JP2001284641A - Image display device - Google Patents

Abstract

(57) [Summary] [Problem] Mounting and electrode wiring are easy and production efficiency is good.
An image display element capable of displaying a high-quality image is provided. SOLUTION: A substrate for crystal growth in which each layer of a light emitting diode element having a multilayer structure is sequentially crystal grown is divided into a rod-like body in which a plurality of light emitting diode elements are linearly arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode device, and more particularly, to a chip using a plurality of light emitting diode devices using LEDs.

[0002]

2. Description of the Related Art With the rapid development of technology in recent years, it has become possible to process a large amount of information data.
There is an increasing demand for a full-color display device capable of processing and displaying a large amount of image information. One of such display devices uses a light-emitting diode (hereinafter, referred to as an LED) element. That is, by arranging LED elements that can be driven at high luminance and low voltage in a desired shape such as a matrix and driving each of the LED elements, a display device that can obtain a desired image can be manufactured. Japanese Patent Application Laid-Open Nos. 56-1738, 5-53511 and 7-3359
No. 42, JP-A-9-197979, JP-A-1
0-22529, JP-A-8-306961, JP-A-7-129097, JP-A-6-232
As described in JP-A-456-456 and JP-A-6-45660, many display devices in which LED elements are arranged in a matrix have been proposed.

[0003]

By the way, in the process of manufacturing such a display device, an LED is mounted on a large screen.
Although it is necessary to mount and wire the elements one by one, it is easily conceivable that this process requires a very long time and the production yield is lowered. Therefore, for example, as described in JP-A-7-129097, LE
It is possible to solve the problem of the yield per unit and the manufacturing time by dividing the matrix into small units of a matrix of 3 × 3 elements and arranging a large number of mounting wirings in parallel for each unit.

[0004] However, in this case, if the unit is made too small, there is a problem that the yield is reduced when the unit is mounted as a large screen and wiring is performed. Therefore, it is necessary to form a unit having an optimal size for mounting wiring. As a method for taking out electrodes when the unit is formed as described above, for example, Japanese Patent Application Laid-Open No. Sho 56-1738
However, in the case of such a method, there is a problem in that the boundaries between the units become conspicuous and the original image information cannot be displayed.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and provides an image display element capable of easily mounting and electrode wiring, having high production efficiency, and displaying a high-quality image. The purpose is to:

[0006]

In the image display device according to the present invention, a substrate for crystal growth, in which each layer of a light-emitting diode device having a multilayer structure is sequentially grown, is divided, and a plurality of light-emitting diode devices are linearly formed. Characterized in that they are arranged in the form of rods.

The image display element according to the present invention is a rod-shaped body in which a substrate for crystal growth, in which each layer of a light emitting diode element having a multilayer structure is sequentially grown, is divided and a plurality of light emitting diode elements are linearly arranged. It has been.

In this image display element, a plurality of light emitting diode elements are arranged.
Since the number of steps for mounting the ED element and the number of wirings for the electrodes are greatly reduced, the production efficiency is excellent, and a high-quality image with good visibility can be displayed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

First Embodiment FIGS. 1 to 3 show an example of an image display device to which the present invention is applied. FIG. 1 is a plan view of an image display device 1 to which the present invention is applied. FIG. 2 is a longitudinal sectional view taken along line X ₁ -X ₂ in FIG. FIG. 3 is a longitudinal sectional view of the LED element portion.

The image display element 1 to which the present invention is applied is provided with a plurality of LED elements each having an active layer formed between an n-conductive side semiconductor layer and a p-conductive side semiconductor layer. Here, the p-conducting side refers to a semiconductor layer between the active layer and the p-electrode, and the n-conducting side refers to
It refers to the semiconductor layer on the side opposite to the conductive side. That is, the image display element 1 to which the present invention is applied is, for example, an LED
An Si substrate, which is a substrate 3 for crystal growth of an element, and an Al, which is an n-side buffer layer 4 formed on one main surface of the Si substrate.
An N: Si layer, a GaN: Si layer that is an n-side buffer layer 5 formed on the AlN: Si layer, and an AlGaN: Si layer that is an n-side cladding layer 6 formed on the GaN: Si layer. An InGaN / GaN layer as an active layer 7 formed on an AlGaN: Si layer, an AlGaN: Mg layer as a p-side cladding layer 8 formed on the InGaN / GaN layer, and an AlGaN: Mg layer formed on an AlGaN: Mg layer A GaN: Mg layer serving as the p-side contact layer 9, a p electrode 10 formed on the GaN: Mg layer, and an n electrode formed on the other main surface of the Si substrate.
A plurality of LED elements 2 each having the electrode 11 are provided.

