JP2016129189A - Infrared light emission element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared light emission element that can suppress radiation of wavelengths of a visible light region.SOLUTION: In an infrared light emission element that has a light emission part in which a first conduction type first semiconductor layer, an active layer and a second conduction type second semiconductor layer are successively formed in this order on a substrate, and a first electrode and a second electrode for injecting current to the light emission part, a visible light reflection layer having a function of reflecting visible light is provided in the second semiconductor layer or adjacently to the second semiconductor layer.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an infrared light emitting device.

  In recent years, light emitting diodes (LEDs) that emit light in the infrared region have been increasingly used for illumination of security imaging devices such as security cameras and illumination for photographing of mobile devices. Infrared light emission requires that the emission wavelength is invisible to the human eye due to its characteristics.

  However, the emission spectrum of infrared light emitting LEDs has a broad shape on the short wavelength side. When an infrared device is used for a high-brightness / high-power device as in lighting applications, the broad spectrum on the short wavelength side. The portion has a light emission intensity that is visible to humans, and red light emission can be recognized by human eyes. Since it is a product characteristic of a security imaging device that is invisible to humans, the emission of visible light has been a problem, meaning that the product characteristic is impaired.

  In order to solve this problem, it is possible to adopt a method of inserting a filter that absorbs visible light, but the illumination becomes larger and the portability is greatly reduced, making it difficult to adopt it for mobile devices that require light weight. Therefore, there is a need for a small and lightweight infrared light emitting LED that can cut visible light without increasing the weight of the device.

In the infrared light emitting LED for illumination, a wavelength having a peak wavelength near 860 nm where the photosensitivity of the imaging device (CCD or CIS) is most excellent is selected, so that Al _z Ga _1-z As (0 ≦ z ≦ 0.6) It is common to use a system material. Usually, the emission wavelength from the LED shows a shape in which the emission spectrum has a tail on the short wavelength side according to the state density.

For example, when the emission peak wavelength is 860 nm, the longer wavelength side than the emission peak wavelength is invisible, but the emission component on the shorter wavelength side, particularly the emission component in the wavelength range shorter than 780 nm, is recognized as visible light. In order not to generate visible light shorter than 780 nm, the Al composition of the active layer material system is increased, a multiple quantum well (MQW) is used, or In _t Ga _1-t As (0 ≦ t ≦ 0.3). There is also a method of shifting the peak wavelength to the longer wavelength side and shifting the tail of the emission spectrum to the longer wavelength side by a method of using a system material. However, since the sensitivity to the imaging device (CCD or CIS) is lowered if it is shifted too much to the long wavelength side such as the 950 nm band, it is not a desirable measure as an infrared light emitting LED for illumination use. Therefore, it is required to realize radiation prevention of a wavelength component shorter than 780 nm without increasing the device size while maintaining the peak wavelength near 860 nm.

  In order to solve the problem that visible light is emitted by the infrared light emitting LED for illumination, for example, Patent Document 1 discloses a method of cutting a visible light component of light emitted from a light source using a filter. When an LED is used as a light source, the LED itself is a point light source, but is designed so that light spreads at a certain angle due to the nature of use as illumination. According to the technique disclosed in Patent Document 1, it is necessary to provide a filter on the entire surface of the light emission window radiated from the light source device. Most of the lighting fixtures for crime prevention are used outdoors, and it is indispensable to have weather resistance. However, providing a film-like substance at the radiation opening tends to cause physical friction and damage due to changes in temperature and humidity. It is not suitable as a method applied to crime prevention lighting. In addition, since the filter is provided on the entire surface of the light source having a spread, it is easy to increase the size and increase the weight as compared with the method of cutting visible light with the LED itself as the point light source. Also, miniaturization is difficult. In order to cut the visible light component of a lighting fixture incorporating an infrared light emitting LED and achieve miniaturization without causing an increase in weight, it is preferable to provide a function of a cut filter inside the LED element. There is no disclosed technique in which a cut filter is provided inside.

  On the other hand, as a method of reflecting light emitted from the active layer, there is a technique disclosed in Patent Document 2, for example. Patent Document 2 discloses a technique of providing a distributed Bragg reflection (DBR) film in a lower direction opposite to the light extraction of the active layer as a layer having a function of reflecting main light emitted from the active layer. . In the technique disclosed here, a DBR film is provided in order to suppress light absorption to the absorption substrate side, and the object of light reflection is all the light emitted from the active layer.

  Patent Document 3 discloses a technique in which a metal reflective film and DBR are combined. Although films having reflective functions of different properties are combined, the object of light reflection is all the light emitted from the active layer as in Patent Document 2, and all the light that is not intended to extract light is also reflected. The same. Therefore, no technology has been disclosed so far that discloses a structure of a light-emitting element having a function of cutting light that is not desired to be extracted from light emitted from the light-emitting layer.

JP 2011-180172 A Japanese Patent No. 559029 Special table 2014-524673

  In a light-emitting element that emits infrared light, there is a problem of emitting light in the visible region having a wavelength shorter than the peak wavelength when energized to emit infrared light. This problem becomes more conspicuous as the brightness and output become higher as in lighting applications. Although such a problem can be avoided by inserting a filter, it causes an increase in weight and volume due to the provision of the filter and is not suitable for miniaturization. In addition, the provision of a filter has a problem that it is easily damaged due to physical friction or changes in temperature and humidity.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an infrared light-emitting element that suppresses emission of wavelengths in the visible light region.

In order to achieve the above-described object, according to the present invention, a light emitting unit is provided, in which a first conductive type first semiconductor layer, an active layer, and a second conductive type second semiconductor layer are sequentially formed on a substrate. In an infrared light emitting device having a first electrode and a second electrode for injecting current into the light emitting part,
There is provided an infrared light emitting element characterized in that a visible light reflecting layer having a function of reflecting visible light is provided in the second semiconductor layer or adjacent to the second semiconductor layer.

  With such an infrared light emitting element, it is possible to suppress the emission of wavelengths in the visible light region.

At this time, the visible light reflection layer further includes:
It is preferable that it is provided in the first semiconductor layer or adjacent to the first semiconductor layer.
If it is such, even if it is the case of a transparent board | substrate, for example, the radiation | emission of the wavelength of visible light region can be suppressed.

Or, further, an infrared light reflection layer having a function of reflecting infrared light,
It is preferable that it is provided in the first semiconductor layer or adjacent to the first semiconductor layer.
With such a configuration, for example, infrared light absorbed by the substrate can be effectively extracted, so that an infrared light emitting element with high luminous efficiency can be obtained.

At this time, it is preferable that the infrared light reflection layer is a distributed Bragg reflection (DBR) layer.
If it is such, the layer which reflects infrared light can be formed comparatively easily.

The infrared light reflection layer is
It is preferable to be composed of an alternating layered structure of Al _z Ga _1-z As (0 ≦ z ≦ 1) and Al _{z ′} Ga _{1-z ′} As (0 ≦ z ′ <1).
If it is such, infrared light can be reliably reflected.

The visible light reflection layer is preferably a distributed Bragg reflection (DBR) layer.
If it is such, the layer which reflects visible light can be formed comparatively easily.

