when the net charge of the living body is negative or doped with a group III element when the net charge is positive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for forming a microelectronic device such as a micromachine and a nanomachine, and in particular, a microelectronic used in an environment in which a biopolymer and / or a tissue of a living body exists. It relates to materials for constructing the device.

[0002]

2. Description of the Related Art In recent years, a micromachine called a micromachine or a nanomachine (hereinafter abbreviated as M & N machine) has realized a very sensitive and minute sensor, and a robot for removing cells and treating in living tissue. There is a lot of research going on. M & N machine is the process technology of recent semiconductor, especially silicon integrated circuit,
In particular, the feasibility is expected due to the remarkable progress of the fine processing technology. And among semiconductors,
In particular, silicon has advanced process technology for microfabrication, has excellent mechanical characteristics, and has a built-in integrated circuit that enables one-chip and miniaturization. The miniaturization and high performance of machines using silicon are particularly expected.

[0003] Applications of M & N machines to sensors include:
A pressure sensor, an acceleration sensor, a temperature sensor, a flow meter, an ion sensor for chemical analysis, and the like have been devised. Among these, an example of application to a pressure sensor is shown in FIG. 11 [Reference; Esashi: “Semiconductor Micromechanical Machining and Sensor”, Sensor Technology, Vol. 114 (Showa 60)]. In the example shown in FIG. 11, the back surface side of the silicon substrate 50 is thinly processed by anisotropic etching to form the diaphragm 51. Further, a strain detecting gauge 52 made of polysilicon is installed on the surface of the silicon diaphragm 51. When pressure is applied to the diaphragm 51 of this thing,
The diaphragm 51 bends in proportion to the magnitude of the pressure, and the resistance value of the polysilicon strain gauge 52 on the diaphragm 51 changes. This change is detected by a bridge circuit via the electrode 53 to know the pressure value. As shown in the example of FIG. 11, it is understood that the microfabrication process technology of the silicon substrate is important in manufacturing the M & N sensor.

Next, an in-vivo working robot using an M & N machine will be described. Although this has not been realized yet, as one attempt, an array type cantilever actuator aiming to be applied as a moving foot of a self-propelled robot will be described. Figure 12 shows the outline [Reference; N. Takeshima and H. Fujita: "Poly.
imide Bimorph Actuators for a Ciliary Motion Syste
m ”1991 ASME WinterMeeting, DSC-Vol32 (Micromech
anical Sensors, Actuators, and Systems), pp.203-
209.]. In the example shown in FIG. 12, two kinds of thin films having different thermal expansion coefficients are laminated on a silicon substrate, and the substrate is made to run by the displacement of the thin films in the vertical direction. In FIG. 12, two types of polyimide thin films 61 and 62 having different thermal expansion coefficients are provided on a silicon substrate 60.
Are laminated so as to sandwich the nichrome wiring 63 (which functions as a heater) therebetween, and by being separated from the silicon substrate 60 via the hollow portion 64, they function as a cantilever. This cantilever is warped to one side due to residual stress in the initial state, but the nichrome wiring 6 in the center
Heat is generated by passing an electric current through 3, and as a result, it is displaced in the opposite direction like a bimetal. By carrying out this motion continuously, it is intended to realize an artificial micro robot that freely moves around in the living body.

Although the above is only one example of an M & N machine, the basic technology of the other than the one shown here is to create a minute artificial system by a fine processing process mainly using a silicon substrate. It is intended to be realized.

[0006]

As described above, in the M & N machine using silicon as the main semiconductor substrate, various sensing, removal of biological substances, and surgical treatment are performed in the living body and in the environment similar to the living body. However, when these M & N machines made of silicon substrates are immersed in a living body and an environment similar to the living body for a long time, molecules such as proteins, which are biological constituents, are adsorbed on the silicon surface. It became clear that they aggregated. When such biopolymer adsorption / aggregation occurs on the silicon surface, the movement function and the sensing function of the M & N machine are significantly deteriorated, and it becomes impossible to sufficiently function in the living body.

Therefore, one object of the present invention is to provide a material for electronic devices in which adsorption and aggregation of biological constituents such as biopolymers do not easily occur.

A further object of the present invention is to provide a silicon material which is less likely to adsorb and agglomerate biological constituents such as biopolymers for electronic devices such as M & N machines which use silicon as a main semiconductor substrate.