As shown in FIGS. 1 to 3, the image display element 1 is formed by cleaving or cutting the LED element 2 into a rod shape from a substrate used for crystal growth of the LED element 2, and forming a straight line on the substrate. It is characterized by a plurality of arrangements.

That is, the image display element 1 has a predetermined number of L
Since the ED element 2 is disposed on the substrate 3 for crystal growth of the LED element 2 and is used as a basic unit, the number of steps for mounting a display device or the like on another substrate can be greatly reduced. It becomes possible. Therefore, since the mounting of the LED element 2 can be performed easily and efficiently, the production efficiency can be improved.

An n-electrode 11 common to all the LED elements 2 on the image display element 1 is formed on the main surface of the image display element 1 opposite to the side where the LED elements 2 are formed. . Therefore, it is possible to greatly reduce the number of electrode wirings when manufacturing a display device and the like, and it is possible to easily and efficiently perform the wiring of the electrodes. The reliability of the wiring can also be improved.

In the image display element 1, L
A nitride is grown on a substrate 3 for crystal growth of the ED element 2, and the LED element 2 is formed of a nitride semiconductor.

By forming the LED element 2 using a nitride semiconductor, it is possible to obtain RGB, and it is possible to obtain the effect of increasing the light emission efficiency with less deterioration. And, as the nitride semiconductor, GaN-based III
A -V group can be suitably used.

In the image display element 1, L
The substrate 3 for crystal growth of the ED element 2 is characterized by using a material having a Mohs hardness of 7 or less.

A nitride-based crystal such as GaN is usually grown on a sapphire substrate, but sapphire has a Mohs hardness of 9, is very hard, and can be formed with high precision by means of a dicing saw or the like which usually cleaves. It is very difficult to cut. When a sapphire substrate is cut into a bar shape using a dicing saw, a variation of about 20 μm usually occurs in one cut surface in the longitudinal direction. However, if the variation in the cutting at the cleavage is large, a problem occurs in a process of mounting the image display element 1 on another substrate, which is a process after manufacturing the display device. Therefore, it is necessary to suppress the variation in cutting in the longitudinal direction of the image display element 1 to about 10 μm on both side surfaces of the image display element 1.

Therefore, a material having a Mohs hardness of 6 or less is LE
By using as a substrate 3 for crystal growth of a D element,
Variations in the dimensions of the cut surface during the cleavage can be reduced, the cleavage can be performed with high accuracy, and the yield can be improved. As a material satisfying such a condition, for example, quartz having a Mohs hardness of 7 or single crystal silicon having a Mohs hardness of 7 can be suitably used. Among them, quartz has a variation of about 5 μm when cutting with a dicing saw, but in the case of single crystal silicon, the variation of cutting when cutting with a dicing saw is 1-2 μm. Since the degree is very small, single crystal silicon can be more preferably used. In addition, single crystal silicon is less expensive than sapphire or the like, and high quality LED elements 2 can be manufactured at low cost by using single crystal silicon as the substrate 3 for crystal growth of LED elements.

In the above-described LED element 2, the color of light emitted from the LED element 2 can be changed by doping the InGaN of the InGaN / GaN layer, which is the active layer 7, with a rare earth element. Where In
Rare earth elements that can be doped into GaN include, for example, L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu and the like can be used. In particular, red light emission can be obtained by doping Eu, Sm, and Er, green light emission can be obtained by doping Tb, and blue light emission can be obtained by doping Tm. .

As described above, three kinds of image display elements in which InGaN is doped with a predetermined rare earth element and three kinds of LED elements of, for example, a first color, a second color, and a third color are respectively arranged are manufactured. As shown in FIG. 4, the image display elements of the first color and the image display element 1 of the second color are used as shown in FIG.
Third, the color display device can be simply and efficiently constructed by sequentially arranging the image display elements 14 of the third color in this order and wiring the p-electrode 10 and the n-electrode 11 using, for example, wires. .

In the above, the rare earth element to be doped into InGaN is selected, and the first color is blue, ie, 450 to 4
80 nm emission wavelength band, the second color is green, that is, 500 to
540 nm emission wavelength band, the third color is red, ie, 610
By setting the emission wavelength band to ６640 nm, R
The three colors of RGB can be aligned, and the image display elements of these three colors of RGB are sequentially arranged as shown in FIG. 4, and the p-electrode and the n-electrode are wired using, for example, a wire.
A high-quality full-color display device can be configured simply and efficiently.