The visible light reflecting layer is
_{(Al x Ga 1-x)} y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) and _{(Al x 'Ga 1-x} ') y 'In 1-y' P Alternating layered structure consisting of (0 ≦ x ′ ≦ 1, 0.4 ≦ y ′ ≦ 0.6),
Alternatively, it is composed of (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) and Al _z Ga _1-z As (0 ≦ z ≦ 1). It is preferable that it is comprised from either of alternate lamination structure.
If it is such, visible light can be reflected reliably.

The second electrode is formed on the substrate opposite to the light emitting unit;
It is preferable that a metal layer and a dielectric film provided with an opening filled with a conductive material are sequentially formed between the substrate and the light emitting portion.
Anything like this can be suitably applied to the present invention.

The second electrode is formed on the substrate opposite to the light emitting unit;
It is preferable that a metal layer and a transparent conductive film are sequentially formed between the substrate and the light emitting portion.
Anything like this can be suitably applied to the present invention.

The second electrode is formed in a partial region on the substrate on the side where the light emitting unit is formed,
The light emitting unit and the first electrode are sequentially formed on the substrate in a portion other than the region where the second electrode is formed,
It is preferable that the substrate is transparent with respect to light emitted from the light emitting unit.
Anything like this can be suitably applied to the present invention.

The first semiconductor layer is
_{Al z Ga 1-z As (} 0 ≦ z ≦ 0.6) or _{from (Al x Ga 1-x)} y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) Consisting of
The second semiconductor layer is
From Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) Consisting of
The active layer is
A layer made of Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or In _t Ga _1-t As (0 ≦ t ≦ 0.3),
And a layer having a multiple quantum well (MQW) structure in which Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or In _t Ga _1-t As (0 ≦ t ≦ 0.3) is a well layer. It is preferable that it consists of either of these.
Anything like this can be suitably applied to the present invention.

  The infrared light emitting device of the present invention can suppress the emission of wavelengths in the visible light region.

It is the schematic which showed the structure of the epitaxial substrate in 1st embodiment of this invention. It is the schematic which showed the light emitting element of 1st embodiment of this invention. It is the schematic which showed the structure of the epitaxial substrate in 2nd embodiment of this invention. It is the schematic which showed the light emitting element of 2nd embodiment of this invention. It is the schematic which showed the structure of the epitaxial substrate in 3rd embodiment of this invention. It is the schematic which showed the structure of the epitaxial substrate in 3rd embodiment of this invention. In 3rd embodiment of this invention, it is the schematic at the time of providing the 2nd metal film on the permanent substrate. It is the schematic which showed the joining board | substrate in the light emitting element of 3rd embodiment of this invention. It is the schematic which showed an example of the light emitting element of 3rd embodiment of this invention. It is the schematic which showed the structure of the epitaxial substrate in 4th embodiment of this invention. It is the schematic which showed the joining board | substrate in the light emitting element of the 4th embodiment of this invention. It is the schematic which showed the light emitting element of 4th embodiment of this invention. It is the schematic which showed the light emitting element of 5th embodiment of this invention. It is the schematic which showed the light emitting element of the 6th embodiment of this invention. 3 is a schematic diagram illustrating a configuration in a first semiconductor layer in Example 1. FIG. 3 is a schematic diagram illustrating a configuration in a second semiconductor layer in Example 1. FIG. 4 is a graph showing measurement results of Example 1 and Comparative Example 1. It is a graph which shows the measurement result of Example 2 and Comparative Example 2. 6 is a schematic diagram illustrating a configuration in a first semiconductor layer in Example 3. FIG. 6 is a schematic diagram showing a configuration in a second semiconductor layer in Example 3. FIG. 6 is a graph showing measurement results of Example 3 and Comparative Example 3. 6 is a graph showing measurement results of Example 4 and Comparative Example 4. 6 is a graph showing measurement results of Example 5 and Comparative Example 5. 6 is a graph showing measurement results of Example 6 and Comparative Example 6.

Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.
As described above, when the infrared light emitting element is energized to emit light, the emission spectrum is broad and the spectrum tail is drawn on the short wavelength side, so that light in the visible region is emitted from the infrared light emitting element, The higher the intensity of the infrared light emitting element, the higher the base of the spectrum, that is, the radiant intensity of the visible light component.

  Therefore, the present inventor has made extensive studies in order to suppress visible light emission from the infrared light emitting element. As a result, by providing a visible light reflecting layer that is substantially transparent to infrared light and reflective to visible light on the light extraction surface side, emission of visible light from the light emitting element is suppressed. The present invention has been found. In the present invention, a light having a wavelength shorter than 780 nm is visible light, and a light having a wavelength of 780 nm or more is infrared light.

  Hereinafter, an example of an embodiment of the light emitting device of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, first, a starting substrate 401 is prepared.
As the starting substrate 401, one having a crystal axis in the [001] direction can be used, but one having a crystal axis inclined in the [110] direction from the [001] direction can be preferably used. As the starting substrate 401, GaAs or Ge can be preferably used. If the starting substrate 401 is selected from the above materials, the material of the active layer 404 described later can be epitaxially grown in a lattice matching system, so that the quality of the active layer can be easily improved, and the luminance of the light emitting element can be increased and the life characteristics can be improved. Can be realized.

Next, a first conductive type first semiconductor layer 403, an active layer 404, a second conductive type second semiconductor layer 405, and a current diffusion layer 406 having substantially the same lattice constant as the starting substrate 401 are formed on the starting substrate 401. The layers are sequentially formed by epitaxial growth using MOVPE (metal organic vapor phase epitaxy), MBE (molecular beam epitaxy), or CBE (chemical beam epitaxy).
As described above, the light emitting portion 410 is formed by the first semiconductor layer 403, the active layer 404, and the second semiconductor layer 405.

  Although not shown in the drawing, the first semiconductor layer 403 or the second semiconductor layer 405 is not a single condition film, but is generally stacked under two or more conditions from the viewpoint of life and luminance design. Therefore, the first semiconductor layer 403 or the second semiconductor layer 405 includes the concept of a stacked structure having one or more kinds of compositions and doping concentrations.

Specifically, the composition of the first semiconductor layer 403, the second semiconductor layer 405, and the active layer 404 in the present invention can be as follows.
The first semiconductor layer 403 includes Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6).
The second semiconductor layer 405 is made of Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6).

The active layer 404 is composed of Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or In _t Ga _1-t As (0 ≦ t ≦ 0.3), and Al _z Ga _{1− z} As (0 ≦ z ≦ 0.6) or a layer of a multiple quantum well (MQW) structure having a well layer of In _t Ga _1-t As (0 ≦ t ≦ 0.3) can do.
Regarding the design of the active layer, the wavelength can be adjusted other than the wavelength resulting from the material composition by using a superlattice represented by a multiple quantum well (MQW). barrier layer in the _{(Al x Ga 1-x)} y in 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) or _{Al z Ga 1-z As (} 0 <z ≦ 0. 45) and the like can be used.

  For example, AlInGaP or AlGaAs can be selected for the first semiconductor layer 403 and the second semiconductor layer 405, but the selection is not necessarily performed using the same material as that of the active layer 404.

Further, the current diffusion layer 406 can be composed of a semiconductor layer or a transparent conductive film. The current diffusion layer 406 may not be provided if current dispersion is sufficiently ensured by the shape or arrangement of the current injection electrode provided in the infrared light emitting element. Note that the current diffusion layer 406 may be formed by the HVPE method (hydride vapor phase epitaxy) in addition to the above-described growth method.
In this way, the epitaxial substrate 411 can be manufactured.

