JP3303711B2 - ELEMENT ELECTRODE AND ITS MANUFACTURING METHOD - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode of a light emitting element or a light receiving element and a method of manufacturing the same, and more particularly, to a translucent metal electrode provided on a light input or output side of the element and a method of manufacturing the same.

[0002]

2. Description of the Related Art A gallium nitride (GaN) based compound semiconductor light emitting device as shown in FIG. 8 has been disclosed as a device provided with a metal electrode having a light-transmitting property on the light extraction side (Japanese Patent Application Laid-Open No. Hei 6 (1994) -61532). -314822). In this light emitting device, an n-type GaN-based compound semiconductor layer 2 and a p-type GaN-based compound semiconductor layer 3 are sequentially laminated on a sapphire substrate 1, and a part of the p-type semiconductor layer 3 is removed by etching to form an n-type semiconductor layer. 2 are exposed, and an n-type electrode 4 and a p-type electrode 5 are formed on the n-type semiconductor layer 2 and the p-type semiconductor layer 3, respectively. The p-type electrode 5 is formed, for example, by depositing 0.03 μm-thick Ni, then depositing 0.07 μm-thick Au, and alloying Ni and Au by thermal annealing to obtain an ohmic contact and to be translucent. . Thereby, light can be extracted from the p-type electrode 5 side.

[0003]

However, including the above case, the thickness of a metal electrode having a light-transmitting property is generally required to be about 100 mm in consideration of the adhesion to the element. The thickness has a light-transmitting property, but there is a problem that a reduction in transmittance is unavoidable, and the amount of light emission cannot be improved.

[0004] Accordingly, an object of the present invention is to improve the transmittance of an electrode and improve the luminous efficiency or the light-receiving efficiency in view of the above-mentioned problems.

[0005]

Means for Solving the Problems To solve the above-mentioned problems, the means described in claim 1 can be adopted.
According to this means, the light-transmitting metal electrode provided on the light input or output side of the element is cured by heat treatment.
By gathering, a relatively thick region and a relatively thin or completely unformed region are mixed on the electrode forming surface of the element, and the relatively thick region is formed continuously in a substantially mesh shape. You. As a result, there is a slight current diffusion in the element, and if the interval between the relatively mesh-like and relatively thick regions is sufficiently small, the electrode is not formed over the entire surface on the electrode forming surface. A current can flow across the region, and in a relatively thin region formed between the relatively thick regions, light transmittance is improved, and as a result, light transmittance in the entire electrode can be improved. Aggregation in this case means that
Aggregation to the extent that connection is not lost.
It can be controlled by degree, time, atmosphere, etc. This continuous abbreviation
Uniform surface light emission can be obtained by injecting current into the element by the network.
And light transmittance in relatively thin areas
Thus, it is possible to obtain an element having improved transmittance over the entire electrode.
Wear.

According to the second aspect of the present invention, the first metal and the second metal are formed on the electrode forming surface of the device, and the first metal and the second metal are reacted by heat treatment, and the reaction product is appropriately formed. To produce a light-transmitting metal electrode provided on the light input or output side of the device. Aggregation in this case refers to agglomeration to such an extent that the lateral connection of the reaction products is not lost, and can be controlled by the temperature, time, atmosphere, etc. of the heat treatment. In addition, the formation of the first metal and the second metal here includes not only the formation of a layer made of each metal but also the simultaneous formation in the state of an alloy.
Thus, a relatively thick region and a region that is relatively thin or not formed at all are mixed on the electrode formation surface, and the relatively thick region can be formed substantially continuously in a mesh shape. The continuous mesh allows current to be injected into the element to obtain uniform surface light emission, and at the same time, to improve the light transmittance in a relatively thin region, thereby obtaining an element having improved transmittance over the entire electrode. it can.

According to the third aspect of the present invention, the first metal is formed of one or more noble metals, so that the metal electrode is formed in a desired substantially mesh shape.