[0009]

A material for an electronic device according to the present invention is a material for constituting an electronic device used in an environment containing a biopolymer and / or a biological tissue, and has a biological height in the environment. It has a surface whose valence electrons are controlled according to the effective electrostatic charge of the molecule and / or biological tissue,
Thereby, adsorption and aggregation of biopolymers and / or biological tissues on the surface are suppressed.

The electronic device material according to the present invention is, for example, a predetermined material to which an impurity element for controlling valence electrons is added, and the impurity element concentration in the predetermined material is higher than that in the predetermined material. Also biopolymers and /
Alternatively, it may be raised in the surface portion to be brought into contact with the living tissue.

The material for electronic devices according to the invention can be applied in particular to micromachines or nanomachines. The micromachine is a micromachine manufactured mainly by using a silicon substrate by using a semiconductor microfabrication technology (micrometer level), and is applied to various sensors, robots and the like. Nanomachines are those that have raised the level of microfabrication of micromachines to the level of the nm level. With this level of machine, it is possible to work at the molecular level.

The electronic device material according to the present invention may be composed of a semiconductor crystal doped with an impurity element. The semiconductor includes a simple substance such as silicon and germanium and a compound such as GaAs and CdS. Further, the material of the present invention may be composed of other materials as long as the valence electrons can be controlled by doping with an impurity element, for example, a ferroelectric material such as barium titanate or strontium titanate. It can also be configured. Moreover, for valence electron control, the material of the present invention can have a PN junction. A semiconductor material having a PN junction can be applied to the present invention.

A particularly preferable material constituting the present invention is a silicon crystal. For doping an impurity element into a silicon crystal, an element of Group V of the periodic table is usually used for N-type doping, and a group III of the periodic table is used for P-type doping.
Group elements are used. When the effective electrostatic charge of the biopolymer and / or the biological tissue under the use environment is negative, the material of the present invention is preferably composed of a silicon crystal having a surface doped with a Group V element. On the other hand, when the effective electrostatic charge is positive, the material of the present invention is preferably composed of a silicon crystal having a surface doped with a Group III element.

In addition, biopolymer and //
Alternatively, when the biological tissue has a negative effective electrostatic charge, the surface of the biological polymer and / or the tissue to be in contact with the biological tissue is made of an N-type silicon crystal doped with an impurity element so as to have a lower electric resistance value than the inside. Inventive material can be constructed. On the other hand, when the effective electrostatic charge is positive, the material of the present invention can be composed of a P-type silicon crystal doped with an impurity element so that its surface portion has a lower electric resistance value than the inside.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In a biopolymer such as a protein, recognition between molecules in a living body or in an environment similar to that in a living body is mostly recognized by a geometrically specific structure and electrostatic property. It is performed by various interactions (electrostatic repulsion / attractive force, van der Waals force). In the interaction between molecules based on electrostatic energy, the slight difference in the spatial charge distribution on the outermost surface of each molecule is decisive for the degree of recognition between molecules and the ease of forming molecular aggregates. It is believed that this will have a significant impact. The present inventor has researched and developed an M & N machine using a semiconductor substrate typified by silicon for the purpose of sensing various biological constituent molecules in vivo, removing biological substances, surgical treatment, and the like. At some stage, it was found that the surface of the silicon substrate specifically causes an adsorption reaction with a biopolymer (specifically, protein).

[0016] In the apparatus shown in Fig. 1, when the present inventor brought a buffer solution containing a protein into contact with silicon as a substrate of an M & N machine, protein crystals were deposited on the silicon surface. It was found that the degree of conversion greatly depends on the type of silicon substrate. In the apparatus shown in FIG. 1A, the buffer solution 12 is contained in the container 11,
A dialysis membrane tube 13 is provided therein. A dialysis membrane tube 13 contains a mother liquor 14 containing a biopolymer and a Si crystal 15 doped with a predetermined impurity. The dialysis membrane tube 13 is sealed with a packing 16 and immersed in the buffer solution 12. The opening of the container 11 is covered with the film 17. In this device, as dialysis proceeds, biopolymer crystals are deposited from the mother liquor 14 on the Si crystals 15. Figure 1 (b)
In the device shown in (1), the buffer solution 22 is contained in the lower part of the container 21. On the other hand, a Si crystal 25 is placed on the upper portion of the container 21, and a droplet 24 of a mother liquor containing a biopolymer is placed thereon. Si on which the buffer solution 22 and the droplet 24 are placed
The opening of the container 21 containing the crystal 25 is closed by a cap 27. Then, a gentle equilibrium is established between the buffer solution 22 and the droplet 24 due to evaporation of volatile components in both, and biopolymer crystal precipitation is performed on the Si crystal 25.

