JP3018174B1 - Physical / chemical phenomena detector - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To output a change in a physical or chemical phenomenon as a change in an electron beam due to field emission, process two-dimensional detection signals of a physical or chemical phenomenon in parallel, and directly observe the distribution thereof. An apparatus for detecting physical and chemical phenomena, comprising: a field emission type micro electron source (13); and a physical / chemical phenomenon detection sensor (17, 22, 2) connected to the field emission type micro electron source.
3) a detection device having a pair of detection elements, etc., wherein the detection element controls the amount of electrons emitted from the field emission type small electron source (13) by the sensor, and the plurality of detection elements are at least They can be arranged one-dimensionally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting physical and chemical phenomena, and more particularly to controlling the potential of a field emission type micro electron source by the output voltage from various physical and chemical detecting devices, The phenomenon is collected by changing the amount of electron beam. Further, the phenomenon is observed in one or more dimensions. Further, the present invention relates to a device for observing and measuring physical and chemical phenomena.

[0002]

2. Description of the Related Art Here, physical / chemical phenomena include light, ion concentration, magnetism, pressure, acceleration, and velocity in a broad sense, such as temperature, visible light, ultraviolet light, infrared light, X-rays, and electromagnetic waves. , Sound waves, ultrasonic waves, oxidation-reduction potential, and reaction rate. Conventionally, these phenomena are caused by temperature sensors,
Using elements called optical sensors, physical sensors, and chemical sensors, they were observed after being converted into various electrical signals representing current, voltage, resistance, capacitance, potential, and the like.

For example, in the case of a pyroelectric sensor, which is a typical temperature sensor, when the temperature changes, an electric charge is generated in the pyroelectric body, and the resulting potential change is amplified and read by, for example, an FET. A photodiode, which is a typical optical sensor, extracts electric charges generated by light in the form of electric current. A pressure sensor using a piezoresistance effect, which is a typical physical sensor, reads a resistance change due to pressure. In addition, ISFET (Ion Sensitive Field Effect Transistor) is a typical chemical sensor.
The pH measuring apparatus using (or) measures the pH value of the solution by measuring the current flowing through the ISFET, utilizing the phenomenon that the channel conductance changes due to the adsorption of hydrogen ions to the responsive film.

[0004] However, these conventional pyroelectric sensors, optical sensors, pressure sensors using the piezoresistive effect, or chemical sensors are usually used alone.
A plurality of detection elements are arranged in one or more dimensions, for example, two-dimensionally,
It has been very difficult to simultaneously obtain two-dimensional information from an inspection object and to two-dimensionally image it as it is.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is intended to output a change in a physical or chemical phenomenon as a change in an electron beam due to field emission. By arranging various sensors and field emission devices that form a pair with them in a two-dimensional manner, for example, the two-dimensional detection signals of physical and chemical phenomena are processed in parallel, and the distribution can be directly observed. It is assumed that. Further, it is another object of the present invention to realize an image apparatus suitable for observation with high resolution and high sensitivity by making use of the characteristics of an electron beam that can be easily accelerated and deflected.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a physical / chemical phenomenon detecting device, comprising a field emission type micro electron source and a physical / chemical phenomenon detection sensor connected to the field emission type micro electron source. And a sensor for controlling the amount of electrons emitted from the field emission type micro electron source.

This field emission type micro electron source is a detection device having a gate electrode near the tip thereof.
This is a detection device in which a plurality of detection elements are arranged at least one-dimensionally.

[0008] Further, the detection device is a temperature sensor in which the sensor is formed by a set of a pyroelectric body and an FET, and an output of the pyroelectric body is connected to a gate of the FET.

The sensor is a photodetection sensor having a semiconductor pn junction consisting of a p-type base portion and an n-type portion;
This is a detection device in which a field emission type micro electron source is arranged on the surface of a mold portion. This photodetection sensor is a detection device formed on a substrate that can transmit light. This is a detection device that is a pn junction that causes avalanche multiplication inside.

