JP3460260B2 - Light emitting device manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device used as a surface light emitter such as a backlight of a liquid crystal display or a self-luminous display, and a method for manufacturing the same.

[0002]

2. Description of the Related Art An EL (electroluminescence) type is known as a conventional light emitting device used as a surface light emitter such as a backlight of a liquid crystal display or a self-luminous display.

The structure of such a light emitting device will be described with reference to FIG. 11. In this light emitting device, a transparent electrode 104 is formed on a glass substrate 102, a lower insulating film 107 is formed thereon, and a transparent insulating film 107 is formed thereon. The light emitting layer 106 is formed on the top surface, the upper insulating film 108 is formed thereon, and the upper electrode 1 is formed thereon.
10 is formed.

In the case of a surface light emitter such as a backlight of a liquid crystal display, for the light emitting layer 106, a material in which light emitting centers (light emitting particles) are dispersed in an organic material is used. In this case, a ZnS crystal having luminescent centers dispersed therein is used.

As the transparent electrode 104 and the upper electrode 110, a wide surface-shaped one is used in the case of a surface light-emitting body, and a plurality of electrodes each crossing each other is used in the case of a self-luminous display. It

When a voltage is applied between the transparent electrode 104 and the upper electrode 110, electrons are injected into the light emitting layer 106, which is accelerated by the electric field and collides with the light emission center in the light emitting layer 106, at which time light is emitted. To do. 112 is the light.

[0007]

However, in the EL type light emitting device as described above, the luminous efficiency is extremely low,
Therefore, there is a problem that power consumption is large in order to obtain a large emission intensity. This is because the organic substances or ZnS crystals that make up the majority of the light emitting layer 106 do not emit light by themselves, but only the emission centers dispersed in such non-emissive substances emit light.

Therefore, it is a main object of the present invention to provide a light emitting device which can be used as a surface light emitting device, a self-luminous display, etc., and has a high luminous efficiency, and a manufacturing method thereof.

[0009]

SUMMARY OF THE INVENTION The light emitting device of the invention, Briefly, quantum box as a light emitting layer, luminescence by forming the oxide layer or a nitride layer only in the surface layer of the fine particles expressing formed Ri quantum effects It is characterized by using a quantum box layer that is an aggregate of.

In such a light emitting device, since all the quantum boxes forming the quantum box layer emit light, the luminous efficiency is high.

Moreover, the light emission of the quantum box is due to the quantum effect, and almost all the electrons injected into the quantum box emit light between the energy levels of the quantum box and recombine, so that the light emission efficiency is originally high. This also contributes to the improvement of the luminous efficiency of the light emitting device of the present invention.

Briefly, the manufacturing method of the present invention deposits fine particles on a substrate by a plasma CVD method, and oxidizes or only oxidizes only the surface layer portion of each fine particle previously deposited without exposing the substrate to the atmosphere. The feature is that the quantum box layer is formed by nitriding.

Since fine particles have a large surface area, if the substrate on which they are deposited is exposed to the atmosphere before the oxidation or nitriding treatment,
Although water adheres to the surface of the fine particles and it becomes difficult to uniformly form the quantum boxes by the subsequent oxidation or nitriding treatment, the above method can prevent the occurrence of such a problem. .

In most cases, the fine particles generated in plasma are charged, more specifically, negatively charged. In the manufacturing method of the present invention, by utilizing this property, it is necessary for the substrate side. It is possible to selectively guide and deposit the fine particles at various positions. This makes it possible to omit the fine processing step of the fine particle film, which has been difficult in the past. It is also possible to control the size of fine particles to be deposited.

[0015]

1 is a schematic sectional view partially showing an embodiment of a light emitting device according to the present invention.

This light emitting device is an example of a surface light emitting body such as a backlight of a liquid crystal display, and is made of a glass substrate 2, a transparent electrode 4 formed on the substrate 2 in a plane shape, and Quantum box layer 6 formed on the entire area of transparent electrode 4, and insulating film 8 formed on the entire area of quantum box layer 6
And an upper electrode 10 formed on the entire area of the insulating film 8.

