JPH07247199A - Method of manufacturing visible light-emitting silicon and method of manufacturing element using the same - Google Patents

Abstract

(57) [Summary] [Purpose] Visible light emission equivalent to that of porous silicon is possible, and it is also possible to easily control the size such as film thickness and shape according to the function of the device. It is an object of the present invention to provide a method for producing silicon and a method for producing an element using the same. [Structure] Amorphous silicon containing no hydrogen atoms is produced, and this amorphous silicon is crystallized to produce ultrafine crystalline silicon. Further, the ultrafine crystalline silicon produced as described above is irradiated with light. By immersing in a mixed solution containing hydrofluoric acid and performing etching, visible light emitting silicon (visible light emitting microcrystalline silicon) is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing visible light-emitting silicon and a method for producing an element using the same.
More specifically, the present invention relates to a method for producing visible light-emitting silicon that exhibits luminescence emission in the visible region equivalent to that of porous silicon (porous silicon), and a method for producing an element using the same.

[0002]

BACKGROUND OF THE INVENTION Conventionally, silicon (Si) has been an indirect transition type semiconductor and has a band gap of "1.1e".
Since it is in the near-infrared region as V, it has been considered difficult to apply it as a light emitting device in the visible light region.

However, in recent years, hydrofluoric acid (HF)
It is shown that porous silicon produced by anodizing silicon in the chemical conversion liquid shows strong photoluminescence emission of visible light at room temperature, and it can be used as a light emitting device using silicon or on the same silicon substrate. It was expected to open the way for the development of optoelectronic devices in which light emitting devices and electronic devices were formed.

However, since porous silicon is manufactured by anodization, it is impossible to control the size such as film thickness and shape required when it is applied as an element. It has been pointed out that it is extremely difficult to apply, it can emit visible light as well as porous silicon, and can easily control the size such as film thickness and shape. There has been a strong demand for the production of silicon applicable as a device.

The present invention has been made in view of the above-mentioned demands, and an object thereof is to enable visible light emission equivalent to that of porous silicon and to provide a film thickness and a shape corresponding to the function of the element. It is intended to provide a method of manufacturing visible light-emitting silicon and a method of manufacturing an element using the same, in which the sizes of the above can be easily controlled.

[0006]

In order to achieve the above object, in the method for producing visible light-emitting silicon according to the present invention and the method for producing an element using the same, amorphous silicon containing no hydrogen atom is produced. , This amorphous silicon is crystallized to produce ultra-fine crystalline silicon, and the ultra-fine crystalline silicon produced as described above is dipped in a mixed solution containing hydrofluoric acid under light irradiation and etched. By doing so, visible light emitting silicon (visible light emitting microcrystalline silicon) is manufactured.

[0007]

The visible light emitting microcrystalline silicon produced as described above has dangling bonds on its surface terminated with at least hydrogen atoms or oxygen atoms, and thus has a visible light equivalent to that of porous silicon. It will emit light.

Further, in the method for producing visible light emitting silicon and the method for producing an element using the same according to the present invention, visible light emitting microcrystalline silicon or a thin film of visible light emitting microcrystalline silicon is formed by using thin film forming technology or planar processing technology without performing anodization. Since the element is manufactured using it, it is possible to easily control the size such as the film thickness and the shape according to the function of the element, so that it is possible to manufacture a light emitting element of any size. Further, it becomes possible to manufacture an optoelectronic element in which a light emitting element and an electronic element are formed on the same silicon substrate.

[0009]

Embodiments of the method for producing visible light-emitting silicon and the method for producing an element using the same according to the present invention will be described below in detail with reference to the drawings.

First, an embodiment of the method for producing visible light emitting silicon according to the present invention will be described.

[First Step: Production of Amorphous Silicon] Amorphous silicon having a desired thickness is formed on a silicon substrate by a thin film production technique such as an electron beam heating method or a sputtering method from a high-purity silicon single crystal. Form a thin film.

That is, using a high-purity silicon single crystal as a source material, an amorphous silicon thin film having a desired thickness is formed on a silicon substrate by an electron beam heating method in an ultrahigh vacuum.