Image display element 1 configured as described above
Can be manufactured as follows.

First, a single crystal silicon substrate 3 for crystal growth of an LED element is prepared, and the single crystal silicon substrate is washed with an organic solvent or the like. The cleaned substrate is, for example, MO
CVD (Metal Organic Chemical Vapor Deposition)
Inserted into the apparatus, and set the substrate temperature to, for example, 800 to 1050 ° C.
Thermal cleaning is performed by heating to a temperature of

Next, on one main surface of the single crystal silicon substrate,
For example, an AlN: Si layer is formed as the n-side buffer layer 4 at a growth temperature of 700 to 1000 ° C.

Next, a single crystal silicon substrate is
Heat to a temperature of about 1000 ° C. to form a GaN: Si layer having a thickness of 0.1 μm or more as a buffer layer 5 on the AlN: Si layer.

Next, a single crystal silicon substrate is
By heating to a temperature of 0 ° C., an (Al) GaN: Si layer having a thickness of about 1 μm is formed as an n-side cladding layer 6 on the GaN: Si layer. Here, the Al layer may be mixed if necessary, and need not necessarily be formed.

Next, a single crystal silicon substrate is
Is heated to a temperature of about 800 ° C., and an active layer 7 having a multi-quantum-well (MQW) structure is formed on the AlGaN layer.
To form an InGaN / GaN layer with a thickness of about 1 to 6 nm. Here, the content of In in the InGaN / GaN layer depends on the required emission wavelength, that is, the emission color, but is preferably about 1% to 80%. For example,
Blue light emission can be obtained by setting the In content in the InGaN / GaN layer to about 20%, green light emission can be obtained by setting the content of In to about 40%, and 50% or more. Accordingly, red light emission can be obtained. In addition, as the active layer, InGaN / GaN
Alternatively, InGaN / AlGaN, InGaN / AlN, or the like can be used.

By doping InGaN with a rare earth element, the wavelength of light emitted from the LED element 2, that is, the color can be changed. Here, rare earths that can be doped into AlGaN include, for example, La, Ce, P
r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu and the like can be used.
In particular, red light emission can be obtained by doping Eu, Sm, and Er, green light emission can be obtained by doping Tb, and blue light emission can be obtained by doping Tm. .

Next, a single crystal silicon substrate is for example 980
C., and an AlGaN: Mg layer as a p-side cladding layer 8 on the InGaN / GaN layer is 0.1 to 0.2.
It is formed to a thickness of about μm. Here, by mixing boron into AlGaN, it is possible to obtain the effect of improving the characteristics of the underlying InGaN and improving the luminous efficiency by suppressing overflow electrons.

Next, a single-crystal silicon substrate is
To 980 ° C., and on the AlGaN: Mg film,
GaN: Mg is formed to a thickness of about 0.1 μm as the p-side contact layer 9.

In the above, as a raw material of Ga, trimethylgallium (TMGa) or triethylgallium (T
EGa) can be used. Further, NH3 can be used as a raw material of N. As a raw material of Mg, bismethylcyclopentadienyl magnesium ((MeCp) ₂ Mg) or dicyclopentane magnesium (Cp ₂ Mg) can be used.

Next, the substrate on which the crystal has been grown as described above is annealed at a temperature of, for example, about 800 ° C. for 10 minutes to activate the p-type carriers.

Next, an electrode pad 16 is formed on the GaN: Mg layer.
To form The substrate is washed, and then a resist is applied to the main surface of the substrate on which the crystal is grown by a spin coater,
Exposure and development are performed using a photomask corresponding to the size and shape of the electrode pad 16. Then, after development, for example, Ni / Pt / Au is
An electrode pad is formed by depositing a film having a thickness of about 00 nm by an evaporation method and performing lift-off with acetone.

Next, a transparent electrode is formed. The substrate on which the electrode pads 16 are formed is washed, and then a resist is applied to the main surface of the substrate on which the crystal has been grown by a spin coater,
Exposure and development are performed using a photomask corresponding to the size and shape of the transparent electrode 17 to be formed. And after development,
For example, a transparent electrode 17 is formed by depositing Au to a film thickness of 10 nm by an evaporation method and performing lift-off with acetone.

