JP2002246647A - Wavelength conversion type semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion type semiconductor device that improves the reflection factor of an electrode functioning as a reflection surface, and at the same time reduces contact resistance. SOLUTION: The wavelength conversion type semiconductor device 10 contains a lower p-type layer 13 and an upper n-type layer 12 for composing a pn junction, a wavelength conversion material 17 that is provided at the upper portion, a first electrode 14 that is provided on the lower surface of the p-type layer and prevents excitation light from the pn junction that is electrically in contact with the p-type layer from being transmitted to the outside, and a second electrode 16 that surrounds the end face of the p-type layer and the n-type layer and is electrically in contact with only the n-type layer. The wavelength conversion type semiconductor device 10 is composed so that the second electrode can be composed of a high reflection factor metal layer 16a that is made of a material having a high reflection factor near the wavelength of excitation light from the pn junction and is as thick as 10 nm or more, and a contact metal thin-film layer 16b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength conversion type semiconductor device, and more particularly to an electrode structure having a high reflectance.

[0002]

2. Description of the Related Art Conventionally, for example, typical gallium nitride-based (In (y) Al (1-xy) Ga (x) N: x + y
.Ltoreq.1, 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) A wavelength conversion type semiconductor device using a device is configured as shown in FIG. 10, for example. In FIG. 10, the wavelength conversion type semiconductor device 1 is configured as a gallium nitride-based white LED, and the n-type gallium nitride-based layer 3 and the p-type gallium nitride-based layer are sequentially stacked on the lower surface of the transparent substrate 2. Layer 4, a p-type gallium nitride-based electrode 5 formed on the surface of the p-type gallium nitride-based layer 4, and an n-type gallium nitride-based layer 3 and a p-type gallium nitride-based An insulating film 6 formed to cover the junction of the layer 4; an n-type gallium nitride-based electrode 7 formed to cover the entire end surface around the n-type gallium nitride-based layer 3; And the wavelength conversion material 8 provided on the
a.

The transparent substrate 2 is made of a material which is transparent to excitation light, which will be described later, such as a sapphire C-plane substrate. The n-type gallium nitride-based layer 3 and the p-type gallium nitride-based layer 4 are formed by a film forming method such as MOCVD (metal organic chemical vapor deposition). These n-type gallium nitride-based layer 3 and p-type gallium nitride-based layer 4
After film formation, a peripheral end face is formed as shown in the figure by a dry etching method such as an RIE method (reactive ion etching method) using chlorine gas.

The p-type gallium nitride-based electrode 5 is an N-type electrode capable of making good electrical contact with the p-type gallium nitride-based layer 4.
It is made of a metal such as i or Rh. The insulating film 6
Is made of a transparent material such as SiO ₂ or Al ₂ O _{3 which} has little absorption of excitation light which is not deteriorated by excitation light to be described later and has high transmittance.

The n-type gallium nitride-based electrode 7 is made of Ti
/ Al laminated electrode. Further, the above n
The gallium nitride-based electrode 7 is formed so as to cover the end face of the chip so as not to emit the excitation light from the end faces (chip end faces) of the n-type gallium nitride based layer 3 and the p-type gallium nitride based layer 4. Thus, the n-type gallium nitride-based electrode 7 reflects the incident excitation light.

The p-type gallium nitride based electrode 5
And the n-type gallium nitride-based electrode 7 is a bonding pad 5 made of Au bump or Ti and Au, respectively.
a, 7a and eutectic electrodes 5b, 7 made of Au-Sn alloy
b, it is mechanically fixed to the extraction electrodes 9a and 9b of the submount 9 and is also electrically connected. The extraction electrodes 9a and 9b are, for example, 25 mm in diameter.
Using Au wires 9c and 9d of about μm, the wires are pulled out to the outside by wire bonding.

The wavelength conversion material 8 is constituted by combining, for example, a YAG-based phosphor or a ZnS-based phosphor, and when excitation light is incident, generates fluorescence having a wavelength different from the excitation light. The light is emitted toward the outside.

The wavelength conversion type semiconductor device 1 having such a configuration
According to the method, the excitation light is generated at the junction between the n-type gallium nitride-based layer 3 and the p-type gallium nitride-based layer 4 by applying a drive voltage between the extraction electrodes 9a and 9b of the submount 9. Then, the excitation light is reflected by the inner surfaces of the p-type gallium nitride-based electrode 5 and the n-type gallium nitride-based electrode 7 and enters the transparent substrate 2 from the upper surface of the n-type gallium nitride-based layer 3. Then, the excitation light transmitted through the transparent substrate 2 is incident on the wavelength conversion material 8, and the wavelength conversion material 8
Generates different wavelengths of light depending on the incident excitation light and emits the light upward. Thus, the wavelength conversion type semiconductor element 1 emits, for example, white light.

[0009]

By the way, in the wavelength conversion type semiconductor device 1 having such a configuration, the amount of light emitted from the wavelength conversion material 8 is smaller than the amount of excitation light incident on the wavelength conversion material 8. Dependent. Therefore, in order to increase the luminous efficiency of the wavelength conversion type semiconductor element 1, the light amount of the excitation light may be increased. For this reason, the end faces around the n-type gallium nitride-based layer 3 and the p-type gallium nitride-based layer 4 are inclined at an inclination angle of, for example, about 45 degrees ± 5 degrees as shown in the figure, so that the n-type gallium nitride-based electrode is formed. The excitation light reflected by 7 is guided toward the wavelength conversion material 8.

However, since the n-type gallium nitride-based electrode 7 has a relatively low reflectance with respect to the excitation light, the light incident on the n-type gallium nitride-based electrode 7 is Part of the light is absorbed by the n-type gallium nitride-based electrode 7 without being reflected. For this reason, the quantity of the excitation light incident on the wavelength conversion material 8 is reduced, and the luminous efficiency of the wavelength conversion type semiconductor element 1 is reduced, so that there is a problem that the characteristics of the device cannot be sufficiently brought out. . In addition, since the contact resistance between the n-type gallium nitride-based electrode 7 and the n-type gallium nitride-based layer 3 is relatively large, Joule heat is generated and the temperature rises, so that the characteristics of the electronic device are increased. However, there is a problem that is reduced.

Also, in a wavelength conversion type semiconductor device such as an ultraviolet LED using an n-ZnO-based light emitting device, the wavelength of the n-type ZnO-based electrode is similarly low because the reflectance is low. There is a problem that the luminous efficiency of the conversion-type semiconductor element is lowered and the contact resistance of the second electrode is increased by heat treatment in the manufacturing process, and the characteristics of the electronic device are deteriorated.