Further, using a high-purity silicon single crystal as a target material, an amorphous silicon thin film having a desired thickness is formed on a silicon substrate by a sputtering method in an argon (Ar) atmosphere.

In the above-mentioned amorphous silicon thin film forming process, hydrogen is completely removed by extracting hydrogen gas by using the getter action of titanium to prevent the bonding between silicon atoms and hydrogen atoms. Amorphous silicon not containing is formed.

Further, the substrate temperature of silicon is set to about 2
By keeping the temperature below 50 ° C., the crystallization of the amorphous silicon formed on the substrate is surely prevented.

FIG. 1 shows an electron beam vapor deposition apparatus for carrying out the electron beam heating method described above, which includes a vacuum chamber 10, an electron beam generation source 12 arranged in the vacuum chamber 10, and an inside of the vacuum chamber 10. And a silicon substrate 20 at a temperature of about 250 ° C. and a group of pumps including a sublimation pump 14, a diffusion pump 16 and a rotary pump 18 for making the chamber ultra-vacuum.
Substrate temperature controller 2 that controls to hold below
2 and.

In the electron beam evaporation apparatus constructed as described above, a high-purity silicon single crystal is arranged as the source material 24. Then, the electron beam emitted from the electron beam generation source 12 collides with the source material 24 to emit silicon atoms from the source material 24. In this way, the silicon atoms released from the source material 24 adhere to the silicon substrate 20 and form an amorphous film on the silicon substrate 20.
Form a thin film of silicon.

FIG. 2 shows a sputtering apparatus for carrying out the above-mentioned sputtering method, and the components common to those of the electron beam evaporation apparatus of FIG. The description is omitted.

In this sputtering apparatus, argon gas is introduced into the vacuum chamber, and the ionized Ar ⁺ ions are made to collide with the target material 26 under the control of the high-frequency controller 21, so that the silicon atoms released from the target material 26 are removed. Attached to the silicon substrate 20,
A thin film of amorphous silicon is formed on the silicon substrate 20.

[Second Step: Crystallization of Amorphous Silicon: Preparation of Ultrafine Crystalline Silicon] The amorphous silicon prepared in the first step is heat-treated in an argon atmosphere. At this time, the heat treatment temperature and the heating time are appropriately controlled to form a thin film of silicon fine particles having a crystal size of several nm to several tens of nm. In this specification, a thin film of fine silicon particles formed by crystallizing amorphous silicon is referred to as "ultrafine crystalline silicon" in the present specification.
Is called.

FIG. 3 shows a heating device for carrying out the above heat treatment, and a quartz tube 30 in which a silicon substrate 20 on which a thin film of amorphous silicon is formed is placed in an electric furnace.
Are installed. In the quartz tube 30, oxygen (O ₂ )
A gas supply system 32 for supplying gas, hydrogen (H ₂ ) gas, nitrogen (N ₂ ) gas and argon gas,
The above various gases are introduced according to the use. And
An electric furnace is arranged so as to surround the quartz tube 30.

Further, a thermocouple 34 is arranged in the quartz tube 30, and the temperature and heating time of the silicon substrate 20 are controlled by the temperature controller 36.

Therefore, in the above-mentioned heating device, the crystal size can be several nm to several tens nm by appropriately controlling the heat treatment temperature and the heating time by the temperature controller 36.
The ultra-fine crystalline silicon with the silicon fine particles is prepared from amorphous silicon.

[Third Step: Making Ultrafine Crystalline Silicon Visible Light Emitting: Preparation of Visible Light Emitting Microcrystalline Silicon] The ultrafine crystalline silicon produced in the second step was exposed to hydrofluoric acid (H
It is immersed in a mixed solution of F) and ethanol (EtOH) and etched to terminate dangling bonds on the surface of ultrafine crystalline silicon with hydrogen atoms and oxygen atoms.

