JP5381680B2 - Semiconductor light emitting device, method for manufacturing semiconductor light emitting device, lamp, electronic apparatus and mechanical device - Google Patents

Description

  The present invention relates to a semiconductor light-emitting element, a method for manufacturing a semiconductor light-emitting element, a lamp, an electronic device, and a mechanical device, and more particularly to a semiconductor light-emitting element capable of obtaining excellent light extraction efficiency and a method for manufacturing the same.

  Conventionally, as a semiconductor light emitting device used for a light emitting diode (LED) lamp, an n-type semiconductor layer made of a GaN-based compound semiconductor, a light emitting layer, and a p type semiconductor layer are stacked in this order on a sapphire single crystal substrate. Some have a positive electrode formed on a p-type semiconductor layer and a negative electrode formed on an n-type semiconductor layer.

In general, external quantum efficiency is used as an index indicating the output of a semiconductor light emitting device. The external quantum efficiency is a product of the internal quantum efficiency and the light extraction efficiency.
As a method for improving the light extraction efficiency, there is a method for reducing light absorption by an electrode formed on the light extraction surface.

  For example, in Patent Document 1, a first conductive type semiconductor layer, a light emitting layer, and a second conductive type semiconductor layer are laminated in this order, and an electrode connected to the second conductive type semiconductor layer includes a lower conductive oxide film and An upper conductive oxide film formed on the lower conductive oxide film so as to have a region in which a part of the surface of the lower conductive oxide film is exposed; and the upper conductive oxide film The electrode connected to the first conductive semiconductor layer is formed of a conductive oxide film and a metal film disposed on the conductive oxide film, and the upper and lower layers A semiconductor in which the conductive oxide film and the conductive oxide film are made of an oxide containing at least one element selected from the group consisting of zinc (Zn), indium (In), tin (Sn), and magnesium (Mg) A light emitting element is described.

Moreover, as a translucent conductive film used for an electrode formed on the light extraction surface, ITO (Indium Tin Oxide (In ₂ O ₃ —SnO ₂ )), IZO (Indium Zinc Oxide (In ₂ O ₃ —ZnO)) ) And GZO (gallium zinc oxide (ZnO—Ga ₂ O ₃ )).
In Patent Document 2, as a light-transmitting conductive material, ZnO and an alkaline earth metal fluoride compound, ZnO and a lanthanide fluoride metal compound, ZnO and an alkali metal fluoride compound, ZnO and ZrO ₂ , or ZnO and YF are disclosed. _A compound containing 3 wt% or more of the above-mentioned compound containing ₃ as a main component and ZnO as a main component is described.
Further, in Patent Document 3, as a transparent conductive film of an electrochromic light control device, ZnO and an alkaline earth metal fluoride compound or AlF ₃ are used as main components, and an alkaline earth metal fluoride compound or AlF ₃ is used. What contains 10 wt% or more is described.

JP 2005-317931 A JP 2005-219982 A Japanese Patent No. 2005-292474

  However, in the technique described in Patent Document 1, the light incident on the conductive oxide film constituting the electrode formed on the light extraction surface is attenuated by multiple reflection in the conductive oxide film. Due to the large amount of absorption, a sufficiently high light extraction efficiency could not be obtained.

The present invention has been made in view of the above problems, and can prevent multiple reflections in a transparent conductive film constituting an electrode formed on a light extraction surface, and can provide a semiconductor with excellent light extraction efficiency. An object of the present invention is to provide a light emitting element and a method for manufacturing the same.
Another object of the present invention is to provide a lamp, an electronic device, and a mechanical device including a semiconductor light emitting element having excellent light extraction efficiency.

In order to solve the above-mentioned problems, the present inventor has intensively studied as follows, paying attention to the multiple reflection in the transparent conductive film constituting the electrode formed on the light extraction surface.
The present inventor believes that the light attenuated by the multiple reflection in the transparent conductive film is the light emitted from the light emitting layer constituting the semiconductor layer, and has a large angular difference from the thickness direction of the semiconductor light emitting element. Light that has low rectilinearity in the thickness direction, and light that is emitted from the light emitting layer constituting the semiconductor layer and that has a small straight angle difference with respect to the thickness direction of the semiconductor light emitting element, is a conductive oxide. It was confirmed that the light was emitted through the film.

And this inventor repeated earnest examination and was excellent in the light extraction efficiency by providing the low-refractive-index conductive film which is less than the refractive index of a semiconductor layer and a transparent conductive film between a semiconductor layer and a transparent conductive film. It was found that can be obtained.
That is, in such a semiconductor light emitting device, light with low straightness emitted from the semiconductor layer is reflected by the low refractive index conductive film and returned to the semiconductor layer, so light with low straightness emitted from the semiconductor layer is emitted. Can be prevented from entering the transparent conductive film, and multiple reflection in the transparent conductive film can be prevented. In addition, the light having low rectilinearity returned to the semiconductor layer is converted into light having high rectilinearity within the semiconductor layer and then incident on the transparent conductive film through the low refractive index conductive film. The light passes through the film and the transparent conductive film and is emitted without being multiple-reflected in the transparent conductive film.
Therefore, the amount of light absorption due to attenuation in the transparent conductive film is very small, and excellent light extraction efficiency can be obtained. That is, the present invention relates to the following.

(1) On a substrate, a semiconductor layer having an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer, a low refractive index conductive film, and a transparent conductive film are provided in this order, and the low refractive index conductive film The semiconductor light emitting element characterized by having a refractive index less than that of the semiconductor layer and the transparent conductive film.

(2) The semiconductor light emitting device according to (1), wherein the refractive index of the low refractive index conductive film is less than 1.9.
(3) The semiconductor light-emitting device according to (1) or (2), wherein the refractive index of the transparent conductive film is in the range of 1.9 to 2.2.
(4) The semiconductor light emitting element according to any one of (1) to (3), wherein a refractive index of the semiconductor layer is in a range of 1.9 to 2.6.

(5) The semiconductor light-emitting element according to any one of (1) to (4), wherein a protective film is provided on the transparent conductive film, and a refractive index of the protective film is less than 2.
(6) The semiconductor light-emitting element according to any one of (1) to (5), wherein the low refractive index conductive film contains gallium zinc oxide and calcium fluoride.
(7) The specific resistance of the low refractive index conductive film is in the range of 10 ⁻⁵ to 10 ⁴ Ω · cm. The semiconductor light emitting device according to any one of (1) to (6),
(8) The semiconductor light-emitting element according to any one of (1) to (7), wherein a film thickness of the low refractive index conductive film is in a range of 80 nm to 300 nm.

(9) A step of providing a semiconductor layer having an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer on a substrate, and a low refractive index whose refractive index is less than the refractive index of the semiconductor layer on the semiconductor layer. A method of manufacturing a semiconductor light emitting device, comprising: providing a conductive film; and providing a transparent conductive film having a refractive index equal to or higher than the refractive index of the low refractive index conductive film on the low refractive index conductive film. .
(10) A lamp comprising the semiconductor light emitting device according to any one of (1) to (8).
(11) An electronic device in which the lamp according to (10) is incorporated.
(12) A mechanical apparatus in which the electronic device according to (11) is incorporated.