Next, element isolation is performed. The element isolation can be performed by etching the GaN: Si film to a predetermined thickness using, for example, reactive ion etching (RIE).

Next, the back surface of the substrate is polished. On the surface on the side where the electrode pads 16 and the like of the substrate subjected to element isolation are formed,
A photoresist is applied by a spin coater as a protective film. Then, the back surface of the substrate, that is, the main surface on the side opposite to the side on which the electrode pads 16 and the like are formed, is polished using a polishing machine or the like until the thickness of the LED element becomes about 100 μm, for example.

Next, an n-electrode 11 is formed. n electrode 11
, Au, Al or Cu is used. The oxide film formed on the back surface of the back-polished substrate, that is, the main surface on the polished side is removed by wet etching or the like. Next, the photoresist formed as a protective film on the surface of the substrate, that is, the surface on the side on which the electrode pads 16 and the like are formed is removed with acetone or the like, and the back surface of the substrate, that is, the main surface on the side on which the wet etching is performed, is removed. The n-electrode 11 is formed by depositing Au to a thickness of about 300 nm by an evaporation method.

Next, cleavage is performed by using, for example, a dicing saw or the like so that a plurality of LED elements 2 are linearly arranged on the image display element 1, so that the image display element 1 as shown in FIGS. Can be produced. At this time,
The n-electrode 11 produced above is also separated into each image display element 1.

Second Embodiment FIGS. 5 to 7 show other examples of the image display device to which the present invention is applied. FIG. 5 shows an image display element 25 to which the present invention is applied.
FIG. Figure 6 is a longitudinal sectional view of the X ₃ -X ₄ line of FIG. FIG. 7 is a longitudinal sectional view of the LED element portion.

The image display element 25 includes an LED element 26
And a GaN: S n-side buffer layer 18 formed on one main surface of the Si substrate.
an i-layer, SiO ₂ which is formed on the GaN layer and has a mask 20 having an active layer growth hole 19, a GaN: Si layer which is an n-side cladding layer 21 formed in the active layer growth hole 19, An InGaN / GaN layer as an active layer 22 formed in the layer growth hole 19 and on the mask 20;
A, which is the p-side cladding layer 23 formed on the / GaN layer
1GaN: Mg layer; GaN: Mg layer which is p-side contact layer 24 formed on AlGaN: Mg layer;
N: LED element 26 having p electrode 10 formed on Mg layer and n electrode 11 formed on the other main surface of Si substrate
Are provided.

The basic configuration of the image display element 25 is almost the same as that of the first embodiment except that the mask 20 is used when forming the active layer 22. Have. Therefore, here, the formation of the active layer 22 using the mask 20 different from the first embodiment will be described.

In the LED element 26, a GaN layer serving as an n-side buffer layer 19 is formed on one main surface of a single crystal silicon substrate serving as a substrate 3 for crystal growth of the LED element. SiO ₂ is formed as a mask 20. Then, the active layer growth holes 19 are provided in the mask so as to be arranged in a predetermined straight line in the vertical and horizontal directions as shown in FIGS. Active layer growth hole 19
Is a center portion when the active layer 22 is grown, and the bottom of the active layer growth hole 19 is
A GaN: Si layer is formed to a thickness of, for example, about 1 μm. The active layer growth hole 19 is formed on the GaN: Si layer.
And an InGaN / GaN layer as the active layer 22 is further formed, for example, in a hexagonal shape along the upper surface of the mask 20.

With the above-described configuration, the positioning of the LED element 26 on the image display element 25 can be easily and reliably performed, and the image display element 25 having a good arrangement accuracy of the LED element 26 can be obtained. it can.

The image display element 25 constructed as described above
Can be manufactured as follows.

First, a single crystal silicon substrate is prepared as a substrate 3 for crystal growth of an LED element, and the single crystal silicon substrate is washed using an organic solvent or the like. Clean the substrate
MOCVD (Metal Organic Chemical Vapor Depositio
n)) Insert into the apparatus and set the substrate temperature to, for example, 800 to 10
Thermal cleaning is performed by heating to a temperature of 50 ° C.

Next, on one main surface of the single crystal silicon substrate,
For example, a GaN: Si layer is formed as the n-side buffer layer 18 at a growth temperature of 800 to 1000 ° C. The thickness of the GaN: Si layer varies depending on the doping concentration of Si, but is preferably about 3 μm.