In view of the above, an object of the present invention is to provide a wavelength conversion type semiconductor device in which the reflectance of an electrode functioning as a reflection surface is increased and the contact resistance is reduced. In the following, a description will be given of the most used wavelength conversion type semiconductor element.

[0013]

According to a first aspect of the present invention, the above object is provided on a lower p-type layer and an upper n-type layer constituting a pn junction, and on a lower surface of the p-type layer. In addition, the first electrode that does not transmit the excitation light from the pn junction electrically in contact with the p-type layer to the outside, and surrounds the end faces of the p-type layer and the n-type layer and electrically contacts only the n-type layer And a second electrode, wherein the second electrode is a high-reflectivity metal layer having a thickness of 10 nm or more made of a material having high reflectivity in the vicinity of the wavelength of the excitation light from the pn junction. And a contact metal thin film layer.

According to a second aspect of the present invention, there is provided a semiconductor device comprising: a lower p-type layer and an upper n-type layer forming a pn junction; a wavelength conversion material disposed above these layers; A first electrode provided on the lower surface of the mold layer and not transmitting the excitation light from the pn junction electrically in contact with the p-type layer to the outside, and surrounding the end faces of the p-type layer and the n-type layer and n-type layer A second electrode electrically contacting only with the second electrode, wherein the second electrode is made of a material having a high reflectivity near the wavelength of the excitation light from the pn junction. This is achieved by a wavelength conversion-type semiconductor element characterized by comprising a high-reflectance metal layer having a thickness of 10 nm or more and a contact metal thin film layer.

According to a third aspect of the present invention, there is provided a semiconductor device comprising: a lower p-type gallium nitride-based layer (In (y) Al (1-xy) Ga (x) N: x + y
.Ltoreq.1,0.ltoreq.x.ltoreq.1,0.ltoreq.y.ltoreq.1) and an upper n-type gallium nitride-based layer, a wavelength converter disposed above these layers, and a lower surface of the p-type gallium nitride-based layer. A first electrode for p-type gallium nitride that does not transmit the excitation light from the pn junction electrically in contact with the p-type gallium nitride-based layer to the outside, and an end face of the p-type gallium nitride-based layer and a region of the pn junction. An insulating film surrounding the end face and being transparent in the vicinity of the wavelength of the excitation light from the pn junction; and an insulating film surrounding the end faces of the p-type gallium nitride-based layer and the n-type gallium nitride-based layer and having only the n-type gallium nitride-based layer. A second electrode for an n-type gallium nitride system in electrical contact, wherein the second electrode has a reflectivity near the wavelength of the excitation light from the pn junction. A high-reflectance metal layer of at least 10 nm Characterized in that it is composed of a metal thin film layer, the wavelength conversion-type semiconductor device is achieved.

In the wavelength conversion type semiconductor device according to the present invention, the peripheral end faces of the p-type gallium nitride-based layer and the n-type gallium nitride-based layer are preferably inclined vertically or downward.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the contact metal thin film layer has a thickness of 10 nm.
It is as follows.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the contact metal thin film layer is made of Ni, Ti,
It is composed of W, Cr, Zr, In, Sn, V, or an alloy film or a laminated film mainly composed of these metals.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the high reflectivity metal layer is formed of Ag, Rh and Al.
Alternatively, it is composed of an alloy film or a laminated film containing these metals.

The wavelength conversion type semiconductor device according to the present invention preferably comprises a metal single layer film, a laminated film, an alloy film or a conductive transparent oxide film between the contact metal thin film layer and the high-reflectance metal layer. An intermediate electrode layer is provided.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the wavelength conversion type semiconductor device is a white LED, and the first electrode is a p-type gallium nitride based ohmic electrode.

According to a third aspect of the present invention, there is provided a lower p-type ZnO-based layer and an upper n-type ZnO-based layer constituting a pn junction, and a wavelength converter disposed above these layers. Material and p-type ZnO provided on the lower surface of the p-type ZnO-based layer.
A first electrode for p-type ZnO that does not transmit the excitation light from the pn junction electrically in contact with the O-based layer to the outside;
Surrounding the end face of the O-based layer and the end face of the region of the pn junction,
an insulating film that is transparent in the vicinity of the wavelength of the excitation light from the n-junction, and n-type ZnO surrounding the end faces of the p-type ZnO-based layer and the n-type ZnO-based layer and electrically contacting only the n-type ZnO-based layer
And a second electrode for the system, wherein the second electrode has a thickness of 10 nm or more made of a material having high reflectivity in the vicinity of the wavelength of the excitation light from the pn junction. This is achieved by a wavelength conversion type semiconductor device, which is constituted by a high reflectance metal layer and a contact metal thin film layer.

In the wavelength conversion type semiconductor device according to the present invention, the peripheral end faces of the p-type ZnO-based layer and the n-type ZnO-based layer are preferably inclined vertically or downward.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the contact metal thin film layer has a thickness of 10 nm.
It is as follows.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the contact metal thin film layer is made of Ni, Ge,
Se, Rh, Te, Re, Ir, Pt, Au, Co, P
d, W, Cr, Zr, Ag, V, In, Sn or an alloy film or a laminated film containing at least one of these metals.

In the wavelength conversion type semiconductor device according to the present invention, preferably, the high reflectivity metal layer is formed of Ag, Rh and Pt.
Alternatively, it is composed of an alloy film or a laminated film containing at least one kind of these metals.

The wavelength conversion type semiconductor device according to the present invention preferably comprises a metal single layer film, a laminated film, an alloy film or a conductive transparent oxide film between the contact metal thin film layer and the high-reflectance metal layer. An intermediate electrode layer is provided.

Preferably, in the wavelength conversion type semiconductor device according to the present invention, the wavelength conversion type semiconductor device is an ultraviolet LED, and the first electrode is a p-type ohmic electrode for ZnO.

According to the second configuration, the excitation light is generated at the pn junction between the n-type layer and the p-type layer by applying the driving voltage between the first electrode and the second electrode. I do. Then, part of the excitation light is reflected by the inner surfaces of the first electrode and the second electrode, and the other part directly enters the wavelength conversion material from the upper surface of the n-type layer. Then, the excitation light is incident on the wavelength conversion material, and the wavelength conversion material generates light having a different wavelength by the incident excitation light and emits the light upward.