The quantum box layer 6 is, for example, as shown in FIG.
It is an assembly of a large number of quantum boxes 60 in which the oxide layer or the nitride layer is formed only on the surface layer portion 62 of the fine particles 61. A quantum box means a particle having a three-dimensional shape (for example, a box shape, a spherical shape, etc.) in which a quantum effect appears.

When forming the quantum box as described above, the surface layer portion 62 may be either an oxide or a nitride, but the oxide has a larger energy bandgap and is likely to have many quantization levels. Therefore, it is advantageous when controlling the emission color. For example, when the fine particles 61 are Si, the surface layer portion 62 is SiO ₂ or Si ₃ N ₄ , but the band gap of SiO ₂ is about 10 eV and the band gap of Si ₃ N ₄ is about 5.2 eV.

Returning to FIG. 1, in such a light emitting device, when a voltage is applied between the transparent electrode 4 and the upper electrode 10, an electric field is applied to the quantum box layer 6 by this, and the quantum box layer 6 is caused. Each of the quantum boxes that compose is emitted by a quantum effect. That is, the entire region of the quantum box layer 6 emits light in a plane. 12 is the light.

Moreover, in this light emitting device, since all the quantum boxes forming the quantum box layer 6 emit light, most of the light emitting layer is made of a substance that does not emit light, and the emission centers are dispersed in it. The luminous efficiency is much higher than that of the conventional EL type light emitting device.

Further, the light emission of the quantum box is due to the quantum effect, and almost all the electrons injected into the quantum box emit light between the energy levels of the quantum box and recombine, so that the light emission efficiency is originally high. This also contributes to the improvement of the luminous efficiency of this light emitting device.

Therefore, this light emitting device can obtain a large light emission intensity while suppressing the power consumption to be small.

FIG. 3 shows another embodiment. This light emitting device has a substrate 2, a convex portion 2a formed on the substrate 2, and the above-mentioned convex portion 2a formed on the convex portion 2a. Such a quantum box layer 6, and first and second electrodes 14 and 16 formed so as to sandwich the quantum box layer 6 from the left and right,
It is provided with an insulating film 8 formed between both electrodes 14 and 16 and the quantum box layer 6. The insulating film 8 may be provided only between the one electrode 14 or 16 and the quantum box layer 6.

The light emitting action of this light emitting device is the same as that of the embodiment of FIG. 1, but in this embodiment the quantum box layer 6 is laterally sandwiched by the electrodes 14 and 16, so that the quantum box layer 6 is formed. The light 12 can be taken out from the vertical direction. Therefore, it is not necessary to use transparent electrodes for the electrodes 14 and 16, and the substrate 2 is not limited to the glass substrate and may be another opaque substrate as long as light in the upward direction is used. Therefore, the selection range of the electrode material and the substrate material is widened.

FIG. 4 shows still another embodiment. This light emitting device includes a substrate 2 and first and second light emitting devices which are juxtaposed on the substrate 2 with a gap therebetween. The electrodes 14 and 16, the quantum box layer 6 described above formed between the electrodes 14 and 16, and the insulating film 8 formed between the quantum box layer 6 and the electrodes 14 and 16. I have it. The insulating film 8 may be provided only between the one electrode 14 or 16 and the quantum box layer 6.

The light-emitting function of this light-emitting device and the peculiar effect of widening the selection range of the electrode material and the substrate material are the same as those in the embodiment of FIG. 3, but in this embodiment, the convex portion is formed on the substrate 2. Since there is no need to provide the structure, the structure is simpler.

If the transparent electrode 4 and the upper electrode 10 in the light emitting device of FIG. 1 are used as a plurality of electrodes and are arranged so as to intersect each other to form a plurality of pixels, a self-luminous display is formed. be able to.

A self-luminous display can also be formed by forming a large number of the structures shown in FIG. 3 or 4 on one substrate so that each of them forms a pixel.

Next, a method of manufacturing the light emitting device as shown in each of the above embodiments will be described.