  In the semiconductor light-emitting device of the present invention, a semiconductor layer having an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer, a low refractive index conductive film, and a transparent conductive film are provided in this order on a substrate. Since the refractive index of the low refractive index conductive film is less than the refractive index of the semiconductor layer and the transparent conductive film, the light having a low straightness emitted from the semiconductor layer is reflected by the low refractive index conductive film. And returned to the semiconductor layer. Therefore, it is possible to prevent light having low rectilinearity emitted from the semiconductor layer from entering the transparent conductive film and performing multiple reflection, and absorption due to attenuation of light in the transparent conductive film can be prevented. Further, in the semiconductor light emitting device of the present invention, the reflected light reflected by the low refractive index conductive film and returned to the semiconductor layer is multiple-reflected within the semiconductor layer to be a highly linear light, and the low refractive index conductive film And are transmitted through the transparent conductive film. As a result, in the semiconductor light emitting device of the present invention, excellent light extraction efficiency can be obtained.

According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor light-emitting element, comprising: providing a semiconductor layer having an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer on a substrate; A method of providing a low-refractive-index conductive film having a refractive index lower than the refractive index of the layer and a step of providing a transparent conductive film having a refractive index equal to or higher than the refractive index of the low-refractive-index conductive film on the low-refractive-index conductive film Therefore, the semiconductor light emitting device of the present invention having excellent light extraction efficiency can be obtained.
Moreover, since the lamp | ramp, electronic device, and mechanical apparatus of this invention are equipped with the semiconductor light-emitting device of this invention, they are excellent with the semiconductor light-emitting device which has the outstanding light extraction efficiency.

It is the top view which showed an example of the semiconductor light-emitting device of this invention. It is sectional drawing in the A-A 'line | wire of the semiconductor light-emitting device shown in FIG. FIG. 3 is a manufacturing process diagram for explaining an example of a method for manufacturing the semiconductor light emitting element shown in FIGS. 1 and 2. FIG. 3 is a manufacturing process diagram for explaining an example of a method for manufacturing the semiconductor light emitting element shown in FIGS. 1 and 2. FIG. 3 is a manufacturing process diagram for explaining an example of a method for manufacturing the semiconductor light emitting element shown in FIGS. 1 and 2. FIG. 3 is a manufacturing process diagram for explaining an example of a method for manufacturing the semiconductor light emitting element shown in FIGS. 1 and 2. FIG. 3 is a manufacturing process diagram for explaining an example of a method for manufacturing the semiconductor light emitting element shown in FIGS. 1 and 2. It is the cross-sectional schematic diagram which showed an example of the lamp | ramp of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show the characteristic portions for explaining the present invention in an enlarged manner, and the dimensional ratios of the respective constituent elements are not always the same as the actual ones.
"Semiconductor light emitting device"
1 is a plan view showing an example of the semiconductor light emitting device of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA ′ of the semiconductor light emitting device shown in FIG. A semiconductor light emitting device 1 shown in FIGS. 1 and 2 includes an n-type semiconductor layer 12, a light-emitting layer 13, a p-type semiconductor layer 14, and a low refractive index conductive material on one surface 11a (upper surface in FIG. 2) of a substrate 11. The film 39 and the transparent conductive film 15 are laminated in this order.

  A semiconductor light emitting device 1 shown in FIGS. 1 and 2 is a face-up type semiconductor light emitting device 1. A circular positive electrode 17 is formed on the transparent conductive film 15 of the semiconductor light emitting device 1. Further, in the semiconductor light emitting device 1, the light emitting layer 13, the p-type semiconductor layer 14, and the n-type semiconductor layer 12 are partially cut out to expose a part of the n-type semiconductor layer 12, and the n-type semiconductor layer 12 is exposed. A circular negative electrode 18 is formed on the exposed surface 12a.

Further, in the semiconductor light emitting device 1 shown in FIGS. 1 and 2, the side surface 17b and the upper surface peripheral portion 17a of the positive electrode 17, the side surface 15b and one surface 15a of the transparent conductive film 15, the side surface 39b of the low refractive index conductive film 39, The side surface of the light emitting layer 13 and the p-type semiconductor layer 14, a part of the side surface of the n-type semiconductor layer 12, the exposed surface 12a of the n-type semiconductor layer 12, the side surface of the negative electrode 18 and the upper surface peripheral portion are continuously covered. Thus, the protective film 16 is formed.
The protective film 16 is preferably provided in order to suppress the deterioration of the semiconductor light emitting element 1, but the protective film 16 may not be provided.

<Board>
As the substrate 11, sapphire single crystal (Al ₂ O ₃ ; A plane, C plane, M plane, R plane), spinel single crystal (MgAl ₂ O ₄ ), ZnO single crystal, LiAlO ₂ single crystal, LiGaO ₂ single crystal. Known substrate materials such as oxide single crystal such as MgO single crystal, Si single crystal, SiC single crystal, GaAs single crystal, AlN single crystal, GaN single crystal and boride single crystal such as ZrB ₂ are used without any limitation. be able to. Among these substrate materials, it is particularly preferable to use a sapphire single crystal and a SiC single crystal as the substrate 11. The plane orientation of the substrate is not particularly limited. Moreover, a just board | substrate may be sufficient and the board | substrate which provided the off angle may be sufficient.
The substrate 11 may be a substrate that has been processed to form a convex portion described in JP-A-2009-123717 on a main surface that is a surface on which a semiconductor layer on the substrate is grown. The processed substrate for forming such a convex portion is arbitrarily selected.

<Semiconductor layer>
As shown in FIG. 2, a semiconductor layer in which at least an n-type semiconductor layer 12, a light emitting layer 13, and a p-type semiconductor layer 14 are stacked is formed on the substrate 11. The refractive index of the semiconductor layer is equal to or higher than the refractive index of the low refractive index conductive film 39, and is preferably in the range of 1.9 to 2.6. If the refractive index of the semiconductor layer is less than 1.9, it may be less than the refractive index of the low refractive index conductive film 39. In addition, when the refractive index of the semiconductor layer exceeds 2.6, a material used for forming the semiconductor layer is limited, and thus a good semiconductor layer may not be obtained.

In the semiconductor light emitting device 1 of the present embodiment, at least the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 are made of a nitride-based compound semiconductor, and are made of a GaN-based compound semiconductor. preferable. The refractive index of the GaN compound semiconductor is 2.4. As the GaN-based compound semiconductor, for example, the general formula _{Al X Ga Y In Z N 1} -A M A ( and in 0 ≦ X ≦ 1,0 ≦ Y ≦ 1,0 ≦ Z ≦ 1, X + Y + Z = 1. Symbol M Represents a Group V element different from nitrogen (N), and 0 ≦ A <1).