[0010] Alternatively, the sensor is a pressure detecting sensor, and the pressure detecting sensor is a pressure detecting device having a piezoresistive element.

Further, the present invention is a detecting device in which an anode is disposed so as to face a field emission type micro electron source, and at least one focusing electrode or at least one focusing electrode is provided between the anode and the field emission type micro electron source. This is a detection device in which a deflection electrode is arranged, and has a fluorescent film on an anode and enables two-dimensional observation of an electron distribution which is an output of a plurality of field emission type micro electron sources.

Further, the present invention is a detection device in which an anode is capable of detecting, as an electric signal, a distribution of electrons output from a plurality of field emission type micro electron sources, and detects electrons emitted from the field emission type micro electron source by the anode. A detection device that accelerates and causes electron amplification, and adds a capacitor to a field emission type microelectron source, and further adds a means for emitting electrons at a predetermined time interval, so that the capacitor has a predetermined time interval. And a detecting device having means for sequentially reading out the signals stored in the capacitor.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In field emission, electrons are emitted from the surface of a metal or semiconductor under a strong electric field. The electrons are emitted to the outside through the surface potential barrier by the quantum mechanical tunnel effect, and the density of the emitted current changes depending on the change in the electric field intensity on the surface.

The present invention realizes a physical / chemical phenomenon detection device suitable for high-resolution and high-sensitivity observation by utilizing characteristics of an electron beam such as easy acceleration and deflection. The present invention is effectively applied to an apparatus for imaging a phenomenon by one or more dimensions of an event. That is, the output of the physical and chemical phenomena is converted into an electron beam and output, and the physical and chemical phenomena are converted into two.
Provided is a device capable of simultaneously acquiring, measuring, and observing a dimensional output distribution.

The physical and chemical phenomena in the present invention include light, concentration, temperature, magnetism, pressure, acceleration, velocity, sound waves, and ultrasonic waves in a broad sense such as visible light, ultraviolet light, infrared light, X-rays, and electromagnetic waves. , Oxidation-reduction potential, reaction rate, and various other physical and chemical phenomena. In the prior art, these phenomena were observed after being converted into various electric signals such as current, voltage, resistance, capacitance, and potential.
A detection element for converting a chemical phenomenon into an electron beam is devised, and the elements are arranged in at least one dimension so that the distribution can be observed.

In order to achieve the above object, the field emission type micro electron source in the detecting element according to the present invention is arranged so as to be electrically separated, and its electric potential is controlled by physical and chemical phenomena. And control the amount of electron beams emitted from the field emission microelectron source. Further, since the output is an electron beam, it can be integrated in one or more dimensions, and can be operated in parallel. Therefore, it is possible to easily observe the two-dimensional distribution of physical and chemical phenomena.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described here is merely an example, and the present invention is not limited to the following embodiment. Those skilled in the art can make various modifications and implementations within the scope of the present invention. In the description of the following embodiments and the drawings, similar elements are denoted by the same reference numerals.

FIG. 1 is a sectional view of a main part of a temperature detecting element according to a first embodiment of the present invention. For example, two n-diffusion regions 11 and 12 serving as a source and a drain of an FET are formed on a p-type silicon substrate 10, and a field emission fine electron source 13 is formed on one of the regions 12. A thin gate oxide film 14 is formed on the substrate surface between the two n diffusion regions 11 and 12, and a polycrystalline silicon or metal gate electrode 15 is formed thereon. The n-diffusion region 11 where the micro electron source 13 does not exist is normally connected to the ground line 16 and is kept at the ground potential. This structure is the same as the drain side 1 of the MOSFET structure usually used.
This is equivalent to a structure in which the microelectron source 13 is manufactured.

Adjacent to the polycrystalline silicon or metal electrode 15 corresponding to the gate electrode of the MOSFET, for example, P
ZT (Lead (Pb) Zirconate Titanate), PLZT (Lead
A pyroelectric body 17 such as ad (Pb) Lanthanum Zirconate Titanate) or PVDF is formed on the same silicon substrate 10. FIG. 2 shows a pair of a micro electron source 13 and a pyroelectric body 17 arranged above a MOSFET formed in a matrix on the surface of a silicon substrate 10. 16 is a ground line.