FIG. 5 is a schematic view showing an example of a plasma CVD apparatus used for carrying out the manufacturing method of the present invention. A high-frequency electrode 26 and a holder / electrode 28 are housed in a vacuum container 24 that is evacuated by a vacuum evacuation device 32 so as to face each other. The holder / electrode 28 is grounded here. The substrate 2 on which the particles are to be deposited is placed on the holder / electrode 28. The substrate 2 is heated by, for example, the heater 30 in the holder / electrode 28.

A raw material gas 40 is introduced into the vacuum container 24 via a gas introducing portion 34 connected to the high frequency electrode 26. In this example, from gas sources 42 and 44 via mass flow controllers 46 and 48, respectively,
The gas forming the raw material gas 40 is supplied to the gas introduction unit 34. Reference numeral 50 denotes a heater used for vaporizing the gas from the gas source 42, which may be unnecessary depending on the type of gas.

A high frequency power supply 3 is provided between the high frequency electrode 26 and the holder / electrode 28 via a matching box 36.
A high frequency power having a frequency of, for example, 13.56 MHz is supplied from 8.

In such an apparatus, the raw material gas 40 is introduced into the vacuum container 24 to make the inside of the vacuum container 24 to be, for example, about several hundred mTorr, and the high frequency power is supplied from the high frequency power supply 38 between the high frequency electrode 26 and the holder / electrode 28. When electric power is supplied, high-frequency discharge is generated between the electrodes 26 and 28, and plasma 52 is generated. The source gas 40 is activated by the plasma 52, a chemical reaction proceeds, fine particles are generated, and these are deposited on the substrate 2 to form a fine particle film. For example, when a mixed gas of SiH ₄ and H ₂ is used as the source gas 40, Si particles are deposited on the substrate 2.

After depositing the fine particles on the substrate 2 in this manner, the source gas 40 is oxygen (when oxidation treatment is performed without exposing the substrate 2 to the atmosphere, that is, without breaking the vacuum of the vacuum container 24). ) Or ammonia (when performing a nitriding treatment) to generate oxygen plasma or ammonia plasma as plasma 52 in the vacuum container 24, whereby only the surface layer portion of each fine particle previously deposited on the substrate 2 is generated. Oxidize or nitrid. As a result, the quantum box layer 6 as described above can be formed on the substrate 2.

Since the fine particles have a large surface area, when the substrate 2 on which the fine particles are deposited is exposed to the atmosphere before the oxidation or nitriding treatment, water adheres to the surface of the fine particles and the quantum box is formed by the subsequent oxidation or nitriding treatment. Although it is difficult to form uniformly, the above method can prevent the occurrence of such a problem.

FIG. 6 shows an example of the potential of the plasma 52 during the film formation. The high-frequency electrode 26 is DC-cut by a blocking capacitor included in the matching box 36. Since many high-electrons, which are light and have much higher mobility than ions, enter the high-frequency electrode 26. The surface of the high-frequency electrode 26 has a negative potential, whereas the potential (potential) V _P of the plasma 52 is positive. The substrate 2 is at the ground potential because the holder / electrode 28 is grounded in this example. Ion sheaths 52a and 52b are formed between the surfaces of the substrate 2 and the high-frequency electrode 26 and the plasma 52, respectively.

When the fine particles are deposited by the plasma CVD method as described above, the fine particles generated in the plasma 52 are normally charged by the collision of electrons in the plasma 52 and the impact of ions. More specifically, electrons are lighter than ions and have much higher mobility, so that the particles are usually negatively charged. By utilizing this property, it is possible to selectively guide the particles to a necessary portion on the substrate 2 side by electrostatic force (Coulomb force). It is also possible to control the size of fine particles to be deposited.

For example, FIG. 7 shows an example of a method of manufacturing the light emitting device as described in FIG. 1. First, as shown in FIG. With a voltage applied, fine particles are deposited on the substrate 2 by the plasma CVD method using the apparatus shown in FIG.

When a positive voltage is applied to the transparent electrode 4, the fine particles produced in the plasma 52 and negatively charged are attracted by the positive potential of the transparent electrode 4, and as a result, as shown in FIG. 7B. The fine particle film 5 can be formed by selectively depositing fine particles only on the transparent electrode 4 on the substrate 2. Therefore, if the transparent electrode 4 is formed in a desired pattern, the fine particle film 5 can be formed according to the pattern.