According to a fourth aspect of the present invention, the second metal is silver (Ag), cobalt (Co), chromium (Cr), copper (Cu), iron (F).
e), germanium (Ge), indium (In), magnesium
(Mg), manganese (Mn), nickel (Ni), palladium (Pd),
It is composed of one or more of platinum (Pt), tin (Sn), tantalum (Ta), titanium (Ti), vanadium (V), zinc (Zn), and zirconium (Zr). As a result, a relatively thin or no-formed region can be satisfactorily formed.

According to a fifth aspect of the present invention, the first metal is made of gold (Au) and the second metal is the metal of the fourth aspect, so that gold (Au) and another metal can be used. A solid solution is formed, and the solid solution is favorably aggregated to form a relatively thick region and a relatively thin region or a region which is not formed at all into desired shapes.

When the thickness of the first and second metals exceeds 200 °, the transmittance decreases, and when the thickness is less than 5 °, the adhesion decreases, so that the first and second metal films are formed as described in claim 6. When the thickness is 5 to 200 °, the transmittance can be secured and the adhesion can be improved.

According to a seventh aspect of the present invention, the first metal is formed in a granular form on the electrode forming surface of the device by the first metal forming step, and then the first metal and the electrode forming surface are formed by the second metal forming step. A second metal having a composition different from that of the first metal is formed thereon. Thus, the second metal grows in the lateral direction with the first metal formed as a nucleus as a nucleus, and the second metal does not exist at all between the relatively thick portion substantially continuous in a network and the nucleus. Alternatively, a thinly stretched portion is formed, and the transmittance in the portion where the second metal does not exist at all or the thinly stretched portion is improved, and the same effect as the means according to claim 2 can be obtained.

According to the present invention, when the first metal is made of gold (Au), the second metal is made of copper (Cu) or indium.
(In), magnesium (Mg), manganese (Mn), lead (Pb), palladium (Pd), tin (Sn), tantalum (Ta), titanium (Ti), vanadium (V), zinc (Zn), zirconium (Zr). This makes it possible to form a thin film of the second metal with the first metal as a core.

According to the ninth aspect, the fine particles are dispersed on the electrode forming surface of the element by the fine particle forming step, the fine particles are adsorbed on the electrode forming surface, and the fine particles are formed on the electrode forming surface and the fine particles by the metal layer forming step. Then, a metal layer is formed. And
The fine particles are removed from the electrode forming surface by the fine particle removing step. Thereby, the electrode formation surface is exposed in the portion where the fine particles are removed, that is, since the metal is not formed, the metal layer can be formed in a substantially mesh shape, and the transmittance in the portion where the electrode formation surface is exposed is Is improved, and an effect equivalent to the means described in claim 2 can be obtained.

According to the tenth aspect, by setting the thickness of the metal layer to be equal to or less than the diameter of the fine particles, the fine particles can be removed more favorably.

According to the eleventh aspect, the fine particles are dispersed on the electrode forming surface of the element by the fine particle forming step,
Fine particles are fixed to the electrode forming surface. Here, the fixation of the fine particles refers to a situation where the fine particles cannot be easily removed, for example, such that a part of the fine particles is embedded in the electrode forming surface. Then, a metal layer is formed on the electrode forming surface and the fine particles by the metal layer forming step, and the metal layer is formed as a thin film using the fine particles as nuclei. As a result, a portion where the nucleus and the nucleus are continuously formed in a substantially mesh shape, and a portion where a metal layer does not exist at all or a thin portion is formed therebetween, and a metal layer does not exist at all or becomes thin. The transmittance in the stretched portion is improved, and the same effect as the means according to claim 2 can be obtained.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, the present invention will be described based on specific embodiments. FIG. 1 is a schematic cross-sectional view of a light emitting device 100 formed of a GaN-based compound semiconductor formed on a sapphire substrate 11. On the sapphire substrate 11
A buffer layer 12 of AlN having a thickness of about 25 nm is provided, and a high carrier concentration n ⁺ layer 13 of silicon (Si) doped GaN having a thickness of about 4.0 μm is formed thereon. Silicon (Si) is formed on the high carrier concentration n ⁺ layer 13.
A cladding layer 14 made of doped n-type GaN and having a thickness of about 0.5 μm is formed.