  The GaN-based compound semiconductor may contain other group III elements in addition to Al, Ga, and In. For example, Ge, Si, Mg, Ca, Zn, Be, P, As, and B may be used as necessary. You may contain elements, such as. Furthermore, GaN-based compound semiconductors contain not only intentionally added elements, but also impurities that are inevitably included depending on the film forming conditions and the like, as well as trace impurities contained in the raw materials and reaction tube materials. There is a case.

In the semiconductor light emitting device 1 of the present embodiment, an intermediate layer 31 and a base layer 32 may be formed in order from the substrate 11 side between the substrate 11 and the n-type semiconductor layer 12 (see FIGS. 3 to 7). ).
<Intermediate layer (buffer layer)>
The intermediate layer 31 is preferably made of polycrystalline _{Al X Ga 1-X N (} 0 ≦ x ≦ 1) , more preferably a single crystal _{Al X Ga 1-X N (} 0 ≦ x ≦ 1) For example, the thickness may be 0.01 to 0.5 μm made of polycrystalline Al _X Ga _1-X N (0 ≦ x ≦ 1). The intermediate layer 31 reduces the difference in lattice constant between the substrate 11 and the base layer 32 and facilitates the formation of a c-axis oriented single crystal layer on the (0001) plane (C plane) of the substrate 11. There is. Therefore, when the single crystal underlayer 32 is laminated on the intermediate layer 31, the underlayer 32 with better crystallinity can be formed. In the present invention, the intermediate layer 31 is not an essential configuration.

<Underlayer>
The underlayer 32 is composed of an Al _X Ga _1-X N layer (0 ≦ x ≦ 1, preferably 0 ≦ x ≦ 0.5, more preferably 0 ≦ x ≦ 0.1) on the intermediate layer 31. It is preferable. The film thickness of the underlayer 32 is preferably 0.1 μm or more, more preferably 0.5 μm or more, and most preferably 1 μm or more. By setting the thickness of the underlayer 32 to 1 μm or more, an Al _X Ga _1-X N layer with good crystallinity can be easily obtained. The underlayer 32 is preferably 12 μm or less. If the thickness of the underlayer exceeds 12 μm, the growth time becomes long and the manufacturing cost increases, which is not preferable.
The underlayer 32 is preferably undoped (<1 × 10 ¹⁷ / cm ³ ). When the underlayer 32 is undoped, good crystallinity can be maintained. In addition, when the n-type impurity is doped in the base layer 32, it is preferably in the range of 1 × 10 ¹⁷ to 1 × 10 ¹⁹ / cm ³ . The n-type impurity doped in the underlayer 32 is not particularly limited, and examples thereof include Si, Ge, and Sn, and Si and Ge are preferable.

<N-type semiconductor layer>
The n-type semiconductor layer 12 is preferably composed of an n-type contact layer 33 and an n-type cladding layer 34 (see FIGS. 3 to 7). The n-type contact layer 33 may also serve as the n-type cladding layer 34.

The n-type contact layer 33 is formed from an Al _X Ga _1-X N layer (0 ≦ x ≦ 1, preferably 0 ≦ x ≦ 0.5, more preferably 0 ≦ x ≦ 0.1), similarly to the base layer 32. It is preferable that The n-type contact layer 33 is preferably doped with n-type impurities. The n-type impurity concentration of the n-type contact layer 33 is preferably 1 × 10 ¹⁷ to 1 × 10 ¹⁹ / cm ³ , and more preferably 1 × 10 ¹⁸ to 1 × 10 ¹⁹ / cm ³ . When the concentration of the n-type impurity in the n-type contact layer 33 is 1 × 10 ¹⁷ to 1 × 10 ¹⁹ / cm ^3, it is possible to maintain good ohmic contact with the negative electrode and to suppress the generation of cracks and to have good crystallinity. Can be maintained. Although it does not specifically limit as an n-type impurity of the n-type contact layer 33, For example, Si, Ge, Sn, etc. can be mentioned, Si and Ge are preferable.

  The total film thickness of the n-type contact layer 33 and the base layer 32 is preferably 1 to 20 μm, more preferably 2 to 15 μm, and further preferably 3 to 12 μm. When the total film thickness of the n-type contact layer 33 and the base layer 32 is 1 to 20 μm, the crystallinity of the GaN-based compound semiconductor can be maintained better.

  An n-type cladding layer 34 is preferably provided between the n-type contact layer 33 and the light emitting layer 13. When the n-type cladding layer 34 is provided, even if there is a portion where the flatness is deteriorated on the outermost surface of the n-type contact layer 33, it can be filled, and good flatness can be obtained. The n-type cladding layer 34 can be formed of AlGaN, GaN, GaInN, or the like. In the specification, the composition ratio of each element may be omitted and described as AlGaN or GaInN. The n-type cladding layer 34 may have a superlattice structure in which two or more compositions selected from these compositions are stacked a plurality of times. Further, the band gap of the n-type cladding layer 34 is larger than the band gap of the light emitting layer 13.

The film thickness of the n-type cladding layer 34 is not particularly limited, but is preferably 0.005 to 1 μm, and more preferably 0.005 to 0.5 μm. The n-type doping concentration of the n-type cladding layer 34 is preferably 1 × 10 ¹⁷ to 1 × 10 ²⁰ / cm ³ , and more preferably 1 × 10 ¹⁸ to 1 × 10 ¹⁹ / cm ³ . When the n-type doping concentration of the n-type cladding layer 34 is 1 × 10 ¹⁷ to 1 × 10 ²⁰ / cm ³ , good crystallinity can be maintained and the operating voltage of the semiconductor light emitting element 1 can be reduced.

<Light emitting layer>
Examples of the GaN-based compound semiconductor used for the light emitting layer 13 include Ga _1-s In _s N (0 <s <0.4). The film thickness of the light emitting layer 13 is not particularly limited, but it is preferable to set the film thickness to the extent that a quantum effect can be obtained, that is, the critical film thickness. Specifically, the thickness of the light emitting layer 13 is preferably 1 to 10 nm, and more preferably 2 to 6 nm. The light emission output can be improved by setting the thickness of the light emitting layer 13 to 1 to 10 nm.

The light emitting layer 13 may have a single quantum well (SQW) structure or a multiple quantum well (MQW) structure. As a multiple quantum well (MQW) structure, for example, a well layer made of Ga _1-s In _s N (hereinafter referred to as GaInN well layer) and Al _c Ga _1-c N (0 having a larger band gap energy than this well layer) ≦ c <0.3 and b> c)), and a plurality of such barrier layers (hereinafter referred to as Al _c Ga _1-c N barrier layers) stacked in a staggered manner. The well layer and / or the barrier layer constituting the multiple quantum well (MQW) structure may be doped with impurities. Specifically, a Si-doped GaN barrier layer may be used as a barrier layer constituting a multiple quantum well (MQW) structure.