When patterning a fine particle film, conventionally, the fine particle film is first coated on the substrate in a rough pattern, or fine particles are deposited on the entire surface of the substrate by a plasma CVD method, and then the fine particle film is subjected to photolithography and Although processing was performed by dry etching, when processing is performed using photolithography and dry etching techniques, blurring of the mask pattern due to light diffraction and undercutting due to side etching inevitably occur. Microfabrication was very difficult. Further, according to experiments, it is confirmed that fine processing by dry etching is almost impossible, although the reason is not clear for the fine particle film.

On the other hand, according to the above method, the fine particles can be selectively deposited on the transparent electrode 4 in accordance with the pattern thereof, so that the fine processing step of the fine particle film, which has been difficult in the past, can be omitted. it can.

The size of the fine particles deposited on the transparent electrode 4 can also be controlled. This is for the following reasons.

The particles formed in the plasma 52 have a property that the larger the particle size, the larger the surface area, and thus more likely to carry a lot of negative charges. According to an experiment, the size of the fine particles deposited on the substrate 2 varies depending on the negative charge of the fine particles in the plasma 52, the weight of the fine particles, and the electric field of the sheath 52a (see FIG. 6) on the substrate 2. It is confirmed.

That is, the potential difference of the portion of the sheath 52a on the substrate 2 (this means that if the substrate 2 has a zero potential, the plasma 52
Is smaller than the potential V _P of the plasma 52), the fine particles in the plasma 52 are attracted and deposited on the side of the substrate 2 with a small particle size, and when the potential difference of the sheath 52a part is medium, The fine particles are attracted and deposited on the substrate 2 side when the particle size becomes medium, and when the potential difference in the portion of the sheath 52a is large, the fine particles in the plasma 52 are attracted to the substrate 2 side only when the particle size becomes large. It has the property of being deposited. That is, if the potential difference of the sheath 52a is small, fine particles having a small particle diameter are selectively deposited on the substrate 2, and if the potential difference of the sheath 52a is medium, the fine particles having a medium particle diameter are selectively deposited on the substrate 2. If the potential difference of the sheath 52a is large, fine particles having a large particle size are selectively deposited on the substrate 2.

By controlling the magnitude of the voltage applied to the transparent electrode 4, the potential on the substrate 2 side in FIG. 6 (more specifically, the potential of the transparent electrode 4 above it) rises and falls. , Without changing the potential V _{P of the} plasma 52,
At the transparent electrode 4 portion, the potential difference at the sheath 52a portion is controlled, and as a result, the size of the fine particles deposited on the transparent electrode 4 can be controlled by the above properties. For example, when a large positive voltage is applied to the transparent electrode 4, the potential difference in the sheath 52a becomes small, so that fine particles having a small particle size can be selectively deposited on the transparent electrode 4.

Further, the particle size of the fine particles deposited on the transparent electrode 4 can be changed by changing the magnitude of the positive voltage applied to the transparent electrode 4 during the fine particle deposition.

The size of the fine particles forming the quantum box determines the energy level (quantization level) in which the electrons exist. The smaller the fine particles, the more the electrons can exist only in the higher energy level. Because of the large energy difference between the two, light with a color close to blue is emitted, and conversely, the larger the particles, the light with a color close to red is emitted.

Therefore, white light can be emitted by gradually or stepwise changing the particle size of the fine particles deposited on the transparent electrode 4 as described above. This is particularly effective when, for example, the light emitting display is used as a backlight of a liquid crystal display.

Returning to FIG. 7, after the fine particles are deposited on the transparent electrode 4 as described above to form the fine particle film 5, the fine particle film 5 is formed without exposing the substrate 2 to the atmosphere as described above. Only the surface layer portion of each of the constituent fine particles is oxidized or nitrided (FIG. 7C). As a result, the quantum box layer 6 (see FIG. 7D) as described above is formed on the transparent electrode 4.