In such an apparatus, for example, a water-soluble protein molecule has a negative effective surface charge under a certain pH condition, but in this case, a large number of protein crystals are deposited on the P-type silicon surface, Protein crystallization and aggregation may be suppressed on the N-type silicon surface. This phenomenon is interpreted as follows. When the effective charge on the surface of the protein molecule in the solution is negative, the P-type silicon surface and the protein molecule are in ohmic contact with each other, and holes are supplied from the silicon side, so that the protein molecule is electrostatically siliconized. It is adsorbed or aggregated on the surface. The same applies when the N-type layer is formed on the surface of the P-type silicon substrate,
The surface of the silicon substrate forms an ohmic contact surface with respect to molecules having a negative effective surface charge, so that the molecules are adsorbed or aggregated on the silicon surface. on the other hand,
When the effective charge of the protein molecule surface in the solution is negative, the N-type silicon surface and the protein molecule form a Schottky contact, and a space charge layer is induced near the silicon surface. The space charge layer capacitance is formed so as to be in balance with the electrostatic capacitance given by the sum of the electric double layer repulsive force on the protein solution side and the Van der Waals force. Therefore, in this case, since no carrier is supplied from the silicon side, it is presumed that protein molecules are hardly adsorbed on the silicon surface. The same applies to the case where the P-type layer is formed on the surface of the N-type silicon substrate, and since the silicon substrate is reverse-biased with respect to molecules having a negative effective surface charge, The space charge layer is induced and stabilized so as to balance with the electrostatic capacity given by the sum of the electric double layer repulsive force on the protein solution side and the Van der Waals force.

Further, the water-soluble protein molecule has a negative effective surface charge under a certain pH condition. In this case, many protein crystals are deposited on the surface of the N-type silicon of high resistance, while the N of low resistance is formed. It was also found that almost no protein crystallization occurred on the surface of the silicon type. This phenomenon is interpreted as follows. First, consider the case where a protein molecule having a negative effective surface charge is in contact with the silicon surface. Since the concentration of the dopant (for example, phosphorus atom) between the high resistance N-type silicon and the low resistance N-type silicon is high in the low resistance N-type silicon, the depletion layer width of the space charge layer induced near the surface of the silicon has a low resistance. It is narrower in N-type silicon. Therefore, since the depletion layer capacitance of the low resistance N-type silicon is larger than that of the high resistance N-type silicon, the surface potential of the low resistance N-type silicon is smaller than that of the high resistance N-type silicon. On the other hand, since the surface potential of the N-type silicon surface has a positive polarity, it is considered that electrostatic attraction acts between the biopolymer having a negative surface potential and the silicon surface. However, since the surface potential of the low resistance N-type silicon is lowered as described above, the electrostatic attractive force acting on the biopolymer is suppressed to a low level, and the low resistance N-type silicon is more effective than the high resistance N-type silicon surface. It is considered that crystallization and aggregation of the polymer did not occur easily.

From the above, when a biopolymer and / or a biological tissue having a negative effective surface charge is in contact with an N-type silicon substrate, impurities are doped so that the surface of the silicon substrate becomes N-type with low resistance. Is effective. Further, when a biopolymer and / or a biological tissue having a positive effective surface charge is in contact with a P-type silicon substrate, it is effective to dope the impurities so that the surface of the silicon substrate becomes P-type with low resistance. .

In general, the cohesiveness between charged substances or charged molecules in an electrolyte solution depends on the sum of the electric double layer repulsive force and the Van der Waals force between them. Therefore,
In the case of aggregating substances or molecules with each other, and in the case of limiting aggregation, it is very important to artificially control the salt concentration for adjusting the surface potential added to the electrolyte solution. However, such an operation is almost impossible in the actual living body. On the other hand, according to the present invention,
Since the electrostatic properties of the material surface are adjusted in advance by valence electron control, it is basically unnecessary to adjust the salt concentration. Also, adjusting the salt concentration is easy. When an electronic device such as an M & N machine applied in a living body is made of the material of the present invention, adsorption and aggregation of a substance such as a biopolymer on the device surface can be restricted by controlling valence electrons.
It is possible to maintain the function of the device for a long time without deteriorating in an environment containing a biopolymer and / or a living tissue.