<P-type semiconductor layer>
The p-type semiconductor layer 14 is preferably composed of a p-clad layer 37 and a p-contact layer 38 (see FIGS. 3 to 7). The p contact layer 38 may also serve as the p clad layer 37.
The p-cladding layer 37 has a composition that is larger than the band gap energy of the light emitting layer 13 and is not particularly limited as long as it can confine carriers in the light emitting layer 13. For example, the p-cladding layer 37 may be made of Al _d Ga _1-d N (0 ≦ d ≦ 0.4, preferably 0.1 ≦ d ≦ 0.3). The film thickness of the p-cladding layer 37 is not particularly limited, but is preferably 1 to 400 nm, and more preferably 5 to 100 nm. The p-clad layer 37 can be formed of AlGaN, GaN, or the like. The p-clad layer 37 may have a superlattice structure in which two or more compositions selected from these compositions are stacked a plurality of times.
The p-type doping concentration of the p-clad layer 37 is preferably 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , and more preferably 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ³ . By setting the p-type doping concentration of the p-cladding layer 37 to 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , a good p-type crystal can be obtained without reducing the crystallinity.

As the p contact layer 38, a GaN-based compound semiconductor containing Al _e Ga _1-e N (0 ≦ e <0.5, preferably 0 ≦ e ≦ 0.2, more preferably 0 ≦ e ≦ 0.1). Is preferably used. By making the Al composition in Al _e Ga _1-e N 0 ≦ e <0.5, it is possible to maintain good crystallinity and to make good ohmic contact with the p ohmic electrode. The concentration of the p-type dopant in the p contact layer 38 is preferably 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , and more preferably 5 × 10 ^{19 to} 5 × 10 ²⁰ / cm ³ . By setting the concentration of the p-type dopant in the p contact layer 38 to 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , it is possible to maintain a good ohmic contact, prevent the generation of cracks, and maintain a good crystallinity. it can. Although it does not specifically limit as a p-type dopant (p-type impurity) of the p contact layer 38, For example, Mg is mentioned. The film thickness of the p contact layer 38 is not particularly limited, but is preferably 0.01 to 0.5 μm, and more preferably 0.05 to 0.2 μm. The light emission output can be improved by setting the film thickness of the p contact layer 38 to 0.01 to 0.5 μm.

<Low refractive index conductive film><Transparent conductive film>
As shown in FIG. 2, a low refractive index conductive film 39 is provided on the p-type semiconductor layer 14 of the semiconductor layer, and a transparent conductive film 15 is provided on the low refractive index conductive film 39. As shown in FIGS. 1 and 2, the low-refractive index conductive film 39 and the transparent conductive film 15 cover almost the entire surface of the p-type semiconductor layer 14 in order to diffuse the current over a wide range on the p-type semiconductor layer 14. It is preferably formed so as to cover, but it may be formed in a lattice shape or a tree shape with a gap.

  Note that the transparent conductive film 15 is preferably provided over the entire area on the p-type semiconductor layer 14 in order to efficiently diffuse the current. However, as shown in FIG. It may be provided only in the part. In addition, the low refractive index conductive film 39 is provided in the entire region on the p-type semiconductor layer 14 in order to more effectively prevent light having low straightness from entering the transparent conductive film 13. Although it is preferable, as shown in FIG. 2, it may be provided only in a part on the p-type semiconductor layer 14.

  The film thickness of the low refractive index conductive film 39 is preferably in the range of 80 to 300 nm. When the film thickness of the low refractive index conductive film 39 is less than the above range, there may be a case where the function of efficiently reflecting light with low straightness by the low refractive index conductive film 39 cannot be obtained sufficiently. Further, when the film thickness of the low refractive index conductive film 39 exceeds the above range, even if the transparent conductive film 15 is provided on the low refractive index conductive film 39, a sufficient current can be applied to a wide range on the p-type semiconductor layer 14. It may not be possible to diffuse.

As shown in FIG. 2, the low refractive index conductive film 39 is provided between the p-type semiconductor layer 14 of the semiconductor layer and the transparent conductive film 15. The refractive index of the low refractive index conductive film 39 is less than the refractive index of the semiconductor layer and the transparent conductive film 15, and is preferably less than 1.9, more preferably 1.4 or more.
When the refractive index of the low refractive index conductive film 39 is equal to or higher than the refractive index of the semiconductor layer and the transparent conductive film 15, the low refractive index conductive film 39 reflects light having low straightness emitted from the semiconductor layer to cause the semiconductor layer The function to return to is not fully obtained. When the refractive index of the low refractive index conductive film 39 is less than 1.9, the difference between the refractive index of the low refractive index conductive film 39 and the refractive index of the semiconductor layer and the transparent conductive film 15 can be made sufficiently large. As a result, it is possible to efficiently reflect the light having low rectilinearity emitted from the semiconductor layer, and it is more effective that the light having low rectilinearity emitted from the semiconductor layer is incident on the transparent conductive film 15 and undergoes multiple reflection. Can be prevented.
However, if the refractive index of the low-refractive-index conductive film 39 is less than 1.4, the difference between the refractive index of the semiconductor layer and the transparent conductive film 15 becomes too large, and the light emitted from the semiconductor layer is more than necessary. In some cases, the light is reflected, and even light with high straightness is reflected.

The specific resistance of the low refractive index conductive film 39 is preferably in the range of 10 ⁻⁵ to 10 ⁴ Ω · cm. When the specific resistance of the low refractive index conductive film 39 is within the above range, current can be uniformly diffused on the p-type semiconductor layer 14. Further, the specific resistance of the low refractive index conductive film 39 is preferably as low as possible. However, when the specific resistance is less than the above range, the choice of materials used for the low refractive index conductive film 39 becomes narrow.

The low refractive index conductive film 39 includes gallium zinc oxide (GZO) and calcium fluoride (CaF ₂ ) in order to have a refractive index of less than 2 and a specific resistance within the above range. Is preferred.
The refractive index of gallium zinc oxide (GZO) is 2.0, and the refractive index of calcium fluoride (CaF ₂ ) is 1.3. In order to obtain a low refractive index while sufficiently ensuring the conductivity of the low refractive index conductive film 39 by mixing gallium zinc oxide having high conductivity and insulating calcium fluoride having a low refractive index, As the low refractive index conductive film 39, one containing 10% by mass to 75% by mass of gallium zinc oxide is preferably used, and one containing 15% by mass to 60% by mass is more preferably used. Among them, for example, it is preferable to use a low refractive index conductive film 39 containing about 25% by mass of gallium zinc oxide and about 75% by mass of calcium fluoride. The low refractive index conductive film 39 containing 25% by mass of gallium zinc oxide and 75% by mass of calcium fluoride has a refractive index of 1.55 and a specific resistance of 1 × 10 ⁻² Ω · cm.

