JPH06275866A - Porous semiconductor light-emitting device and manufacture thereof - Google Patents

Abstract

PURPOSE:To efficiently change the light-emitting mechanism of a porous semiconductor layer by a method wherein an Si or SiC semiconductor layer is anodized in a hydrofluoric acid solution to form the porous semiconductor layer and the porous semiconductor layer is immersed in pure water to which ultrasonic waves have been applied. CONSTITUTION:A substrate electrode 3 composed of Au, Al, an ITO (an indium- tin oxide) or the like is formed on the back of an Si substrate 1, it is immersed in a hydrofluoric acid solution 5 together with a counter electrode 4 formed of Pt, Au or the like, and an anodic oxidation operation is performed by using the counter electrode 4 as a cathode and by using the substrate electrode 3 as an anode. By the anodic oxidation operation, a porous Si layer 2 is formed, it is the aggregate of quantum wires, and it can emit light. When the porous Si layer 2 which is composed of the quantum wires is immersed in pure water to which ultrasonic waves have been applied, a light-emitting mechanism from the porous Si layer can be changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device and a method for manufacturing the same, and more particularly to a porous semiconductor light emitting device which obtains a light emitting function by forming a thin wire into a porous structure and a method for manufacturing the same.

Light emitting devices using Si, which have been considered impossible in the past, are about to be realized by making porous with hydrofluoric acid. The Si light emitting device facilitates the realization of an optoelectronic integrated circuit on a Si wafer, and also opens the way for optical coupling between wafers. Furthermore, even in SiC, a light emitting element is being realized by making it porous.

[0003]

2. Description of the Related Art Silicon (Si) has an indirect transition type band structure and is generally unsuitable as a light emitting device material. Therefore, GaAs or InP having a direct transition band structure has been used as a light emitting element material.

However, it has been discovered that when Si is anodized in an aqueous solution of hydrofluoric acid to form a thin linear porous structure on the surface, Si exhibits a light emitting function. Si 100 Å
When formed into the following columns, quantization occurs in the two-dimensional direction,
The band structure changes.

When such porous Si was irradiated with excitation light, light emission of about 1.4 to 1.6 eV was observed (L.
T. Canham, Appl. Phys. Lett., 57 (10), 1046 (1990),
V.Lehmann and U. Gosele, Appl. Phys. Lett., 58
(8), 856 (1991) N. Koshida and H. Koyama, Jpn. J. A
ppl. Phys., 30 (7B), L1221 (1991)).

Similarly, in SiC, a light emission phenomenon was observed by thinning. By utilizing these phenomena, a light emitting semiconductor device can be realized using Si, SiC, or the like.

[0007]

It is possible to form a light emitting semiconductor device by using Si or SiC by utilizing the quantum wire structure by porosification, but it is said that the manufacturing technique has not been sufficiently developed. I can not say.

An object of the present invention is to provide a novel method for manufacturing a light emitting semiconductor device having a quantum wire structure by making it porous. Another object of the present invention is to provide a novel light emitting semiconductor device having a quantum wire structure by making it porous.

[0009]

A method of manufacturing a porous semiconductor light emitting device according to the present invention comprises an anodizing step of forming a porous semiconductor layer by anodizing a semiconductor layer of Si or SiC in a hydrofluoric acid solution, and the porous layer. Immersing the semiconductor layer in pure water to which ultrasonic waves are applied.

Further, the method for manufacturing a porous semiconductor light emitting device of the present invention comprises an anodizing step of forming a porous semiconductor layer by anodizing a semiconductor layer of Si or SiC in a hydrofluoric acid solution, and forming the porous semiconductor layer with fluorine. Exposing to gas.

The method for manufacturing a porous semiconductor light emitting device according to the present invention comprises the steps of irradiating the surface of a semiconductor layer of Si or SiC with reactive ions, and anodizing the semiconductor layer in a hydrofluoric acid solution to form a porous semiconductor layer. And an anodic oxidation step for forming.

