JP2012104730A - Semiconductor light-emitting element - Google Patents

Abstract

A semiconductor light emitting device having high output, high efficiency, and low operating voltage is provided.
A semiconductor light emitting device includes a semiconductor layer including at least a support substrate and a light emitting layer, a metal reflection layer, a dielectric layer, an interface electrode, an insulating protective film, a transparent layer. The conductive film 21, the metal distribution electrode 12, the first electrode 13, and the second electrode 17 are included. In the region immediately above in the depth direction of the interface electrode 8, the semiconductor layer 14 is removed by etching, leaving a semiconductor layer on the second main surface of the semiconductor layer 14 in contact with the interface electrode 8, and the light emitting layer 5 on the interface electrode 8. Is not formed.
[Selection] Figure 15

Description

  The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device that can be suitably used for a light emitting device having a substrate-replaceable structure.

  Light-emitting diodes (hereinafter referred to as “LEDs”), which are semiconductor light-emitting elements, are capable of growing GaN-based and AlGaInP-based high-quality crystals by the MOVPE method, so that blue, green, orange, yellow, red High brightness LED can be manufactured. And with the increase in the brightness of LEDs, their applications have spread to automobile brake lamps, liquid crystal display backlights, and the like, and the demand is increasing year by year.

  Since high-quality crystals can be grown by the MOVPE method, the internal efficiency of LEDs is approaching the theoretical limit value. However, the light extraction efficiency from the LED is still low, and it is important to improve the light extraction efficiency. This type of high-intensity red LED is formed of, for example, an AlGalnP-based material, and includes an n-type AlGalnP layer and a p-type AlGalnP layer made of an AlGalnP-based material having a lattice-matched composition on a conductive GaAs substrate. It has a double hetero structure having a light emitting layer (active layer) made of AlGalnP or GalnP sandwiched. However, since the band gap of the GaAs substrate is narrower than the band gap of the light emitting layer, most of the light from the light emitting layer is absorbed by the GaAs substrate, causing a problem that the light extraction efficiency is remarkably lowered.

  There is a method in which light absorption in the GaAs substrate is reduced and light extraction efficiency is improved by forming a multilayer reflective film structure composed of semiconductor layers having different refractive indexes between the light emitting layer and the GaAs substrate. However, this method can only reflect light having a limited incident angle to the multilayer reflective film structure.

  Therefore, a method has been proposed in which a double heterostructure made of an AlGalnP-based material is attached to a Si support substrate having a higher thermal conductivity than a GaAs substrate through a highly reflective metal film, and then the growth GaAs substrate is removed. (See Patent Document 1). According to this conventional method, since the metal film is used as the reflection film, high reflection is possible without selecting the incident angle of light to the metal film, and high brightness of the LED can be realized.

  On the other hand, a conventional LED chip employs an LED element structure in which a metal reflective layer is sandwiched between an active layer and a Si support substrate. However, when manufacturing an LED chip, the raw material cost in the semiconductor epitaxy growth using the organic metal raw material containing a rare metal is large. Therefore, it is necessary to thin the semiconductor crystal layer. However, in the LED chip, it is difficult to uniformly inject electricity into the active layer in the chip due to the current dispersion effect by only the thin semiconductor layer.

  Therefore, a surface electrode made of metal is stretched over the entire chip as in the LED chip shown in FIG. 19, and the current flows more uniformly in the chip surface, which is more reliable and has a high maximum applied current value. The chip is realized. By causing the current to flow uniformly in the chip surface, it is possible to reduce the forward voltage during driving and effectively increase the efficiency.

  However, the surface electrode that spreads the current in the chip surface acts greatly as an absorption factor when taking out the light emitted from the active layer to the outside of the chip (it becomes a shadow), and the light output is reduced. There was a problem.

  To solve such a problem, a method has been proposed in which a current is spread over the entire chip using a transparent conductive film instead of a metal electrode (see Patent Document 2 and Patent Document 3).