At this time, as shown in FIG. 1, a visible light reflection layer 430 is provided in the second semiconductor layer 405.
In the present invention, the visible light reflecting layer 430 may be provided in the second semiconductor layer 405 or adjacent to the second semiconductor layer 405. As shown in FIG. 1, the absolute intermediate position of the second semiconductor layer 405 is used. It is not limited to.
As described above, the visible light reflecting layer 430 may be provided at any position in the second semiconductor layer 405. For example, the position on the starting substrate 401 side in contact with the second semiconductor layer 405 or the second semiconductor layer 405 is provided. You may provide in the position on the opposite side to the starting board | substrate 401 side which touches.
In FIG. 1, the visible light reflection layer 430 is provided in the entire region of the second semiconductor layer 405, but the visible light reflection layer 430 may be provided in a partial region of the second semiconductor layer 405.

The visible light reflection layer 430 may be any layer that mainly reflects visible light. For example, the visible light reflection layer 430 may be a distributed Bragg reflection (DBR) layer.
If it is such, the layer which reflects infrared light can be formed comparatively easily.

More specifically, the visible light reflection layer 430 includes (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) and (Al _{x ′} Ga _{1-x ′} ) _{y ′} In _{1-y ′} P (0 ≦ x ′ ≦ 1, 0.4 ≦ y ′ ≦ 0.6) (where x≈x ′), or (Al _x Al ₁ Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) and Al _z Ga _1-z As (0 ≦ z ≦ 0.6) It can be comprised from either of these.
If it is such, visible light can be reflected reliably.
The visible light reflection layer 430 described above can be configured in the same manner in other embodiments of the present invention described later.

Next, a first electrode 440 and a second electrode 441 for supplying a potential to the infrared light emitting element are formed (see FIG. 2).
The first electrode 440 can be provided on the current diffusion layer 406 or on the second semiconductor layer 405 when the current diffusion layer 406 is not provided.
The second electrode 441 can be provided on the starting substrate 401 opposite to the light emitting unit 410. Although not shown, the second electrode 441 includes at least the current diffusion layer 406, the second semiconductor layer 405, and the active layer 404, and the first electrode 440 and the first electrode 440 so as to be in contact with the first semiconductor layer 403 or the starting substrate 401. You may provide in the same surface side.

After the first electrode 440 and the second electrode 441 are formed, they can be divided into individual dies by scribing or blade dicing.
A rough surface, a texture structure, a moth-eye structure, or a dielectric antireflection film can be provided on the first electrode 440 side, which is the light extraction surface, in order to improve the light extraction efficiency from the die.
A dielectric protective film can be formed on the surface of the first electrode 440 to improve the weather resistance of the die.

(Second embodiment)
Next, the infrared light emitting device in the second embodiment of the present invention will be described.

  The light emitting device of the second embodiment (FIG. 4) is different from the light emitting device of the first embodiment (FIG. 2) in that an infrared light reflection layer 200 is provided between the first semiconductor layer 403 and the starting substrate 401. ) Is different.

As shown in FIG. 3, on the starting substrate 401, a first conductive type infrared light reflecting layer 200, a first conductive type first semiconductor layer 403, an active layer 404, having substantially the same lattice constant as the starting substrate 401, An epitaxial substrate 511 is produced in which a light emitting portion 410 composed of a second semiconductor layer 405 of the second conductivity type and a current diffusion layer 406 are sequentially formed by epitaxial growth.
A visible light reflection layer 430 is provided in the second semiconductor layer 405. Note that the current diffusion layer 406 is not necessarily provided.

In the present invention, the infrared light reflection layer 200 may be provided at any position in the first semiconductor layer 403 or provided adjacent to the first semiconductor layer 403, as shown in FIG. It is not limited.
In such a case, since infrared light absorbed by the starting substrate 401 can be effectively extracted, an infrared light-emitting element with high emission efficiency can be obtained.

The infrared reflection layer 200 may be any layer that mainly reflects infrared light. For example, the infrared reflection layer 200 may be a distributed Bragg reflection (DBR) layer.
If it is such, the layer which reflects infrared light can be formed comparatively easily.

More specifically, the infrared reflective layer 200 includes an Al _z Ga _1-z As (0 ≦ z ≦ 1) and Al _{z ′} Ga _{1-z ′} As (0 ≦ z ′ <1) alternating layered structure ( However, it can be constituted by z≈z ′).
If it is such, infrared light can be reliably reflected.

  At this time, the visible light reflection layer 430 may be provided at any position in the second semiconductor layer 405 as in the first embodiment described above. The visible light reflecting layer 430 can also be selected from the same composition as in the first embodiment described above.

Next, a first electrode 440 and a second electrode 441 for supplying a potential to the infrared light emitting element are formed (see FIG. 4).
The first electrode 440 can be provided on the current diffusion layer 406 or on the second semiconductor layer 405 when the current diffusion layer 406 is not provided.
The second electrode 441 can be provided on the starting substrate 401 opposite to the light emitting unit 410. Although not shown, the second electrode 441 includes at least the current diffusion layer 406, the second semiconductor layer 405, and the active layer 404, and the first electrode 440 and the first electrode 440 so as to be in contact with the first semiconductor layer 403 or the starting substrate 401. You may provide in the same surface side.

After the first electrode 440 and the second electrode 441 are formed, they can be divided into individual dies by scribing or blade dicing.
A rough surface, a texture structure, a moth-eye structure, or a dielectric antireflection film can be provided on the first electrode 440 side, which is the light extraction surface, in order to improve the light extraction efficiency from the die.
A dielectric protective film can be formed on the surface of the first electrode 440 to improve the weather resistance of the die.

(Third embodiment)
Next, the form of the infrared light emitting element in the third embodiment is shown.

As shown in FIG. 5, an etch stop layer 300 having substantially the same lattice constant as that of the starting substrate 401 is formed on the starting substrate 401 by epitaxial growth, and the second conductive type second semiconductor layer 405, the active layer 404, the first layer is formed. An epitaxial substrate 611 on which a conductive first semiconductor layer 403 and a current diffusion layer 406 are formed is manufactured.
A visible light reflection layer 430 is provided in the second semiconductor layer 405. The current diffusion layer 406 may not be formed.

The etch stop layer 300 can be made of, for example, Al _z Ga _1-z As (0 ≦ z ≦ 0.6).

  At this time, the visible light reflection layer 430 may be provided at any position in the second semiconductor layer 405 as in the first embodiment described above. Moreover, the visible light reflection layer 430 can select the same composition as 1st embodiment mentioned above.

Next, as shown in FIG. 6, the dielectric film 701 is formed on the surface of the current diffusion layer 406 or on the surface of the first semiconductor layer 403 when the current diffusion 406 is not provided. An opening 702 is provided in part of the dielectric film 701, and a third electrode 703 filled with a conductive material is provided in the opening 702.
As the conductive material filled in the third electrode, for example, a material in which an AuBe layer, a Ni layer, and an Au layer are sequentially stacked can be suitably used.