Further, the porous semiconductor light emitting device of the present invention includes a porous semiconductor layer of Si or SiC, a transparent conductive film formed on the surface of the porous semiconductor layer and having an area significantly smaller than the area of the porous semiconductor layer, And a conductive film formed on the opposite side of the transparent conductive film to the porous semiconductor layer and having a significantly larger area than the transparent conductive film.

Further, the porous semiconductor light emitting device of the present invention has a porous semiconductor layer of Si or SiC, and an electron field emitter arranged so as to face the porous semiconductor layer.

[0014]

By immersing the porous semiconductor layer anodized in hydrofluoric acid in pure water to which ultrasonic waves are applied, the light emitting mechanism of the porous semiconductor layer can be efficiently changed.

By exposing the porous semiconductor layer anodized in hydrofluoric acid to fluorine gas, a good surface can be obtained,
A good light emission phenomenon can be obtained. After irradiating the surface of the semiconductor layer with reactive ions and then anodizing the semiconductor layer in a hydrofluoric acid solution, porosity can be promoted without irradiation of ultraviolet rays. It is considered that the porosity progresses based on the minute irregularities on the surface of the semiconductor layer generated by the ion irradiation.

Efficient light emission can be achieved by forming a conductive layer having a remarkably large area on one surface of the porous semiconductor layer and forming a transparent conductive film having a remarkably small area on the other surface. . It is considered that the electric field is concentrated on the transparent conductive film side.

By injecting electrons from the field emitter of electrons into the porous semiconductor layer, it is possible to emit light from the porous semiconductor layer.

[0018]

EXAMPLES FIGS. 1A to 1C are schematic sectional views showing the formation of a porous semiconductor layer. As shown in FIG. 1 (A), a substrate electrode 3 made of Au, Al, ITO (indium tin oxide) or the like is formed on the back surface of the Si substrate 1, and together with a counter electrode 4 made of Pt, Au, or the like, It is dipped in a hydrofluoric acid aqueous solution 5 and anodized with the counter electrode 4 as a cathode and the substrate electrode 3 as an anode.

For example, the Si substrate 1 has a specific resistance of 10 Ωc.
It is a p-type (100) plane substrate of about m. Hydrofluoric acid aqueous solution 5
Is a 10-50% HF aqueous solution, for example a 48% HF aqueous solution. DC power supply E between the counter electrode 4 and the substrate electrode 3,
The switch SW is connected to allow a current having a current density of about ²⁰ to 100 mA / cm ² to flow through the Si substrate 1. For example, a current of 25 mA / cm ² is passed in a 48% HF aqueous solution, and anodization is performed for 20 seconds. By this anodization,
A porous Si layer 2 having a film thickness of about 0.4 μm is formed. The porous Si layer 2 is a set of quantum wires and is capable of emitting light.

When the quantum wire thinned porous Si layer 2 is immersed in pure water by anodic oxidation in a hydrofluoric acid solution, the light emission mechanism from the porous Si layer changes. FIG. 1B shows two forms of pure water treatment for anodized porous Si layers. In the configuration shown on the left side of FIG. 1B, ultrasonic waves are emitted from the ultrasonic wave generator 11 into the pure water 6, and the pure water treatment is performed while receiving the ultrasonic waves.

When the anodized porous Si layer 2 is immersed in pure water, the reaction proceeds while generating bubbles from the surface. By applying ultrasonic waves, the generated bubbles are quickly separated from the surface, and a uniform reaction proceeds.
The porous Si layer 2 is arranged so as to face upward in order to facilitate the removal of bubbles.

In the form on the right side of FIG. 1 (B), pure water 6
Are heated by the heater 12. By controlling the temperature of pure water, the reaction rate of the reaction between the porous Si layer 2 and pure water can be controlled.

FIG. 1C shows another treatment which replaces the pure water treatment. In the diagram on the left side of FIG. 1C, the Si substrate 1 is heated by the heater 13 to be oxidized in an atmosphere containing water vapor. As the atmosphere containing water vapor, various gas atmospheres containing water vapor such as air containing water vapor and oxygen containing water vapor can be used.