  However, in the so-called substrate-replaceable LED chip having a metal reflective layer between the active layer and the Si support substrate, as shown in FIG. 20, the first conductivity type in the epitaxy growth is the final after the substrate is replaced. It becomes the light extraction surface side of the LED chip. In compound semiconductors, it is generally known that p-type dopants (Zn, Mg, etc.) are likely to diffuse with respect to n-type dopants. Therefore, at the time of epitaxy growth, it is desirable to first grow an n-type layer in which dopant is difficult to diffuse, and then epitaxially grow a p-type layer in which dopant is easy to diffuse. Therefore, the bonded type LED chip employs an n-type layer on the light extraction surface side. However, the n-type layer generally has a limited doping concentration, and it is difficult to make an ohmic junction or a tunnel junction electrically with the transparent conductive film.

  On the other hand, since it is possible to increase the doping concentration in the p-type layer, for example, an electrically ohmic junction such as a transparent conductive film typified by ITO and a Zn-doped GaAs or AlGaAs layer is possible.

  On the other hand, a method for obtaining ohmic contact between a transparent conductive film and a semiconductor layer using a metal electrode has been proposed (see Patent Document 4).

  In the method described in Patent Document 4, a relatively thin transparent metal electrode having an ohmic contact relationship with the transparent conductive film is uniformly formed in the element surface. It flows directly under the electrode. Therefore, even if the metal electrode is made thin and transparent, most of the emitted light passes through the metal electrode and is emitted outside the LED chip. It was a structure that could not be expected to increase.

JP 2005-175462 A JP 2002-329889 A Japanese Patent No. 4255710 JP 2006-1000056 A

  An object of the present invention is to provide a semiconductor light emitting device having high output, high efficiency and low operating voltage.

[1] The present invention is formed on a support substrate, a semiconductor layer including a light emitting layer, a metal reflective layer provided between the support substrate and the light emitting layer, and a first main surface of the semiconductor layer. An insulating protective film, a transparent conductive film formed on the first main surface of the insulating protective film, and the insulating protective film are provided between the semiconductor layer and the transparent conductive film. A distribution electrode; and an interface electrode that electrically connects the metal reflection layer and the second main surface of the semiconductor layer, and the interface electrode is provided in a region immediately below in the depth direction of the distribution electrode. In the semiconductor light emitting device, the light emitting layer of the semiconductor layer is not provided in a region immediately above the interface electrode in the depth direction.

[2] In the invention described in [1] above, only the region where the distribution electrode is formed on the first main surface of the semiconductor layer is removed by etching in the insulating protective film, It is formed so as to cover the exposed side surface other than the first main surface, and the transparent conductive film is in contact with the distribution electrode, the first main surface of the semiconductor layer, or both. .

[3] In the invention described in [1] or [2] above, a surface electrode is formed on the transparent conductive film, and the distribution electrode is not provided in a region immediately below in the depth direction of the interface electrode. It is characterized by that.

[4] In the invention described in [1] or [2] above, the interface electrode is not formed in a region immediately below in the depth direction of the second electrode. All of the electrodes and the interface electrode do not interfere with each other on the same axis in the depth direction.

[5] In the invention according to any one of [1] to [4], Al _X Ga _1-X As (provided that 0 ≦ 0) is provided between the second main surface of the semiconductor layer and the distribution electrode. X ≦ 0.3) is formed, and the contact layer is not formed on a surface other than the region directly under the distribution electrode.

[6] In the invention according to any one of [1] to [5], the second main surface of the semiconductor layer in contact with the transparent conductive film is formed with the second electrode and the distribution electrode. A rough surface having an uneven shape is formed on a surface other than the region.

[7] In the invention according to any one of [1] to [6], a dielectric layer is provided between the dielectric layer and the metal reflective layer, and the interface electrode is formed of the dielectric layer. It is characterized by being provided so as to pass through.

  According to the present invention, it is possible to obtain a semiconductor light emitting device that realizes high output, high efficiency, and low operating voltage.