A first metal film 710 is provided on the dielectric film 701 and the third electrode 703.
The first metal film 710 may be composed of one or more kinds of metals and one or more kinds of layer structures in order to maintain a reflection function.
For example, the first metal film 710 may have a laminated structure of Au / Ti / Au. Instead of Ti, a multilayer structure of a metal such as Ni, Pt, and Mo and Au may be used.

As shown in FIG. 7, a permanent substrate 720 is prepared, and a second metal film 721 is provided on the permanent substrate 720.
The permanent substrate 720 can be any material as long as it is a flat and conductive substrate. For example, an easily available and inexpensive Si substrate can be used.
The second metal film 721 can be made of one or more kinds of metals and one or more kinds of layer structures. For example, the second metal film 721 may have a stacked structure of Au / Pt / Au / Ti. Instead of Ti, a multilayer structure of a metal such as Ni, Pt, and Mo and Au may be used.

  As shown in FIG. 8, a first metal film 710 and a second metal film 721 are bonded to face each other, and a bonded substrate 730 in which an epitaxial substrate 611 and a permanent substrate 720 are bonded is manufactured.

  The starting substrate 401 is removed from the bonding substrate 730 by wet etching, and a light emitting element substrate 740 is manufactured as shown in FIG.

When the etch stop layer 300 is not used as an ohmic contact layer, the etch stop layer 300 is removed by wet etching or the like, and a first electrode 440 is formed on the second semiconductor layer 405 as shown in FIG.
Although not shown, when the etch stop layer 300 is used as a contact layer, the first electrode 440 is formed on the etch stop layer 300, and the etch stop layer 300 in a region other than the first electrode 440 is removed by wet etching or the like.

Next, the second electrode 441 is formed on the surface of the permanent substrate 720 that faces the first electrode 440.
After the formation of the first electrode 440 and the second electrode 441, it is divided into individual dies by scribing or blade dicing. In order to improve the light extraction efficiency from the die on the second electrode 440 side of the light extraction surface, a rough surface, a texture structure, a moth-eye structure, or a dielectric antireflection film can be provided. A dielectric protective film can be formed on the second electrode 441 side in order to improve the weather resistance of the die.

  FIG. 9 illustrates an example in which the first electrode 440 and the second electrode 441 are provided on opposite surfaces, but the second electrode 441 is brought into contact with the first semiconductor layer 403, the current diffusion layer 406, or the first metal film 710, It can also be provided on the same side as the first electrode 440.

(Fourth embodiment)
Next, the fourth embodiment of the present invention will be described.
Similar to the third embodiment, an epitaxial substrate 611 as shown in FIG. 5 is produced.

After that, as shown in FIG. 10, when the current diffusion layer 406 surface and the current diffusion layer 406 are not provided, a transparent conductive film 851 is formed on the first semiconductor layer 403 surface.
At this time, when the epitaxial substrate 611 is manufactured, a contact layer 807 is separately provided, a pattern is formed according to a required area and arrangement, and the transparent conductive film 851 and the current diffusion layer 406 or the first semiconductor layer 403 are formed. The contact layer 807 may be left in between.
If the influence of light absorption is sufficiently small, such as the contact layer 807 being a very thin film, the pattern may not be formed and may be left uniformly.

Further, a first metal film 710 is provided on the transparent conductive film 851.
The first metal film 710 can be the same as that of the third embodiment.

As in the third embodiment, as shown in FIG. 7, a permanent substrate 720 is prepared, and a second metal film 721 is provided on the permanent substrate 720.
The permanent substrate 720 and the second metal film 721 can be the same as those in the third embodiment.

  As shown in FIG. 11, the first metal film 710 and the second metal film 721 are bonded to face each other, and a bonded substrate 880 in which the epitaxial substrate 611 and the permanent substrate 720 are bonded is manufactured.

  The starting substrate 401 is removed from the bonding substrate 880 by wet etching, and a light emitting element substrate 890 is manufactured as shown in FIG.

When the etch stop layer 300 is not used as an ohmic contact layer, the etch stop layer 300 is removed by wet etching or the like, and a first electrode 440 is formed on the second semiconductor layer 405 as shown in FIG.
Although not shown, when the etch stop layer 300 is used as a contact layer, the first electrode 440 is formed on the etch stop layer 300, and the etch stop layer 300 in a region other than the first electrode 440 is removed by wet etching or the like.

  A second electrode 441 is formed on the surface of the permanent substrate 720 opposite to the first electrode 440.

  After the first electrode 440 and the second electrode 441 are formed, they are divided into individual dies by scribing or blade dicing. In order to improve the light extraction efficiency from the die on the light extraction surface side, a rough surface, a texture structure, a moth-eye structure, or a dielectric antireflection film can be provided. A dielectric protective film can be formed on the second electrode 441 side in order to improve the weather resistance of the die.

  FIG. 12 illustrates an example in which the first electrode 440 and the second electrode 441 are provided on the opposing surfaces, but the second electrode 441 is brought into contact with the first semiconductor layer 403, the current diffusion layer 406, or the first metal film 710, It can also be provided on the same surface side as the first electrode 440.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described.
On the starting substrate, an etch stop layer 600 having substantially the same lattice constant as the starting substrate, a second conductivity type second semiconductor layer 405, an active layer 404, a first conductivity type first semiconductor layer 403, a buffer layer 906, a support An epitaxial substrate 911 in which the substrate / window layer 907 is sequentially formed by epitaxial growth is produced.
A visible light reflection layer 430 is provided on each of the first semiconductor layer 403 and the second semiconductor layer 405.

After removing the starting substrate by wet etching or the like, the first electrode 950 is formed.
When the etch stop layer 600 is used as a contact layer, as shown in FIG. 13, a first electrode 950 is formed on the etch stop layer 600, and a region other than the first electrode 950 is removed by wet etching or the like.
Although not shown, when the etch stop layer 600 is not used as a contact layer, the etch stop layer 600 is removed by wet etching or the like, and the first electrode 950 is formed on the second semiconductor layer 405.

  A part of the surface having the first electrode 950 is cut away by wet etching or dry etching to form an opening region 951 in which the first semiconductor layer 403, the buffer layer 906, or the supporting substrate / window layer 907 is exposed. A second electrode 952 is formed in part.

After the formation of the first electrode 950 and the second electrode 952, the wafer is divided into individual dies by scribing or blade dicing. A rough surface, a texture structure, or a moth-eye structure can be provided on the light extraction surface side in order to improve the light extraction efficiency from the die.
A dielectric protective film can be formed on the surface side on which the first electrode 950 and the second electrode 952 are provided in order to improve the weather resistance of the die.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described.

An etch stop layer 600, a second conductivity type second semiconductor layer 405, an active layer 404, a first conductivity type first semiconductor layer 403, and a current diffusion layer 406 having substantially the same lattice constant as the start substrate are formed on the start substrate. An epitaxial substrate 1011 formed sequentially by epitaxial growth is produced.
A visible light reflection layer 430 is provided on each of the first semiconductor layer 403 and the second semiconductor layer 405. The current diffusion layer 406 is not necessarily provided.

A transparent adhesive with respect to the emission wavelength is applied to the surface of the current diffusion layer 406 or, if the current diffusion layer 406 is not provided, to form an adhesive layer 1040 (see FIG. 14). .
For the adhesive layer 1040, a thermosetting BCB adhesive or the like can be used.