  The transparent conductive film 15 is preferably excellent in light transmittance in order to efficiently extract light from the light emitting layer 13 to the outside of the semiconductor light emitting element 1. Furthermore, the transparent conductive film 15 preferably has excellent conductivity in order to diffuse current uniformly over the entire surface of the p-type semiconductor layer 14.

  The refractive index of the transparent conductive film 15 is not less than the refractive index of the low refractive index conductive film 39 and is preferably in the range of 1.9 to 2.2. If the refractive index of the transparent conductive film 15 is less than 1.9, it may be less than the refractive index of the low refractive index conductive film 39. Moreover, when the refractive index of the transparent conductive film 15 exceeds 2.2, the choice of the material used for forming the transparent conductive film 15 becomes narrow, which is not preferable.

The specific resistance of the transparent conductive film 15 is lower than the specific resistance of the low refractive index conductive film 39, and specifically, it is preferably in the range of 10 ⁻⁵ to 10 ⁻¹ Ω · cm. When the specific resistance of the transparent conductive film 15 is within the above range, current can be diffused uniformly and efficiently on the p-type semiconductor layer 14 together with the low refractive index conductive film 39. Moreover, although the specific resistance of the transparent conductive film 15 is so preferable that it is low, when it is less than the said range, the choice of the material used for the transparent conductive film 15 becomes narrow.

Specifically, the material of the transparent conductive film 15 includes a conductive oxide containing any one of In, Zn, Al, Ga, Ti, Bi, Mg, W, and Ce, zinc sulfide, or chromium sulfide. Examples thereof include translucent conductive materials selected from the group consisting of any one of them. For example, as the conductive oxide, ITO (indium tin oxide (In ₂ O ₃ —SnO ₂ )), IZO (indium zinc oxide (In ₂ O ₃ —ZnO)), AZO (zinc aluminum oxide (ZnO—Al ₂ O ₃ )), GZO (gallium zinc oxide (ZnO—Ga ₂ O ₃ )), fluorine-doped tin oxide, titanium oxide and the like. Among these, it is preferable to use ITO or IZO which is excellent in light transmittance and conductivity and sufficiently obtains a difference in refractive index from the low refractive index conductive film 39. The refractive indexes of ITO and IZO are in the range of 2 to 2.2.

  The film thickness of the transparent conductive film 15 is preferably 35 nm to 2000 nm, more preferably 50 nm to 1000 nm, and most preferably 100 nm to 500 nm. When the film thickness of the transparent conductive film 15 is less than 35 nm, the current diffusion efficiency becomes insufficient and sufficient conductivity may not be obtained. When the film thickness of the transparent conductive film 15 exceeds 2000 nm, the transmittance is lowered, the light extraction efficiency is lowered, and the output of the semiconductor light emitting element 1 may be insufficient. When the film thickness of the transparent conductive film 15 is in the range of 35 to 2000 nm, the semiconductor light-emitting device 1 having a low driving voltage and excellent light extraction efficiency is obtained because good conductivity is obtained.

<Positive electrode>
The positive electrode 17 is formed on the one surface 15 a of the transparent conductive film 15. The positive electrode 17 is used as a bonding pad. As the positive electrode 17, various structures using known materials such as Au, Al, Ni, and Cu can be used without any limitation. The thickness of the positive electrode 17 is preferably 100 nm to 10 μm, and more preferably 300 nm to 3 μm. By setting the thickness of the positive electrode 17 to 300 nm or more, bondability as a bonding pad can be improved. Moreover, manufacturing cost can be reduced by making the thickness of the positive electrode 17 into 3 micrometers or less.

<Negative electrode>
The negative electrode 18 is in contact with the n-type semiconductor layer 12 by being formed on the exposed surface 12 a of the n-type semiconductor layer 12. The negative electrode 18 is used as a bonding pad. As the negative electrode 18, various known compositions and structures can be used without any limitation.

<Protective film>
The protective film 16 is provided on the transparent conductive film 15, prevents moisture and the like from entering the semiconductor light emitting element 1, and suppresses deterioration of the semiconductor light emitting element 1.
As the protective film 16, an insulating transparent film is used. The insulating transparent film used for the protective film 16 is preferably a material having a refractive index of less than 2. Specifically, the protective film 16 is preferably made of a material containing SiO ₂ (refractive index 1.45).

  Moreover, it is preferable that the protective film 16 has irregularities formed on at least a part of its surface. By setting it as such a protective film 16, the light extraction efficiency of the semiconductor light-emitting device 1 can be further improved.

"Manufacturing method of semiconductor light emitting device"
Next, as a method for manufacturing the semiconductor light emitting device of the present invention, the method for manufacturing the semiconductor light emitting device 1 shown in FIGS. 1 and 2 will be described as an example.
3 to 7 are manufacturing process diagrams for explaining an example of a method for manufacturing the semiconductor light emitting device shown in FIGS. To manufacture the semiconductor light emitting device 1 shown in FIGS. 1 and 2, first, a GaN-based compound semiconductor is formed on one surface 11a of the substrate 11, and at least n is formed on the one surface 11a of the substrate 11 as shown in FIG. A semiconductor layer in which the type semiconductor layer 12, the light emitting layer 13, and the p type semiconductor layer 14 are laminated in this order is provided. Further, the intermediate layer 31 and the base layer 32 may be sequentially formed between the substrate 11 and the n-type semiconductor layer 12 from the substrate 11 side.

  The method for forming the GaN-based compound semiconductor that constitutes the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 is not particularly limited, and MOCVD (metal organic chemical vapor deposition), HVPE (hydride vapor phase epitaxy). Method), MBE (molecular beam epitaxy method) and the like can be applied. As a method for forming a GaN-based compound semiconductor, it is preferable to use the MOCVD method from the viewpoints of film thickness controllability and mass productivity.

When MOCVD is used as a method for forming a GaN-based compound semiconductor, hydrogen (H ₂ ), nitrogen (N ₂ ), or the like can be used as a carrier gas, and trimethylgallium (TMG) or triethyl as a Ga source that is a group III material. Gallium (TEG), trimethylaluminum (TMA) or triethylaluminum (TEA) as an Al source, trimethylindium (TMI) or triethylindium (TEI) as an In source, ammonia (NH ₃ ) as an N source as a group V source, hydrazine (N ₂ H ₄ ) or the like can be used.

In addition, when forming a GaN-based compound semiconductor using the MOCVD method, monosilane (SiH ₄ ) or disilane (Si ₂ H ₆ ), which is an Si raw material, germanium gas (GeH ₄ ), which is a Ge raw material, Organic germanium compounds such as tetramethyl germanium ((CH ₃ ) ₄ Ge) and tetraethyl germanium ((C ₂ H ₅ ) ₄ Ge) can be used.
When MOCVD is used, biscyclopentadienyl magnesium (Cp ₂ Mg), bisethylcyclopentadienyl magnesium (EtCp ₂ Mg), etc., which are Mg raw materials, can be used as the p-type dopant.

  When MBE is used as a method for forming a GaN-based compound semiconductor, elemental germanium can be used as an n-type dopant.