It is a figure for demonstrating the manufacturing process of the semiconductor light-emitting element of the substrate pasting type which concerns on typical Example 1 of this invention. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is a figure for demonstrating the next process of FIG. It is an upper surface external view of the LED element in Example 1 of this invention. It is the transmittance | permeability measurement result of the transparent conductive film in Example 1 of this invention. It is an operating voltage evaluation result of the LED element in Example 3 of this invention. 6 is an upper surface external view of an LED element in Comparative Example 1. FIG. FIG. 6 is a cross-sectional view on the line of the cross section A of the LED element in Comparative Example 1. It is sectional drawing on the line of the cross section A of the LED element in the comparative example 2. FIG. 14 is an upper surface external view of an LED element in Comparative Example 2. FIG. It is the calculation result of the average reflectance in a reflection layer at the time of using the material of refractive index 1.45 for a dielectric material layer. It is the calculation result of the average reflectance in a reflection layer at the time of using the material of refractive index 2.0 for a dielectric material layer.

  Hereinafter, as preferred embodiments of the present invention, examples and comparative examples will be given and specifically described with reference to the accompanying drawings. In addition, in this Example, the manufacturing process shown in FIGS. 1-15 is called the 1st process-15th process in order below.

[Example 1]
(First step)
In FIG. 1, an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P etching stop layer 2 having a carrier concentration of 5 × 10 ¹⁷ / cm ³ is formed on an n-type GaAs substrate 1 by 100 nm. The n-type GaAs contact layer 3 having a carrier concentration of 8 × 10 ¹⁷ / cm ³ is 100 nm, and the n-type (Al _0.7 Ga _0.3 ) _0.5 In having a carrier concentration of 5 × 10 ¹⁷ / cm ³ is used. Light emission of multiple quantum well structure with _0.5 P clad layer 4 of 1000 nm, undoped Ga _0.5 In _0.5 P and undoped (Al _0.6 Ga _0.9 ) _0.5 In _0.5 P pair layer (active layer) 5 repeating 30 pairs each thickness of 4nm and 8 nm, total ^{360nm, 8 × 10 17 / cm} 3 p -type with a carrier concentration of _{(Al 0.7} Ga _{0.3) 0.5} The p-type GaP contact layer 7 having a carrier concentration of n _0.5 P cladding layer 6 ^{1000nm, 5 × 10 18 / cm} 3 100nm, are successively stacked and grown by MOVPE, to obtain a compound semiconductor layer 14. The wavelength of the light generated from the light emitting layer 5 of the compound semiconductor layer 14 is designed to be about 630 nm red at the emission peak wavelength.

The growth temperature in the MOVPE growth was 650 ° C. from the n-type etching stop layer 2 to the p-type GaP contact layer 7. The growth pressure was about 6666 Pa (50 Torr). The growth rate of each layer was about 0.3 to 1.1 nm / sec, and the V / III ratio was about 150. Here, the V / III ratio refers to a ratio (quotient) when the denominator is the number of moles of a group III material such as TMGa or TMAI and the molecule is the number of moles of a group V material such as AsH ₃ or PH _3. .

As a raw material used in the MOVPE growth, for example, trimethylgallium (TMGa) or triethylgallium (TEGa) in the case of Ga, trimethylaluminum (TMAl) in the case of Al, or trimethylindium (TMAln) in the case of In is used. Using. In addition, arsenic (AsH ₃ ) was used as the As source, and hydride gas such as phosphine (PH ₃ ) was used as the P source.

As an additive material for an n-type layer such as the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P etching stop layer 2, hydrogen selenide (H ₂ Se) was used. Disilane (Si ₂ H ₆ ), monosilane (SiH ₄ ), diethyl tellurium (DETe), and dimethyl tellurium (DMTe) can also be used as other additive materials for the n-type layer.

As an additive material for p-type layers such as p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 6 and p-type GaP contact layer 7, biscyclopentadienyl magnesium (Cp ₂ Mg) was used. Dimethyl zinc (DMZn) and diethyl zinc (DEZn) can also be used as other additive materials for the p-type layer. Here, Mg, which hardly causes dopant diffusion, was employed as the p-type dopant.

(Second step)
Next, as shown in FIG. 2, after this LED epitaxial wafer (hereinafter referred to as LED wafer) is unloaded from the MOCVD apparatus, a dielectric layer 15 is formed on the surface of the p-type GaP contact layer 7 using a plasma CVD apparatus. The SiO ₂ film was formed at about 340 nm.