[0024] In FIG. 1 (C) the right figure, fluorine gas to the porous Si layer 2, for example, F ₂ 5%, by contacting the N ₂ 95% dilution fluorine gas, the reaction of the porous Si layer 2 and the fluorine gas Let me do it.

FIG. 2 is a table showing experimental results of pure water treatment and fluorine gas treatment. First, on the Si substrate that is the sample,
Anodic oxidation with a current of 25 mA / cm ² is performed for 100 seconds in a 48% HF aqueous solution to form a porous Si layer of about 2 μm.

Sample 1 was prepared by immersing the porous Si layer in pure water at 24 ° C. and performing pure water treatment for 60 minutes while applying ultrasonic waves. The peak wavelength of photoluminescence was 710 nm. When ultrasonic waves were not applied, pure water treatment for 4 hours was required to obtain similar results under the same conditions.

Sample 2 is porous Si in pure water at 45.degree.
This was a sample in which the layer was immersed and treated with pure water for 30 minutes while applying ultrasonic waves, and the peak wavelength of the photoluminescence peak was 675 nm. The peak wavelength is shorter than that of Sample 1.

Sample 3 is a sample in which the porous Si layer was immersed in pure water at 45 ° C. for 60 minutes while applying ultrasonic waves, and the peak wavelength of photoluminescence was 620 nm.
The wavelength was further shortened.

Sample 4 is a sample in which the porous Si layer was immersed in pure water heated to 70 ° C. for 3 minutes, and the peak wavelength of photoluminescence was 610 nm. When the effect of pure water treatment was judged from these four samples based on the PL peak wavelength, when ultrasonic waves were applied, the speed of pure water treatment increased about four times. Also, when the temperature of pure water is raised,
The reaction rate is further improved.

For example, it can be seen that when pure water is heated to 70 ° C., the reaction significantly progresses in 3 minutes without applying ultrasonic waves. However, this reaction rate is too fast and is not suitable for fine control. In order to form a light emitting semiconductor device, the pure water temperature is preferably about 45 ° C. or lower.

If the temperature of pure water is too low, the reaction of pure water treatment does not proceed easily. Even in such a case, the reaction can be advanced by applying ultrasonic waves. The pure water temperature when ultrasonic waves are used is preferably about 20-45 ° C, and the pure water temperature when ultrasonic waves are not applied is preferably about 30-45 ° C.

FIG. 3 shows changes in the infrared absorption spectrum when the pure water treatment corresponding to Sample 1 was performed. In the figure, the horizontal axis represents the wave number in cm ⁻¹ , and the vertical axis represents the transmittance on an arbitrary scale.

Curve a shows the absorption spectrum of the sample immediately after anodic oxidation, curve b shows the absorption spectrum of the sample treated with pure water for 1 hour, and curve c shows the absorption spectrum of the sample treated with pure water for 3 hours. The spectrum is shown.

Area of 500-750 cm ^-1 and 200
The absorption observed in the region of 0 to 2200 cm ⁻¹ is considered to be the absorption due to the vibration of SiH, SiH ₂ , and SiH _x , respectively. The absorption observed in the region of 900 to 1000 cm ⁻¹ can be identified as SiH ₃ and SiH _2, and the absorption amount decreases as the pure water treatment progresses.

The absorption appearing at about 1100 to 1250 cm ^-1 is fixed to the absorption due to the vibration of Si-O-Si, and the absorption amount increases as the pure water treatment progresses. Furthermore, the sample of curve a produces a faint emission at wavelengths of 800 nm and above, the sample of curve b produces an emission of wavelength 690 nm and the sample of curve c produces a more distinct emission at a wavelength of 630 nm.

From such experimental data, it is considered that the pure water treatment plays a role of controlling the size of the quantum wire and a surface state. The increase in Si—O absorption as a result of pure water treatment can be attributed to the fact that the oxidized state of the surface is more favorable for light emission of short wavelength.

Returning to FIG. 2, sample 5 shows a case where fluorine gas treatment is performed instead of pure water treatment. 24 samples
When the temperature was kept at 0 ° C. and the fluorine gas was flowed for 10 minutes, the emission wavelength of photoluminescence changed to 600 nm.