FIG. 4 shows an apparatus for terminating the surface of ultra-fine crystalline silicon with hydrogen atoms and oxygen atoms. In the Teflon berth 42 placed on the ultrasonic heating table 40, there is shown an apparatus. , A mixed solution of hydrofluoric acid and ethanol is filled, and the silicon substrate 20 having ultrafine crystalline silicon formed on the surface thereof is immersed therein. And the ultrasonic heating table 4
0 controls the temperature of the mixed solution of hydrofluoric acid and ethanol, and etching is performed under the irradiation of light from a light source 44 such as a mercury lamp or a tungsten lamp to dang the surface of the ultrafine crystalline silicon. The ring bond is terminated with hydrogen atoms and oxygen atoms.

When the light source 44 irradiates the light, a filter 46 that transmits only a predetermined wavelength is provided to control the wavelength of the light irradiating from the light source 44 or to efficiently irradiate the silicon substrate 20 with the light. As shown in FIG.
The light flux may be condensed by means of.

The ultrafine crystalline silicon thus terminated with hydrogen atoms or oxygen atoms exhibits an emission spectrum as shown in FIG. 5 at room temperature, similar to porous silicon. That is, the ultrafine crystalline silicon functions as a light emitting portion that emits photoluminescence at room temperature, and silicon that emits visible light (visible light emitting microcrystalline silicon)
Was manufactured.

The experimental conditions for obtaining the emission spectrum of FIG. 5 are: (1) Amorphous silicon film thickness: 1000 Å (2) Heat treatment temperature and time: Argon gas at 820 ° C. Heat treatment for 1 msec (3) Etching treatment: Immersed in a mixed solution of 25% hydrofluoric acid at a liquid temperature of 50 ° C for 90 minutes (4) Light irradiation during etching treatment: 1 m at a wavelength of 1 μm
Irradiation with light having an intensity of W / cm ² (5) In measurement of light emission, light emission is measured at room temperature (RT) using a helium-cadmium (He-Cd) laser as an excitation laser.

According to the above-described method of producing visible light-emitting silicon, a light-emitting portion having an arbitrary pattern is formed at an arbitrary position by an electron beam method or a sputtering method, which can control the film thickness and size with extremely high accuracy. Therefore, it becomes possible to easily control the size when applied to a light emitting device or an electronic device.

The wavelength of the light emitted from the visible light emitting microcrystalline silicon can be changed by changing the ratio of hydrogen atoms and oxygen atoms that terminate the surface of the ultrafine crystalline silicon.

The wavelength of the light emitted from the visible light-emitting microcrystalline silicon depends on the particle size of the visible light-emitting microcrystalline silicon, the temperature at the time of heat treatment, the termination of the surface of the microcrystal with hydrogen atoms or oxygen atoms, and the like. , The wavelength of the light emitted from the light source 44 used for light irradiation when the surface of the microcrystal is terminated by hydrogen atoms and oxygen atoms (the filter 46).
Can be controlled by. ), It depends on the treatment time of various treatments such as heat treatment, etching treatment, or termination treatment of the surface of the microcrystal with hydrogen atoms or oxygen atoms, so that it is possible to control to any wavelength by changing these. .

Next, a method of manufacturing a light emitting device using the above visible light emitting microcrystalline silicon will be described.

That is, the method for producing silicon that emits visible light as described above in a light emitting portion having a required size at a required location according to the structure of a device designed in advance by using a planar processing technique (first
Process: Amorphous silicon fabrication, 2nd process: Amorphous silicon crystallization (fabrication of ultrafine crystal silicon), 3rd process: Ultrafine crystal silicon visible light emission (fabrication of visible light emitting microcrystalline silicon)) It is manufactured, and an electrode for current injection is further formed. Then, the element is separated and enclosed to manufacture a light emitting element.

That is, according to the method for producing microcrystalline silicon that emits visible light according to the present invention, the element pattern is controlled by using the lithographic technique, and a light emitting element having a predetermined shape is produced only at a predetermined position. Will be able to.

FIG. 6 shows a manufacturing process of a light emitting device, and the light emitting device can be manufactured on a silicon substrate by the above method. That is, the silicon substrate 100 (see FIG.
The surface of (a) is dry-oxidized to form the SiO ₂ film 102 (FIG. 6B). Then, visible light emitting microcrystalline silicon is produced on the surface of the SiO ₂ film 102 by the above-described method for producing visible light emitting silicon (first step, second step and third step).