(Third step)
Next, as shown in FIG. 3, while using a general photolithography apparatus such as a resist coating apparatus and a mask aligner and a manufacturing technique, an opening is formed in the SiO ₂ film using a hydrofluoric acid etching solution diluted with pure water. The interface electrode 8 was formed in the opening by a vacuum deposition method.

  As shown in FIG. 15, the interface electrode 8 is formed of AuBe alloy (gold / beryllium alloy, Au: 99 wt% / Be: 1 wt%) with a film thickness of 340 nm from the side in contact with the p-type GaP contact layer 7. . The interface electrode 8 is designed to be disposed in a region other than the distribution electrode (metal distribution electrode) 12 formed in the eighth step and the surface electrode pad 17 formed in the final fifteenth step. It is important to do. The electrode pattern of the LED element of Example 1 is shown in FIG.

  Referring to FIG. 16, FIG. 16 schematically shows an arrangement relationship of the annular interface electrode 8, the dot-shaped metal distribution electrode 12, and the surface electrode pad 17. In the figure, the interface electrode 8 is formed in an annular shape. The annular interface electrodes 8 are densely arranged so as to surround the plurality of dot-shaped metal distribution electrodes 12, and the distance between the annular interface electrode 8 and the dot-shaped metal distribution electrodes 12 is constant. Is kept at a distance interval of. The line width of the annular interface electrode 8 is set to about 2 μm. The pair of the annular interface electrode 8 and the dot-shaped metal distribution electrode 12 is preferably formed in a circular shape when viewed from above. A rectangular shape such as a square or a hexagon is not preferable because current concentration may occur in the corners.

  As shown in FIG. 16, the pair of the annular interface electrode 8 and the dot-shaped metal distribution electrode 12 is densely arranged around the surface electrode pad 17 and arranged in a square lattice pattern. By arranging these electrodes 8 and 12 densely, it is possible to effectively use the region of the semiconductor layer, and it is possible to reduce a useless region that does not contribute to light emission. The surface electrode pad 17 has a circular shape with a diameter of 100 μm. As a pair of the circular surface electrode pad 17, the annular surface electrode 8, and the dot-shaped metal distribution electrode 12, on the axis in the depth direction from the first main surface that is the light extraction surface of the LED element. It is important to arrange them so as not to overlap each other. In this embodiment, an example in which pairs of circular electrodes 8 and 12 are arranged in a square lattice shape is shown. However, the present invention is not limited to the illustrated example. Other forms such as a lattice may be used.

  The size of the interface electrode 8 is preferably formed so that the current path between the interface electrode 8 and the metal distribution electrode 12 does not become too long. If the current path is long, the LED operating voltage becomes high due to the resistance of the epi layer, which is not preferable. If a plurality of interface electrodes 8 having a small size are formed, the number of arrangement of the metal distribution electrodes 12 also increases, and these electrodes serve as a shield, which is not preferable because the light extraction efficiency of the LED element decreases. Accordingly, the size of the interface electrode 8 is preferably determined by the thickness of the epi layer, the element size, and the like, and is preferably designed as appropriate according to the required operating voltage, output, and the like.

(4th process)
Next, as shown in FIG. 4, Au (gold) as the metal reflective layer 9 is sputtered to a thickness of 400 nm on the epitaxial wafer having the SiO ₂ film as the dielectric layer 15 and the interface electrode 8. Formed. On the metal reflective layer 9, Ti (titanium) as the alloying barrier layer 16 was formed in a thickness of 100 nm, and Au (gold) as the metal bonding layer 11a was sequentially formed in a thickness of 500 nm.

(5th process)
On the other hand, as shown in FIG. 5, Ti (titanium) and Au (gold) were sequentially formed on the surface of a conductive p-type Si substrate prepared as the Si support substrate 10 with a film thickness of 300 nm and 500 nm, respectively. . Ti becomes the alloying prevention barrier layer 18 which also serves as the ohmic contact metal, and Au becomes the metal bonding layer 11b. At this time, the plane orientation of the Si support substrate 10 is not particularly limited, and does not affect the characteristics of the LED element to be completed later.

  As this Si support substrate 10, it is preferable to use a substrate having a resistivity of 0.01 Ω · cm or less, more preferably a resistivity of 0.005 Ω · cm or less, for the following two reasons. Is preferred.