After that, the quantum box layer 6 is formed by a known method.
An insulating film 8 is formed thereon (FIG. 7D), and an upper electrode 10 is further formed thereon (FIG. 7E). As a result, the light emitting device as described in FIG. 1 is obtained.

A more specific example according to the method of FIG. 7 will be described. After a liquid crystal panel is manufactured, ITO (tin-doped indium) is applied to the display area of the liquid crystal on the back surface of the glass substrate. The transparent electrode was formed, and Si fine particles were attracted and deposited on the transparent electrode by SiH ₄ (silane) plasma while a positive voltage was applied to the transparent electrode. At that time, the voltage applied to the transparent electrode is
The particle size was gradually changed so that the particle size was suitable for emitting white light. After depositing Si particles on the transparent electrode, the source gas is switched to NH ₄ (ammonia) to generate ammonia plasma without breaking the vacuum, and only the surface layer of each Si particle is nitrided to form a quantum box. Layers were formed. The processing conditions and the like of this embodiment are summarized as follows.

Application of light emitting device: backlight of liquid crystal display, substrate: glass substrate (back surface of liquid crystal panel), substrate size: 10 inches (diagonal), transparent electrode: IT
O, applied voltage: Gradually change positive voltage, source gas during film formation: SiH ₄ 40 sccm, gas pressure: 800 mTorr
r, substrate temperature: 150 ° C., deposited fine particles: Si, fine particle diameter: 50 to 500 nm, high frequency power: 400 W, post-treatment: nitriding with ammonia plasma

FIG. 8 shows an example of a method for manufacturing the light emitting device as described with reference to FIG. 3, in which a convex portion 2a is formed on a portion of the substrate 2 made of an insulating material where fine particles are to be deposited. Then, fine particles are deposited on the substrate 2 by the plasma CVD method described above (FIG. 8).
A).

When the convex portion 2a is formed on the substrate 2 made of an insulating material, the convex portion 2a is positively charged during film formation. This is because the ions in the plasma 52a are accelerated and collide with the substrate 2 due to the potential difference (for example, about 500 to 600 V) in the sheath 52a portion of the plasma 52, and at that time, the convex portion 2
Since the electric field is concentrated on a, ions collide intensively there, and a large number of electrons are emitted from the projections 2a by this collision. Moreover, since the substrate 2 is made of an insulating material, the projections 2a are positive. Because it is charged. It should be noted that although electrons are incident on the substrate 2 from the plasma 52, as for the convex portion 2a, more electrons are emitted than the incident electrons, and as a result, they are positively charged. The degree of positive charging of the convex portion 2a can be controlled by the height of the convex portion 2a.

As described above, in this method, since the convex portion 2a is positively charged, the fine particles produced in the plasma 52 and negatively charged are attracted by the positive charge of the convex portion 2a, and the convex portion 2a is charged. The fine particle film 5 is formed by selectively depositing on the surface (FIG. 8B). Therefore, even with this method
It is possible to omit the fine processing step of the fine particle film which has been difficult in the past.

The convex portion 2a on the substrate 2 may be made of the same material as the other portions, but may be made of a different material. If made of a different material, the convex portion 2a may have a convex shape other than the height. Part 2a
The degree of positive charging of the convex portion 2a can be controlled more freely because the degree of positive charging of the convex portion 2a can be changed.

In this way, by controlling the degree of positive charging of the convex portion 2a depending on the height and material of the convex portion 2a, it is possible to control the easiness of collecting the fine particles on the convex portion 2a. It is possible to control the size of the fine particles deposited on the convex portion 2a, and by extension, the emission color, by the action described above in the embodiment of FIG. For example,
By increasing the height of the convex portion 2a and increasing the positive potential of the convex portion 2a, the potential difference in the sheath 52a is reduced, so that fine particles having a small particle diameter can be selectively deposited on the convex portion 2a. it can.

After the fine particles are deposited on the convex portions 2a as described above to form the fine particle film 5, the surface layer portion of each fine particle forming the fine particle film 5 is not exposed to the atmosphere of the substrate 2 as described above. Only oxidize or nitride (FIG. 8C). As a result, the quantum box layer 6 (see FIG. 8D) as described above is formed on the convex portion 2a.