The material of the present invention is a substance having the above-mentioned electrostatic properties, capable of controlling the amount of charge and polarity, and any substance that is chemically stable in a solution. Although it is good, one of the most preferable substances is silicon which is a semiconductor crystal.

The P-type and N-type silicon crystals to which the elements of group III and group V of the periodic table used in the present invention have the same characteristics as a silicon wafer used in a usual LSI process. Anything is fine. The specific resistance of the silicon crystal is preferably in the range of about 0.0001 to 1000 Ωcm, more preferably 0.000.
1 to 100 Ωcm, more preferably 0.000
It is 1 to 10 Ωcm.

The impurity concentration of the group III and group V elements in the periodic table used for doping in the present invention is 10 ¹²
The range of -10 ²¹ / cm ³ is desirable, and more desirably 1
0 ¹³ to 10 ²¹ / cm ³ , more preferably 10 ¹⁴
It is -10 ²¹ / cm ³ .

The crystal surface is preferably mirror-polished in order to suppress generation of extra crystal nuclei. Various methods are conceivable as a method for producing P-type and N-type valence electron-controlled silicon used in the present invention, and any method may be used, but the simplest and accurate control of the impurity concentration can be performed. An ion implantation method can be given as an example of the method. In the case of this method, P-type and N-type valence electron control can be easily performed by implanting and annealing ions of elements belonging to Group III and Group V of the periodic table into silicon. More preferably, boron (B) is the group III element and phosphorus (P) is the group V element.

In the present invention, when P / N type and N / P type junctions are formed in silicon, the thickness can be set as follows. First, in the case of N / P type junction, it is preferable to form a P type silicon layer on the surface of the N type silicon in a range of preferably 1 to 200 μm, more preferably 3 to 50 μm. The same is true for P / N type junctions,
It is preferable to form an N-type layer of similar thickness on the surface of P-type silicon.

In the present invention, when an N-type or P-type impurity layer is formed on the silicon surface to form a low resistance layer,
The thickness can be set to 1 to 200 μm, and 3 to 50
The range of μm is more desirable. When forming an impurity layer,
If the content is outside this range, the production may not be easy or the effect may be lost.

Although an example using silicon, which is a semiconductor crystal capable of controlling valence electrons, has been described above, in order to achieve the object of the present invention, it is not limited to silicon, and a substance having a similar function and a solution are used. Various substances can be used as long as they are stable. For example, inorganic compounds, organic compounds, organic polymers, etc., whose charge distribution is controlled, can be further cited as candidates. Further, a composite material in which a semiconductor, a metal, an organic compound, an inorganic compound, or the like is combined may be used.

FIG. 2 shows a schematic sectional structure of a specific example of the electronic device material according to the present invention. In the material shown in FIG. 2A, the low resistance material 32a is formed on the high resistance material 31a.
Is provided. The low resistance material 32a forms a surface with which a biopolymer or a biological tissue contacts. Such a structure can be obtained by forming a high resistance layer inside and a low resistance layer on the surface portion of a predetermined material. In order to obtain the low resistance layer, for example, the impurity element may be added to the surface portion in a predetermined material more than in the inside. A more specific example is shown in FIGS. In the material shown in FIG. 2B, the inside is made of high resistance N-type silicon 31b and the surface portion is made of low resistance N-type silicon 32b. Such a material is obtained, for example, by introducing an impurity element (for example, phosphorus) into the surface of an N-type silicon crystal in a larger amount than in the inside. In the material shown in FIG. 2C, the inside is made of high resistance P-type silicon 31c and the surface portion is made of low resistance P-type silicon 32c. Such a material is obtained, for example, by introducing a larger amount of an impurity element (for example, boron) into the surface of a P-type silicon crystal than inside. In the material shown in FIG. 2D, high resistance N type silicon 31d is formed on P type silicon 33, and low resistance N type silicon 32d is formed thereon. The low resistance N-type silicon 32d forms a surface that comes into contact with a biopolymer or a biotissue. Such a structure can also be obtained by adjusting the concentration of impurities introduced into silicon. FIG.
The material shown in (e) has a high resistance P on the N-type silicon 34.
The type silicon 31e is formed, and the low resistance P-type silicon 32e is formed thereon. Low resistance P type silicon 32
e forms the surface with which the biopolymer or biological tissue contacts. Such a structure can also be obtained by controlling the introduction of impurities.