When fluorine gas is brought into contact with the Si quantum wires,
Silicon oxide that may be present on the Si surface is etched,
It is considered that a clean Si surface is exposed. Upon removal of this sample in air, the clean Si surface will immediately oxidize and an oxidized surface will develop. From the viewpoint of shortening the emission wavelength, the fluorine gas treatment can be as effective as the pure water treatment.

FIG. 4 shows an absorption spectrum of a quantum wire subjected to a fluorine gas treatment. The horizontal axis shows the wave number in cm ^-1 ,
The vertical axis represents the transmittance on an arbitrary scale. The absorption of Si—O observed at about 1000 to 1250 cm ⁻¹ when the pure water treatment progressed is also observed in the fluorine gas treated sample. The absorption spectrum of the sample treated with fluorine gas is similar to that of the thermal oxide film of silicon.

By such pure water treatment, steam treatment, or fluorine gas treatment, a porous semiconductor layer having suitable light emitting performance can be formed. FIG. 5 shows a porous semiconductor light emitting device according to an embodiment of the present invention. Figure 5
(A) shows a cross-sectional view of a porous semiconductor light emitting device using Si.

Current density 25 mA in 48% HF aqueous solution
/ In cm ² by 20 seconds anodizing, the (100) plane p-type Si surface of the substrate 1 of the specific resistance 10 .OMEGA.cm, forming a porous semiconductor layer 2 having a thickness of about 0.4 .mu.m,
While applying ultrasonic waves, the porous semiconductor layer 2 is prepared by immersing in pure water at 45 ° C. for about 1 hour.

An n-type IT is formed on the surface of the porous semiconductor layer 2.
About 3000 Å of O (indium tin oxide film) 7 is deposited by sputtering. A region 7a to be an electrode is left in the central portion, and the ITO film 7 around it is removed by etching,
An insulating film 8 such as SiO ₂ is formed. ITO film 7a in the center
The electrode 9 that contacts the substrate is formed, and the substrate electrode 3 is also formed on the back surface of the Si substrate 1. The size of the ITO film 7a is significantly smaller than that of the electrode 3 on the back surface. For example, when the electrode 3 on the back surface has a size of 5 to 10 mm square, the size of the ITO film 7a on the front surface is about 0.5 mm square.

As described above, by limiting the size of the electrode on the light emitting surface, light emission can be efficiently generated at a relatively low voltage. FIG. 5B schematically shows a distribution of lines of electric force in the semiconductor light emitting device shown in FIG. Since the size of the upper electrode 7a is significantly smaller than that of the lower electrode 3, the lines of electric force from the lower electrode 3 toward the upper electrode 7a are rapidly concentrated near the upper electrode 7a.

Due to the concentration of the lines of electric force, a strong electric field is generated in the vicinity of the upper electrode 7a. Therefore, a high electric field can be generated by a relatively low voltage, and light emission can be efficiently generated.

FIG. 6 is a graph showing the characteristics of the semiconductor light emitting device shown in FIG. FIG. 6 (A) shows the IV characteristic, and FIG. 6 (B) shows the wavelength distribution of the emission intensity. Figure 6
As shown in (A), this semiconductor light emitting device exhibits characteristics like a Schottky diode, and increases the current value almost linearly as the forward voltage is applied. When applying 8V,
A current of about 0.3 A flows, and about 17 V is applied, about 0.68
A current flows.

FIG. 6B shows a light emission intensity distribution when a forward bias of 12 V is applied to the semiconductor light emitting device. The peak wavelength of light emission is about 510 nm. Light emission of a short wavelength, which is difficult to obtain from a conventional Si light emitting device, is obtained.

FIG. 7 is a schematic sectional view of a porous semiconductor light emitting device according to another embodiment of the present invention. The porous semiconductor layer 2 is formed on the surface of the Si substrate 1, and the plurality of ITO electrodes 7a to 7e separated by the insulating film 8 on the surface thereof.
Are formed.