That is, amorphous silicon 104 is formed on the surface of the SiO ₂ film 102 (the first step of the method for producing visible light-emitting silicon) (FIG. 6C), and this is heat-treated (visible light-emitting silicon is used). The second step of the manufacturing method), the etching treatment (the third step of the method for manufacturing visible light emitting silicon)
Process) to produce visible light emitting microcrystalline silicon 106 (FIG. 6D). And visible light emitting microcrystalline silicon 10
A light emitting diode (LED) is obtained as a light emitting element by forming the electrodes 108 and 110 with gold (Au) or the like on the surface of 6, and visible light is emitted when the electrodes 108 and 110 are energized.

Further, FIG. 7 shows an example in the case of constructing a laser, and the same components as those in FIG. 6 are designated by the same reference numerals, and a detailed description thereof will be omitted. In the case of forming a laser, the visible light emitting microcrystalline silicon 106 is formed by a mirror 11 made of gold or the like.
It suffices to dispose it in the resonator constituted by 2, 114. The mirrors 112 and 114 also function as electrodes.

Further, when manufacturing an optoelectronic device,
Simultaneously with the fabrication of the light emitting element described above, a planar processing technology of silicon is used to form an electronic element that controls the light emitting element next to the light emitting element, and the function, number, and position of the light emitting element and the electronic elements are determined according to the application. Then, the optoelectronic device is manufactured on the silicon substrate.

FIG. 8 shows an example of an optoelectronic element. The same components as those in FIG. 6 are designated by the same reference numerals, and detailed description thereof will be omitted. However, a single silicon substrate is used. On 100, an optical signal receiving part made of visible light emitting microcrystalline silicon, an IC part as an electronic element, an LED part made of visible light emitting microcrystalline silicon, and a laser made of visible light emitting microcrystalline silicon. And an optoelectronic device having a section can be manufactured.

That is, according to the method for producing visible light-emitting silicon of the present invention, silicon can be made to emit visible light without using anodization. Therefore, if an electronic element such as an adjacent IC is masked, It is possible to completely prevent an adjacent electronic element from being attacked during an etching process (the third step of the method for producing visible light-emitting silicon), and to fabricate the light emitting element and the electronic element on the same silicon substrate. can do.

That is, the light emitting element can be manufactured on the same silicon substrate as the electronic element, and the silicon-based optoelectronic integrated circuit can be easily manufactured.

In the above embodiment, the etching was performed with the mixed solution of hydrofluoric acid and ethanol, but ethanol (EtOH) may not be used.

Also, Japanese Patent Application No. 5-776 filed by the present applicant.
As shown in No. 95 “Porous Silicon and Method for Producing the Same”, deterioration of light emission may be prevented by adding hydrochloric acid (HCl) to a mixed solution of hydrofluoric acid and ethanol.

[0044]

Since the present invention is constructed as described above, it has the following effects.

Silicon capable of emitting visible light equivalent to that of porous silicon can be manufactured, and when this visible light emitting silicon is applied as an element, it has a size such as a film thickness and a shape depending on the function of the element. The control can be easily performed.

That is, amorphous silicon containing no hydrogen atoms is produced, and the amorphous silicon is crystallized to produce ultrafine crystalline silicon. Further, the ultrafine crystalline silicon is mixed with hydrofluoric acid under light irradiation. Since the visible light emitting microcrystalline silicon was produced by etching in the liquid, the dangling bond on the surface of the visible light emitting microcrystalline silicon is to be terminated by at least hydrogen atoms or oxygen atoms. It emits visible light emission equivalent to that of silicon.

Moreover, since visible light emitting microcrystalline silicon and an element using the same can be manufactured by using a thin film manufacturing technique and a planar processing technique without performing anodization, the film thickness and the thickness depending on the function of the element can be obtained. Since it is possible to easily control the size such as the shape, it is possible to manufacture a light emitting element of any size, and to manufacture an optoelectronic element in which the light emitting element and the electronic element are formed on the same silicon substrate. You will be able to.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view of an electron beam vapor deposition apparatus for carrying out an electron beam heating method used in the present invention.