In the vicinity of the upper portion of the micro electron source 13, a gate electrode 18 for extracting electrons is arranged. For example, a DC voltage of +100 V is applied to the gate electrode 18. Then, the electrons emitted from the minute electron source 13 reach the anode 19 and are observed as a current. Normally, for example, +1000 V is applied to the anode 19.

When the amount of heat applied to the pyroelectric body 17 changes and the potential generated in the pyroelectric body 17 changes, the change is represented by M
By transmitting the current to the gate electrode 15 of the OSFET, the current flowing between the source and the drain changes, and the minute electron source 13
The amount of electrons emitted from the substrate.

This temperature detecting element can measure not only the temperature distribution but also the light intensity.
For example, when infrared light is incident, the intensity and time change of the incident infrared light can be observed by measuring the temperature rise of the pyroelectric body 17 due to heat generated by the infrared light. For example, when a pyroelectric material such as PZT is used, infrared light having a wavelength of about 10 microns can be efficiently detected. There is no device that detects infrared light of about 2 microns or more and emits electrons corresponding to the amount of infrared light.

Further, by arranging the detecting elements in at least one dimension in an array, it is possible to measure the temperature or the spatial distribution of infrared irradiation. FIG. 2 shows a two-dimensional arrangement of the temperature detecting elements.

FIG. 3 is a sectional view of a main part of a photodetector according to a second embodiment of the present invention. The structure is such that a field emission microelectron source 13 and a silicon pn junction 22 in which an n-type diffusion layer 20 is formed on a p-type single crystal silicon substrate 10 are connected in series. The anode 19 is an n-type micro electron source 13
Is used by applying a positive voltage to. Further, a gate electrode 18 is formed near the micro electron source 13 in FIG. When the light is not irradiated, the n-type region 20 below the microelectron source 13 is in an electrically floating state, so that the potential is increased by emitting electrons in the n-type region 20. . As a result, the pn junction 2 between the tip and the base
2, a depletion layer corresponding to the potential of the n-type region 20 expands.
The potential of the tip 21 of the microelectron source 13 is controlled by the gate electrode 18.
To a value obtained by dividing the threshold voltage of the microelectron source 13 from the voltage of the microelectron source 13, and a state of equilibrium is reached. At this time, only the threshold voltage of the minute electron source 13 is applied between the minute electron source 13 and the gate electrode 18, and no field emission occurs.

Next, when light is applied to the microelectron source 13 in this state, the light is absorbed by the depletion layer between the tip and the base, and electron-hole pairs are generated. Then, the electrons are collected at the tip 21 of the electron microelectron source 13 and the potential of the n-type region of the electron microelectron source 13 decreases. As a result, the above-mentioned equilibrium state is broken, and the electrons collected in the n-type region are emitted from the small electron source 13. When the light irradiation stops, the state returns to the equilibrium state again. When an electric field of 3 × 10 ⁵ V / cm or more is applied to the pn junction 22, electrons generated by light multiply by an avalanche in the depletion layer, and more than one electron per incident photon. Can be released.

The photodetector according to the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, in the above-described embodiment, a description has been given of a three-electrode element in which the microelectron source 13 has the gate electrode 18 and the anode 19; Although the scanning function has not been described in the above embodiment, the scanning function can be provided by temporally changing the voltage applied to the gate electrode 18. It is also possible to use a quadrupole element to which a converging electrode for converging the emission current or a deflection electrode for controlling the direction of the electron flow is added (not shown).

Further, as for the pn junction, the case where single crystal silicon is used has been described, but an amorphous silicon-based thin film can also be used. Further, as shown in FIG. 5, it is also possible to integrally form the element and the anode manufactured in a two-dimensional array form. In this case, as shown in FIG. 5, the anode 19 and the element can be sealed by a sealing member 27 and the inside thereof can be maintained at a vacuum.

