JPH0750432A - Light-emitting element and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an Si or Ge light-emitting element, which has a high luminous efficiency and high satisfactory can-stability, by a method wherein a substrate formed with a film, in which at least one kind of fine particles out of the Sn and Pb fine particles of a group IVb and the Ar, Sb and Bi fine particles of a group Vb are made of disperse, on its surface is formed into an Si substrate or Ge substrate. CONSTITUTION:At least one kind of fine particles 13 out of dispersed Sn and Pb fine particles of a group IVb and dispersed As, Sb and Bi fine particles of a group Vb directly generate some surface structure, which affects light emission, between a film 12 and an Si substrate 11 or a Ge substrate or via the film 12, which is used as a dispersion medium, and light is emitted in the interface between the film 12 with the fine particles 13 dispersed and the substrate 11 or the Ge substrate by light excitation. Accordingly, the light emission, which has a high luminous efficiency and a satisfactory can-stability, is given. Moreover, a light-emitting element consists of a low-cost material including Si and in addition, the element can be generally manufactured by a sputtering technique without depending upon a high-degree technique, such as an epitaxy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Si-based or Ge-based light emitting device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Semiconductor light-emitting devices such as light-emitting diodes and semiconductor lasers are small in size, operate at low voltage, have high conversion efficiency, and have a long life. In recent years, it has been used extensively in each field, and its production volume is expanding rapidly. For example, conventional semiconductor lasers are GaAs, InP, InAs, InSn
It is made of compound semiconductors such as
Are most manufactured, and the principle of light emission has been clarified.

In other words, the emitted light is excited by a photon (light) or an electron beam having an energy larger than the energy between two energy bands in a pn junction diode using a compound semiconductor of GaAs. It is said that, when holes generated in the p-type semiconductor and electrons generated in the n-type semiconductor are directly recombined with each other, photons equivalent to the energy between the two energy bands are emitted.

However, in order to manufacture a light emitting device of these compound semiconductors, expensive raw materials are used, and advanced techniques such as molecular beam epitaxy (MBE) and metalorganic vapor phase epitaxy (MOVPE) are required.

On the other hand, general semiconductors such as Si and Ge are of indirect type, and even if excited holes or electrons are generated, some of the energy is changed to phonons, so the recombination probability is low, It has been said that it hardly emits light (for example, "Practical Laser Technology", p. 94, Norimitsu Hirai, Kyoritsu Shuppan Co., Ltd., 1987).

Recently, however, light emission in the visible region at room temperature has been reported due to ultrafine materials such as Si and Ge and ultrafine particles ("Surface Science", Vol. 14, No. 2). , March 1993 issue). For example, (a) porous Si obtained by anodizing crystalline Si in HF, (b) Si fine particles formed by hydrogen plasma sputtering of Si or vapor deposition in an inert gas, (c) formed by a solution synthesis method, etc. Si-based polymer such as polysilane, (d)
Ge fine particles embedded in SiO ₂ and (e) a pn junction diode using a SiGe / Si heterostructure that emits electroluminescence at room temperature in the infrared region.

It is considered that the microstructure on the surface or interface of Si or Ge is involved in these light emission,
The principle has not been clarified yet, and (a) and (b) are Si
Because the surface of is exposed, the stability of light emission is poor,
The luminous efficiency of (c) and (d) is low. Further, (e) requires an advanced epitaxy technique to obtain a heterostructure.
As described above, although there are great expectations for Si-based and Ge-based light-emitting elements, ones that can withstand practical use have not yet been obtained.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a high luminous efficiency and a good storage stability, and a Si-based or Ge-based light-emitting device, and a method for manufacturing the same. The purpose is to provide.

[0009]

[Means for Solving Problems] The above-mentioned purpose is IVb
A light emitting device characterized by being a Si substrate or a Ge substrate on the surface of which a film having at least one kind of fine particles selected from the group consisting of Sn, Pb and Vb group As, Sb and Bi is dispersed. To be done.

Further, the above object is to provide IVb group Sn, Pb and Vb group As, S on the surface of the Si substrate or the Ge substrate.
and a method of manufacturing a light emitting device, which comprises forming a film in which at least one kind of fine particles of b and Bi are dispersed by sputtering.

[0011]

The reason why the Si-based or Ge-based light-emitting device according to the present invention has a high luminous efficiency and a good storage stability is not uncertain at present. However, dispersed IVb group Sn, Pb and Vb As are present. , Sb, Bi at least one kind of fine particles, directly or through a film as a dispersion medium, between the Si substrate or the Ge substrate, some surface structure involved in light emission (such as strained superlattice) ) Is generated, and light is excited at the interface between the film in which the fine particles are dispersed and the Si substrate or the Ge substrate.