In this case, since the second electrode includes the high-reflectance metal layer, the amount of excitation light reflected by the second electrode increases, and the excitation light is incident on the wavelength conversion material. The amount of light will increase. Accordingly, the amount of light emitted from the wavelength conversion material also increases, so that the luminous efficiency of the wavelength conversion type semiconductor device is improved. If the thickness of the high-reflectance metal layer is 10 nm or less, the reflectance will decrease, and the amount of excitation light incident on the wavelength conversion material will also decrease.

Further, since the second electrode includes the contact metal thin film layer, the contact metal thin film layer has good electrical contact with the n-type gallium nitride based layer. Is reduced, the driving voltage applied between the first electrode and the second electrode can be reduced, and a power-saving semiconductor device can be obtained, and the amount of heat generated decreases. Therefore, the deterioration of the characteristics of the semiconductor element due to heat can be suppressed.

According to the third configuration, by applying a driving voltage between the first electrode and the second electrode, a pn junction between the n-type gallium nitride-based layer and the p-type gallium nitride-based layer is formed. As a result, excitation light is generated. Then, a part of the excitation light is reflected by the inner surfaces of the first electrode and the second electrode,
Another part directly enters the wavelength conversion material from the upper surface of the n-type gallium nitride-based layer. Then, the excitation light is incident on the wavelength conversion material, and the wavelength conversion material generates light having a different wavelength by the incident excitation light and emits the light upward.

In this case, since the second electrode includes the high-reflectance metal layer, the amount of excitation light reflected by the second electrode increases, and the excitation light enters the wavelength conversion material. The amount of light will increase. Accordingly, the amount of light emitted from the wavelength conversion material also increases, so that the luminous efficiency of the n-type gallium nitride-based wavelength conversion type semiconductor device is improved. If the thickness of the high-reflectance metal layer is 10 nm or less, the reflectance will decrease, and the amount of excitation light incident on the wavelength conversion material will also decrease.

Further, since the second electrode includes the contact metal thin film layer, the contact metal thin film layer has good electrical contact with the n-type gallium nitride-based layer. Is reduced, the driving voltage applied between the first electrode and the second electrode can be reduced, and a power-saving semiconductor device can be obtained, and the amount of heat generated decreases. Therefore, the deterioration of the characteristics of the semiconductor element due to heat can be suppressed.

If the peripheral end faces of the p-type gallium nitride-based layer and the n-type gallium nitride-based layer are vertically or inclined downward, the p-type gallium nitride-based layer and the n-type The contact area with the gallium nitride-based layer will increase, and the adhesion of the second electrode will improve, and the excitation light reflected by the second electrode will be reflected upward. As a result, the efficiency of extracting the excitation light is improved.

The contact metal thin film layer has a thickness of 10 n
In the case of m or less, the absorption of the excitation light by the contact metal thin film layer is suppressed, so that the reflection efficiency of the excitation light by the second electrode, that is, the high reflectance metal layer is improved.

The contact metal thin film layer is made of Ni, T
When i, W, Cr, Zr, In, Sn, V, or an alloy film or a laminated film in which these metals are the main materials, the first electrode is used because of the low contact resistivity described above. In addition, the driving voltage applied between the second electrodes can be low.

The high reflectivity metal layer is made of Ag, Rh and A
1 or an alloy film or a laminated film containing these metals, each of these materials has a wavelength of 37.
Since it has a reflectance of 50% or more at 0 nm or more, a second electrode having a high reflectance can be obtained.

When an intermediate electrode layer made of a metal single layer film, a laminated film, an alloy film or a conductive transparent oxide film is provided between the contact metal thin film layer and the high-reflectance metal layer, the contact metal Electrode peeling between the thin film layer and the high-reflectance metal layer is suppressed.

In the case where the wavelength conversion type semiconductor element is a white LED and the first electrode is a p-type gallium nitride based ohmic electrode, the first electrode further contacts the p-type gallium nitride based layer. The resistivity is reduced, and brighter white light can be extracted.

According to the third configuration, by applying a drive voltage between the first electrode and the second electrode, the n-type Z
Excitation light is generated at a pn junction between the nO-based layer and the p-type ZnO-based layer. Then, a part of the excitation light is reflected by the inner surfaces of the first electrode and the second electrode, and the other part is directly incident on the wavelength conversion material from the upper surface of the n-type ZnO-based layer. Then, the excitation light is incident on the wavelength conversion material, and the wavelength conversion material generates light having a different wavelength by the incident excitation light and emits the light upward.

In this case, since the second electrode includes the high-reflectance metal layer, the amount of excitation light reflected by the second electrode increases, and the excitation light is incident on the wavelength conversion material. The amount of light will increase. Accordingly, the amount of light emitted from the wavelength conversion material also increases, so that the luminous efficiency of the n-type ZnO-based wavelength conversion type semiconductor element is improved.
If the thickness of the high-reflectance metal layer is 10 nm or less, the reflectance will decrease, and the amount of excitation light incident on the wavelength conversion material will also decrease.

Further, since the second electrode includes the contact metal thin film layer, the contact metal thin film layer has good electrical contact with the n-type ZnO-based layer. The contact resistivity will be reduced,
The driving voltage applied between the first electrode and the second electrode can be reduced, and a power-saving semiconductor device can be obtained. In addition, since the amount of generated heat is reduced, deterioration in characteristics of the semiconductor device due to heat is suppressed. In addition, since the separation of the second electrode from the n-type ZnO-based layer is suppressed, the stability of the second electrode is improved.

In the case where the peripheral end faces of the p-type ZnO-based layer and the n-type ZnO-based layer are vertically or inclined downward, the p-type ZnO-based layer and the n-type ZnO-based layer of the second electrode And the contact area of the second electrode will be increased, and the adhesion of the second electrode will be improved, and the excitation light reflected by the second electrode will be reflected upward,
The efficiency of extracting the excitation light is improved.

The contact metal thin film layer has a thickness of 10 n
When it is less than m, the absorption efficiency of the excitation light by the second electrode, that is, the high-reflectivity metal layer is improved by suppressing the absorption of the excitation light by the contact metal thin film layer.

The contact metal thin film layer is made of Ni, G
e, Se, Rh, Te, Re, Ir, Pt, Au, C
In the case of being composed of o, Pd, W, Cr, Zr, Ag, V, In, Sn or an alloy film or a laminated film containing at least one of these metals, the above-mentioned contact resistivity is low. Therefore, the driving voltage applied between the first electrode and the second electrode can be low.