Here, the case where the n-type semiconductor layer 12, the light-emitting layer 13, and the p-type semiconductor layer 14 are formed by growing a GaN-based compound semiconductor using the MOCVD method will be described in detail.
First, as shown in FIG. 3, an intermediate layer (buffer layer) 31 and a base layer 32 are sequentially formed on one surface 11 a of the substrate 11. Thereafter, the n-type contact layer 33 and the n-type cladding layer 34 are stacked in this order on the base layer 32 to form the n-type semiconductor layer 12.

When forming the n-type semiconductor layer 12 using the MOCVD method, it is preferable that the pressure in the growth furnace is in the range of 15 to 40 kPa.
In addition, it is preferable to set it as 800-1200 degreeC, and, as for the growth temperature at the time of growing the base layer 32, it is more preferable to set it as 1000-1200 degreeC. By growing the underlayer 32 within the above temperature range using the MOCVD method, the underlayer 32 with good crystallinity can be obtained.
The growth temperature of the n-type contact layer 33 is preferably 800 to 1200 ° C., more preferably 1000 to 1200 ° C., similarly to the growth temperature of the base layer 32.
The growth temperature of the n-type cladding layer 34 is preferably 500 to 1000 ° C., and more preferably 6000 to 900 ° C.

Next, as shown in FIG. 3, an Al _c Ga _1-c N barrier layer and a GaInN well layer are stacked a plurality of times on the n-type semiconductor layer 12, and finally the Al _c Ga _1-c N barrier layer. The layers are stacked to form the light emitting layer 13 having a multiple quantum well structure.
The growth temperature of the Al _c Ga _1-c N barrier layer is preferably 700 ° C. or higher, and more preferably 800 to 1100 ° C. By setting the growth temperature of the Al _c Ga _1-c N barrier layer to 800 to 1100 ° C., an Al _c Ga _1-c N barrier layer with good crystallinity can be obtained.
The growth temperature of the GaInN well layer is preferably 600 to 900 ° C, more preferably 700 to 900 ° C. By setting the growth temperature of the GaInN well layer to 600 to 900 ° C., a GaInN well layer with good crystallinity can be obtained.
In order to improve the crystallinity of the light emitting layer 13 having the MQW structure composed of the Al _c Ga _1-c N barrier layer and the GaInN well layer, the Al _c Ga _1-c N barrier layer is formed at the time of forming the Al _c Ga _1-c N barrier layer. It is preferable to change the growth temperature and the growth temperature at the time of forming the GaInN well layer.

  Next, as shown in FIG. 3, a p-type semiconductor layer 14 is formed by stacking a p-type cladding layer 37 and a p-type contact layer 38 on the light emitting layer 13. Thereby, the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 are formed on the substrate 11.

Next, as shown in FIG. 4, a low refractive index conductive film 39 having a refractive index lower than the refractive index of the semiconductor layer is formed on the p-type semiconductor layer 14 by sputtering.
In the present embodiment, two targets, a target made of gallium zinc oxide (GZO) and a target made of calcium fluoride (CaF ₂ ), are simultaneously used as targets for forming the low refractive index conductive film 39. It is preferable to form a low refractive index conductive film 39 made of a mixed film of gallium zinc (GZO) and calcium fluoride (CaF ₂ ).

  Next, as shown in FIG. 5, the transparent conductive film 15 having a refractive index equal to or higher than the refractive index of the low refractive index conductive film 39 is formed on the entire surface of the low refractive index conductive film 39 using, for example, ITO or IZO. To do.

Next, the translucent electrode 15 and the low refractive index conductive film 39 other than the predetermined region are removed by, for example, a generally known photolithography technique.
Subsequently, for example, patterning is performed by a photolithography technique, and as shown in FIG. 6, a part of the semiconductor layer (p-type semiconductor layer 14, light-emitting layer 13, n-type semiconductor layer 12) in a predetermined region is etched. The exposed surface 12a made of the n-type contact layer 33 is exposed.

Next, as shown in FIG. 7, the negative electrode 18 is formed on the exposed surface 12 a made of the n-type contact layer 33. The negative electrode (n-type electrode) 18 is preferably formed of a Ti / Au two-layer structure from the exposed surface 12a side.
Thereafter, as shown in FIG. 7, the positive electrode 17 is formed on the one surface 15 a of the translucent electrode 15. As the positive electrode (p-type electrode) 17, for example, a three-layer structure including a metal reflective layer made of Al, a barrier layer made of Ti, and a bonding layer made of Au is used from the translucent electrode 15 side. It is preferable to form using a technique.
Further, the positive electrode 17 and the negative electrode 18 may have the same structure or different structures. When the positive electrode 17 and the negative electrode 18 have the same structure, for example, a first layer made of Au, a second layer made of Ti, a third layer made of Al, a fourth layer made of Ti, and made of Au It is good also as a thing of the 5 layer structure formed by laminating | stacking the 5th layer which becomes.

Next, the protective film 16 is formed. The protective film 16 is formed by using a known photolithography technique and lift-off technique by using a film forming method capable of forming a dense film such as a sputtering method or a CVD method over the entire region except for the central portion of the positive electrode 17 and the negative electrode 18. It is preferable. In particular, as a method for forming the protective film 16, it is preferable to use a CVD method capable of obtaining a dense film.
In addition, when forming what has unevenness | corrugation in at least one part of the surface as the protective film 16, the film | membrane used as the protective film 16 is formed, for example using a sputtering method, CVD method, etc., and predetermined on it It can be formed by a method of forming a resist pattern having the following shape and performing dry etching.

  Thereafter, the substrate on which the protective layer 16 is formed is divided (chiped), whereby the semiconductor light emitting device 1 shown in FIGS. 1 and 2 is obtained.

  Since the semiconductor light emitting element 1 of the present embodiment includes the low refractive index conductive film 39 having a refractive index lower than the refractive index of the semiconductor layer and the transparent conductive film 15, the light is emitted from the light emitting layer 13 constituting the semiconductor layer. Of the emitted light, for example, light having a low linearity such as light exceeding ± 30 ° with respect to the thickness direction of the semiconductor light emitting element 1 (light having a large incident angle with respect to the interface) is incident on the transparent conductive film 15. Instead, it is reflected by the low refractive index conductive film 39 and returned to the semiconductor layer. Therefore, in the semiconductor light emitting device 1 according to the present embodiment, light with low rectilinearity emitted from the semiconductor layer is prevented from being incident on the transparent conductive film 15 and being subjected to multiple reflection, and attenuation of light within the transparent conductive film 15. Absorption by is prevented.

  Further, in the semiconductor light emitting device 1 of the present embodiment, the reflected light reflected by the low refractive index conductive film 39 and returned to the semiconductor layer is multiple-reflected within the semiconductor layer, for example, the thickness of the semiconductor light emitting device 1. Light having high straightness such as light of ± 30 ° or less with respect to the direction (light having a small incident angle with respect to the interface) is transmitted through the low refractive index conductive film 39 and the transparent conductive film 15 and emitted. Is done. As a result, in the semiconductor light emitting device 1 of the present embodiment, excellent light extraction efficiency can be obtained.