FIG. 4 shows an embodiment as a pressure detecting element.
You. For example, SOI (Si
licon On Insulator) Field emission micro electron source on a part of the substrate
13 and in series with it, for example, n-type silicon.
A piezo resistor made of a material that can
The resistance element 23 is connected. Piezoresistive element 23
The other terminal is fixed at the ground potential. Piezo resistance
SiO 2 on the back surface of the element 23 _TwoConnected via membrane 25
The silicon substrate 24 is, for example,
Etched with an anisotropic etchant such as
A recess 28 is formed. Piercing for pressure changes from the back
Silicon substrate 24 so that zo-resistive element 23 is sensitive
Is thinned.

The operation will be briefly described. In the equilibrium state where no pressure is applied, the potential of the microelectron source 13 is a potential obtained by subtracting the threshold value of the microelectron source 13 from the potential of the anode 19 and further adding a voltage drop by the piezoresistive element 23. Therefore, electrons corresponding to the emission are emitted. When the pressure changes and the resistance value of the piezoresistive element 23 changes, the potential of the microelectron source 13 also changes, and changes from the amount of emitted electrons when no pressure is applied.

By arranging the detection elements in one or more dimensions, it is possible to detect the spatial distribution of pressure. Also, 2
It is also possible to integrally form the element and the anode 19 formed in a dimensional array. In this case, as shown in FIG. 5, each element can be sealed and kept in a vacuum.

FIG. 5 shows one method of imaging according to the present invention. In the present invention, since the output is taken out in the form of an electron beam, the individual elements are arranged two-dimensionally as in the embodiment shown in FIG.
In the direction of emission of the electron beam. The anode 19 can be formed, for example, by attaching a transparent electrode member to a glass substrate 26. If a material in which a phosphor is applied to the surface of the transparent electrode member is used, a two-dimensional distribution of the intensity of the electron beam can be observed as a light emission intensity distribution of the phosphor. The element structure at this time may be either with or without the gate electrode 18.

In another imaging method, for example, the individual elements shown in the above embodiment are two-dimensionally arranged.
Then, a mechanism for sequentially switching the gate electrode 18 of each element for each element is formed. This mechanism can be formed using, for example, a shift register formed on the silicon substrate 10 on which the microelectron source 13 is formed or on another substrate (not shown). In addition, anode 1
As 9, any conductive material such as a metal plate, a semiconductor film such as silicon, a glass substrate with a surface electrode, or a phosphor coated thereon may be used.

By switching the gate electrode 18 in order, the output signal of each element reaches the anode 19 in order, so that the current flowing through the anode 19 is monitored and the timing of switching the gate 18 is corresponded. The output value of the element at the location can be known. In other words, by switching the gate voltage and synchronizing the output signal, the detected two-dimensional information can be displayed on a monitor such as a television or a monitor of a computer. In this way, it is possible for the anode 19 to detect, as an electric signal, the distribution of electrons output from the plurality of microelectron sources 13.

As shown in FIG. 7, a laminated material such as molybdenum 41 and amorphous silicon 42 is used as the anode 19, and a voltage of, for example, about 10 KV is applied to the anode 19. It is also possible to sufficiently accelerate the electrons emitted from the microelectron source 13 to cause, for example, impact ionization in the amorphous silicon 42 to amplify the electrons. As amorphous silicon in this case, for example, hydrogenated amorphous silicon is suitable.

Further, by adding a capacitor to the microelectron source 13 and adding a means for emitting electrons at a predetermined time interval, an electric signal at a predetermined time interval is stored in the capacitor. Then, by sequentially reading out the signals stored in the capacitor, it is possible to output the distribution of electrons output from the micro electron source 13 as an electric signal.