  The first reason for using low resistance Si for the Si support substrate 10 is to obtain a good ohmic contact of the electrode with the Si support substrate. For example, in order to obtain ohmic contact with a Si support substrate having a relatively high resistivity of 0.02 Ω · cm or more, Al (aluminum) or the like is formed on the back electrode and heat-treated at a temperature of 400 ° C. or more. is required. However, it is technically difficult to produce a highly efficient and highly reliable LED element so as not to affect the characteristics of the LED element while being exposed to a high temperature of 400 ° C. or higher. Moreover, since Al is a difficult-to-cut material, when pure Al or the like is formed on the back electrode of the LED wafer, it is technically difficult to suppress chipping such as back surface chipping in a dicing process for forming an element.

  The second reason is to reduce the operating voltage when a large current is passed through the LED element. In the substrate-replaceable type LED element, there is an object of selecting a substrate having a thermal conductivity of the Si support substrate 10 higher than that of the original starting substrate and enabling a large current drive. The rated current of the LED element is 70 mA for a 300 μm square, 350 mA for a 800 μm square, 700 mA for a 1000 μm square, etc., which is an overwhelmingly large current compared to a conventional LED element based on GaAs. Has many uses. For this reason, the voltage generated by the series resistance of the substrate is also a large factor, and the difference in resistivity divides the difference of several hundred mV. Therefore, the resistivity of the Si support substrate 10 is preferably as low as possible.

(Sixth step)
Next, as shown in FIG. 6, the metal bonding layer 11 a on the surface of the LED epitaxial wafer manufactured as shown in FIGS. 1 to 5 and the metal bonding layer 11 b on the surface of the Si support substrate 10 are respectively Au layer surfaces. After being superposed so as to be bonded, they were bonded together by a thermocompression bonding method. In this bonding, the LED wafer is heated to a temperature of 350 ° C. under a pressure of about 1.5 MPa (15 Kgf / cm ² ) in an atmosphere having a pressure of about 1.33 Pa (0.01 Torr). A bonded wafer was obtained by holding in the state for 30 minutes.

(Seventh step)
Next, as shown in FIG. 7, the n-type GaAs substrate 1 which is the substrate material of the LED wafer bonded to the Si support substrate 10 is removed by wet etching using a mixed etchant of ammonia water and hydrogen peroxide water. The n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P etching stop layer 2 was exposed. Next, the etching stop layer 2 was removed by wet etching using hydrochloric acid to expose the n-type GaAs contact layer 3.

(8th step)
Next, as shown in FIG. 8, using a resist coating device, a mask aligner, and a developing device, the exposed surface of the n-type GaAs contact layer 3 is subjected to dot-shaped metal distribution electrode patterning. The metal distribution electrode 12 was formed by vapor-depositing the electrode structure using. As for the structure of the metal distribution electrode 12, AuGe (gold / germanium alloy), Ni (nickel), and Au (gold) were sequentially formed in thicknesses of 50 nm, 10 nm, and 50 nm, respectively.

After the metal distribution electrode 12 is formed, an n-type GaAs other than directly below the metal distribution electrode 12 is formed using a mixed etchant of sulfuric acid, hydrogen peroxide solution, and water, using the previously formed metal distribution electrode 12 as a mask material. The contact layer 3 was removed by wet etching, and the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 4 was exposed by this selective etching. This state is shown in FIG.

(9th step)
As shown in FIG. 9, after exposing the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 4, the diameter of φ1 μm is applied to the entire surface of the LED wafer using photolithography technology. A periodic dot pattern was formed. The pitch of each dot is 2 μm, and the arrangement rule is a square lattice. However, this dot pattern is not formed in the portion (coordinates) where the circular surface electrode pad 17 is formed. The LED wafer on which the dot-shaped opening portions are formed is immersed in hydrochloric acid diluted with pure water, and the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P which is the uppermost layer of the semiconductor layer. The dot-shaped partial etching of the clad layer 4, so-called roughening etching was performed. The etching time at this time is about 30 seconds, and the etching depth is about 1 μm at the deepest place. By this roughening etching, a rough surface structure 22 that causes irregular reflection on the first main surface of the semiconductor layer is formed. After the roughening etching, the photoresist film used as a mask was removed by organic cleaning.