A permanent substrate 1020 that is transparent to the emission wavelength is prepared, and an adhesive that is transparent to the emission wavelength is applied to form an adhesive layer 1041. In the example, a method of forming an adhesive layer on both the epitaxial substrate 1011 and the permanent substrate 1020 is shown, but a method of forming only one of the surfaces may be used.
A thermosetting BCB adhesive or the like can also be used for the adhesive layer 1041.
For the permanent substrate 1020, for example, sapphire, quartz, GaP, or the like can be used.

The epitaxial substrate 1011 provided with the adhesive layer 1040 and the permanent substrate 1020 provided with the adhesive layer 1041 are joined with the adhesive layer 1040 and the adhesive layer 1041 facing each other to produce a joined substrate.
In the example, a method using an adhesive is shown as a method for obtaining a bonded substrate. However, a direct bonding method in which OH groups are formed on the surface of the epitaxial substrate 1011 and the surface of the permanent substrate 1020 by chemical treatment and then bonded may be selected. .

The starting substrate is removed from the bonding substrate by wet etching or the like, so that the light-emitting element substrate 1060 is manufactured. A first electrode 1050 is formed on the surface of the light emitting element substrate 1060 from which the starting substrate is removed.
For example, when the conductivity type of the second semiconductor layer 405 is N-type, the first electrode 1050 can be made of a metal containing AuGe or the like. More specifically, it can be made of a laminated structure of AuGe / Ni / Au.

When the etch stop layer 600 is used as a contact layer, as shown in FIG. 14, a first electrode 1050 is formed on the etch stop layer 600, and a region other than the first electrode 1050 is removed by wet etching or the like.
Although not shown, when the etch stop layer 600 is not used as a contact layer, the etch stop layer 600 is removed by wet etching or the like, and the first electrode 1050 is formed on the second semiconductor layer 405.

A part of the surface having the first electrode 1050 is cut out by wet etching or dry etching to form an opening region 1051 in which the first semiconductor layer 403 or the current diffusion layer 406 is exposed, and the second electrode is formed in part of the opening region 1051. 1052 is formed.
For example, when the conductivity type of the first semiconductor layer 403 is P type, the second electrode 1052 can be made of a metal containing AuBe or the like. More specifically, it can be made of a laminated structure of AuBe / Ti / Au.

  After the formation of the first electrode 1050 and the second electrode 1052, the wafer is divided into individual dies by scribing or blade dicing. In order to improve the light extraction efficiency from the die on the light extraction surface side, a rough surface, a texture structure, a moth-eye structure, or a dielectric antireflection film can be provided. A dielectric protective film can be formed on the surface side where the first electrode 1050 and the second electrode 1052 are provided in order to improve the weather resistance of the die.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these.

Example 1
A starting substrate 401 of an N-type GaAs substrate having a thickness of 280 μm with a crystal axis inclined by 15 ° in the [110] direction from the [001] direction was prepared (see FIG. 1). On the starting substrate 401, an N-type GaAs buffer layer (not shown) of 0.5 μm, a first semiconductor layer 403 of an N-type clad layer made of AlGaInP is 2 μm by an MOVPE method, an active layer 404 made of GaAs or AlGaAs is 1 μm, and AlGaAs. An epitaxial substrate 411 was fabricated by sequentially laminating a second semiconductor layer 405 of P-type clad layer composed of 2 μm and a current diffusion layer 406 composed of AlGaAs in an order of 2 μm. Here, the N-type cladding layer is exemplified as AlGaInP, but the same effect can be obtained with AlGaAs.

  In the first semiconductor layer 403, as shown in FIG. 15, the Al composition is low on the side close to the active layer 404, the low Al composition layer 403A, and the Al composition is high on the side far from the active layer 404. Layer 403B was placed.

The low Al composition layer 403A was formed with a composition of (Al _x Ga _1-x ) _y In _1-y P (x = 0.4, y≈0.5) and a thickness of 0.1 μm. The low Al composition layer 403A was formed without doping.

The high Al composition layer 403B was formed with a composition of (Al _x Ga _1-x ) _y In _1-y P (x = 0.85, y≈0.5) and a thickness of 1.9 μm.
In the high Al composition layer 403B, a low doping region 403AA having a low doping concentration is disposed in a region adjacent to the low Al composition layer 403A, and a high doping concentration is provided in a region far from the low Al composition layer 403A. Region 403AB was placed.
In this embodiment, the low doping region 403AA is formed with a doping concentration of 1E + 17 / cm ³ and a thickness of 0.5 μm. The doping concentration of 403AB was 8E + 17 / cm ³ and the thickness was 1.4 μm.

  In the second semiconductor layer 405, as shown in FIG. 16, the Al composition is low on the side close to the active layer 404, the low Al composition layer 405A, and the Al composition is high on the side far from the active layer 404, and the high Al composition is high. Layer 405B was placed.

The low Al composition layer 405A was formed with a composition of Al _z Ga _1-z As (z = 0.3) and a thickness of 0.1 μm. The low Al composition layer 405A was formed without doping.

The high Al composition layer 405B was formed with a composition of Al _z Ga _1-z As (z = 0.45) and a thickness of 1.9 μm.
In the high Al composition layer 405B, a low doping region 405AA having a low doping concentration is disposed in a region adjacent to the low Al composition layer 405A, and a high doping concentration is provided in a region far from the low Al composition layer 405A. Region 405AB was placed.
In this embodiment, the low doping region 405AA has a doping concentration of 1E + 17 / cm ³ and a thickness of 0.5 μm. Further, the doping concentration of 405AB was 8E + 17 / cm ³ and the thickness was 1.4 μm.

The active layer 404 is a multiple quantum well (MQW) in which the well layer is GaAs and the barrier layer is Al _z Ga _1-z As (z = 0.3), the barrier layer thickness is 7 nm, the well layer is 7 nm, and the period is 9 cycles. did. Here, the barrier layer is exemplified as AlGaAs, but the same effect can be obtained even when AlGaInP is used.

Next, a first electrode 440 and a second electrode 441 for supplying a potential to the light emitting element were formed as shown in FIG.
The first electrode 440 was formed of AuBe / Ti / Au on the current diffusion layer 406.
The second electrode 441 was made of AuGe / Ni / Au on the starting substrate 401 opposite to the light emitting unit 410. The AuGe thickness was 100 nm, the Ni thickness was 10 nm, and the Au thickness was 200 nm.

The visible light reflection layer 430 is formed in the second semiconductor layer 405 and effectively reflects light in the visible light region, so that (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1). , 0.4 ≦ y ≦ 0.6) and Al _z Ga _1-z As (0 ≦ z ≦ 0.6), x = 1, y≈0.5, z = 0.1 It was.

After the formation of the first electrode 440 and the second electrode 441, it was divided into individual dies by scribing or blade dicing.
Furthermore, the first electrode 440 side of the light extraction surface was roughened to improve the light extraction efficiency from the die.
The surface of the first electrode 440 side was coated with a dielectric protective film made of SiO ₂ with a thickness of 500 nm in order to improve the weather resistance of the die.

  An element for measurement was produced from the die produced as described above. The element for measurement was manufactured by fixing a die on TO-18 with Ag paste and connecting with a Au wire. The spectrum was measured at IF = 20 mA, and the results are shown in FIG. In FIG. 17, the measurement result of the comparative example 1 mentioned later was also shown collectively.