After that, an insulating film 8 is formed by a known method so as to cover the quantum box layer 6 and the substrate 2 in this example (FIG. 8D), and then the insulating film 8 is interposed to form the quantum box. The first and second electrodes 1 sandwich the layer 6 from the left and right.
4 and 16 are formed (FIG. 8E). As a result, a light emitting device having a structure substantially similar to that described with reference to FIG. 3 is obtained.

In this example, unlike the example of FIG. 3, the insulating film 8 is also formed on the quantum box layer 6, but the insulating film 8 is formed.
Is transparent, there is no problem in upward light emission, and if the substrate 2 is transparent, there is no problem in downward light emission, or if the insulating film 8 is an obstacle, a mask is used to It is sufficient to prevent the insulating film 8 from being formed on the layer 6.

FIG. 9 shows an example of a method of manufacturing the light emitting device as described with reference to FIG. 4, in which the insulating film 8 is formed so as to cover between the electrodes 14 and 16 provided on the substrate 2. Preliminarily (FIG. 9A), while a negative voltage is applied to the electrodes 14 and 16 from the DC power supply 54, fine particles are deposited on the substrate 2 by the plasma CVD method as described above (FIG. 9B).

When a negative voltage is applied to the electrodes 14 and 16, the negative particles charged in the plasma 52 and negatively charged are repelled by the negative voltage of the electrodes 14 and 16, and as a result, on the substrate 2. The particulate film 5 is formed by selectively depositing only between the electrodes 14 and 16 (FIG. 9).
C). Therefore, also by this method, it is possible to omit the fine processing step of the fine particle film, which has been difficult in the past.

Further, in the case of this embodiment, the electrodes 14 and 16 are
The potential at the site between and can be controlled to some extent by the negative voltage applied to electrodes 14 and 16 (this is due to potential bleeding from electrodes 14 and 16 on both sides), and by doing so, Since it is possible to control the potential difference of the sheath 52a with respect to the portion between the electrodes 14 and 16, the fine particles deposited between the electrodes 14 and 16 by the action described above in the embodiment of FIG. It is possible to control the size of, and thus the emission color. For example, when a large negative voltage is applied to the electrodes 14 and 16, the potential difference in the sheath 52a increases, so that fine particles having a large particle size are selectively applied to the electrodes 14 and 16.
Can be deposited between.

After the fine particles are deposited between the electrodes 14 and 16 as described above to form the fine particle film 5, the fine particles forming the fine particle film 5 are not exposed to the atmosphere of the substrate 2 as described above. Only the surface layer portion of is oxidized or nitrided (FIG. 9D). As a result, the insulating film 8 is formed between the electrodes 14 and 16.
And the quantum box layer 6 as described above is formed,
A light emitting device having a structure substantially similar to that described with reference to FIG. 3 can be obtained.

According to the method shown in FIGS. 7 and 9,
When a negative or positive voltage is forcibly applied to the electrodes 4, 14, 16 by the DC power supply 54, the charging phenomenon is not used, and thus the substrate 2 may be either an insulator or a semiconductor.

[0066] In any of the methods of FIG. 7 to FIG. 9, may be used in combination to control the potential of the plasma 52 V _P (see FIG. 6), if so, the potential V _P of the plasma 52 Also by the sheath 52a
Since it is possible to control the potential difference in the part of FIG.
The size of the particles selectively deposited on the substrate 2 and thus the emission color can be controlled by the action as described in the embodiment. For example, by increasing the potential V _{P of the} plasma 52, the sheath 52
Since the potential difference at a becomes large, fine particles having a large particle diameter can be selectively deposited on the substrate 2.

The potential V _P of the plasma 52 is the energy that contributes to the generation of the plasma 52, for example, in the case of the plasma CVD apparatus of FIG.
It can be controlled by controlling the magnitude of the high-frequency power supplied between 6 and 28. For example, if the high frequency power is increased, the potential V _{P of the} plasma 52 is also increased.