The high-reflectivity metal layer is made of Ag, Rh and P
t, or an alloy film or a laminated film containing at least one of these metals, since each of these materials has a reflectance of 50% or more at a wavelength of 370 nm or more, high reflectance is obtained. A second electrode at a rate will be obtained.

When an intermediate electrode layer made of a metal single layer film, a laminated film, an alloy film or a conductive transparent oxide film is provided between the contact metal thin film layer and the high reflectance metal layer, the contact metal Electrode peeling between the thin film layer and the high-reflectance metal layer is suppressed.

When the wavelength conversion type semiconductor device is an ultraviolet LED and the first electrode is a p-type ZnO-based ohmic electrode, the contact resistivity of the first electrode to the p-type ZnO-based layer is further increased. Is reduced, and brighter ultraviolet light can be extracted.

[0050]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows the configuration of a second embodiment of the wavelength conversion type semiconductor device according to the present invention. In FIG. 1, a wavelength conversion type semiconductor device 10 is a white LED as a gallium nitride type wavelength conversion type semiconductor device, and is an n-type gallium nitride type layer (In (Y) Al (1-xy) Ga (x)
N: x + y ≦ 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) 12, p-type gallium nitride-based layer 13, and p-type gallium nitride-based electrode 14 formed on the surface of p-type gallium nitride-based layer 13 An insulating film 15 formed so as to cover from the p-type gallium nitride-based electrode 14 to the junction between the n-type gallium nitride-based layer 12 and the p-type gallium nitride-based layer 13; And a wavelength conversion material 17 provided on the transparent substrate 11, and the entire surface is covered with the mold resin 18. It is constituted by.

The transparent substrate 11 is made of, for example, sapphire C
It is made of a material that is transparent to excitation light described below, such as a surface substrate. The n-type gallium nitride-based layer 12 and p
The gallium nitride-based layer 13 is formed on the transparent substrate 11 by a film forming method such as MOCVD (metal organic chemical vapor deposition).
Are sequentially formed on the lower surface of the substrate.

These n-type gallium nitride-based layers 12 and p
The gallium nitride-based layer 13 is formed such that the peripheral end faces are inclined as shown in the figure by dry etching such as RIE (reactive ion etching) using chlorine gas, for example, after film formation. Accordingly, the contact area of the insulating film 15 with the n-type gallium nitride-based layer 12 and the p-type gallium nitride-based layer 13 is increased, so that the adhesion of the insulating film 15 is improved, and the reliability at the time of forming the insulating film 15 is improved. And the peeling of the insulating film 15 is suppressed. Therefore, the reliability of the electrical insulation between the n-type gallium nitride-based layer 12 and the p-type gallium nitride-based layer 13 is improved, and the yield of a so-called excitation light source element is improved. Further, due to the inclination of the end faces around the n-type gallium nitride-based layer 12 and the p-type gallium nitride-based layer 13, the excitation light is reflected by the second electrode 16 described later toward the upper transparent substrate,
The efficiency of light incidence on the wavelength conversion material 17 is improved.
In addition, the inclination angle of the end face around the n-type gallium nitride-based layer 12 and the p-type gallium nitride-based layer 13 may be 90 degrees or less from the viewpoint of the adhesion of the insulating film 15, and from the viewpoint of the reflection efficiency. Is preferably set to 45 degrees ± 5 degrees.

The p-type gallium nitride-based electrode 14
It is made of a metal such as Ni or Rh that can make good electrical contact with the type gallium nitride-based layer 13. The insulating film 15 is made of SiO2, A which is not deteriorated by excitation light described later.
It is made of a transparent material such as l2 O3.

The n-type gallium nitride-based electrode 16 is formed of n
-Type gallium nitride-based layer 12 and p-type gallium nitride-based layer 13
Is formed so as to cover the chip end face so as not to emit the excitation light from the end face (chip end face). Thus, the n-type gallium nitride-based electrode 16 reflects incident excitation light.

The p-type gallium nitride-based electrode 1
The 4 and n-type gallium nitride based electrodes 16 are Au
Eutectic electrode 1 made of bump or bonding pads 14a, 16c made of Ti and Au and Au-An alloy
4b, 16d, it is mechanically fixed to the extraction electrodes 19a, 19b of the submount 19, and is also electrically connected. The extraction electrodes 19a, 19b
Is, for example, generally an Au wire 1 having a diameter of about 25 μm.
9c and 19d are drawn out by wire bonding.

The wavelength conversion material 17 is constituted by combining, for example, a YAG-based phosphor or a ZnS-based phosphor, and when excitation light is incident, generates fluorescence having a wavelength different from the excitation light. The light is emitted toward the outside.

The above configuration is almost the same as the conventional wavelength conversion type semiconductor device 1 shown in FIG. 10, but in the wavelength conversion type semiconductor device 10 according to the embodiment of the present invention,
The second electrode 16 has a different configuration in that it is configured as shown in FIG. That is, in FIG.
The second electrode 16 is an electrode for n gallium nitride,
High reflectivity metal layer 16a and contact metal thin film layer 16b
And is composed of

The high reflectance metal layer 16a is made of a material having a high reflectance of, for example, 50% or more at a wavelength of 370 nm or more, which is the wavelength of the excitation light from the pn junction, for example, Ag, R
h and Al or an alloy film or a laminated film containing these metals. Further, the high reflectance metal layer 1
6a is selected to have a thickness of 10 nm or more so that the excitation light is reflected without transmitting through the high-reflectivity metal layer 16a, and preferably 100 nm or more to obtain sufficient reflected light.

The contact metal thin film layer 16b is formed of n
Having a low contact resistivity with respect to the type gallium nitride-based layer 12, for example, Ni, Ti, W, Cr, Zr, In, S
It is composed of n, V or an alloy film or a laminated film containing these metals as a main material. In particular, when the contact metal thin film layer 16b is made of a metal containing Ti, Zr, V, and W, these metals easily react with the n-type gallium nitride-based layer 12 to form the n-type gallium nitride. System layer 12
And a good ohmic contact is obtained.

Further, the contact metal thin film layer 16b
In order to increase the reflection efficiency of the highly reflective metal layer 16a, that is, to increase the light transmittance of the contact metal thin film layer 16b itself, its thickness is selected to be 10 nm or less. In order to obtain, its thickness is 3
nm or less. The contact metal thin film layer 16b may have at least one atomic layer. However, since the contact resistivity increases in inverse proportion to the film thickness, a good contact resistivity with the n-type gallium nitride-based layer 12 is obtained. Is preferably selected to be 0.5 nm or more.