As shown in FIG. 17, it can be seen that in the wavelength region shorter than 780 nm, most wavelengths are not detected as the EL spectrum as compared with Comparative Example 1.
Further, almost no luminescence was visually recognized.

(Example 2)
As shown in FIG. 3, an epitaxial substrate 511 was produced in the same manner as in Example 1 except that the infrared light reflection layer 200 was provided between the starting substrate 401 and the first semiconductor layer 403.
Then, the 1st electrode 440 and the 2nd electrode 441 were formed like Example 1, and the light emitting element as shown in FIG. 4 was manufactured.

  The infrared light reflection layer 200 has an alternately laminated structure of AlAs and GaAs and has a function of mainly reflecting the wavelength of infrared light (850 to 860 nm).

  With the die produced as described above, a measurement element was produced and measured in the same manner as in Example 1. And it showed in FIG. 18 with the measurement result of the comparative example 2 mentioned later.

As shown in FIG. 18, it can be seen that in the wavelength region shorter than 780 nm, most wavelengths are not detected as the EL spectrum as compared with Comparative Example 2.
Further, almost no luminescence was visually recognized.

Example 3
A starting substrate 401 similar to that in Example 1 was prepared (see FIG. 5).
An N-type GaAs buffer layer (not shown) of 0.5 μm is formed on the starting substrate 401 by MOVPE, an etch stop layer 300 made of AlInP having substantially the same lattice constant as that of the substrate is formed, and an N-type cladding layer made of AlGaInP is formed. Two semiconductor layers 405, 2 μm of active layer 404 made of AlGaAs, 1 μm of P-type clad first semiconductor layer 403 made of AlGaAs, and 2 μm of current spreading layer 406 made of AlGaAs are sequentially laminated to produce an epitaxial substrate 611. (See FIG. 5).

  In the first semiconductor layer 403, as shown in FIG. 19, the Al composition is low on the side close to the active layer 404, the low Al composition layer 403A, and the Al composition is high on the side far from the active layer 404. Layer 403B was placed.

The low Al composition layer 403A was formed with a composition of Al _z Ga _1-z As (z = 0.3) and a thickness of 0.1 μm. The low Al composition layer 403A was formed without doping.

The high Al composition layer 403B was formed with a composition of Al _z Ga _1-z As (z = 0.45) and a thickness of 1.9 μm.
In the high Al composition layer 403B, a low doping region 403AA having a low doping concentration is disposed in a region adjacent to the low Al composition layer 403A, and a high doping concentration is provided in a region far from the low Al composition layer 403A. Region 403AB was placed.
In this embodiment, the low doping region 403AA is formed with a doping concentration of 1E + 17 / cm ³ and a thickness of 0.5 μm. The doping concentration of 403AB was 8E + 17 / cm ³ and the thickness was 1.4 μm.

  In the second semiconductor layer 405, as shown in FIG. 20, the Al composition is low on the side close to the active layer 404, the low Al composition layer 405A, and the Al composition is high on the side far from the active layer 404. Layer 405B was placed.

The low Al composition layer 405A was formed with a composition of (Al _x Ga _1-x ) _y In _1-y P (x = 0.4, y≈0.5) and a thickness of 0.1 μm. The low Al composition layer 405A was formed without doping.

The high Al composition layer 405B was formed with a composition of (Al _x Ga _1-x ) _y In _1-y P (x = 0.85, y≈0.5) and a thickness of 1.9 μm.
In the high Al composition layer 405B, a low doping region 405AA having a low doping concentration is disposed in a region adjacent to the low Al composition layer 405A, and a high doping concentration is provided in a region far from the low Al composition layer 405A. Region 405AB was placed.
In this embodiment, the low doping region 405AA has a doping concentration of 1E + 17 / cm ³ and a thickness of 0.5 μm. Further, the doping concentration of 405AB was 8E + 17 / cm ³ and the thickness was 1.4 μm.

A visible light reflection layer 430 is provided in the second semiconductor layer 405.
The visible light reflecting layer 430 and the active layer 404 have the same configuration as in Example 1.

Next, as shown in FIG. 6, a dielectric film 701 was formed on the surface of the current diffusion layer 406 of the epitaxial substrate 611. The dielectric film 701 is made of SiO ₂ and has a thickness of 430 nm, which is about half of the emission wavelength.

After a pattern was formed on a part of the dielectric film 701 by photolithography, an opening portion 702 was provided by etching treatment with hydrofluoric acid or the like, and a third electrode 703 was provided in the opening 702.
The third electrode 703 employs a structure in which an AuBe layer is 200 nm, an Ni layer is 20 nm, and an Au layer is 210 nm sequentially stacked.

A first metal film 710 was provided on the dielectric film 701 and the third electrode 703.
The first metal film 710 has a laminated structure of Au / Ti / Au in order to maintain a reflection function. The thicknesses were 600 nm, 100 nm, and 600 nm, respectively.

As shown in FIG. 7, a permanent substrate 720 was prepared, and a second metal film 721 was provided on the permanent substrate 720. The permanent substrate 720 is an Si substrate because it is easily available and inexpensive.
The second metal film 721 was made of Au / Pt / Au / Ti. The thicknesses were 600 nm, 10 nm, 600 nm, and 10 nm, respectively.

As shown in FIG. 8, a first metal film 710 and a second metal film 721 are bonded to face each other, and a bonded substrate 730 in which an epitaxial substrate 611 and a permanent substrate 720 are bonded is manufactured.
The starting substrate 401 was removed from the bonding substrate 730 with an etching solution such as ammonia water, so that a light-emitting element substrate 740 was manufactured (see FIG. 9).

  The etch stop layer 300 was removed by wet etching, and a first electrode 440 was formed on the second semiconductor layer 405 as shown in FIG. The first electrode 440 was formed by laminating an AuGe layer of 200 nm, a Ti layer of 100 nm, and an Au layer of 1700 nm.

A second electrode 441 was formed on the surface of the permanent substrate 720 opposite to the first electrode 440.
The second electrode 441 is made of Ti / Au in order to form an ohmic contact with the Si permanent substrate 720. The thickness was 100 nm and 200 nm, respectively.

After the formation of the first electrode 440 and the second electrode 441, it was divided into individual dies by scribing or blade dicing. The first electrode 440 side, which is the light extraction surface side, was roughened in order to improve the light extraction efficiency from the die.
The surface of the first electrode 440 side was covered with a dielectric protective film made of SiO ₂ with a thickness of 500 nm in order to improve the weather resistance of the die.

  With the die produced as described above, a measurement element was produced and measured in the same manner as in Example 1. And it showed in FIG. 21 with the measurement result of the comparative example 3 mentioned later.

As shown in FIG. 21, it can be seen that in the wavelength region shorter than 780 nm, most wavelengths are not detected as the EL spectrum as compared with Comparative Example 3.
Further, almost no luminescence was visually recognized.

Example 4
As shown in FIG. 12, a contact layer 807 made of GaP is provided on the current diffusion layer 406, a pattern is formed, and the contact layer 807 is left between the transparent conductive film 851 and the current diffusion layer 406. Produced an infrared light emitting device as shown in FIG. 12 in the same manner as in Example 3 to produce a die.
Note that ITO was used for the transparent conductive film 851.