(10th step)
Next, as shown in FIG. 10, only the portion of the epitaxy layer of the LED element is intentionally separated in the wafer state, and the n-type cladding layer 4, the active layer 5, and the p-type cladding layer 6 on the interface electrode 8 are separated. A resist mask 20 for removing the film was formed by photolithography. The resist mask 20 is formed so that the center position of the designed element coincides with the center position of the resist mask having an approximately 280 μm square shape, and the interface electrode 8 is formed in the square mask portion. An open portion having the same design as the pattern is formed.

(11th step)
After forming the resist mask, as shown in FIG. 11, the n-type clad layer 4, the active layer 5, and the p-type clad layer 6 which are semiconductor layers are etched. 3 side surfaces of the AlGaInP-based semiconductor were removed. The p-type GaP contact layer 7 was not etched and the resist mask was removed by ashing. Thus, the epi layer was separated into an element shape of about 280 μm square, and the semiconductor layer in the region immediately above the interface electrode 8 could be removed leaving the p-type GaP contact layer 7.

(12th step)
Next, as shown in FIG. 12, a SiN film 24 as an insulating protective film was formed on the surface of the LED wafer that had been processed as shown in FIGS. The SiN film 24 is formed by supplying SiH ₄ gas (monosilane) and N ₂ O gas (nitrous oxide) into the plasma CVD, a film forming pressure of about 39997 Pa (300 Torr), a wafer temperature of about 300 ° C., and RF The operation was performed at an input power of 100 W.

When the thickness of the formed SiN film 24 was measured with a scanning electron microscope, the thickness of the semiconductor layer on the light extraction surface was about 250 nm. Further, it was confirmed that the thickness of the SiO ₂ insulating protective film deposited on the exposed side surface of the semiconductor layer, which is the side surface of the LED element, was thinner than that on the light extraction surface and about 110 nm at the thinnest point. Further, when the SiN film 24 of the Si support substrate for monitoring 10 set in the same batch was measured using spectroscopic ellipsometry, it was confirmed that the refractive index was 2.22.

(13th step)
Next, in order to partially remove and open the SiN film 24, a resist mask using a positive photoresist was formed using a photomask in which the chrome mask portion of the photomask used for forming the metal distribution electrode was inverted. . After the resist mask was formed, the LED wafer was immersed in buffered hydrofluoric acid for 10 minutes, and the SiN film 24 was removed by etching until the metal distribution electrode 12 was exposed. The state after this etching is shown in FIG.

(14th step)
Next, as shown in FIG. 14, an ITO transparent conductive film 21 was formed on the surface of the LED wafer where the metal distribution electrode 12 was exposed using a sputtering apparatus. The ITO film sputtering target used had a Sn concentration of 5% in terms of weight percent. The ITO transparent conductive film 21 is preferably formed so as to be in ohmic contact with the metal distribution electrode 12. When adopting a configuration in which the ITO transparent conductive film 21 is brought into contact with one surface (first main surface) of the semiconductor layer 14, for example, a configuration in which the insulating protective film 24 is provided only on a part of the surface of the LED wafer, The transparent conductive film 21 is preferably formed so as to be in Schottky contact with one surface of the semiconductor layer 14.

As a sputtering apparatus, an RF magnetron sputtering apparatus was used, and the film was formed with an RF input power of 50 W, no introduction of oxygen gas, a chamber pressure of 0.5 Pa, and a film formation time of 30 minutes. Regarding the thickness of the obtained ITO film, the Si dummy substrate sample put in the simultaneous batch was evaluated by spectroscopic ellipsometry. As a result, the ITO film had a thickness of about 80 μm and a refractive index of 1.98. As a result of evaluating the resistivity of the ITO film by the pow method, the resistivity was 4.5 × 10 ⁻⁴ / cm ³ .

  Furthermore, when the transmittance of the ITO film alone was evaluated using a reflectance measuring device, it was confirmed that the film had a favorable transmittance of 97.3% at a wavelength of visible light of 630 nm. The transmittance | permeability measurement result of the ITO transparent conductive film 21 is shown in FIG.