For example, FIG. 8 shows an embodiment of an element structure capable of performing the above operation. The light receiving area and the electron storage area are a semiconductor pn junction (p-Si substrate 47, n-Si area 44).
And the n-Si region 44 is electrically floating. Then, the p-Si substrate 47, the n-Si region 4
4, 48, the gate insulating film 46, and the gate electrode 45 form a transistor. When a voltage equal to or higher than the threshold value of the transistor is applied to the gate electrode 45 of the transistor, the electrons accumulated in the region 44 move to the small electron source region 13 and the electrons are emitted. Then, the area 44
Is reverse biased to a value obtained by removing the threshold voltage of the microelectron source 13 from the voltage of the gate 18 of the microelectron source 13, and when the voltage applied to the gate electrode 45 disappears, the region 44 floats electrically again. State, and p corresponding to the capacity 43
The depletion layer of the n-junction spreads. When light or the like enters this region, electrons are generated and accumulated in the region 44. Again the gate electrode 4
When a voltage equal to or higher than the threshold value of this transistor is applied to the transistor 5, the electrons accumulated in the region 44 are removed from the small electron source region 13.
And electrons are emitted. A signal can be read by repeating the above.

FIG. 6 shows a method for forming a basic micro electron source 13. For example, the silicon substrate 30 is thermally oxidized to about 30
A 0 nm SiO ₂ film 31 is formed (a). Then the diameter 4
Patterning is performed so that the SiO ₂ film 32 of about a micron remains (b). Using the SiO ₂ film 32 as a mask, the silicon substrate 3 isotropically formed by dry etching or the like.
0 is etched to form the tip 33 of the microelectron source 13 (c). Next, an SiO ₂ film 34 of about 10 nm is formed by oxidation for the purpose of sharpening the tip 33 and electrical insulation (d).

Further, an SiO ₂ film 35 is deposited thereon by about 1 μm by an electron beam evaporation method or the like, and a metal film 36 such as molybdenum or the like to be a gate electrode is deposited thereon by about 2 μm.
Deposit 00 nm (e). Thereafter, exposed portions of the SiO ₂ and edge coating by dipping the device into hydrofluoric acid, SiO ₂ film 32 on the distal end portion 33 of the micro electron source 13,
By removing the metal film 35 and the metal film 36, a diameter of 3 μm is obtained.
The micro electron source 13 having a height of about 1 μm and a height of about 1 μm is completed (f).

As shown in FIG. 1, one embodiment of the manufacturing method in the case where the micro electron source 13 is formed on the drain 12 will be described below. For example, after performing the above-described processes (a) to (c) (until the gate metal is deposited), a general MOS
A transistor process is performed to form a gate oxide film of the transistor and a gate electrode (polycrystalline silicon) of the transistor. At this time, the gate electrode of the microelectron source is simultaneously formed using polycrystalline silicon. Then the sauce,
The drain region (where the microelectron source is manufactured) is formed by diffusion or ion implantation technology. The structure of FIG. 1 can be formed by the steps described above.

The pyroelectric body 17 is formed on the substrate 10 by using any method such as vapor deposition, sputtering, and vapor phase growth.
After a pyroelectric film is formed under appropriate conditions, the pyroelectric film is patterned and formed by photolithography. If necessary, a lift-off method can be used.

[0041]

As described above, according to the present invention, the amount of electrons emitted from a microelectron source can be varied by controlling the potential of the microfield emission type microelectron source with a physical / chemical sensor or the like. By converting the physical / stoichiometric amount into the amount of the electron beam, the spatial distribution can be easily observed using the detection elements of the present invention arranged in one or more dimensions. In addition, by arranging this element two-dimensionally, adding capacitance to its detection element, accumulating signals for a certain period of time, and outputting it in time series, it can be applied to high-sensitivity imaging elements of physical and chemical phenomena. Can be.

While several embodiments of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a main part of a temperature detecting element of the present invention.

FIG. 2 is a diagram showing a structure in which a temperature detecting element of the present invention is two-dimensionally arranged.

FIG. 3 is a diagram showing a cross section of a main part of the photodetector of the present invention.

FIG. 4 is a diagram showing a cross section of a main part of the pressure detecting element of the present invention.

FIG. 5 is a cross-sectional view illustrating an imaging method according to the present invention.

FIG. 6 is a diagram showing a method for forming a micro electron source.