Next, SiO ₂ is formed as a mask 20 to a thickness of about 0.2 μm on the GaN: Si layer. Then, as shown in FIG. 8, a predetermined number of active layer growth holes 19 having a depth of about 0.2 μm are formed in the mask so as to be linearly arranged vertically and horizontally, respectively. Here, the active layer growth hole 19 opened in the mask is a portion that becomes the center of the active layer 22 in a later step, and corresponds to a pixel when a display device or the like is configured. The mask 20 may be formed using SiN.

Next, a single crystal silicon substrate is
To 1000 ° C. to form a GaN: Si layer of about 1 μm as the n-side cladding layer 21, and further heat the single crystal silicon substrate to a temperature of, for example, 600 to 800 ° C.
a multiple quantum well structure (MQW: Multi-Qu
InGaN (3 nm to 3 nm) as the active layer 22 of antum-Well)
(About 6 nm) / GaN (about 5 nm) is formed. Here, the GaN: Si layer and the InGaN / GaN layer are not formed on the mask 20 at first, but are formed in the active layer growth holes 19 opened in the mask 20. After the active layer growth holes 19 are filled, the active layer growth holes 19 are spread around the upper surface of the mask 20 around the active layer growth holes 19 and formed in a hexagonal shape. At this time, adjustment is made so that adjacent active layers 22 that have grown from each active layer growth hole 19 are not connected to each other.

As described above, the mask 2 is formed on the GaN: Si layer.
0 is formed, the active layer 22 is formed by opening the active layer growth hole 19 in the mask 20, and the adjacent active layer 22 grown in each active layer growth hole 19 is controlled so as not to be connected. The element isolation process performed in the first embodiment can be simplified.

The content of In in the InGaN / GaN film varies depending on the required emission wavelength, but is 1% to 8%.
It is preferable to set it to about 0%. As the barrier layer, InGaN / AlGaN besides InGaN / GaN is used.
And InGaN / AlN can also be used.

Further, similarly to the first embodiment, InG
By doping aN with a rare earth element, the LED element 26
Can change the color of the luminescence obtained from

Next, a single crystal silicon substrate is, for example, 800
By heating to a temperature of about 980 ° C., an AlGaN: Mg layer is formed on the InGaN / GaN film as the p-side cladding layer 23 to a thickness of about 0.1 to 0.2 μm.

Next, a single crystal silicon substrate is
Heated to a temperature of ９980 ° C., on the AlGaN: Mg layer,
GaN: Mg of 0.1 μm as the p-side contact layer 24
It is formed to a film thickness of about. GaN: Mg as the p-side contact layer 24 is formed with a high Mg concentration.

Here, G covering the active layer 22 is formed.
B is mixed into the aN layer and the AlGaN layer as necessary,
BAlGaN or the like having a high Al content may be used. By mixing B, it is possible to obtain the effect of improving the stability of InGaN thereunder and suppressing the electron overflow and improving the luminous efficiency.

In the above, the same materials as in the first embodiment can be used as the raw materials for Ga, N, and Mg.

Next, an electrode pad 16 is formed on the GaN: Mg layer.
To form The substrate is washed, a resist is applied to the main surface of the substrate on which the crystal has been grown by a spin coater, and exposure and development are performed using a photomask corresponding to the size and shape of the electrode pad 16. Then, after development, for example, Ni /
Pt / Au are 10 nm, 100 nm, and 300 n respectively.
An electrode pad 16 is formed by depositing a film having a thickness of about m by a vapor deposition method and performing lift-off with acetone. Also, instead of Ni / Pt / Au, Ti / Al / Pt / A
u or the like may be formed.

Next, a transparent electrode 17 is formed. The substrate on which the electrode pads 16 are formed is washed, a resist is applied to the main surface of the substrate on which the crystal is grown by a spin coater, and exposure is performed using a photomask corresponding to the size and shape of the transparent electrode 17 to be formed. And development. Then, after development, for example, a film of Au is formed to a film thickness of 10 nm by an evaporation method, and lift-off is performed with acetone to form the transparent electrode 17.

Next, element isolation is performed. Element isolation can be performed using, for example, reactive ion etching (RIE). In this case, since the adjacent active layer and clad layer are not in contact with each other and are formed independently, the shape of the element can be adjusted by etching the side surface. Normally, since the above-described active layer and the like grow in a hexagonal shape, element isolation may be performed by etching in a hexagonal shape.