  Next, a resist mask for removing the ITO transparent conductive film 21 that becomes the dicing street portion of the LED element was formed by photolithography. The resist mask is formed so that the center position of the designed element coincides with the center position of the resist mask having an approximately 280 μm square shape.

  After forming the resist mask, in order to etch the ITO transparent conductive film 21, the ITO transparent conductive film 21 was etched until it was exposed to a commercially available ITO etchant (ITO-07N manufactured by Kanto Chemical Co., Ltd.) and the compound semiconductor layer 14 was exposed.

(15th step)
Next, as shown in FIG. 15, the back electrode 13 was formed on the entire surface of the second main surface of the Si support substrate 10 by vacuum deposition. The back electrode 13 was formed by sequentially forming Ti (titanium) and Au (gold) with thicknesses of 10 nm and 300 nm, respectively. Then, the alloy process which is an alloying process of an electrode was performed with the alloy apparatus provided with the upper and lower independent heater. The alloying conditions were to heat to a temperature of 400 ° C. in a nitrogen gas atmosphere and heat-treat for 5 minutes in that state. The LED wafer was placed on a graphite tray and placed on a lower plate with a lower heater incorporated therein.

  The back electrode 13 before the alloy treatment was gold with a metallic luster on the appearance, but in the appearance after the alloy treatment, the metallic luster was almost lost, and the color changed to a color close to cream, The alloying of the Si support substrate 10 and Au could be seen. Ti is agglomerated by subjecting the electrode to an alloying process, and is in a state where it partially exists as a Ti aggregate in the alloyed back electrode 13.

  Furthermore, after the alloy process, circular surface electrode pad patterning was performed again using a photolithography technique and a vacuum deposition technique, and then a surface electrode pad 17 was formed.

  The structure of the surface electrode pad 17 is Ti (titanium) and Au (gold) from the ITO transparent conductive film 21 side, and the film thicknesses are 30 nm and 1000 nm, respectively. After the surface electrode pad 17 is formed, it is important to perform the wire bonding process that the alloy process is not performed and the non-alloyed state is maintained until the LED element is completed.

  The substrate-replaceable type LED wafer formed as described above is made into an element by using a dicing apparatus so that the circular pad portion of the surface electrode pad 17 is arranged at the approximate center. The chip size of the LED element depends on the mask pitch in the photomask for photolithography used when forming the surface electrode or the like, and the chip pitch of the LED element manufactured in Example 1 is about 330 μm. Yes.

  Next, the LED chip processed by the dicing process was mounted on a lead frame called a TO-18 stem using Ag (silver) epoxy resin. Further, wire bonding was performed on the formed surface electrode pad 17 and the lead of the stem, so that the LED element was made ready to emit light.

  When the LED characteristics of the completed LED element at the time of 20 mA driving were evaluated, the light emission output was 12.2 mW and the operation voltage was 1.98 V. The light emission efficiency defined by the obtained light output / input power was 30.8%. A high-efficiency red LED element with a low operating voltage could be obtained in a substrate output type high-power LED element.

[Example 2]
Example 2 illustrates an example of an infrared LED element having an emission wavelength of 850 nm.

The difference from Example 1 is the material structure of the semiconductor layer. In the first embodiment, the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P etching stop layer 2, the n-type GaAs contact layer 3, and the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 4, undoped Ga _0.5 In _0.5 P and undoped (Al _0.6 Ga _0.9 ) _0.5 In _0.5 P Structure in which an active layer 5, a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 6 and a p-type GaP contact layer 7 are sequentially grown by pairing with each other In Example 2, on the n-type GaAs substrate 1, an n-type Ga _0.5 In _0.5 P etching stop layer, an n-type GaAs contact layer, an n-type Al _0.4 Ga _{0. 6} As cladding layer, an undoped _Al 0.2 Ga Active layer of multiple quantum well structure according to _.8 As and undoped GaAs and the pair, the p-type _Al 0.4 _{Ga 0.6} As cladding layer, and the p-type _Al 0.15 _{Ga 0.85} As contact layer are successively grown The LED structure is used. In addition, the dopant of each n-type layer and p-type layer is the same as that in the first embodiment.