In any of the methods shown in FIGS. 7 to 9 and the method of controlling the potential V _{P of the} plasma 52 in combination with the method, a positive or negative bias voltage is applied to the entire substrate 2. You may use together. This is, for example, as shown in FIG. 10, the bias power supply 5 is connected between the holder / electrode 28 holding the substrate 2 and the ground.
6 is connected, and a positive or negative bias voltage is applied to the holder / electrode 28 by the bias power source 56.

In this way, the potential difference in the portion of the sheath 52a can be controlled by the bias voltage of the substrate 2 as well, so that the substrate 2 will be affected by the action described in the embodiment of FIG. It is possible to control the size of the fine particles to be selectively deposited, and thus the emission color.
For example, by applying a negative bias voltage to the entire substrate 2, the potential difference in the sheath 52a increases, so that fine particles having a large particle size can be selectively deposited on the substrate 2.

[0070]

As described above, according to the present invention, the following effects can be obtained.

[0071]

[0072]

According to the manufacturing method of the first to third aspects, it is possible to prevent the moisture in the atmosphere from adhering to the surface of the fine particles having a large surface area and form the quantum boxes uniformly in the quantum box layer. it can.

In addition to that, according to the manufacturing method of the first aspect , since the fine particles produced in the plasma are negatively charged, a positive voltage is applied to the transparent electrode on the substrate. Fine particles for forming the quantum box layer can be selectively deposited on the transparent electrode on the substrate by the suction action of both charges. As a result, it is possible to omit the fine processing of the fine particle film, which has been difficult in the past. Moreover, by adjusting the voltage applied to the transparent electrode, it is possible to control the size of the particles to be deposited, and thus the emission color.

According to the manufacturing method of the second aspect, the fine particles produced in the plasma are negatively charged, whereas the convex portions on the substrate exposed to the plasma are positively charged, so that both charges are charged. By the suction action of, the fine particles for forming the quantum box layer can be selectively deposited on the convex portions on the substrate. As a result, it is possible to omit the fine processing step of fine particles, which has been difficult in the past. Moreover, since the degree of electrification of the convex portion can be changed depending on the height and material of the convex portion, it is possible to control the size of the deposited fine particles, and thus the emission color, to some extent.

According to the manufacturing method of the third aspect , the fine particles formed in the plasma are negatively charged, whereas the negative voltage is applied to the first and second electrodes on the substrate. By the repulsive action of both charges, fine particles for forming the quantum box layer can be selectively deposited between the first and second electrodes on the substrate. As a result, it is possible to omit the fine processing of the fine particle film, which has been difficult in the past. Moreover, by adjusting the voltage applied to the first and second electrodes, it is possible to control the size of the deposited fine particles, and thus the emission color.

According to the manufacturing method of the fourth aspect , since the size of the fine particles selectively deposited on the substrate can be changed during the deposition, the quantum boxes having different sizes can be mixed. It is also possible to obtain a white light emitting device.

According to the manufacturing method of the fifth aspect , the potential difference of the plasma in the sheath portion near the substrate can be controlled by controlling the plasma potential. Therefore, also by this, the selective potential on the substrate can be obtained. It is possible to control the size of the particles deposited on the substrate, and thus the emission color.

According to the manufacturing method of the sixth aspect , the potential difference of the plasma in the sheath portion near the substrate can be controlled by the bias voltage applied to the entire substrate, and this also enables selective selection on the substrate. It is possible to control the size of the particles deposited on the substrate, and thus the emission color.

[Brief description of drawings]

FIG. 1 is a schematic sectional view partially showing an embodiment of a light emitting device according to the present invention.

FIG. 2 is a schematic cross-sectional view showing the structure of a quantum box.

FIG. 3 is a schematic sectional view partially showing another embodiment of the light emitting device according to the present invention.

FIG. 4 is a schematic sectional view partially showing still another embodiment of the light emitting device according to the present invention.

FIG. 5 is a schematic diagram showing an example of a plasma CVD apparatus.

6 is a diagram showing an example of plasma potential in the apparatus of FIG.

FIG. 7 is a diagram showing an example of a method of manufacturing the light emitting device as described in FIG. 1.