Then, a film thickness of about 35 is formed on the cladding layer 14.
バ リ ア GaN barrier layer 151 and about 35 膜厚 thick In
Light emitting layers 15 having a multiple quantum well structure (MQW) composed of well layers 152 made of _0.20 Ga _0.80 N are alternately formed. The barrier layer 151 has six layers, and the well layer 152 has five layers. On the light emitting layer 15, a cladding layer 16 of p-type Al _0.15 Ga _0.85 N having a thickness of about 50 nm is formed.
Further, a contact layer 17 of p-type GaN having a thickness of about 100 nm is formed on the cladding layer 16.

A light-transmissive electrode 18A formed by metal evaporation is formed on the contact layer 17, and the electrode 18A is formed on the n ⁺ layer 13.
B is formed. The light-transmissive electrode 18A is composed of a 15 ° -thick gold (Au) bonded to the contact layer 17 and a metal element to be described later such as cobalt (Co) having a 60-thick thickness bonded to the gold (Au). I have. The electrode 18B is made of vanadium (V) having a thickness of 200 ° and aluminum (Al) or an aluminum alloy having a thickness of 1.8 μm.

Next, a method of manufacturing the light emitting device 100 will be described. The light emitting device 100 was manufactured by vapor phase growth using metal organic chemical vapor deposition (hereinafter abbreviated as MOVPE). The gases used were ammonia (NH ₃ ), carrier gas (H ₂ , N ₂ ), trimethylgallium (Ga (CH ₃ ) ₃ ) (hereinafter referred to as “TMG”), and trimethylaluminum (Al (CH ₃ )).
₃ ) (hereinafter referred to as “TMA”), trimethylindium (In
(CH ₃ ) ₃ ) (hereinafter referred to as “TMI”), silane (SiH ₄ ) and cyclopentadienyl magnesium (Mg (C ₅ H ₅ ) ₂ ) (hereinafter “CP
₂ Mg ”).

First, a single crystal sapphire substrate 11 having an a-plane as a main surface, which has been cleaned by organic cleaning and heat treatment, is subjected to MOV.
It is mounted on a susceptor placed in the reaction chamber of the PE device. Next, the sapphire substrate 11 was baked at a temperature of 1100 ° C. while flowing H ₂ at a flow rate of ₂ liter / min for about 30 minutes at normal pressure.

Next, by lowering the temperature to 400 ° C., H ₂
20 liter / min, NH ₃ 10 liter / min, TMA 1.8 ×
The buffer layer 12 of AlN is supplied at a rate of about 10 ^-5 mol / min.
It was formed to a thickness of 5 nm. Next, the temperature of the sapphire substrate 11 was maintained at 1150 ° C., H ₂ was 20 liter / min, NH ₃ was 10 liter / min, TMG was 1.7 × 10 ⁻⁴ mol / min, and 0.86 ppm with H ₂ gas. 20 × 10 diluted silane
^-8 mol / min, film thickness about 4.0 μm, electron concentration 2 ×
A high carrier concentration n ⁺ layer 13 made of GaN having a concentration of 10 ¹⁸ / cm ³ and a silicon concentration of 4 × 10 ¹⁸ / cm ³ was formed.

Next, the temperature of the sapphire substrate 11 is set to 115
Keep at 0 ° C, 10 liter / min of N ₂ or H ₂ , 10 liter of NH ₃
ter / min, TMG at 1.12 × 10 ⁻⁴ mol / min, TMA at ^0.12 mol / min.
Silane diluted to 47 × 10 ⁻⁴ mol / min and 0.86 ppm with H ₂ gas was supplied at 5 × 10 ⁻⁹ mol / min to obtain a film thickness of about 0.5 μm and an electron concentration of 1 × 10 ¹⁸ / cm. ^{3. A} cladding layer 14 made of GaN having a silicon concentration of 2 × 10 ¹⁸ / cm ³ was formed.