Further, an intermediate electrode layer (not shown) is preferably formed between the high-reflectance metal layer 16a and the contact metal thin film layer 16b in order to suppress electrode peeling. This intermediate electrode layer is made of a material that does not impair the reflection efficiency of the high-reflectance metal layer 16a, for example, a metal single-layer film such as Ni or Ti, a laminated film, an alloy film, or a conductive transparent oxide film.

The high reflectance metal layer 16a, the contact metal thin film layer 16b and the intermediate electrode layer are preferably formed by electron beam evaporation or sputtering.
An alloying process may be performed after the formation, or a laminated film may be formed by an alloying process. Further, patterning of the high-reflectivity metal layer 16a, the contact metal thin film layer 16b, and the intermediate electrode layer is performed by a general method. For example, the etching is performed by an etching method or a lift-off method.

The wavelength conversion type semiconductor device 10 according to the embodiment of the present invention is configured as described above. By applying a driving voltage between the extraction electrodes 19a and 19b of the submount 19, the n-type gallium nitride-based layer is formed. Excitation light is generated at the pn junction between the p-type gallium nitride-based layer 13 and the p-type gallium nitride-based layer 13, and the excitation light is applied to the first electrode 14 and the second electrode 16.
And is incident on the transparent substrate 11 from the upper surface of the n-type gallium nitride-based layer 12. Then, the excitation light transmitted through the transparent substrate 11 is incident on the wavelength conversion material 17, and the wavelength conversion material 17 generates light having a different wavelength by the incident excitation light and emits the light upward. . Thus, the wavelength conversion type semiconductor element 10 emits, for example, white light.

In this case, since the second electrode 16 includes the high-reflectance metal layer 16a having, for example, a reflectance of 50% or more, the amount of excitation light reflected by the second electrode 16 increases. And the amount of excitation light incident on the wavelength conversion material 17 increases. Therefore, the wavelength conversion material 1
7, the light emitting efficiency of the n-type gallium nitride-based wavelength conversion type semiconductor element 10 is improved.

Further, since the second electrode 16 includes the contact metal thin film layer 16b, the contact metal thin film layer 16b has good electrical contact with the n-type gallium nitride based layer 12. In addition, the contact resistivity of the second electrode 12 to the n-type gallium nitride-based layer 12 is reduced. Therefore, the driving voltage applied between the first electrode 14 and the second electrode 16 can be reduced, and a power-saving semiconductor element can be obtained.
Deterioration of characteristics of the semiconductor element due to heat can be suppressed.

Further, since the peripheral end faces of the p-type gallium nitride-based layer 13 and the n-type gallium nitride-based layer 12 are inclined downward, the p-type gallium nitride-based layer 13 of the second electrode 16 is formed. Also, the contact area of the second electrode 16 with the n-type gallium nitride-based layer 12 and the insulating film 15 increases, so that the adhesion of the second electrode 16 is improved and the excitation light reflected by the second electrode is reduced. Since the light is reflected upward, the extraction efficiency of the excitation light is improved.

Here, various characteristics of the second electrode 16 will be verified. For this verification, a sample electrode 20 shown in FIG. 3 was manufactured. This sample electrode 20 has, for example, n to
On the n-type gallium nitride-based layer 21 having a carrier density of 5 × 10 ¹⁸ / cm ³ , an electrode 22 having the same configuration as the above-mentioned second electrode 16, that is, a contact metal thin film layer 23 and a high reflectivity metal layer 24 Are sequentially formed and are patterned by a lift-off method. The contact metal thin film layer 23 is configured in the same manner as the contact metal thin film layer 16b described above.
It is composed of an i-film. In addition, the high reflectance metal layer 24
Has the same configuration as the high-reflectance metal layer 16a described above, and is made of, for example, an Al film having a thickness of 300 nm. For comparison, the same n-type gallium nitride-based layer 21 was used for comparison.
A reference electrode having a 25-nm-thick Ti film and a 1-μm-thick film, which are generally used in the past, was also fabricated. Here, the electrode patterns of the sample electrode 20 and the reference electrode are formed in an annular shape as shown in FIG.

A drive voltage was applied to the sample electrode 20 and the reference electrode by the drive power supply 25, and the current-voltage characteristics were measured.
A characteristic curve as shown in the graph of FIG. 5 was obtained. As a result, it was confirmed that the current-voltage characteristics of both the sample electrode 20 and the reference electrode were substantially equal.

Next, the reflectances of the sample electrode 20 and the reference electrode were measured. In the measurement of the reflectivity, both electrodes were formed without patterning on a quartz substrate having a thickness of 1 mm, and the reflectivity was measured by allowing light to enter from the quartz substrate side. Did not perform the above-described alloying treatment.) However, reflection spectrum characteristics as shown in the graph of FIG. 6 were obtained. As a result, the reference electrode has a reflectance of 4 at a wavelength of 370 nm or more.
0%, while the sample electrode 20 has a wavelength of 3%.
It was about 75% at 70 nm or more, and it was confirmed that the reflectance was 50% or more.

The wavelength conversion type semiconductor device 10 and the conventional wavelength conversion type semiconductor device 1 shown in FIG.
Each white LED was manufactured, and the relative total luminous flux was compared. As each white LED, a p-type and an n-type gallium nitride-based layer are sequentially formed on a sapphire substrate by MOCVD to produce a gallium nitride-based ultraviolet LED as an excitation light source element, and RIE using a chlorine-based gas is performed. About 4 p from the surface of the p-type and n-type gallium nitride-based layers.
Etching was performed by about 00 nm to expose the n-type gallium nitride-based layer. Then, as the first electrode 14, about 300
A Rh film of about 400 nm is formed, and an SiO ₂ layer of about 400 nm is formed as the insulating film 15. Thereafter, an electrode having the same configuration as the sample electrode 20 or the reference electrode as the second electrode 16 is formed on the end face of the chip. To form Ti
Bonding pad comprising A and Au and A
A eutectic electrode made of a u-Sn alloy was formed. Here, all the electrodes and the insulating films were formed by the electron beam evaporation method, and were patterned by the lift-off method. Finally, in a state where all the electrodes are formed, each chip is separated by a so-called scribing method, and each chip is die-bonded to a submount, and an oxide insulating film that reflects ultraviolet light and transmits visible light. A white LED was manufactured by placing a wavelength conversion material composed of a phosphor and a phosphor on a sapphire substrate and sealing it with a mold resin.