  Further, in the semiconductor light emitting device 1 of the present embodiment, light with low straightness emitted from the semiconductor layer is reflected by the low refractive index conductive film 39 without being incident on the transparent conductive film 15 and returned to the semiconductor layer. Therefore, absorption due to light attenuation in the transparent conductive film 15 can be prevented regardless of the refractive index of the transparent conductive film 15. Therefore, an optimal material can be used for the transparent conductive film 15 regardless of the refractive index. For example, as the material of the transparent conductive film 15, ITO or IZO having a refractive index in the range of 1.9 to 2.2 can be used. Materials can be used.

  In the semiconductor light emitting device 1 of the present embodiment, when the refractive index of the semiconductor layer is in the range of 1.9 to 2.6, a sufficient difference in refractive index between the low refractive index conductive film 39 and the semiconductor layer is ensured. can do. As a result, the low rectilinear light emitted from the semiconductor layer can be efficiently reflected by the low refractive index conductive film 39, and the low rectilinear light emitted from the semiconductor layer is incident on the transparent conductive film 15. Multiple reflections can be prevented more effectively.

Further, in the semiconductor light emitting device 1 of the present embodiment, light with low straightness emitted from the semiconductor layer is reflected by the low refractive index conductive film 39 without being incident on the transparent conductive film 15 and returned to the semiconductor layer. Therefore, absorption due to attenuation of light in the protective film 16 is prevented regardless of the refractive index of the protective film 16 to which light emitted from the semiconductor layer through the low refractive index conductive film 39 and the transparent conductive film 15 enters. it can. Therefore, an optimal material can be used for the protective film 16 regardless of the refractive index. For example, a material such as SiO ₂ (refractive index 1.45) having a refractive index of less than 2 is used as the material of the protective film 16. be able to.

  Further, in the semiconductor light emitting device 1 of the present embodiment, when the low refractive index conductive film 39 includes gallium zinc oxide and calcium fluoride, the excellent low refractive index conductive film 39 having a low refractive index and specific resistance is provided. It will have.

  In this embodiment, when at least the n-type semiconductor layer 12, the light-emitting layer 13, and the p-type semiconductor layer 14 constituting the semiconductor light-emitting element 1 are made of a GaN-based compound semiconductor, a wavelength range of 380 to 480 nm. Therefore, it is possible to obtain a high optical conversion efficiency of current.

  In addition, the method for manufacturing the semiconductor light emitting device 1 of the present embodiment includes a step of providing a semiconductor layer having the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 on the substrate 11, and A step of providing a low refractive index conductive film 39 having a refractive index lower than that of the semiconductor layer; and a transparent conductive film 15 having a refractive index equal to or higher than the refractive index of the low refractive index conductive film 39 on the low refractive index conductive film 39. Therefore, the semiconductor light emitting device 1 of the present embodiment having excellent light extraction efficiency can be obtained.

"lamp"
Next, as a lamp of the present invention, a lamp provided with the semiconductor light emitting element 1 shown in FIGS. 1 and 2 will be described as an example.
FIG. 8 is a schematic cross-sectional view showing an example of the lamp of the present invention. In the lamp 5 (LED lamp) shown in FIG. 8, the semiconductor light emitting device 1 shown in FIGS. 1 and 2 is bonded to the frames 51 and 52 with wires 53 and 54, and sealed in a shell shape with a mold 55 made of a transparent resin. It has been stopped.

  The lamp 5 of the present embodiment can be manufactured by a conventionally known method using the semiconductor light emitting device 1 shown in FIGS. 1 and 2, for example, by the method shown below. First, the semiconductor light emitting element 1 is bonded to one of the two frames 51 and 52 (the frame 51 in FIG. 8) using a resin or the like, and the positive electrode 17 and the negative electrode 18 of the semiconductor light emitting element 1 are made of gold or the like. The semiconductor light-emitting element 1 is mounted by bonding to the frames 51 and 52 with wires 53 and 54 made of material, respectively. Thereafter, the periphery of the semiconductor light emitting element 1 is sealed with a mold 55 to obtain the lamp 5 or the like.

The lamp of the present invention is not limited to the lamp 5 shown in FIG. For example, the lamp of the present invention may be a lamp that emits white light by mixing the light emission color of the semiconductor light emitting element 1 and the light emission color of the phosphor.
The lamp of the present invention may be a bullet type for general use, a side view type for portable backlight use, a top view type used for a display, or the like.

  Since the lamp 5 of this embodiment includes the semiconductor light emitting element 1 shown in FIGS. 1 and 2, the lamp 5 is excellent with a semiconductor light emitting element having excellent light extraction efficiency.

  In addition, electronic devices such as a backlight, a mobile phone, a display, various panels, a computer, a game machine, and a lighting incorporating the lamp 5 of this embodiment, and a mechanical device such as an automobile incorporating such an electronic device are excellent. Thus, the semiconductor light emitting device 1 having the light extraction efficiency is provided.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
Example 1
The semiconductor light emitting device 1 shown in FIGS. 1 and 2 was manufactured by the following method.
First, using MOCVD, as shown in FIG. 3, a buffer layer 31 made of AlN, an underlayer 32 made of undoped GaN, and an n-type contact layer made of Si-doped n-type GaN are formed on one surface 11a of the substrate 11. 33 and an n-type cladding layer 34 made of In _0.03 Ga _0.97 N were stacked in this order to form the n-type semiconductor layer 12.

Next, on the n-type semiconductor layer 12, an Al _c Ga _1-c N barrier layer and a GaInN well layer are stacked six times, and finally, an Al _c Ga _1-c N barrier layer is stacked to form a multiple quantum layer. A light emitting layer 13 having a well structure was formed. Next, a p-type semiconductor layer 14 was formed by laminating a p-type cladding layer 37 made of Mg-doped AlGaN and a p-type contact layer 38 made of Mg-doped p-type GaN on the light emitting layer 13. Thus, a semiconductor layer (low refraction 2.4) composed of the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 was formed on the substrate 11.

Next, the p-type semiconductor layer 14 is formed of a mixed film of gallium zinc oxide (GZO) and calcium fluoride (CaF ₂ ) by sputtering (gallium zinc oxide 25 mass%, calcium fluoride 75 mass%), A low refractive index conductive film 39 (low refraction 1.55, specific resistance 1 × 10 ⁻² Ω · cm) having a thickness of 100 nm was formed. In the sputtering method for forming the low refractive index conductive film 39, two targets, a target made of gallium zinc oxide (GZO) and a target made of calcium fluoride (CaF ₂ ), were used simultaneously. Thereby, as shown in FIG. 4, the layers up to the low refractive index conductive film 39 were formed.