[0023] After forming the clad layer 14 described above, followed by N ₂ or H ₂ 20liter / min and NH ₃ 10liter / min, TMG
Is supplied at 2.0 × 10 ^-4 mol / min to give a film thickness of about 35 °.
A barrier layer 151 made of GaN was formed. Next, TMG was added to 7.2 × 10 _{4 while} the supply amounts of N ₂ or H ₂ and NH ₃ were kept constant.
^-5 mol / min, TMI is supplied at 0.19 × 10 ^-4 mol / min, and a well layer 15 of In _0.20 Ga _0.80 N having a thickness of about 35 ° is formed.
2 was formed. Further, the barrier layer 151 and the well layer 152
Were formed under the same conditions for five periods, and a barrier layer 151 made of GaN was formed thereon. Thus, MQW of five periods
The light emitting layer 15 having the structure was formed.

Next, the temperature of the sapphire substrate 11 is set to 110
Keep at 0 ° C, 10 liter / min of N ₂ or H ₂ , 10 liter of NH ₃
ter / min, TMG 1.0 × 10 ⁻⁴ mol / min, TMA 1.0
X 10 ^-4 mol / min, CP ₂ Mg was supplied at 2 x 10 ^-5 mol / min, the film thickness was about 50 nm, and the magnesium (Mg) concentration was 5 x 10 ⁵ mol / min.
¹⁹ / cm ³ magnesium (Mg) doped p-type Al _0.15 Ga
_A cladding layer 16 of _0.85 N was formed.

Next, the temperature of the sapphire substrate 11 is set to 110
Held in 0 ° C., N ₂ or H ₂ 20liter / min, 10Li and NH ₃
ter / min, TMG 1.12 × 10 ^-4 mol / min, CP ₂ Mg 2
Supplied in × 10 ^-5 mol / min, to form a contact layer 17 made of a film thickness of about 100 nm, magnesium (Mg) of magnesium concentration ^{5 × 10 19 / cm 3 (} Mg) doped with p-type GaN.

Next, an etching mask is formed on the contact layer 17, the mask in a predetermined region is removed, and the portions of the contact layer 17, the cladding layer 16, the light emitting layer 15, and the cladding layer 14 which are not covered with the mask are removed. , A part of the n ⁺ layer 13 was etched by reactive ion etching using a gas containing chlorine to expose the surface of the n ⁺ layer 13. Next, an electrode 18B for the n ⁺ layer 13 and a translucent electrode 18A for the contact layer 17 were formed in the following procedure.

(1) A photoresist is applied, a window is formed in a predetermined region on the exposed surface of the n ⁺ layer 13 by photolithography, and the window is evacuated to a high vacuum of the order of 10 ⁻⁶ Torr or less. Of vanadium (V) and aluminum (Al) having a thickness of 1.8 μm were deposited. Next, the photoresist is removed. As a result, the electrode 18 on the exposed surface of the n ⁺ layer 13
B is formed. (2) Next, a photoresist 19 is uniformly applied on the surface, and the photoresist 19 on the electrode forming portion on the contact layer 17 is removed by photolithography.
A window 19A is formed as shown in FIG. (3) After evacuating the photoresist 19 and the exposed contact layer 17 to a high vacuum of the order of 10 ⁻⁶ Torr or less by using a vapor deposition apparatus, a 15 mm-thick gold (Au) film is formed. As shown in FIG. 2, a first metal layer 81 is formed. (4) Subsequently, a cobalt film having a thickness of 60 ° is formed on the first metal layer 81.
(Co) is deposited, and as shown in FIG.
To form (5) Next, the sample is taken out of the vapor deposition apparatus, and Au and Co deposited on the photoresist 19 are removed by a lift-off method, so that a light-transmissive electrode 18A for the contact layer 17 is formed. (6) Next, in order to form a bonding electrode pad 20 on a part of the translucent electrode 18A, a photoresist is uniformly applied, and the photoresist is formed on the electrode pad 20 forming portion. Open the window. Next, a film of cobalt (Co) or nickel (Ni) and gold (Au), aluminum (Al), or an alloy thereof is formed to a film thickness of about 1.5 μm by vapor deposition, in the same manner as in step (5). , Co or Ni and Au, A deposited by evaporation on photoresist by lift-off method
The electrode pad 20 is formed by removing the film made of l or an alloy thereof. (7) After that, the sample atmosphere was evacuated with a vacuum pump, and O ₂ gas was supplied to a pressure of 3 Pa.
The contact layer 17 and the cladding layer 16 are heated to 50 ° C. for about 3 minutes to reduce the resistance of the p-type contact layer 17 and the cladding layer 16.
7, an alloying process of the first metal layer 81 and the second metal layer 82,
An alloying process between the electrode 18B and the n ⁺ layer 13 was performed.