With respect to the white LED as a wavelength conversion type semiconductor device according to the embodiment of the present invention and the conventional white LED, the white light obtained by driving with a current of 20 mA DC is totally integrated by an integrating sphere. When the luminous flux was measured, assuming that the total luminous flux of the conventional white LED was 100,
The total luminous flux of the white LED according to the embodiment of the present invention was 152, and it was confirmed that the relative total luminous flux increased significantly.

FIG. 7 shows the configuration of a third embodiment of the wavelength conversion type semiconductor device according to the present invention. In FIG. 7, a wavelength conversion type semiconductor element 30 is a white LED as an n-type ZnO-type wavelength conversion type semiconductor element, and is an n-type ZnO-based layer (oxidized) sequentially laminated on the lower surface of a transparent substrate 31. Zinc system: Cd (y) Mg (1-xy) Zn
(X) O: x + y ≦ 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) 3
2, a p-type ZnO-based layer 33, a p-type ZnO-based electrode 34 formed on the surface of the p-type ZnO-based layer 33,
From the O-based electrode 34 to the n-type ZnO-based layer 32 and the p-type ZnO
Insulating film 3 formed so as to cover up to the junction of system layer 33
5, an n-type ZnO-based electrode 36 formed to cover the entire end surface around the n-type ZnO-based layer 32;
And a wavelength conversion material 37 provided on the substrate, and the entire structure is covered with a mold resin 38.

The transparent substrate 31 is made of, for example, sapphire C
It is made of a material that is transparent to excitation light described below, such as a surface substrate. The n-type ZnO-based layer 32 and the p-type Zn
The O-based layer 33 is formed, for example, by forming a buffer layer (not shown) on the lower surface of the transparent substrate 31 at a temperature lower than the film forming temperature,
It is sequentially formed on the lower surface of the transparent substrate 31 by a film forming method such as the E method (molecular beam epitaxy method) or the MOCVD method.

The n-type ZnO-based layer 32 and the p-type Zn
After the film formation, the O-based layer 33 is formed by, for example, a liquid phase etching method, a gas phase etching method, or the like, with the peripheral end face inclined as shown in the drawing. Thereby, the n-type Z of the insulating film 35 is formed.
Since the contact area with the nO-based layer 32 and the p-type ZnO-based layer 33 is increased, the adhesion of the insulating film 35 is improved, the reliability in forming the insulating film 35 is improved, and the insulating film 3 is formed.
5 is suppressed. Therefore, the reliability of the electrical insulation between the n-type ZnO-based layer 32 and the p-type ZnO-based layer 33 is improved, and the yield of a so-called excitation light source element is improved. Further, the n-type ZnO-based layer 32 and the p-type ZnO-based layer 3
Due to the inclination of the end surface around the second electrode 3, a second electrode 3 described later is formed.
6, the excitation light is reflected toward the upper transparent substrate, and the efficiency of light incidence on the wavelength conversion material 37 is improved. The n-type ZnO-based layer 32 and the p-type ZnO
The inclination angle of the end face around the system layer 33 may be 90 degrees or less from the viewpoint of the adhesion of the insulating film 35, and is preferably set to 45 degrees ± 5 degrees from the viewpoint of the reflection efficiency.

The p-type ZnO-based electrode 34 is made of p-type ZnO.
Ni, Rh capable of good electrical contact with the O-based layer 33
And the like. The insulating film 35 is made of SiO ₂ , Al ₂ O ₃ , S which is not deteriorated by excitation light described later.
It is made of a transparent material such as ix Ny.

The n-type ZnO-based electrode 36 is made of n-type ZnO.
It is formed so as to cover the chip end faces so as not to emit the excitation light from the end faces (chip end faces) of the O-based layer 32 and the p-type ZnO-based layer 33. Thereby, the n-type ZnO
The system electrode 36 reflects incident excitation light.

The p-type ZnO-based electrode 34 and the n-type ZnO-based electrode 36 are respectively formed of Au bumps or bonding pads 34a, 36 made of Ti and Au.
Eutectic electrodes 34b and 36d made of c and Au-Sn alloy
Through the extraction electrodes 39a and 39 of the submount 39.
b is mechanically fixed and electrically connected. The extraction electrodes 39a and 39b are typically made of Au wires 39c and 39d having a diameter of about 25 μm, for example.
Is drawn out by wire bonding.

The wavelength conversion material 37 is constituted by combining, for example, a YAG-based phosphor or a ZnS-based phosphor, and when excitation light is incident, generates fluorescence having a wavelength different from the excitation light. The light is emitted toward the outside.

Here, the second electrode 36 has a different configuration in that it is configured as shown in FIG.
That is, in FIG. 8, the second electrode 36 is an nZnO-based electrode and includes a high-reflectance metal layer 36a and a contact metal thin film layer 36b.

The high reflectivity metal layer 36a is made of a material having a high reflectivity of, for example, 50% or more at a wavelength of 370 nm or more, which is the wavelength of the excitation light from the pn junction, for example, Ag, R
h and Pt or an alloy film or a laminated film containing at least one or more of these metals. further,
The high-reflectivity metal layer 36a has a thickness of 10 so that the excitation light is reflected without passing through the high-reflectivity metal layer 36a.
nm or more, preferably 10 nm to obtain sufficient reflected light.
0 nm or more is selected.

The contact metal thin film layer 36b is formed of n
A material having a low contact resistivity with respect to the type ZnO-based layer 32,
For example, Ni, Ge, Se, Rh, Te, Re, Ir, P
t, Au, Co, Pd, W, Cr, Zr, Ag, V, I
n, Sn, or an alloy film or a laminated film containing at least one of these metals.

Further, the contact metal thin film layer 36b
In order to increase the reflection efficiency of the high-reflection metal layer 36a, that is, to increase the light transmittance of the contact metal thin film layer 36b itself, the thickness is selected to be 10 nm or less. In order to obtain, its thickness is 3
nm or less. The contact metal thin-film layer 36b may have at least one atomic layer. However, since the contact resistivity increases in inverse proportion to the film thickness, the contact metal thin-film layer 36b has to have a good contact resistivity with the n-type ZnO-based layer 32. Is preferably selected to be 0.5 nm or more.

The high-reflectance metal layer 36a and the contact metal thin film layer 36b are preferably formed by electron beam heating evaporation or sputtering, and are formed as a laminated film which has been subjected to alloying processing after formation or alloyed processing. And the high-reflectivity metal layer 36a,
The patterning of the contact metal thin film layer 36b is performed by a general method, for example, an etching method or a lift-off method.