The material of the present invention can be subjected to various microfabrications, for example, grooves can be formed by chemical anisotropic etching as shown in FIG. In the process of forming the groove, first, the Si substrate 41 is prepared (see FIG.
(A)) Next, the SiO ₂ film 42 is formed on the substrate 41 (FIG. 3B). After the SiO ₂ film 42 is etched into a predetermined pattern (FIG. 3C), the Si substrate is etched by, for example, ordinary anisotropic etching (FIG. 3D). By removing the SiO ₂ film, the Si substrate 41 ′ having the groove 43 is obtained.

The biological macromolecules and biological tissues under the environment in which an electronic device such as an M & N machine to which the present invention is applied are used are as follows. The biopolymer contained in the environment in which the electronic device is used is a series of molecules that mainly constitute a part of living tissue in the living body or are essential for the transmission of biochemical reactions and genetic information. Examples thereof include proteins and nucleic acids. More specific examples of biopolymers include DNA, RNA and their polymerase complexes, water-soluble proteins, hydrophobic membrane proteins mainly embedded in cells, receptor proteins and enzymes important for antigen-antibody reaction. , Hydrophobic proteins that make up membranes, enzymes that transfer electrons in cells, fibrous proteins,
Examples thereof include neurotransmitters, receptor proteins and enzymes, and viruses in nerve cells responsible for nerve transmission and information processing. On the other hand, the biological tissue is cells, muscle fibers, etc. that constitute various organs existing in the living body.
Examples of the biological tissue include, for example, nerve cells, hepatocytes, cells forming blood, muscle fiber cells, and cells forming other biological tissues.

[0031]

【Example】

[Precipitation of Protein on Silicon Crystal Surface] The following experiment was conducted in order to investigate the dependency of the protein crystal formed on the silicon surface defect density. Chicken egg white lysozyme (Lysozyme, from Chicken Egg White) pH = 9.1
8 ml of the standard buffer solution to a concentration of 50 mg / ml, and in an apparatus as shown in FIG.
Was encapsulated together with Si crystals in a dialysis tube that had been sufficiently washed by boiling. The following four types of silicon crystals were used. The resistivity of all P-type silicon is 10-20Ωc
m.

(1) Epitaxial wafer: P on
P +, with about 50 nm surface oxide film (2) Epitaxial wafer: P on P +, with surface oxide film removed (3) CZ wafer: P type, with about 50 nm surface oxide film (4) CZ wafer: P type, surface oxidation The film-removed CZ silicon wafer (wafer of silicon single crystal pulled by the Czochralski method) has about 10 surface crystal defects per unit square centimeter, whereas the epitaxial silicon wafer has almost no surface defects. By using these two crystals, the surface defect density dependence of the protein crystal can be investigated. The silicon crystals of (1) to (4) above were cut into a size of about 2 mm × 5 mm square, and immersed in a dialysis tube containing lysozyme in the apparatus as shown in FIG. 1 (a). Further, these dialysis tubes were immersed in a standard buffer solution (200 ml) having a pH of 8.9 and stored in a cool dark place at 10 ° C.

After storing in a cool dark place for 72 hours, the sample was taken out,
The crystals of lysozyme were observed by a microscope. 4 to 7 show the results. FIG. 4 shows (1) and FIG.
Corresponds to (2), FIG. 6 corresponds to (3), and FIG. 7 corresponds to (4) using the silicon crystal. As is clear from the figure, the presence or absence of defects on the crystal surface has no effect on the formation of crystal nuclei and crystal growth of lysozyme.

[Deposition of biopolymer negatively charged in solution on silicon crystal surface] The following experiment was carried out using an aqueous lysozyme solution having the same concentration as described above. The following silicon crystals were produced.

(1) P-type silicon sample A P-type silicon wafer having a specific resistance of 10 to 20 Ωcm and doped with boron by an ion implantation method.

(2) High-resistance N-type silicon sample N-type silicon wafer having a specific resistance of about 100 Ωcm.

(3) N-type silicon sample having a low resistance surface A sample obtained by doping phosphorus atoms by an ion implantation method on an N-type silicon wafer having a specific resistance of about 20 Ωcm. The specific resistance of the low resistance N-type silicon on the surface after ion implantation is about 0.1 Ωcm, and the phosphorus concentration is about 10 ¹⁷ / cm ³ . The low resistance N-type silicon layer has a thickness of about 5 μm.