[0012]

EXAMPLES The light emitting device of the present invention and the method for manufacturing the same will be specifically described below by way of examples, but of course the invention is not limited thereto.

[Example 1] Sputtering was performed using Sn and SiO ₂ as targets with a p-type (100) plane Si wafer as a substrate to form a film having a thickness of about 2 μm. The sputtering conditions were as follows. Equipment: High frequency magnetron type (13.56M
Hz) substrate; 4 inch Si wafer, p-type, (10
0) surface target: about 5 m on 6 inch SiO ₂ (quartz)
Arrange 4 pieces of Sn plates with m-square and thickness of about 1 mm. Trueness; 1 Pa after depressurizing to 10 ^-6 Pa
Ar gas is introduced until high frequency input; 600W substrate temperature; room temperature, 70 ° C, 100 ° C, 150 ° C,
Or 200 ℃

Observation of the obtained Sn-dispersed SiO ₂ film on the Si substrate with a high-resolution transmission electron microscope (TEM) revealed that Sn had a diameter of 10 mm.
It was confirmed that the particles were dispersed as fine particles of nm or less. In FIG. 1, 11 is a Si substrate and 12 is SiO _2.
The film 13 is Sn fine particles.

[Comparative Example 1] SiO ₂ was used without using Sn.
Except for using only (quartz) as a target, sputtering was performed in the same manner as in Example 1 to form a SiO ₂ film having a thickness of about 2 μm on the Si substrate. The substrate temperature was room temperature.

Argon ion lasers (wavelengths 4579Å and 4765Å, output watt density 6 mW / mm ² ) were made incident on the sample surface as excitation light sources for the five samples of Example 1 having different substrate temperatures and the sample of Comparative Example 1. The observed emission spectrum is shown in FIG. In FIG. 2, the horizontal axis represents photon (photon) energy (eV), and the vertical axis represents emission intensity (arbitrary unit).

As is clear from FIG. 2, the SiO 2 of Comparative Example 1
_In the case of the film of ₂ only, no light emission is observed,
In the case of a SiO ₂ film in which Sn is dispersed, the photon energy is about 2.2 regardless of the substrate temperature during sputtering.
Emission in the visible region having the maximum emission intensity was observed at eV. The emission intensity at this time is 0.3 nW / c on average.
It was m ² .

The emission spectrum observed in FIG. 2 is slightly different depending on the substrate temperature,
Hunting due to interference is seen in both cases. This is S
It is understood that the light emission at the interface between the iO ₂ film and the Si substrate is observed through the SiO ₂ film. Therefore, the emission spectrum estimated to be the original emission without interference by the SiO ₂ film was added with a smooth line.

The measurement system shown in the block diagram of FIG. 3 was used to observe the excitation emission spectrum of FIG. In FIG. 3, an argon ion laser oscillator 1 as an excitation light source
After passing through the monochromator 2, the laser from No. 1 was reflected by the reflecting mirrors 3a, 3b, 3c and made incident on the measurement sample S.

The incident laser i is reflected on the surface of the sample S by a laser r
However, since the photon is emitted as the light emission e from the sample S excited by the incident laser i, the light emission e is condensed by the condenser lens 4 and the double monochromator 5 corresponding to the two wavelengths of the excitation. After passing through, it was amplified by a photomultiplier tube 6 for detection. Then, the signal is input to a wave height analyzer (multi-channel analyzer) 8 through a preamplifier 7, and an XY recorder 10 is formed as an emission spectrum showing a relationship between photon energy and emission intensity.
Output to. Microcomputer 9 is wave height analyzer 8
This is for displaying the signal from the device as a light emission spectrum on a cathode ray tube (CRT) not shown and recording it on a floppy disk.

Since the light emission of the same intensity was observed even after the samples obtained in Example 1 were allowed to stand in the atmosphere for one month or more, it was confirmed that these samples had good storage stability. .

[Embodiment 2] In exactly the same manner as in Embodiment 1,
Si in which Sn is dispersed by performing sputtering with the temperature of the Si substrate set to 300 ° C., 400 ° C., and 600 ° C.
A Si substrate having an O ₂ film was obtained.

From these three types of samples, the same excitation and emission spectra as in Example 1 were obtained.

Example 3 A Ge substrate was used instead of the Si substrate in Example 1. For the Ge substrate, p-type (10
A wafer having a 0) plane was used. The same sputtering as in Example 1 was performed except that the type of the substrate was changed to obtain five types of Ge substrates having a SiO ₂ film in which Sn was dispersed and having different substrate temperatures during sputtering. It was observed that these samples emit light in the same manner as the sample of Example 1.

[Example 4] S used in Example 1
Sputtering was carried out under the same apparatus and conditions as in Example 1 except that the n-plate was replaced with a Pb-plate to obtain a Si substrate having a Pb-dispersed SiO ₂ film. The substrate temperature was only room temperature. Luminescence in the visible region was also observed from this sample by the measurement system of FIG.