By this heat treatment, the first metal layer 8 made of Au is formed.
A part of the second metal layer 82 made of 1 and Co reacts to obtain a metal layer in which a relatively thick portion in a plan view is continuous in a substantially mesh shape. FIG. 3 shows a schematic cross-sectional configuration in this state, and FIG. 7 shows a surface photograph by a scanning electron microscope (SEM). A reaction product 83 that is aggregated in a substantially network shape is formed on the contact layer 17, and a second metal layer 82 is formed between the reaction products 83. In FIG. 7, the black portion indicates the background of the GaN contact layer 17 or the extremely thin second metal layer 82, and the white portion, that is, the reaction product 83 is formed in a substantially mesh shape. Thereby, the transmittance in the black portion is improved, and the light emission amount can be increased. The reaction product 83 corresponds to a relatively thick region described in the claims, and the second metal layer 82 formed between the reaction products 83 corresponds to a region that is relatively thin or has no metal layer formed. .

In this embodiment, the first metal layer 81 made of Au is used.
Although the second metal layer 82 made of Co is formed thereon, it may be formed upside down. In the present embodiment, the first metal layer 81 is made of Au. In addition, silver (Ag),
By using a noble metal such as palladium (Pd), an appropriate reaction product can be obtained. In the present embodiment, the second
Although the metal layer 82 was made of Co, silver (Ag), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), and germanium (G
e), indium (In), magnesium (Mg), manganese (M
n), nickel (Ni), palladium (Pd), platinum (Pt), tin (S
n), tantalum (Ta), titanium (Ti), vanadium (V), zinc
One or more of (Zn) and zirconium (Zr) can be used. In particular, these metals are effective when the first metal layer 81 is Au. In the present embodiment, the electrode 18A has a two-layer structure, but may have a three or more-layer structure using the above-described materials. Also, in this embodiment, the alloying treatment temperature is set to about 5
Although it was set to 50 ° C, it can be used in the range of 1000 ° C or less.

Although the light emitting layer 15 of the light emitting element 100 has the MQW structure, it may be a single layer made of SQW, In _0.2 Ga _0.8 N, or other quaternary or ternary AlInGaN having an arbitrary mixed crystal ratio. Mg was used as a p-type impurity, but beryllium (B
e), a group 2 element such as zinc (Zn) can be used. or,
The light-transmitting electrode 18A including the first metal layer 81 and the second metal layer 82 may be formed to have a thickness of 5 to 200 °, respectively. It is preferably within the following range, and more preferably within the range of 40 to 200 ° from the viewpoint of adhesion, light transmission and electrode resistance.

(Second Embodiment) In the first embodiment, after forming the first metal layer 81 made of Au and the second metal layer 82 made of Co, a substantially net-like reaction product is formed by alloying. In the second embodiment, the first metal 810 is formed in a granular form, and the second metal 820 is formed as a thin film using the granular first metal 810 as a nucleus. There is a feature. A photoresist 19 is formed on the contact layer 17 and the window 19 is formed by photolithography.
The process up to the point where A is formed is the same as in the first embodiment. Hereinafter, an electrode forming method according to the second embodiment will be described with reference to FIG.