An electrode 3 formed on the back surface of the Si substrate 1,
Any of the ITO electrodes formed on the surface of the porous semiconductor layer 2 is connected to the DC power source E via the switches SWa to SWe.
It is possible to generate light emission from the vicinity of the selected ITO electrode by connecting to. It can be used for communication, display, etc.

Although the case where the porous semiconductor layer is formed of Si has been described, the effect of this embodiment is considered to be caused by electric field concentration, and the porous semiconductor layer is formed of Si.
It is considered that the same effect can be obtained even if it is formed of C or the like.

Inside the porous semiconductor layer, light is emitted by electron-hole recombination. The generation of electron-holes does not necessarily have to be by current injection. FIG. 7 is a schematic sectional view of a porous semiconductor light emitting device according to another embodiment of the present invention.

On the surface of the quartz substrate 11 (lower side in the figure), IT
An O film 12 is formed, and a polycrystalline Si layer is formed on this. The polycrystalline semiconductor layer is anodized in an aqueous solution of hydrofluoric acid to form the porous semiconductor layer 13. In addition,
The area around the light emitting region is not anodized and is left as it is.

The anodic oxidation is performed, for example, in a 10 to 50% HF aqueous solution at a current density of 20 to 100 mA / cm ² to form a porous layer having a thickness of several hundred nm to several μm. After anodic oxidation, HF cleaning is performed, and then sufficient water cleaning is performed. After that, 800 to 90 in an oxygen atmosphere of several torr
Annealing is performed at 0 ° C. for several tens of minutes. By this annealing, an extremely thin oxide film is formed on the surface and the surface is stabilized.

On the other hand, the Si electron emitter 21 having a sharp tip and the field emitter 20 formed on the opening 17 formed in the Si substrate 16 are hermetically bonded to the porous semiconductor layer 13 by the oxide film 22. . The surface of the Si substrate 16 is covered with an oxide film 18, a metal electrode 19 such as W is formed in the opening 17, and is electrically connected to the electron emitter 21.

By applying a strong electric field to the chip of the electron emitter 21 to a certain extent or more, electrons are emitted from the chip and injected into the porous semiconductor layer 13. An electron-hole pair is formed in the porous semiconductor layer 13 by electron injection, and recombination causes light emission.

FIG. 9 shows a method of forming the field emitter 20. As shown in FIG. 9A, an SOI substrate 24 in which a Si substrate 16, an oxide film 18a, and a Si layer 23 are stacked is prepared, and a mask having a rectangular opening is formed on the Si substrate 16. The opening 17 is formed by performing anisotropic etching with KOH on the opening.

Further, the opening 17 is formed into the Si layer 23 by etching the oxide film 18a in a diluted HF solution.
To reach. After that, the mask is removed, and the exposed Si surface is oxidized to form an oxide film 18b. After the portions other than the opening are covered with the mask, reactive ion etching (RIE) is performed to form the opening 17 of the opening 17. The oxide film on the window is etched to expose the Si layer 23.
After that, the mask is removed.

Next, as shown in FIG. 9B, the opening 1
A wiring 19 is formed by forming a metal layer covering 7 and patterning it. This metal layer is formed of, for example, W.

Next, as shown in FIG. 9C, the Si layer 2
A silicon oxide film is grown to a thickness of about 0.5 μm on the film 3 and patterned to form an oxide film mask 25. Next, as shown in FIG. 9D, the Si layer 23 is etched by reactive ion etching (RIE) using CF ₄ , leaving a substantially conical Si region 23 under the oxide film mask 25. The Si layer in the portion of is removed.

Further, the exposed surface of the Si region 23 is oxidized to leave the Si chip 23 having a sharp tip. After that, as shown in FIG. 9E, an oxide film 22 is deposited by CVD.

Next, as shown in FIG. 9 (F), diluted HF
By etching the oxide film by using
Along with 5, the oxide film 22a thereon is lifted off. In this step, the oxide film on the surface of the Si chip 23 is also removed.

In this way, the Si emitter 23 having a sharp tip is formed. The Si emitter 23
Is surrounded by a thick oxide film 22. The Si emitter thus formed is arranged on the porous semiconductor layer and adhered in a vacuum to form a field emitter having a vacuum inside. A large number of such field emitters may be formed in an array on the SOI substrate.