Next, a transparent conductive film 15 made of ITO (refractive index 2.0, specific resistance 1 × 10 ⁻⁴ Ω · cm) having a film thickness of 250 nm is formed on the entire surface of the low refractive index conductive film 39, and FIG. As shown, each layer up to the transparent conductive film 15 was formed.

Next, the translucent electrode 15 and the low refractive index conductive film 39 other than the predetermined region were removed by a generally known photolithography technique.
Subsequently, patterning is performed by a photolithography technique, and as shown in FIG. 6, a part of the semiconductor layer (p-type semiconductor layer 14, light-emitting layer 13, n-type semiconductor layer 12) in a predetermined region is etched to form n. The exposed surface 12a made of the mold contact layer 33 was exposed.

Next, as shown in FIG. 7, the negative electrode 18 was formed on the exposed surface 12 a made of the n-type contact layer 33. Thereafter, as shown in FIG. 7, the positive electrode 17 was formed on the one surface 15 a of the translucent electrode 15.
The positive electrode 17 and the negative electrode 18 include a first layer made of Au, a second layer made of Ti, a third layer made of Al, a fourth layer made of Ti, and a fifth layer made of Au. A five-layer structure was formed by laminating in order.

Next, a protective film 16 (low refraction 1.45) made of SiO ₂ was formed over the entire region excluding the central portions of the positive electrode 17 and the negative electrode 18 on the substrate 11 using a CVD method.
Then, the semiconductor light emitting element 1 of Example 1 shown in FIG. 1 and FIG. 2 was obtained by dividing | segmenting (chip-izing) the board | substrate with which the protective layer 16 was formed.

(Example 2)
A semiconductor light emitting device 1 of Example 2 was obtained in the same manner as Example 1 except that the film thickness of the low refractive index conductive film 39 was 200 nm.
(Example 3)
A semiconductor light emitting device 1 of Example 3 was obtained in the same manner as in Example 1 except that the film thickness of the low refractive index conductive film 39 was 300 nm.

(Comparative example)
A comparative semiconductor light emitting device was obtained in the same manner as in Example 1 except that the low refractive index conductive film 39 was not provided.

The semiconductor light emitting devices of Examples 1 to 3 and Comparative Example thus obtained were mounted in a TO-18 can package, and the light emission output (Po) at an applied current of 20 mA was measured by a tester.
For the semiconductor light emitting devices of Examples 1 to 3 and Comparative Example, the forward voltage (VF) at an applied current of 20 mA was measured by energization with a probe needle.
Moreover, the light emission wavelength in the applied current 20mA of the semiconductor light emitting element of Examples 1 to 3 and the comparative example was examined.
For Examples 1 to 3, the increase rate of the light emission output relative to the comparative example was calculated.
The results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 3, it was confirmed that the light emission output was increased by providing the low refractive index conductive film 39 as compared with the comparative example.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor light-emitting device, 5 ... Lamp, 11 ... Board | substrate, 11a ... One side, 12 ... N-type semiconductor layer, 13 ... Light emitting layer, 14 ... P-type semiconductor layer, 15 ... Transparent electrically conductive film, 15b ... Side surface, 16 ... Protection 17 ... Positive electrode, 17a ... Periphery of upper surface, 17b ... Side face, 18 ... Negative electrode, 31 ... Buffer layer, 32 ... Underlayer, 33 ... n-type contact layer, 34 ... n-type cladding layer, 37 ... p-type cladding layer , 38 ... p-type contact layer, 39 ... low refractive index conductive film, 51, 52 ... frame, 53, 54 ... wire, 55 ... mold.

Claims (14)

On the substrate, a semiconductor layer having an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer, a low refractive index conductive film, and a transparent conductive film are provided in this order.
Wherein the refractive index of the low refractive index conductive layer, the semiconductor layer and der than the refractive index of the transparent conductive film is, and the refractive index of the low refractive index conductive film, and wherein der Rukoto less than 1.9 A semiconductor light emitting device. On the substrate, a semiconductor layer having an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer, a low refractive index conductive film, and a transparent conductive film are provided in this order.
The refractive index of the low refractive index conductive film is less than the refractive index of the semiconductor layer and the transparent conductive film.
Ri, and the refractive index of the transparent conductive film, a semiconductor light emitting device characterized scope der Rukoto of 1.9 to 2.2. On the substrate, a semiconductor layer having an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer, a low refractive index conductive film, and a transparent conductive film are provided in this order.
The refractive index of the low refractive index conductive film, wherein the semiconductor layer and the Ri der less than the refractive index of the transparent conductive film, and the low-refractive index conductive film, Ru der those containing a gallium oxide zinc calcium fluoride A semiconductor light emitting element characterized by the above.   The refractive index of the said semiconductor layer is the range of 1.9-2.6, The semiconductor light-emitting device in any one of Claims 1-3 characterized by the above-mentioned.   5. The semiconductor light emitting device according to claim 1, wherein a protective film is provided on the transparent conductive film, and the refractive index of the protective film is less than 2. 6.   The semiconductor light emitting element according to claim 1, wherein the low refractive index conductive film contains gallium zinc oxide and calcium fluoride. The specific resistance of the low refractive index conductive film is in the range of 10 ⁻⁵ to 10 ⁴ Ω · cm, and the semiconductor light emitting device according to claim 1.   8. The semiconductor light emitting element according to claim 1, wherein a film thickness of the low refractive index conductive film is in a range of 80 to 300 nm. On a substrate, comprising: providing a semiconductor layer having an n-type semiconductor layer and the light-emitting layer and a p-type semiconductor layer, on the semiconductor layer state, and are less than the refractive index of the refractive index of the semiconductor layer, and 1.9 a step of providing a less than der Ru low refractive index conductive film,
And a step of providing a transparent conductive film having a refractive index equal to or higher than the refractive index of the low refractive index conductive film on the low refractive index conductive film. Providing a semiconductor layer having an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer on a substrate; and a low-refractive-index conductive film having a refractive index lower than the refractive index of the semiconductor layer on the semiconductor layer. Providing, and
Providing a transparent conductive film having a refractive index equal to or higher than the refractive index of the low refractive index conductive film and having a refractive index in the range of 1.9 to 2.2 on the low refractive index conductive film. Manufacturing method of light emitting element. On a substrate, comprising: providing a semiconductor layer having an n-type semiconductor layer and the light-emitting layer and a p-type semiconductor layer, on the semiconductor layer state, and are less than the refractive index of the refractive index of the semiconductor layer, and gallium oxide, zinc a step of providing a der Ru low refractive index conductive film which comprises a calcium fluoride and,
And a step of providing a transparent conductive film having a refractive index equal to or higher than the refractive index of the low refractive index conductive film on the low refractive index conductive film.   A lamp comprising the semiconductor light-emitting device according to claim 1. Electronic apparatus, characterized in that the lamp is incorporated according to claim 1 2. Mechanical apparatus characterized by the electronic device is incorporated according to claim 1 3.

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