Next, the back surface of the substrate is polished. On the surface on the side where the electrode pads 16 and the like of the substrate subjected to element isolation are formed,
A photoresist is applied by a spin coater as a protective film. Then, the back surface of the substrate, that is, the main surface on the side opposite to the side on which the electrode pads 16 and the like are formed, is polished using a polishing machine or the like until the thickness of the LED element becomes about 100 μm, for example.

Next, an n-electrode 11 is formed. n electrode 11
, Au, Al or Cu is used. The oxide film formed on the back surface of the single crystal silicon substrate polished, that is, the main surface on the polished side is removed by wet etching or the like. The surface of the substrate, that is, the electrode pad 1
The photoresist formed as a protective film on the surface on which 6 and the like are formed is removed with acetone or the like, and for example, Au is deposited on the back surface of the substrate, that is, the main surface on the side subjected to wet etching, to a thickness of about 0.2 μm. The n-electrode 11 is formed by forming a film.

Next, a single crystal silicon substrate is
Annealing at a temperature of about 800 ° C. for 10 minutes can activate p-type carriers.

Next, each element is cleaved using, for example, a dicing saw or the like so that a plurality of elements are arranged in the longitudinal direction of each element, so that the image display element 25 as shown in FIGS. Can be made. At this time, the n-electrode 11 provided on the entire main surface opposite to the side on which the crystal was grown of the Si substrate used for crystal growth is also separated into the respective image display elements 25.

[0064]

The present invention will be described below with reference to specific examples.

Example 1 An image display device was manufactured based on the first embodiment described above.

First, a single crystal silicon substrate was prepared and washed with an organic solvent. Then, the washed substrate is
CVD (Metal Organic Chemical Vapor Deposition)
The substrate was inserted into the apparatus, and the substrate was heated to 800 ° C. to perform thermal cleaning.

Next, the single-crystal silicon substrate is heated to 750 ° C., and AlN:
An Si layer was formed to a thickness of 0.1 μm.

Next, the single crystal silicon substrate was heated to 800 ° C., and GaN: S was used as a buffer layer on the AlN: Si layer.
The i layer was formed to a thickness of 0.5 μm.

Next, the single crystal silicon substrate is heated to 1000 ° C., and a GaN: Si layer is covered with AlG as a cladding layer.
An aN: Mg layer was formed to a thickness of 0.2 μm.

Next, the single crystal silicon substrate is heated to 700 ° C., and a multiple quantum well structure (MQW:
InGaN / Ga as active layer of Multi-Quantum-Well)
An N layer was formed with a thickness of 3 nm.

Next, the single crystal silicon substrate was heated to 980 ° C., and a cladding layer was formed on the InGaN / GaN layer.
An lGaN: Si layer was formed to a thickness of 1 μm.

Next, the single crystal silicon substrate is heated to 980 ° C., and a G layer is formed on the AlGaN: Mg film as a contact layer.
aN: Mg was formed to a thickness of 0.1 μm.

Next, the single crystal silicon substrate is washed, a resist is applied by a spin coater to the main surface of the single crystal silicon substrate on which the crystal has been grown, and is exposed using a photomask having a predetermined size and shape. Development was performed. After development, Ni /
Pt / Au are 10 nm, 100 nm, and 300 n respectively.
An electrode pad was formed by forming a film to a thickness of m by a vapor deposition method and performing lift-off with acetone.

Next, the substrate on which the electrode pads are formed is washed, a resist is applied to the main surface of the single crystal silicon substrate on which the crystal has been grown by a spin coater, and a photomask having a predetermined size and shape is used. Exposure and development were performed. After the development, a film of Au was formed to a film thickness of 10 nm by an evaporation method, and lift-off was performed with acetone to form a transparent electrode.

Next, reactive ion etching (R
According to IE), element isolation was performed by etching to a predetermined thickness of the GaN: Si layer.

Next, a photoresist was applied by a spin coater as a protective film on the surface of the single crystal silicon substrate on which the element pads were formed, on which the element isolation was performed. And
Polishing was performed on the back surface of the single crystal silicon substrate, that is, the main surface on the side opposite to the side on which the electrode pads and the like were formed, using a polishing machine until the thickness of the LED element became 100 μm.

Next, the oxide film formed on the back surface of the back-polished single crystal silicon substrate, ie, the main surface on the polished side, was removed by wet etching. Next, the photoresist formed as a protective film on the surface of the substrate, ie, the surface on which the electrode pads and the like are formed, is removed with acetone, and Au is applied to the back surface of the substrate, ie, the main surface on the wet-etched side, by 300 nm. By forming a film having a thickness of
An electrode was formed.