The silicon of (1), (2) and (3) above was processed into a size of about 2 mm × 5 mm square, washed, and then dialyzed with 3 ml of an aqueous solution of lysozyme in the apparatus shown in FIG. 1 (a). It was enclosed in a tube. The pH of the external standard buffer solution was 8.90. FIG. 8, FIG. 9 and FIG. 10 show the results of lysozyme crystal growth on silicon after storage in a cool dark place at 10 ° C. for 72 hours. FIG. 8 corresponds to (1), FIG. 9 corresponds to (2), and FIG. 10 corresponds to (3) using the silicon crystal.

(1) P-type silicon sample When dialysis was performed with a buffer solution of pH = 8.90,
It can be seen that a large amount of lysozyme crystals are randomly deposited on the wafer surface.

(2) Sample of high resistance N-type silicon When dialysis is performed with a buffer solution of pH = 8.90,
It can be seen that a large amount of lysozyme crystals are randomly deposited on the wafer surface.

(3) Silicon sample whose surface has a low resistance N type When dialysis is performed with a buffer solution of pH = 8.90, only crystals of lysozyme are scattered and deposited, and a high resistance N type is formed. It can be seen that the amount of precipitation is much smaller than in the case of the silicon sample.

As shown in the above embodiments, the N-type silicon sample whose surface has a low resistance is compared with the P-type silicon sample and the high-resistance N-type silicon sample.
It can be seen that N-type silicon having a low surface is more suitable as a material constituting an M & N machine that should be applied in an environment containing a polymer that is negatively charged in a solution because of its remarkable crystal growth suppressing effect. .

[0043]

As described above, according to the present invention, when a microelectronic device such as a micromachine or a nanomachine is configured, in a living body and an environment similar to the living body,
Molecules such as proteins that are biological constituents are adsorbed on the device surface,
Agglomeration can be suppressed. By providing an electronic device such as an M & N machine using the material according to the present invention, it is possible to suppress the adsorption and aggregation of biological constituents such as a biopolymer, and to provide a device that can function for a long time in a living body. You can

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a specific example of an apparatus for conducting a biopolymer deposition experiment.

FIG. 2 is a schematic sectional view showing a specific example of a material for an electronic device according to the present invention.

FIG. 3 is a cross-sectional view showing an example of a process for processing the material of the present invention.

FIG. 4 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 5 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 6 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 7 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 8 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 9 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 10 is a micrograph of a crystal structure deposited in an experiment of an example.

FIG. 11 is a perspective view showing an example of an M & N machine sensor.

FIG. 12 is (a) a schematic sectional view and (b) a schematic plan view showing an example of an M & N machine actuator.

Claims (6)

[Claims] 1. A material for constructing an electronic device used in an environment containing a biopolymer and / or a biological tissue, the effective electrostatic charge of the biopolymer and / or the biological tissue in the environment. A material for an electronic device, which has a surface whose valence electrons are controlled according to the above, thereby suppressing adsorption and aggregation of the biopolymer and / or the biological tissue on the surface. 2. The electronic device material is a predetermined material to which an impurity element for controlling the valence electrons is added, and the concentration of the impurity element in the predetermined material is equal to that of the predetermined material. 2. The electronic device material according to claim 1, wherein the surface portion to be brought into contact with the biopolymer and / or the biological tissue is made higher than the inside thereof. 3. The electronic device according to claim 1, wherein the electronic device is a micromachine or a nanomachine.
A material for an electronic device according to. 4. The electronic device material according to claim 1, wherein the electronic device material comprises a semiconductor crystal doped with an impurity element. 5. A silicon crystal having a surface doped with a Group V element when the effective electrostatic charge is negative, and a surface doped with a Group III element when the effective electrostatic charge is positive. The material for an electronic device according to any one of claims 1 to 4, which is made of a silicon crystal. 6. N-type silicon doped with an impurity element such that when the effective electrostatic charge is negative, the surface portion of the biopolymer and / or the biological tissue to be contacted has a lower electric resistance value than the inside. If the effective electrostatic charge is positive, the biopolymer and / or
Alternatively, the surface portion to be brought into contact with the biological tissue is made of a P-type silicon crystal doped with an impurity element so that the electric resistance value thereof is lower than that of the inside thereof. The electronic device material described.