First, the photoresist 19 and the exposed contact layer 17 are evacuated to a high vacuum of the order of 10 ⁻⁶ Torr or less by a vapor deposition apparatus, and then gold (Au) is slightly vapor-deposited to form the first islands. A metal 810 is formed. Here, as a means for forming a metal in an island shape, for example, there is a method of increasing a substrate temperature at the time of forming a metal film and an energy of a deposition source. Subsequently, lead (Pb) is formed on the first metal 810 and the contact layer 17.
Is formed to form a second metal 820. in this case,
Since the Pb-evaporated particles that have reached the sample are easily bonded to Au, they migrate on the surface of the sample and grow with Au formed as islands as nuclei. Next, the sample is taken out of the vapor deposition apparatus, Pb and Au deposited on the photoresist 19 are removed by a lift-off method, and a translucent electrode 18A for the contact layer 17 is formed. The steps after the formation of the bonding electrode pad are the same as those in the first embodiment.

As a result, the first metal 8 formed in a granular form
The second metal 820 grows in the lateral direction with 10 as a nucleus,
A thin film is formed between the metals 810. Therefore, the second metal 82
The transmittance at 0 is improved, and an electrode having excellent light transmittance can be obtained as in the first embodiment. In this embodiment,
Although the first metal 810 is made of gold (Au), a noble metal such as silver (Ag) or palladium (Pd) may be used. Also, the first metal 8
If 10 is made of gold (Au), the second metal 820 is lead (P
b) In addition to indium (In), magnesium (Mg), manganese (Mn), copper (Cu), palladium (Pd), tin (Sn), tantalum
Any one or more of (Ta), titanium (Ti), vanadium (V), zinc (Zn) and zirconium (Zr) can be used. In the present embodiment, the first metal 810 is formed in a granular form by slightly evaporating gold (Au). However, the first metal 810 may be formed in a granular form by a method such as etching. In this case, a metal other than the noble metal is replaced with the first metal 810.
Can be used. In the case where a noble metal is used as the first metal 810, the first metal 810 can be formed into a granular shape by utilizing the surface energy of the noble metal by heat treatment after the first metal 810 is formed.

(Third Embodiment) This embodiment is characterized in that a metal layer is formed on fine particles adsorbed on an electrode forming surface, and then the fine particles are removed to improve the transmittance of the electrode. Things. The steps up to the formation of the window 19A are the same as those in the first embodiment. Hereinafter, an electrode forming method will be described with reference to FIG.

First, on the exposed contact layer 17 and the photoresist 19, Si having a particle size of micron order or less is formed.
The fine particles 84 made of O ₂ are dispersed, and the fine particles 84 are adsorbed on the exposed surface of the contact layer 17. Then, after evacuating to a high vacuum of the order of 10 ⁻⁶ Torr or less using a vapor deposition device,
A metal layer 85 made of gold (Au) is formed on the entire surface to a thickness of 100. FIG. 5A is a schematic sectional view showing this state. Next, the sample was taken out of the vapor deposition apparatus, and the fine particles 84 and Au deposited on the photoresist 19 by the lift-off method were removed.
And the fine particles 84 adsorbed on the contact layer 17 by ultrasonic waves are removed. FIG. 5B is a schematic cross-sectional view showing a state where the fine particles 84 on the contact layer 17 are removed. Thus, the light-transmissive electrode 18A for the contact layer 17 is formed. The steps after the formation of the bonding electrode pad are the same as those in the first embodiment.

The electrode 18A thus obtained has a substantially mesh-like metal layer 85 uniformly spread on a plane, and the fine particles 84 are removed to form a large number of windows 86 where the contact layer 17 is exposed. To improve the transmittance,
The same effect as that of the embodiment can be obtained. Further, in this embodiment, the metal layer 85 has a single-layer structure, but may have a multi-layer structure as long as the total thickness is equal to or less than the particle diameter. Further, in this embodiment, the material of the fine particles 84 is SiO ₂ , but fine particles of micron or submicron order may be used, and metal, ceramic, fired clay or the like may be used. Also, fine particles 8
As a method of adsorbing 4 on the contact layer 17, a general electrostatic attraction or the like can be used, and the fine particle removing step includes ultrasonic waves, compressed air blow, etching, or the like.