  With the die produced as described above, a measurement element was produced and measured in the same manner as in Example 1. And it showed in FIG. 22 with the measurement result of the comparative example 4 mentioned later.

As shown in FIG. 22, it can be seen that in the wavelength region shorter than 780 nm, most wavelengths are not detected as the EL spectrum as compared with Comparative Example 4.
Further, almost no luminescence was visually recognized.

(Example 5)
An N-type GaAs buffer layer (not shown) of 0.5 μm is formed on the starting substrate of N-type GaAs having a thickness of 280 μm whose crystal axis is inclined by 15 ° in the [110] direction from the [001] direction by the MOVPE method. The etch stop layer 300 made of AlInP having substantially the same constant, the second semiconductor layer 405 of the N-type cladding layer made of AlGaInP is 2 μm, the active layer 404 made of AlGaAs is 1 μm, and the first semiconductor layer of the P-type cladding layer made of AlGaAs An epitaxial substrate 911 was produced in which 403 was formed in a thickness of 2 μm, GaP buffer layer 906 was formed in a thickness of 0.1 μm, and GaP support window / window layer 907 was formed in an order of 100 μm by epitaxial growth (see FIG. 13).

  A visible light reflection layer 430 is provided on both the first semiconductor layer 403 and the second semiconductor layer 405.

The configurations in the first semiconductor layer 403 and the second semiconductor layer 405 are as shown in FIGS. 19 and 20 as in the third embodiment.
Similarly to the third embodiment, the active layer 404 is a multiple quantum well (MQW) in which the well layer is GaAs and the barrier layer is Al _z Ga _1-z As (z = 0.3), and the barrier layer thickness is 7 nm, the well layer was 7 nm, and 9 periods.

A first electrode 950 was formed after the starting substrate was removed with ammonia perwater.
The first electrode 950 is made of a metal containing AuGe or the like in order to form an ohmic contact with a semiconductor layer having an N conductivity type. In this example, a stacked structure of AuGe / Ni / Au was used, and the thicknesses thereof were 200 nm, 20 nm, and 1780 nm.

  Part of the surface with the first electrode 950 was cut away by wet etching to form an opening region 951 in which the supporting substrate / window layer 907 was exposed, and a second electrode 952 was formed in part of the opening region 951.

  The second electrode 952 was made of a metal containing AuBe or the like in order to form an ohmic contact in the semiconductor layer having a P conductivity type. In this embodiment, a laminated structure of AuBe / Ti / Au is used, and the thicknesses are 200 nm, 100 nm, and 1700 nm, respectively.

After the formation of the first electrode 950 and the second electrode 952, each of the dice was divided by scribing or blade dicing. The light extraction surface side was roughened to improve the light extraction efficiency from the die.
A dielectric protective film made of SiO ₂ was formed on the surface side where the first electrode 950 and the second electrode 952 were provided in order to improve the weather resistance of the die. The dielectric protective film was coated with a thickness of about 500 nm.

  With the die produced as described above, a measurement element was produced and measured in the same manner as in Example 1. And it showed in FIG. 23 with the measurement result of the comparative example 5 mentioned later.

  As shown in FIG. 23, it can be seen that most wavelengths are not detected as EL spectra in the region shorter than 780 nm compared to Comparative Example 5. Further, almost no luminescence was visually recognized.

(Example 6)
An N-type GaAs buffer layer (not shown) is 0.5 μm by a MOVPE method on a 280 μm thick N-type GaAs substrate whose crystal axis is inclined by 15 ° from the [001] direction to the [110] direction. An etch stop layer 600 made of substantially the same AlInP, an N-type clad layer second semiconductor layer 405 made of AlGaInP is 2 μm, an active layer 404 made of AlGaAs is 1 μm, and a P-type clad first semiconductor layer 403 made of AlGaAs is made. An epitaxial substrate 1011 in which a current diffusion layer 406 made of 2 μm and AlGaInP was sequentially formed by 2 μm was produced.

  In the same manner as in Example 5, the visible light reflecting layer 430 was provided in both the first semiconductor layer 403 and the second semiconductor layer 405.

A thermosetting BCB adhesive transparent to the emission wavelength was applied to the surface of the current diffusion layer 406 to form an adhesive layer 1040.
A permanent substrate 1020 transparent to the emission wavelength was prepared, and a thermosetting BCB adhesive transparent to the emission wavelength was applied to form an adhesive layer 1041.
Sapphire was used for the permanent substrate 1020.

  The epitaxial substrate 1011 provided with the adhesive layer 1040 and the permanent substrate 1020 provided with the adhesive layer 1041 were joined with the adhesive layer 1040 and the adhesive layer 1041 facing each other to produce a joined substrate (see FIG. 14). .

  The starting substrate was removed from the bonding substrate by etching with ammonia water, whereby a light-emitting element substrate 1060 was manufactured. A first electrode 1050 was formed on the surface of the light-emitting element substrate 1060 from which the starting substrate was removed.

  The first electrode 1050 is made of a metal containing AuGe or the like in order to form an ohmic contact in the N-type semiconductor layer. In this example, a stacked structure of AuGe / Ni / Au was used, and the thicknesses thereof were 200 nm, 20 nm, and 1780 nm.

  A part of the surface having the first electrode 1050 was cut out by wet etching to form an opening region 1051 in which the current diffusion layer 406 was exposed, and a second electrode 1052 was formed in a part of the opening region 1051.

  The second electrode 1052 was made of a metal containing AuBe or the like in order to form an ohmic contact in the P-type semiconductor layer. In this embodiment, a laminated structure of AuBe / Ti / Au is used, and the thicknesses are 200 nm, 100 nm, and 1700 nm, respectively.

After the formation of the first electrode 1050 and the second electrode 1052, each of the dies was divided by scribing or blade dicing.
The light extraction surface side was roughened to improve the light extraction efficiency from the die. On the surface side where the first electrode 1050 and the second electrode 1052 are provided, a dielectric protective film made of SiO ₂ is coated with a thickness of 500 nm in order to improve the weather resistance of the die.

  With the die produced as described above, a measurement element was produced and measured in the same manner as in Example 1. And it showed in FIG. 24 with the measurement result of the comparative example 6 mentioned later.

  As shown in FIG. 24, it can be seen that, in the region having a wavelength shorter than 780 nm, most wavelengths are not detected as the EL spectrum as compared with Comparative Example 6. Further, almost no luminescence was visually recognized.

  As described above, in Examples 1 to 6, a visible light reflecting layer capable of reflecting the visible spectrum is inserted into a layer in a direction in which light is emitted, so that visible light in the light emitted from the infrared light emitting element is visible. Most of the wavelength in the light region could be cut.

(Comparative Example 1)
A light-emitting element having the same structure as that of Example 1 was manufactured except that the visible light reflection layer 430 was not laminated (see FIG. 2).
Thereafter, the emission spectrum was measured in the same manner as in Example 1. As described above, the measurement results are shown in FIG.

  As shown in FIG. 17, in Comparative Example 1, the wavelength in the visible light region shorter than 780 nm was measured more strongly than in Example 1. As a result, in Comparative Example 1, red light emission was observed.

(Comparative Example 2)
A light emitting device having the same structure as that of Example 2 was manufactured except that the visible light reflection layer 430 was not laminated (see FIG. 4).
Thereafter, the emission spectrum was measured in the same manner as in Example 2. As described above, the measurement results are shown in FIG.