[Examples 5 to 7] As, Sb, and Bi were replaced by 6 inches S instead of Sn used in Example 1, respectively.
It was placed on the iO ₂ wafer and the sputtering was performed in the same manner as in Example 1 with the temperature of the Si substrate at room temperature. As shown in Table 1, emission spectra similar to those of Example 1 were observed from the obtained three kinds of samples.

[0027]

[Table 1]

[Embodiment 8] Of the four target SiO ₂ and Sn plates in Embodiment 1, _two Sn plates are S
Replaced with two b-plates, and other than that, as in the first embodiment, p
Sputtering was performed using a mold and a (100) surface Si wafer as a substrate. The substrate temperature was only room temperature.

From the obtained Si substrate having a SiO ₂ film in which fine particles of Sn and Sb were mixed and dispersed, an excited emission spectrum in the visible region was observed.

Although the respective embodiments of the present invention have been described above, needless to say, the present invention is not limited to these, and various modifications can be made based on the technical idea of the present invention.

For example, in each of the embodiments, an IVb group S
The film in which at least one of As, Sb, and Bi of the n, Pb, and Vb groups is dispersed is SiO ₂ , but a material transparent to light emission in the visible region, for example, Al ₂ O ₃ can also be used as the film. .

Further, in each of the examples, the (100) plane of the Si substrate or the Ge substrate was sputtered, but other planes such as (110) plane and (111) plane are also IVb.
Since it is presumed that a strained superlattice, which may be a factor of light emission, is generated by a SiO ₂ film in which at least one of Sn, Pb of the group B, and As, Sb, Bi of the group Vb is dispersed,
The use of a surface other than the (100) surface of the Si substrate or the Ge substrate also belongs to the scope of the technical idea of the present invention.

In each of the embodiments, a p-type Si substrate or a Ge substrate is used, but an n-type Si substrate or a G substrate is used.
Even when the e substrate is used, IVb group Sn, P
b, and at least one of As, Sb, and Bi of the Vb group
It is presumed that a strained superlattice, which may be a factor of light emission, is generated by the SiO ₂ film in which the seeds are dispersed. Therefore, even when an n-type Si substrate or a Ge substrate is used, it belongs to the scope of the technical idea of the present invention. I shall.

[0034]

EFFECTS OF THE INVENTION In the semiconductor of Si or Ge, which has been far from practical use even if emission of light is observed,
The Si-based or Ge-based light-emitting element of the present invention has high emission efficiency as described above and gives light emission with good storage stability.
Further, the light emitting device of the present invention is made of an inexpensive material such as Si, and can be manufactured by a general sputtering technique without using a high technique such as epitaxy.

Furthermore, according to the present invention, an optical device such as a light emitting device and an I-device can be formed on the same Si substrate or Ge substrate.
It becomes possible to combine electronic devices such as C.

[Brief description of drawings]

FIG. 1 is a schematic view of a cross section of a main part of a light emitting device of the present invention.

FIG. 2 is a diagram showing an excited emission spectrum of the light emitting device of the present invention.

FIG. 3 is a block diagram of a measurement system for observing the emission spectrum of FIG.

[Explanation of symbols]

11 Si substrate 12 SiO ₂ film 13 Sn fine particles

Claims (10)

[Claims] 1. Group IVb Sn, Pb and Vb Group A
A light emitting device, which is a Si substrate or a Ge substrate having a surface on which a film in which at least one kind of fine particles of s, Sb, and Bi is dispersed is formed. 2. The light emitting device according to claim 1, wherein a crystal orientation of a surface of the Si substrate or the Ge substrate is (100). 3. The light emitting device according to claim 1, wherein the Si substrate or the Ge substrate is p-type. 4. The light emitting device according to claim 1, wherein the dispersion medium of the film is a SiO ₂ film. 5. The light emitting device according to claim 1, wherein the average particle size of the fine particles is 10 nm or less. 6. IVb is formed on the surface of a Si substrate or a Ge substrate.
A method for manufacturing a light-emitting element, which comprises forming a film in which at least one kind of fine particles selected from the group consisting of Sn, Pb and Vb group As, Sb and Bi is dispersed by sputtering. 7. The method for manufacturing a light emitting device according to claim 6, wherein the crystal orientation of the surface of the Si substrate or the Ge substrate is (100). 8. The method for manufacturing a light emitting device according to claim 6, wherein the Si substrate or the Ge substrate is p-type. 9. The method for manufacturing a light emitting device according to claim 6, wherein the dispersion medium of the film is a SiO ₂ film. 10. The method for manufacturing a light emitting device according to claim 6, wherein the average particle size of the fine particles is 10 nm or less.