FIG. 8 is a diagram showing an example of a method of manufacturing a light emitting device as described in FIG.

FIG. 9 is a diagram showing an example of a method of manufacturing the light emitting device as described in FIG.

FIG. 10 is a diagram showing an example in which a bias voltage is applied to the entire substrate.

FIG. 11 is a schematic sectional view partially showing an example of a conventional EL type light emitting device.

[Explanation of symbols]

2 substrates 2a convex part 4 transparent electrodes 6 Quantum box layer 8 insulating film 10 Upper electrode 12 light 14, 16 electrodes 24 vacuum vessels 26 high frequency electrodes 28 Holder and electrode 38 high frequency power supply 40 source gas 52 plasma 54 DC power supply 56 bias power supply

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-206515 (JP, A) JP-A-1-100916 (JP, A) JP-A-1-101388 (JP, A) JP-A-5- 218499 (JP, A) JP 4-112584 (JP, A) JP 3-53567 (JP, A) JP 6-112524 (JP, A) JP 64-12498 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 33/00 H01L 21/205

Claims (6)

(57) [Claims] 1. A glass substrate and a substrate formed on the substrate.
And a transparent electrode formed on the transparent electrode.
Form the oxide or nitride layer only on the surface layer of the particle
It is a collection of quantum boxes that emit a quantum effect.
A quantum box layer and an insulating film formed on the quantum box layer,
In manufacturing a light emitting device including an upper electrode formed on the insulating film, fine particles are deposited on the substrate by a plasma CVD method while applying a positive voltage to the transparent electrode, and then the substrate is formed. Without exposing it to the atmosphere, only the surface layer portion of each fine particle deposited as described above is oxidized or nitrided to form the quantum box layer, and then the insulating film is formed on the quantum box layer. Then, a method for manufacturing a light emitting device, characterized in that the upper electrode is formed on the insulating film. 2. A substrate and a convex portion formed on the substrate
And, it is formed on this convex part, only the surface layer part of the fine particles
Is formed by forming an oxide layer or a nitride layer on the
This is a quantum box layer, which is a collection of quantum boxes that emit light and
The first and the first formed so as to sandwich the quantum box layer from the left and right
Two electrodes and at least one of the electrodes and the quantum box layer
In manufacturing a light emitting device having an insulating film formed between them, fine particles are deposited on the substrate on which the convex portion is formed by a plasma CVD method, and then the substrate is exposed to the atmosphere as described above. Only the surface layer portion of each fine particle deposited in the above is oxidized or nitrided to form the quantum box layer, and then the insulating film is formed so as to cover at least one side surface of the quantum box layer. A method for manufacturing a light-emitting device, characterized in that the first and second electrodes are formed so as to sandwich the quantum box layer from the left and right with an insulating film interposed. 3. A substrate and a gap between the substrate and each other.
First and second electrodes arranged in parallel with each other, and both electrodes
The oxide layer is formed only between the surface layers of the fine particles.
Or, it is formed by forming a nitride layer to generate quantum effect and emit light.
Quantum box layer, which is a collection of quantum box layers,
Between at least one of the first and second electrodes
In manufacturing a light emitting device including the formed insulating film, the insulating film is formed so as to cover at least the inner side surface of at least one of the first and second electrodes, and In the state where a negative voltage is applied to the first and second electrodes, fine particles are deposited on the substrate by the plasma CVD method, and then the fine particles deposited as described above are exposed without exposing the substrate to the atmosphere. A method for manufacturing a light-emitting device, which comprises forming the quantum box layer by oxidizing or nitriding only a surface layer portion. Wherein when depositing the fine particles, the method of manufacturing the light emitting device of claim 1 or 3 wherein changing the size of the voltage applied to the electrode. 5. The method for manufacturing a light emitting device according to claim 1, 2, 3, or 4, wherein the potential of plasma when depositing the fine particles is controlled. 6. A positive or negative bias voltage is applied to the entire substrate when the fine particles are deposited .
2. A method for manufacturing a light emitting device according to 2, 3, 4 or 5 .