Next, cleavage was performed using a dicing saw so that 5 to 50 LED elements were linearly arranged on the image display element to produce an image display element.

Then, the image display device manufactured as described above was bonded as shown in FIG. 4, and wiring of electrodes was performed, thereby forming an LED display device.

When image information was displayed on the LED display device having the above configuration by current driving, an image with high luminance and high color quality could be obtained.

The LED display device obtained above is
It is configured by arranging an image display element having seven LED elements on a substrate used for crystal growth of the LED elements. Accordingly, it is not necessary to arrange the LED elements one by one, and the image display element can be mounted as a basic unit, so that the LED elements can be mounted efficiently and easily. Also, the wiring of the electrodes may be performed for each image display element, and it is not necessary to wire each LED element. Therefore, the wiring of the electrodes can be performed efficiently and easily. The performance has also improved.

Example 2 An image display device was manufactured based on the above-described second embodiment.

First, a single crystal silicon substrate was prepared and washed using an organic solvent. Then, the washed substrate is
CVD (Metal Organic Chemical Vapor Depositio
n)) The substrate was inserted into the apparatus, and the substrate was heated to 800 ° C. to perform thermal cleaning.

Next, the single-crystal silicon substrate was heated to 750 ° C., and GaN:
An Si layer was formed with a thickness of 3 μm.

Next, SiO ₂ was formed to a thickness of 0.2 μm as a mask on the GaN: Si layer. On the mask,
A predetermined number of active layer growth holes having a depth of 0.2 μm were formed in the vertical and horizontal directions.

Next, the substrate was heated to 1000 ° C. to form a GaN: Si layer having a thickness of 1 μm as a cladding layer.
Further, the substrate was heated to 700 ° C. to form InGaN (3 nm) / GaN (5 nm) as an active layer of a multi-quantum-well (MQW) structure on the GaN: Si layer. To produce an LED element that emits red light,
The active layer was doped with Eu. The active layer was not initially formed on the mask, but was formed in the active layer growth holes opened in the mask. After the active layer growth hole was filled, the active layer growth hole was spread around the upper surface of the mask with the center of the active layer growth hole as a center, and formed in a circular shape.

Next, the substrate is heated to a temperature of 1000 ° C.
AlG as a cladding layer on the InGaN / GaN layer film
An aN: Mg layer was formed to a thickness of 0.2 μm.

Next, the substrate is heated to 1000.degree.
GaN: Mg was formed as a contact layer to a thickness of 0.1 μm on the aN: Mg layer.

Next, the single crystal silicon substrate is washed, a resist is applied to the main surface of the substrate on which the crystal has been grown by a spin coater, and exposure and development are performed using a photomask having a predetermined size and shape. Was. After development, Ni / Pt / Au were deposited to a thickness of 10 nm, 100 nm, and 300 nm, respectively, by a vapor deposition method, and lift-off was performed with acetone to form electrode pads.

Next, the substrate on which the above-mentioned electrode pads are formed is washed, a resist is applied to the main surface of the single crystal silicon substrate on which the crystal has been grown by a spin coater, and a photomask having a predetermined size and shape is used. Exposure and development were performed. After the development, a film of Au was formed to a thickness of 10 nm by an evaporation method, and lift-off was performed with acetone to form a transparent electrode.

Next, reactive ion etching (R
According to IE), element isolation was performed by etching the side surfaces of the active layer and the like to a predetermined thickness of the cladding layer.

Next, a photoresist was applied by a spin coater as a protective film on the surface of the single-crystal silicon substrate on which the element pads were formed, on which the element isolation was performed. And
The thickness of the LED element is, for example, 100 μm
Polishing was performed on the back surface of the substrate, that is, the main surface on the side opposite to the side on which the electrode pads and the like were formed.

Next, the oxide film formed on the back surface of the polished single-crystal silicon substrate, ie, the main surface on the polished side, was removed by wet etching. Then, the photoresist formed as a protective film on the surface of the substrate, ie, the surface on which the electrode pads and the like are formed, is removed with acetone, and Au is applied to the back surface of the single-crystal silicon substrate, ie, the main surface on which wet etching is performed. Was formed to a thickness of 500 nm by an evaporation method to form an n-electrode.

Next, the substrate grown above was annealed at a temperature of 800 ° C. to activate p-type carriers.