Although the structure in which the field emitter is arranged in the Si porous semiconductor layer has been described, the structure in which the field emitter is arranged in the SiC porous semiconductor layer can be formed in the same manner.

In order to form a porous SiC semiconductor layer, hitherto, strong ultraviolet irradiation has been performed during anodization. However, the etching efficiency at the time of anodic oxidation of SiC is very sensitive to the ultraviolet intensity, and it is not easy to stably control the fine structure size of the porous SiC (β-SiC) layer under the ultraviolet irradiation.

10 and 11 are schematic cross-sectional views for explaining a method capable of forming a β-SiC porous semiconductor layer without needing to perform ultraviolet irradiation. First, as shown in FIG. 10A, C is formed on a (111) plane p-type Si substrate 31 having a substrate temperature of about 1000 ° C. using trichlorosilane, propane as a source gas and hydrogen as a carrier gas.
By performing VD, the β-SiC layer 3 having a thickness of several μm is formed.
2 is formed into a film.

Next, the surface layer of the β-SiC layer 32 is subjected to ion irradiation treatment using a reactive ion etching device. Here, the ion species for irradiation is ions having reactivity with SiC, such as CF ₄ and Cl ₂ .

By the ion irradiation, the surface layer 32a affected by the ion irradiation is formed on the surface of the SiC layer 32. It is considered that minute unevenness is generated in the surface layer 32a due to the irradiation of the reactive ions.

FIG. 10B shows an ion implantation step for controlling the porosity in the SiC layers 32, 32a. The SiC layer 3 that has been subjected to ion irradiation as shown in FIG.
P-type impurities, for example, B ions are ion-implanted into 2, 32a. For example, the acceleration voltage is several tens to several hundreds ke.
The V and dose amounts are about 10 ¹⁵ cm ^-2 or less. In anodic oxidation in hydrofluoric acid, the semiconductor layer to be anodized is preferably p-type.

Further, the size of the quantum wire structure formed by the p-type impurity concentration can be controlled. Here, fine quantum wires are formed by limiting the dose amount of ion implantation.

After ion-implanting p-type impurities, Au is sputter-deposited on the back surface of the Si substrate 31 to form an ohmic electrode 35. The wafer thus prepared is immersed in an HF aqueous solution and anodized. By anodic oxidation,
The SiC layers 32 and 32a are made porous, as shown in FIG.
A porous semiconductor layer 36 as shown in is formed.

Subsequently, in order to form a pn junction in the porous semiconductor layer 36, p-type impurities such as B ⁺ ions are ion-implanted. The implantation conditions are, for example, an acceleration voltage of 150.
KeV and dose amount are about 10 ¹⁵ cm ^-2 .

Next, as shown in FIG. 11B, the porous β-SiC layer 36 in which p-type impurities are ion-implanted is washed in pure water, and n-type S is formed by CVD, sputtering or the like.
The iC layer 38 is formed by several thousand Å.

Instead of the n-type SiC layer 38, a metal such as Au may be formed by sputtering or the like. n type β
-After forming the SiC layer 38, A
A contact electrode 39 such as u is formed.

Light is emitted from the porous SiC layer 36 by applying a forward bias voltage between the electrodes 35 and 39. Note that the formation rate of the porous semiconductor layer is accelerated by about 1.5 to 2.0 times when the ion irradiation is performed as compared with the case where the ion irradiation step shown in FIG. 10A is not performed.

It is considered that the step of treating the surface with reactive ions prior to the anodizing step for making it porous is effective not only for SiC but also for other semiconductor layers.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to these. For example,
It will be apparent to those skilled in the art that various changes, improvements, combinations and the like can be made.

[0076]

As described above, according to the present invention,
A method for manufacturing a porous semiconductor light emitting device including a novel process is provided.

Further, according to the present invention, a porous semiconductor light emitting device having a novel structure is provided.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining production of a porous semiconductor layer.

FIG. 2 is a table for explaining characteristics of porous semiconductor layers in various samples.