(Fourth Embodiment) In the third embodiment, the fine particles 84 adsorbed on the contact layer 17 are removed. However, the present embodiment is characterized in that the fine particles 84 are left without being removed. is there. Hereinafter, an electrode forming method will be described with reference to FIG.

First, fine particles 84 made of SiO ₂ having a particle size on the order of microns are dispersed on the exposed contact layer 17, and the fine particles 84 are pressed using a lapping machine or the like, so that the fine particles 84 are exposed on the exposed surface of the contact layer 17. Part of the fine particles 85 is embedded and fixed. After this, the window 19A
To form Subsequently, after evacuating to a high vacuum of the order of 10 ⁻⁶ Torr or less using a vapor deposition device, a metal layer 85 made of gold (Au) is formed to a thickness of 100 に over the entire surface. FIG. 6 is a schematic sectional view showing this state. Next, the sample is taken out of the vapor deposition apparatus, the fine particles 84 and Au deposited on the photoresist 19 are removed by a lift-off method, and a translucent electrode 18A for the contact layer 17 is formed. The steps after the formation of the bonding electrode pad are the same as those in the first embodiment.

By forming the electrode 18A in this manner, the metal layer 85 is formed so as to grow laterally with the fine particles 84 as nuclei and to be connected to the metal extending from the adjacent fine particles 84. Therefore, the vicinity of the fine particles 84 is thick, the space between the fine particles 84 is thin, or no metal is formed. Accordingly, the metal layer 85 can be formed in a substantially mesh shape, and good transmittance can be obtained in the metal layer 85, and the same effect as in the first embodiment can be obtained. In the present embodiment, the metal layer 85 has a single-layer structure, but may have a multilayer structure. As the fine particles 84, metal, ceramic, fired clay, diamond powder and the like can be used in addition to SiO ₂ .

In the third and fourth embodiments, the metal layer 8
Although the material of No. 5 was Au, all kinds of metals can be applied. In the third and fourth embodiments, the particle size of the fine particles 84 is on the order of microns, but may be on the order of submicrons.

As a manufacturing method other than the first to fourth embodiments, a photoresist is uniformly applied on the entire surface,
There is a method in which a photoresist is formed in a granular form having a diameter of 1 μm or less on the electrode forming portion on the contact layer 17 by photolithography, and a metal layer is formed on the photoresist. After the formation of the metal layer, a large number of windows are formed by removing the photoresist and the metal layer deposited on the photoresist by vapor deposition, and a thick layer can be formed in a substantially mesh-like continuous metal layer on a plane. The same effects as those of the above embodiments can be obtained. In each of the above embodiments, Ga
Although an N-based compound semiconductor light emitting device has been described, the present invention is not limited to this, and can be applied to other devices having a light-transmitting metal electrode. Also, the present invention relates to LE
It can be used not only for light emitting elements such as D and LD, but also for light receiving elements.

As indicated above, according to the present invention,
A comparatively thick region consisting of metal and a region relatively thin or not formed at all are mixed on the electrode forming surface of the semiconductor layer, and the comparatively thick region is provided in a substantially mesh-like manner. The transmittance in a region that is thin or not formed at all is improved, and the amount of light emission and the amount of light received from the electrode side can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cross-sectional configuration of a light emitting device according to an example of the present invention.

FIG. 2 is a schematic diagram illustrating a cross-sectional configuration of an electrode of a light emitting element according to a manufacturing method of an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a cross-sectional configuration of an electrode after a heat treatment according to the first embodiment of the present invention.

FIG. 4 is a schematic view showing a sectional configuration of an electrode according to a second embodiment of the present invention.

FIG. 5 is a schematic view showing a sectional configuration of an electrode according to a third embodiment of the present invention.

FIG. 6 is a schematic view showing a sectional configuration of an electrode according to a fourth embodiment of the present invention.

FIG. 7 is a scanning electron micrograph showing the surface texture of the electrode according to the first embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a cross-sectional configuration of a conventional light-emitting element.