Next, cleavage was performed using a dicing saw so that seven LED elements were linearly arranged on the image display element, thereby producing an image display element for emitting red light.

An image display element for emitting green light was produced in the same manner as described above except that the active layer was doped with Tb instead of Eu, and the same as above except that the active layer was doped with Tm instead of Eu. Similarly, an image display device for emitting blue light was produced.

Then, the image display device manufactured as described above was bonded as shown in FIG. 4, and wiring of electrodes was performed, thereby forming an LED display device.

When image information was displayed on the thus constructed LED display device by current driving, an image with high luminance and high color quality could be obtained.

The LED display device obtained above is
It is configured by arranging an image display element having seven LED elements on a substrate used for crystal growth of the LED elements. Accordingly, it is not necessary to arrange the LED elements one by one, and the image display element can be mounted as a basic unit. Therefore, the mounting of the LED elements can be performed efficiently and easily. Also, the wiring of the electrodes may be performed for each image display element, and it is not necessary to wire each LED element. Therefore, the wiring of the electrodes can be performed efficiently and easily. The performance has also improved.

[0100]

As described above in detail, in the image display device according to the present invention, the substrate for crystal growth, in which each layer of the light emitting diode device having a multilayer structure is sequentially grown, is divided into a plurality of light emitting diodes. The elements are rod-shaped bodies arranged linearly.

Therefore, the image display device according to the present invention is
It is possible to greatly reduce the number of LED element mounting steps and the number of electrode wirings when forming a display device or the like.

Therefore, the image display device according to the present invention has excellent production efficiency when constructing a display device or the like, and can display a high-quality image with good visibility.

[Brief description of the drawings]

FIG. 1 is a plan view of an example of an image display device to which the present invention is applied.

2 is a longitudinal sectional view of the X ₁ -X ₂ line in FIG.

FIG. 3 is an enlarged vertical cross-sectional view of the LED element section of FIG.

FIG. 4 is a diagram illustrating a state in which a display device is configured using an image display element to which the present invention has been applied.

FIG. 5 is a plan view of another example of the image display element to which the present invention is applied.

FIG. 6 is a longitudinal sectional view taken along line X ₃ -X _{4 in} FIG. 5;

FIG. 7 is an enlarged vertical sectional view of the LED element portion of FIG. 6;

FIG. 8 is a plan view showing a state where active layer growth holes are formed in a mask.

FIG. 9 is a longitudinal sectional view showing a state where active layer growth holes are formed in a mask.

[Explanation of symbols]

Reference Signs List 1 image display element, 2 LED element, substrate for crystal growth of 3 LED element, 4n side buffer layer, 5n side buffer layer, 6n side cladding layer, 7 active layer, 8p side cladding layer, 9p side contact layer , 10 p electrode, 11 n
Electrode, 16 electrode pad, 17 transparent electrode, 18 n-side buffer layer, 19 active layer growth hole, 20 mask, 21
n-side cladding layer, 22 active layer, 23 p-side cladding layer, 24 p-side contact layer, 25 image display device, 2
6 LED element

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Isamu 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Katsuya Shirai 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Shigeru Kojima 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5C094 AA01 AA43 AA44 AA45 BA26 CA19 DA03 EA04 EA07 EB05 5F041 AA14 AA42 CA05 CA33 CA34 CA40 CA57 CA65 CA73 CA76 CA82 CA92 FF06

Claims (7)

[Claims] 1. A substrate for crystal growth, in which each layer of a light emitting diode element having a multilayer structure is sequentially crystal-grown, is divided, and a plurality of light emitting diode elements are formed into a rod-like body linearly arranged on the same substrate. An image display device, comprising: 2. The image display device according to claim 1, wherein said substrate for crystal growth is made of a material having a Mohs hardness of 7 or less. 3. The image display device according to claim 2, wherein the material having a Mohs hardness of 7 or less is single crystal silicon. 4. The image display device according to claim 1, wherein said light emitting diode device is a nitride semiconductor device. 5. The nitride semiconductor device according to claim 1, wherein the nitride semiconductor device is a GaN-based II.
The image display device according to claim 4, wherein the image display device is an IV group semiconductor device. 6. A light emitting diode device comprising:
2. The image display device according to claim 1, wherein the active layer is doped with a rare earth element. 7. The image display device according to claim 1, wherein the image display device is provided with a common electrode of the plurality of light emitting diode devices.