The wavelength conversion type semiconductor device 30 according to the embodiment of the present invention is configured as described above. By applying a drive voltage between the extraction electrodes 39a and 39b of the submount 39, the n-type ZnO-based layer 32 is formed. At the pn junction between the p-type ZnO-based layer 33 and the p-type ZnO-based layer 33, excitation light is generated, and this excitation light is reflected by the inner surfaces of the first electrode 34 and the second electrode 36, and the n-type ZnO-based layer 32 From the top of the transparent substrate 31
Incident on. Then, the excitation light transmitted through the transparent substrate 31 is incident on the wavelength conversion material 37, and the wavelength conversion material 37 generates light of different wavelengths by the incident excitation light and emits the light upward. .

In this case, since the second electrode 36 includes the high-reflectivity metal layer 36a having, for example, a reflectance of 50% or more, the amount of excitation light reflected by the second electrode 36 increases. And the amount of excitation light incident on the wavelength conversion material 37 increases. Therefore, the wavelength conversion material 3
7, the luminous efficiency of the n-type ZnO-based wavelength conversion type semiconductor element 30 is improved.

Further, since the second electrode 36 includes the contact metal thin film layer 36b, the contact metal thin film layer 36b has good electrical contact with the n-type ZnO-based layer 32 even after the heat treatment. Therefore, the contact resistivity of the second electrode 36 to the n-type ZnO-based layer 32 is reduced. Therefore, the driving voltage applied between the first electrode 34 and the second electrode 36 can be reduced, and a power-saving semiconductor device can be obtained. Can be done.
In addition, since the separation of the second electrode 36 from the n-type ZnO-based layer 32 is suppressed, the stability of the second electrode 36 is improved.

The p-type ZnO-based layer 33 and the n-type ZnO
Since the peripheral end face of the system layer 32 is inclined downward, the second electrode 36 of the second electrode 36 with respect to the p-type ZnO-based layer 35 and the n-type ZnO-based layer 32 of the second electrode 36 and the insulating film 35 is formed. Since the contact area is increased, the adhesion of the second electrode 36 is improved, and the excitation light reflected by the second electrode is reflected upward, so that the efficiency of extracting the excitation light is improved. Become.

Here, various characteristics of the second electrode 36 will be verified. For this verification, a sample electrode was prepared. This sample electrode is formed on a quartz substrate, for example, by sequentially forming an electrode having the same configuration as the above-described second electrode 36, that is, a contact metal thin film layer and a high-reflectance metal layer, and pattern-forming the same by a lift-off method. It is configured. The contact metal thin film layer is configured similarly to the above-described contact metal thin film layer 36b, and has a thickness of, for example, 1 n.
m of Ni film. The high-reflectance metal layer has the same configuration as the above-described high-reflectivity metal layer 36a, and is formed of, for example, a 200-nm-thick Ag film.

When the reflectance of the sample electrode was measured by irradiating light from the quartz substrate side, a reflection spectrum characteristic as shown in the graph of FIG. 9 was obtained. As a result, in the sample electrode, the wavelength 3
A reflectance exceeding about 70% was obtained at 70 nm or more.

When the contact resistance was measured when the sample electrode was heat-treated after film formation, a predetermined heat-treatment temperature dependence was obtained. As a result, for example, when heat treatment is performed at 300 ° C. for 20 seconds, 3.71 N ⁻⁸ (Ωcm)
It was confirmed that contact resistance as low as ² ) could be obtained.

[0092]

As described above, according to the present invention, since the second electrode includes the high-reflectance metal layer,
The amount of excitation light reflected by the second electrode increases, and the amount of excitation light incident on the wavelength conversion material increases. Accordingly, the amount of light emitted from the wavelength conversion material also increases, and the luminous efficiency of the wavelength conversion type semiconductor device is improved.

Further, since the second electrode includes the contact metal thin film layer, the contact metal thin film layer has good electrical contact with the n-type gallium nitride-based layer. Is reduced, the driving voltage applied between the first electrode and the second electrode can be reduced, and a power-saving semiconductor device can be obtained, and the amount of heat generated decreases. Therefore, the deterioration of the characteristics of the semiconductor element due to heat can be suppressed, and the separation of the second electrode from the n-type gallium nitride-based layer is suppressed, so that the stability of the second electrode is improved. become. As described above, according to the present invention, it is possible to provide an extremely excellent wavelength conversion type semiconductor element in which the reflectivity of the electrode functioning as the reflection surface is increased and the contact resistance is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a wavelength conversion type semiconductor device according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a configuration of a second electrode in the wavelength conversion type semiconductor device of FIG.

FIG. 3 is a schematic sectional view showing a configuration of a sample electrode for verifying a second electrode in the wavelength conversion type semiconductor device of FIG.

FIG. 4 is a schematic plan view showing an electrode pattern of the sample electrode of FIG.

FIG. 5 is a graph showing current-voltage characteristics of the sample electrode and the reference electrode of FIG.

FIG. 6 is a graph showing reflection spectrum characteristics of the sample electrode and the reference electrode of FIG.

FIG. 7 is a schematic sectional view showing a second embodiment of the wavelength conversion type semiconductor device according to the present invention.

8 is a partially enlarged cross-sectional view illustrating a configuration of a second electrode in the wavelength conversion type semiconductor device of FIG.

FIG. 9 is a graph showing a reflection spectrum characteristic of a sample electrode for verifying a second electrode in the wavelength conversion type semiconductor device of FIG. 7;

FIG. 10 is a schematic sectional view showing a configuration of an example of a conventional wavelength conversion type semiconductor device.

[Explanation of symbols]

 Reference Signs List 10 wavelength conversion type semiconductor element 11 transparent substrate 12 n-type gallium nitride-based layer 13 p-type gallium nitride-based layer 14 p-type gallium nitride-based electrode 14a bonding pad 14b eutectic electrode 15 insulating film 16 n-type gallium nitride-based electrode 16a High reflectivity metal layer 16b Contact metal thin film layer 16c Bonding pad 16d Eutectic electrode 17 Wavelength conversion material 18 Mold resin 19 Submount 19a Extraction electrode 19b Extraction electrode 19c Au wire 19d Au wire 20 Sample electrode 21 n-type gallium nitride based layer 21 REFERENCE SIGNS LIST 22 electrode 23 contact metal thin film layer 24 high reflectance metal layer 25 drive power supply 30 wavelength conversion type semiconductor element 31 transparent substrate 32 n-type ZnO-based layer 33 p-type ZnO-based layer 34 p-type ZnO-based electrode 34 a bonding pad 34 b eutectic Electric 35 insulating film 36 n-type ZnO based electrode 36a and high reflective metal layer 36b contacts the metal thin film layer 36c bonding pad 36d eutectic electrode 37 wavelength converting member 38 molded resin 39 submount