FIG. 2 is a schematic configuration explanatory view of a sputtering apparatus for carrying out a sputtering method used in the present invention.

FIG. 3 is a schematic configuration explanatory view of a heating device for carrying out a heat treatment in the present invention.

FIG. 4 is a schematic structural explanatory view of an apparatus for carrying out a termination treatment of the surface of ultrafine crystalline silicon with hydrogen atoms and oxygen atoms in the present invention.

FIG. 5 is a graph showing an emission spectrum of visible light emitting microcrystalline silicon manufactured according to the present invention.

FIG. 6 is an explanatory diagram showing an example of a manufacturing process when manufacturing a light emitting device (LED) according to the present invention.

FIG. 7 is an explanatory view showing an example of a manufacturing process when manufacturing a laser according to the present invention.

FIG. 8 is an explanatory view showing an example of a manufacturing process when manufacturing an optoelectronic device according to the present invention.

[Explanation of symbols]

100 Silicon Substrate 102 SiO ₂ Film 104 Amorphous Silicon 106 Visible Light Emitting Microcrystalline Silicon 108, 110 Electrode 112, 114 Mirror

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takuo Sugano 2-1, Hirosawa, Wako-shi, Saitama RIKEN

Claims (7)

[Claims] 1. A first step of producing amorphous silicon containing no hydrogen atoms, and a second step of crystallizing the amorphous silicon produced by the first step to produce ultrafine crystalline silicon. A third step of producing visible light-emitting microcrystalline silicon by etching the ultrafine crystalline silicon produced by the second step in a mixed solution containing hydrofluoric acid under light irradiation. A method for manufacturing visible light emitting silicon. 2. The first step is to extract hydrogen atoms by a getter in an ultrahigh vacuum, and to obtain amorphous silicon of a predetermined thickness on a silicon substrate by a thin film forming means from a high-purity silicon single crystal. The method for producing visible light-emitting silicon according to claim 1, which is produced. 3. In the first step, the temperature of the silicon substrate when forming amorphous silicon having a predetermined film thickness on the silicon substrate is about 250 ° C.
The method for producing visible light emitting silicon according to claim 2, wherein: 4. The second step is the amorphous.
2. The method for producing visible light-emitting silicon according to claim 1, wherein silicon is heat-treated in an argon atmosphere and crystallized so as to have silicon fine particles having a crystal size of about several nm to several tens nm to produce ultrafine crystalline silicon. 5. The visible light emission according to claim 1, wherein the third step includes dangling bonds on the surface of the microcrystalline silicon that are terminated with at least hydrogen atoms or oxygen atoms. Method for manufacturing silicon. 6. A first step of producing amorphous silicon containing no hydrogen atoms by using a flat surface processing means of silicon according to a structure of a device designed in advance, and an amorphous. A second step of crystallizing silicon to produce ultrafine crystalline silicon;
The ultrafine crystalline silicon produced by the second step is etched under a light irradiation in a mixed solution containing hydrofluoric acid to produce a visible light emitting microcrystalline silicon, and a predetermined portion is formed. A visible light emitting microcrystalline silicon having a predetermined shape is formed on a substrate, and an electrode for current injection is further formed on the visible light emitting microcrystalline silicon to prepare a light emitting element. Manufacturing method of the existing device. 7. A first step of producing amorphous silicon containing no hydrogen atoms on a silicon substrate using a planar processing means of silicon according to a pre-designed device structure, and the first step. In a mixed solution containing hydrofluoric acid under light irradiation, the second step of crystallizing the amorphous silicon thus produced to produce ultrafine crystalline silicon, and the ultrafine crystalline silicon produced by the second step By the third step of producing visible light emitting microcrystalline silicon by etching with, a visible light emitting microcrystalline silicon having a predetermined shape is produced at a predetermined position, and an electrode for current injection is further provided on the visible light emitting microcrystalline silicon. An electronic element for controlling the light emitting element by using the planar processing means of the silicon on the silicon substrate on which the light emitting element is formed Method for producing a device using the method for manufacturing a silicon to visible light emission, characterized in that formed and to produce optoelectronic devices.