FIG. 7 is a diagram showing a detection element by electron multiplication of the present invention.

FIG. 8 is a diagram showing a capacitance addition detecting element of the present invention.

[Explanation of symbols]

Reference Signs List 10 p-type silicon substrate 11, 12 n-diffusion region 13 electron source 14 gate oxide film 15 gate electrode 16 ground line 17 pyroelectric 18 electron source gate electrode 19 anode 20 n-region 21 ... tip 22 ... pn junction of the electron source 23 ... piezoresistive element 24 ... silicon substrate 25 ... SiO ₂ film 26 ... substrate 27 ... sealing member 28 ... recess 30 ... silicon substrate 31, 32, 34, 35 ... SiO ₂ film 33 ... Tip 36 ... Metal film 41 ... Molybdenum 42 ... Amorphous silicon 43 ... Capacitance 44, 48 ... n-Si region 45 ... Gate electrode 46 ... Gate insulating film 47 ... p-Si substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI G01L 5/00 101 G01L 5/00 101Z H01J 31/12 H01J 31/12 C H01L 29/84 H01L 29/84 B (56) Reference Document JP-A-10-54759 (JP, A) JP-A-9-134685 (JP, A) JP-A-9-63467 (JP, A) JP-A-9-45226 (JP, A) 17328 (JP, A) JP-A-9-15259 (JP, A) JP-A-4-88745 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 1/18 G01D 7 / 00 G01J 1/02 G01J 5/02 G01K 7/00 G01L 5/00 H01J 31/12 H01L 29/84

Claims (16)

(57) [Claims] An apparatus for detecting physical and chemical phenomena, comprising: a detection element having a field emission type micro electron source; and a physical and chemical phenomenon detection sensor connected to the field emission type micro electron source, A detection device, wherein the sensor controls an amount of electrons emitted from the field emission type micro electron source. 2. The detecting device according to claim 1, wherein the field emission type micro electron source has a gate electrode near a tip thereof. 3. The detecting device according to claim 1, wherein a plurality of the detecting elements are arranged at least one-dimensionally. 4. The sensor according to claim 1, wherein the sensor is formed by a set of a pyroelectric element and an FET, and an output of the pyroelectric element is a temperature sensor connected to a gate of the FET. Item 4. The detection device according to any one of items 3. 5. The sensor according to claim 1, wherein the sensor is a photodetection sensor having a semiconductor pn junction including a p-type base portion and an n-type portion, and the field emission type small electron source is arranged on a surface of the n-type portion. The detection device according to any one of claims 1 to 3, wherein: 6. The detection device according to claim 5, wherein the light detection sensor is formed on a substrate that can transmit light. 7. The pn junction according to claim 4, wherein the pn junction causes avalanche multiplication in a depletion layer.
The detection device according to claim 1. 8. The detection device according to claim 1, wherein the sensor is a pressure detection sensor. 9. The detecting device according to claim 7, wherein the pressure detecting sensor has a piezoresistive element. 10. The detection device according to claim 1, wherein an anode is arranged to face the field emission type micro electron source. 11. The detection device according to claim 10, wherein at least one focusing electrode or deflection electrode is disposed between the anode and the field emission type micro electron source. 12. The apparatus according to claim 10, wherein the anode has a fluorescent film, and an electron distribution, which is an output of the plurality of field emission type micro electron sources, can be observed two-dimensionally. The detection device according to claim 1. 13. The detection device according to claim 10, wherein the anode is capable of detecting, as an electric signal, a distribution of electrons output from the plurality of field emission type micro electron sources. . 14. The detection device according to claim 10, wherein electrons emitted from the field emission type micro electron source are accelerated by the anode to cause amplification of the electrons. 15. A capacitor is added to the field emission type micro electron source, and a means for emitting electrons at a predetermined time interval is added, so that the electric signal at the predetermined time interval is stored in the capacitor. The detection device according to any one of claims 1 to 13, wherein: 16. The detection apparatus according to claim 15, further comprising means for sequentially reading out the signals stored in said capacitance.