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Hirasawa 2-9-13 Stanley, Nakameguro, Meguro-ku, Tokyo Inside Electric Co., Ltd. (72) Toshio Tomiyoshi 2-9-13 Stanley, Nakameguro, Meguro-ku, Tokyo − Within Electric Co., Ltd. (72) Inventor Kenichi Morikawa 2-9-13 Stanley, Nakameguro, Meguro-ku, Tokyo − F term within Electric Co., Ltd. 5F041 AA14 AA21 CA02 CA34 CA41 CA65 CA74 CA82 CA92 CA93 CA98 CB15 DA07 DA12 DA20 DA43 DB09 EE25

Claims (16)

[Claims] An excitation light from a pn junction provided on a lower surface of a lower p-type layer and an upper n-type layer and electrically contacting the p-type layer and constituting a pn junction is externally provided. A semiconductor element comprising: a first electrode that does not transmit light; and a second electrode that surrounds end faces of the p-type layer and the n-type layer and is in electrical contact with only the n-type layer. A high-reflectance metal layer having a thickness of 10 nm or more made of a material having a high reflectivity in the vicinity of the wavelength of the excitation light from the pn junction, and a contact metal thin film layer. element. 2. A lower p-type layer and an upper n-type layer constituting a pn junction, a wavelength conversion material disposed above the p-type layer and an upper n-type layer. A first electrode that does not transmit the excitation light from the pn junction that has come into contact with the outside, a second electrode that surrounds the end faces of the p-type layer and the n-type layer, and is electrically contacted only with the n-type layer, A high-reflectivity metal layer having a thickness of 10 nm or more and made of a material having high reflectivity in the vicinity of the wavelength of the excitation light from the pn junction; A wavelength conversion type semiconductor device, comprising: a thin film layer. 3. A lower p-type gallium nitride based layer (In (y) Al (1-xy) Ga (x) constituting a pn junction
N: x + y ≦ 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) and the upper n-type gallium nitride-based layer, the wavelength converter disposed above these layers, and the lower surface of the p-type gallium nitride-based layer A first electrode for p-type gallium nitride that does not allow externally transmitting excitation light from a pn junction electrically connected to the p-type gallium nitride-based layer, an end face of the p-type gallium nitride-based layer, and a pn junction An insulating film that surrounds the end face of the region and is transparent near the wavelength of the excitation light from the pn junction, and the end face of the p-type gallium nitride-based layer and the n-type gallium nitride-based layer, A second electrode for an n-type gallium nitride system electrically contacting only the layer, wherein the second electrode is located near the wavelength of the excitation light from the pn junction. A high-reflectance metal layer having a thickness of 10 nm or more made of a material having a high reflectivity; And a contact metal thin film layer. 4. The wavelength conversion type semiconductor according to claim 2, wherein peripheral end faces of the p-type gallium nitride-based layer and the n-type gallium nitride-based layer are vertically or downwardly inclined. element. 5. The contact metal thin film layer having a thickness of 10
2. The wavelength conversion type semiconductor device according to claim 1, wherein the wavelength is not more than nm. 6. The method according to claim 1, wherein the contact metal thin film layer is made of Ni, T
The wavelength according to any one of claims 2 to 4, wherein i, W, Cr, Zr, In, Sn, V, or any of these metals is composed of an alloy film or a laminated film that is a main material. Conversion type semiconductor device. 7. The high-reflectance metal layer is made of Ag, Rh, and Al, or an alloy film or a laminated film containing these metals. Wavelength conversion type semiconductor device. 8. An intermediate electrode layer comprising a metal single-layer film, a laminated film, an alloy film or a conductive transparent oxide film is provided between the contact metal thin film layer and the high reflectance metal layer. The wavelength conversion type semiconductor device according to any one of claims 2 to 6. 9. The wavelength-converting semiconductor device is a white LED, and the first electrode is a p-type gallium nitride-based ohmic electrode. Wavelength conversion type semiconductor device. 10. A lower p-type ZnO forming a pn junction
System layer and the upper n-type ZnO-based layer, the wavelength conversion material disposed above them, and the pn junction provided on the lower surface of the p-type ZnO-based layer and electrically contacting the p-type ZnO-based layer A first electrode for p-type ZnO that does not transmit the excitation light to the outside, an end surface of the p-type ZnO-based layer and an end surface of the pn junction region, and are transparent near the wavelength of the excitation light from the pn junction. Wavelength conversion including an insulating film and a second electrode for an n-type ZnO-based layer surrounding the end faces of the p-type ZnO-based layer and the n-type ZnO-based layer and electrically contacting only the n-type ZnO-based layer A semiconductor device, wherein the second electrode is a high-reflectance metal layer having a thickness of 10 nm or more made of a material having high reflectivity in the vicinity of the wavelength of the excitation light from the pn junction, a contact metal thin film layer, A wavelength conversion type semiconductor element characterized by comprising: 11. The wavelength conversion type semiconductor device according to claim 9, wherein peripheral end faces of the p-type ZnO-based layer and the n-type ZnO-based layer are vertically or downwardly inclined. 12. The contact metal thin film layer having a thickness of 1
10. The structure according to claim 9, wherein the thickness is 0 nm or less.
0. The wavelength conversion type semiconductor device according to item 0. 13. The method according to claim 13, wherein the contact metal thin film layer comprises Ni,
Ge, Se, Rh, Te, Re, Ir, Pt, Au, C
12. The film according to claim 9, wherein the film is made of an alloy film or a laminated film containing at least one of o, Pd, W, Cr, Zr, Ag, V, In, Sn or any of these metals. The wavelength conversion type semiconductor device according to any one of the above. 14. The method according to claim 9, wherein the high-reflectance metal layer is made of Ag, Rh, and Pt, or an alloy film or a stacked film containing at least one of these metals. The wavelength conversion type semiconductor device according to any one of the above. 15. An intermediate electrode layer comprising a metal single-layer film, a laminated film, an alloy film or a conductive transparent oxide film between the contact metal thin film layer and the high-reflectance metal layer. The wavelength conversion type semiconductor device according to any one of claims 9 to 13. 16. The method according to claim 9, wherein the wavelength conversion type semiconductor element is an ultraviolet LED, and the first electrode is a p-type ZnO-based ohmic electrode. Wavelength conversion type semiconductor element.