FIG. 3 is a graph showing the results of pure water treatment by infrared absorption spectrum.

FIG. 4 is a graph showing the effect of F ₂ gas treatment by infrared absorption spectrum.

FIG. 5 is a schematic cross-sectional view showing the structure of a porous semiconductor light emitting device according to an example of the present invention.

6 is a graph showing characteristics of the porous semiconductor light emitting device shown in FIG.

FIG. 7 is a schematic cross-sectional view showing the structure of a porous semiconductor light emitting device according to another embodiment of the present invention.

FIG. 8 is a sectional view schematically showing the structure of a porous semiconductor light emitting device according to another embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view showing the manufacturing process of the field emitter used in the porous semiconductor light emitting device shown in FIG.

FIG. 10 is a schematic cross-sectional view for explaining a manufacturing process of the porous semiconductor light emitting device according to the embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view for explaining a manufacturing process of the porous semiconductor light emitting device according to the embodiment of the present invention.

[Explanation of Codes] 1 Si substrate 2 Porous Si layer 3 Substrate electrode 4 Counter electrode 5 Hydrofluoric acid aqueous solution 6 Pure water 11 Ultrasonic generator 12, 13 Heater

[Procedure amendment]

[Submission date] October 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

FIG. 2 is a chart for explaining characteristics of porous semiconductor layers in various samples.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor George Jay Collins United States Colorado, Fort Collins, Shore Road 3007

Claims (12)

[Claims] 1. A process of anodizing a semiconductor layer of Si or SiC in a hydrofluoric acid solution to form a porous semiconductor layer, and a process of immersing the porous semiconductor layer in pure water to which ultrasonic waves are applied. A method for manufacturing a porous semiconductor light emitting device including: 2. A porous layer including a step of anodizing a semiconductor layer of Si or SiC in a hydrofluoric acid solution to form a porous semiconductor layer, and a step of immersing the porous semiconductor layer in heated pure water. Manufacturing method of semiconductor light emitting device. 3. A porous layer including a step of anodizing a semiconductor layer of Si or SiC in a hydrofluoric acid solution to form a porous semiconductor layer, and a step of annealing the porous semiconductor layer in an atmosphere containing water vapor. Manufacturing method of semiconductor light emitting device. 4. A porous semiconductor light emitting device comprising: an anodization step of forming a porous semiconductor layer by anodizing a Si or SiC semiconductor layer in a hydrofluoric acid solution; and a step of exposing the porous semiconductor layer to fluorine gas. Production method. 5. A porous semiconductor light emission comprising: a step of irradiating a surface of a semiconductor layer of Si or SiC with reactive ions; and an anodizing step of forming a porous semiconductor layer by anodizing the semiconductor layer in a hydrofluoric acid solution. Device manufacturing method. 6. The reactive ion is CF ₄ or Cl ₂
6. The method for manufacturing a porous semiconductor light emitting device according to claim 5, wherein the plasma is the ions generated. 7. The method according to claim 5, further comprising a step of ion-implanting a p-type impurity into the semiconductor layer before the anodizing step.
Alternatively, the method for manufacturing the porous semiconductor light emitting device according to the sixth aspect. 8. The method for manufacturing a porous semiconductor light emitting device according to claim 5, further comprising a step of ion-implanting p-type impurities into the semiconductor layer after the anodizing step. 9. A porous semiconductor layer of Si or SiC, a transparent conductive film formed on the surface of the porous semiconductor layer and having an area significantly smaller than the area of the porous semiconductor layer, and the transparent conductive film of the porous semiconductor layer. And a conductive film formed on the opposite side of the transparent conductive film and having a significantly larger area than the transparent conductive film. 10. The porous semiconductor light emitting device according to claim 9, wherein a large number of the transparent conductive films are arranged on the porous semiconductor layer. 11. A porous semiconductor light emitting device having a porous semiconductor layer of Si or SiC, and a field emitter of electrons arranged to face the porous semiconductor layer. 12. The electron field emitter is S
The porous semiconductor light emitting device according to claim 11, which has a sharp protrusion formed of i.