[Explanation of symbols]

Reference Signs List 11 sapphire substrate 12 buffer layer 13 high carrier concentration n ⁺ layer 14, 16 cladding layer 15 light emitting layer 17 contact layer 18A, 18B electrode 81 first metal layer 82 second metal layer 83 reaction product 84 fine particles 85 metal layer 100 light emitting element

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-5921 (JP, A) JP-A-6-237012 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 33/00 H01L 31/02-31/10 H01S 5/00-5/50 JICST file (JOIS)

Claims (11)

(57) [Claims] 1. A light-transmitting metal electrode provided on a light input or output side of an element, wherein the metal electrode has a film thickness on an electrode formation surface of the element by being aggregated by heat treatment. An electrode for an element, wherein a relatively thick region and a region that is relatively thin or not formed at all are mixed, and the relatively thick region is formed continuously in a substantially mesh shape. 2. A method for manufacturing a light-transmitting metal electrode provided on a light input or output side of an element, comprising: forming a first metal and a second metal on an electrode forming surface of the element; The first metal and the second metal are caused to react with each other, and the reaction product is agglomerated, so that a region having a relatively large thickness and a region having a relatively small thickness or not formed at all are mixed, A method for manufacturing an electrode of an element, comprising forming a thick region continuously in a substantially mesh shape. 3. The method according to claim 2, wherein the first metal comprises one or more noble metals. 4. The method according to claim 1, wherein the second metal is silver (Ag), cobalt (C
o), chromium (Cr), copper (Cu), iron (Fe), germanium (Ge),
Indium (In), magnesium (Mg), manganese (Mn), nickel (Ni), palladium (Pd), platinum (Pt), tin (Sn), tantalum (Ta), titanium (Ti), vanadium (V), Zinc (Zn),
3. The method according to claim 2, wherein the electrode is made of one or more of zirconium (Zr). 5. The first metal comprises gold (Au), and the second metal comprises silver (Ag), cobalt (Co), chromium (Cr), copper
(Cu), iron (Fe), germanium (Ge), indium (In), magnesium (Mg), manganese (Mn), nickel (Ni), palladium (Pd), platinum (Pt), tin (Sn), tantalum (Ta), titanium
3. The method according to claim 2, wherein the electrode is made of one or more of (Ti), vanadium (V), zinc (Zn), and zirconium (Zr). 6. The method according to claim 2, wherein the thickness of each of the first and second metals is 5 to 200 °. 7. A method for producing a light-transmitting metal electrode provided on a light input or output side of an element, comprising: forming a first metal in a granular form on an electrode forming surface of the element. And a step of forming the first granular material on the first metal and the electrode forming surface.
A second metal forming step of forming a second metal having a composition different from that of the first metal using the metal as a nucleus. 8. The first metal is made of gold (Au), and the second metal is made of copper (Cu), indium (In), magnesium (Mg),
Manganese (Mn), lead (Pb), palladium (Pd), tin (Sn), tantalum (Ta), titanium (Ti), vanadium (V), zinc (Zn),
The method according to claim 7, wherein the electrode is made of one or more of zirconium (Zr). 9. A method for producing a light-transmitting metal electrode provided on a light input or output side of a device, comprising dispersing fine particles on an electrode forming surface of the device, and disposing the fine particles on the electrode forming surface. A fine particle forming step of adsorbing fine particles, a metal layer forming step of forming a metal layer on the electrode forming surface and the fine particles, and a fine particle removing step of removing the fine particles from the electrode forming surface. A method for manufacturing an electrode of an element. 10. The method according to claim 9, wherein a thickness of the metal layer is equal to or less than a diameter of the fine particles. 11. A method for producing a light-transmitting metal electrode provided on a light input or output side of a device, comprising dispersing fine particles on an electrode forming surface of the device, and disposing the fine particles on the electrode forming surface. A method for manufacturing an electrode of an element, comprising: a fine particle forming step of fixing fine particles; and a metal layer forming step of forming a metal layer with the fine particles as nuclei on the electrode forming surface and the fine particles.