  As shown in FIG. 18, in Comparative Example 2, the wavelength in the visible light region shorter than 780 nm was measured more strongly than in Example 2. As a result, in Comparative Example 2, red light emission was observed.

(Comparative Example 3)
A light emitting device having the same structure as that of Example 3 was manufactured except that the visible light reflecting layer 430 was not laminated (see FIG. 9).
Thereafter, the emission spectrum was measured in the same manner as in Example 3. As described above, the measurement results are shown in FIG.

  As shown in FIG. 21, in Comparative Example 3, the wavelength in the visible light region shorter than 780 nm was measured more strongly than in Example 1. As a result, in Comparative Example 3, red light emission was observed.

(Comparative Example 4)
A light emitting device having the same structure as that of Example 4 was manufactured except that the visible light reflecting layer 430 was not laminated (see FIG. 12).
Thereafter, the emission spectrum was measured in the same manner as in Example 4. As described above, the measurement results are shown in FIG.

  As shown in FIG. 22, in Comparative Example 4, the wavelength in the visible light region shorter than 780 nm was measured more strongly than in Example 4. As a result, in Comparative Example 4, red light emission was observed.

(Comparative Example 5)
A light emitting device having the same structure as that of Example 5 was manufactured except that the two visible light reflecting layers 430 of FIG. 13 were not laminated.
Thereafter, the emission spectrum was measured in the same manner as in Example 5. As described above, the measurement results are shown in FIG.

  As shown in FIG. 23, in the comparative example 5, the wavelength in the visible light region shorter than 780 nm was measured more strongly than in the example 5. As a result, in Comparative Example 5, red light emission was observed.

(Comparative Example 6)
A light emitting device having the same structure as that of Example 6 was manufactured except that the two visible light reflecting layers 430 in FIG. 14 were not laminated.
Thereafter, the emission spectrum was measured in the same manner as in Example 6. As described above, the measurement results are shown in FIG.

  As shown in FIG. 24, in Comparative Example 6, the wavelength in the visible light region shorter than 780 nm was measured more strongly than in Example 6. As a result, in Comparative Example 6, red light emission was observed.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

200 ... Infrared light reflection layer, 401 ... Starting substrate, 403 ... First semiconductor layer,
404 ... active layer, 405 ... second semiconductor layer, 406 ... current spreading layer,
410 ... light emitting part,
411, 511, 611, 911, 1011 ... epitaxial substrate,
430 ... Visible light reflection layer, 440, 950, 1050 ... First electrode,
300, 600 ... etch stop layer, 441, 952, 1052 ... second electrode,
701 ... Dielectric film, 702 ... Opening part, 703 ... Third electrode,
710 ... first metal film, 720, 1020 ... permanent substrate, 721 ... second metal film,
740, 890, 1060 ... light emitting element substrate, 807 ... contact layer,
851 ... Transparent conductive film, 880 ... Light emitting element substrate, 906 ... Buffer layer,
907 ... supporting substrate and window layer, 951 and 1051 ... opening region,
1040, 1041 ... Adhesive layer.

(Example 5)
An N-type GaAs buffer layer (not shown) of 0.5 μm is formed on the starting substrate of N-type GaAs having a thickness of 280 μm whose crystal axis is inclined by 15 ° in the [110] direction from the [001] direction by the MOVPE method. An etch stop layer 600 made of AlInP having substantially the same constant, a second semiconductor layer 405 of an N-type cladding layer made of AlGaInP, 2 μm, an active layer 404 made of AlGaAs 1 μm, and a first semiconductor layer made of an AlGaAs P-type cladding layer An epitaxial substrate 911 was produced in which 403 was formed in a thickness of 2 μm, GaP buffer layer 906 was formed in a thickness of 0.1 μm, and GaP support window / window layer 907 was formed in an order of 100 μm by epitaxial growth (see FIG. 13).

Claims (11)

A first electrode for injecting current into the light emitting part, having a light emitting part in which a first conductive type first semiconductor layer, an active layer, and a second conductive type second semiconductor layer are sequentially formed on a substrate; In the infrared light emitting device having the second electrode,
An infrared light emitting element, wherein a visible light reflecting layer having a function of reflecting visible light is provided in the second semiconductor layer or adjacent to the second semiconductor layer. The visible light reflection layer further includes
The infrared light-emitting element according to claim 1, wherein the infrared light-emitting element is provided in the first semiconductor layer or adjacent to the first semiconductor layer. In addition, an infrared light reflection layer having a function of reflecting infrared light,
The infrared light-emitting element according to claim 1, wherein the infrared light-emitting element is provided in the first semiconductor layer or adjacent to the first semiconductor layer.   The infrared light-emitting element according to claim 3, wherein the infrared light reflection layer is a distributed Bragg reflection (DBR) layer. The infrared light reflection layer is
Claims, characterized in that the _{Al z Ga 1-z As (} 0 ≦ z ≦ 1) and the _{Al z 'Ga 1-z'} As (0 ≦ z '<1) alternate stacked structure of are those composed The infrared light emitting device according to claim 3.   The infrared light-emitting element according to claim 1, wherein the visible light reflection layer is a distributed Bragg reflection (DBR) layer. The visible light reflecting layer is
_{(Al x Ga 1-x)} y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) and _{(Al x 'Ga 1-x} ') y 'In 1-y' P Alternating layered structure consisting of (0 ≦ x ′ ≦ 1, 0.4 ≦ y ′ ≦ 0.6),
Alternatively, it is composed of (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) and Al _z Ga _1-z As (0 ≦ z ≦ 1). The infrared light-emitting element according to claim 1, wherein the infrared light-emitting element is formed of any one of an alternately laminated structure. The second electrode is formed on the substrate opposite to the light emitting unit;
The metal layer and a dielectric film provided with an opening filled with a conductive material are sequentially formed between the substrate and the light emitting portion. The infrared light-emitting device according to any one of 7. The second electrode is formed on the substrate opposite to the light emitting unit;
The infrared light emitting device according to any one of claims 1 to 7, wherein a metal layer and a transparent conductive film are sequentially formed between the substrate and the light emitting portion. The second electrode is formed in a partial region on the substrate on the side where the light emitting unit is formed,
The light emitting unit and the first electrode are sequentially formed on the substrate in a portion other than the region where the second electrode is formed,
The infrared light-emitting element according to claim 1, wherein the substrate is transparent with respect to light emitted from the light-emitting portion. The first semiconductor layer is
_{Al z Ga 1-z As (} 0 ≦ z ≦ 0.6) or _{from (Al x Ga 1-x)} y In 1-y P (0 ≦ x ≦ 1,0.4 ≦ y ≦ 0.6) Consisting of
The second semiconductor layer is
From Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or (Al _x Ga _1-x ) _y In _1-y P (0 ≦ x ≦ 1, 0.4 ≦ y ≦ 0.6) Consisting of
The active layer is
A layer made of Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or In _t Ga _1-t As (0 ≦ t ≦ 0.3),
And a layer having a multiple quantum well (MQW) structure in which Al _z Ga _1-z As (0 ≦ z ≦ 0.6) or In _t Ga _1-t As (0 ≦ t ≦ 0.3) is a well layer. The infrared light-emitting element according to claim 1, wherein the infrared light-emitting element is any one of the following.

Images