  The manufacturing method of the LED element using such a semiconductor layer is changed from that using P (phosphorus) for the V group to that using As (arsenic) for the V group as compared with the first embodiment. Therefore, the following etching materials are changed. That is, in the second embodiment, the roughening etching solution described in the first embodiment and the etching solution of the semiconductor layer on the element separation and interface electrode are mixed acid of tartaric acid, hydrogen peroxide, and pure water. Was used.

Note that when etching the semiconductor layer, the etching time was optimized so as not to completely remove the p-type Al _0.15 Ga _0.85 As contact layer.

  The remaining structure was manufactured by the same structure and manufacturing method as the said Example 1. When the LED characteristics at the time of 20 mA drive of the LED element were evaluated, the LED element of Example 2 had a light emission output of 11.5 mW and an operating voltage of 1.45 V, and the light emission efficiency defined by the obtained light output / input power was It was 39.7%, and an infrared LED element with high luminous efficiency could be obtained.

  From the above, as shown in FIG. 15, the semiconductor device has at least the n-type contact layer 3, the active layer 5, the interface electrode 8, the metal distribution electrode 12, and the surface electrode pad 17. If the active layer 5, excluding the contact layer 3 and the metal distribution electrode 12, the interface electrode 8, and the surface electrode pad 17 satisfy the design of an arrangement positional relationship that does not overlap (do not interfere with each other) on the same axis in the stacking direction, It can be seen that a light-emitting element such as red or other visible light or infrared light can obtain the LED element of high output, high efficiency, and low operating voltage, which is the initial purpose of the present invention, without depending on the wavelength. .

[Example 3]
In Example 3, an example of an LED element in which the material of the n-type contact layer is changed is illustrated.

The difference from the first embodiment is that in the first embodiment, the n-type contact layer 3 is made of GaAs, but in this third embodiment, the material of the n-type contact layer is made of AlGaAs. The AlGaAs has four types of Al compositions of 0.1, 0.2, 0.3, and 0.4. The carrier concentration of each AlGaAs contact layer is appropriately changed by setting the flow rate of H ₂ Se so that the carrier concentration is 8 × 10 ¹⁷ / cm ³ like the n-type GaAs contact layer 3 described in Example 1 above. Produced. The remaining configuration and manufacturing method are the same as those in Example 1. The LED characteristic evaluation results at the time of driving the manufactured LED element at 20 mA are summarized in Table 1 below. FIG. 17 shows the operating voltage evaluation result of the LED element.

  As is apparent from Table 1 and FIG. 17, it can be seen that the operating voltage increases as the Al composition of the n-type AlGaAs contact layer increases. If the Al composition of the n-type AlGaAs contact layer increases, the band gap energy of the semiconductor increases, making it difficult to obtain ohmic contact with the metal distribution electrode, and the contact resistance is increased. It is thought that this led to an increase in operating voltage.

  As shown in Table 1, the voltage of the LED element using the n-type AlGaAs contact layer having an Al composition of 0.4 was 2.33 V, and the light emission efficiency was 25.8%. This luminous efficiency is about 4% lower than that in Example 1 using the n-type GaAs contact layer, and it can be seen that the efficiency of the LED element is reduced by increasing the Al composition. Further, the operating voltage of the LED element is 2.33 V at a rated current of 20 mA, which is higher than the voltage specification range of about 2.2 V which is a voltage specification range of a general LED element of the element size manufactured in Example 3. ing.

  The voltage of the LED element changes depending on the electrode configuration of the element, etc., but as shown in Table 1, the voltage increases as the Al composition increases, and the voltage value gradually increases as the voltage increases. In view of the fact that the increase in Al is large, it can be seen that the increase in the Al composition tends to make it difficult to obtain ohmic contact with respect to a certain electrode.

In order to obtain high luminous efficiency such as high output and low operating voltage, the material of the semiconductor contact layer is preferably selected in the range of Al _X Ga _1-X As (where 0 ≦ X ≦ 0.3). Material is preferred. More preferably, when an AlGaAs contact layer is employed, the Al composition is preferably suppressed to about 0.2.

  As described above, at least the n-type contact layer 3, the active layer 5, the interface electrode 8, the metal distribution electrode 12, and the surface electrode pad 17 are included. Of these semiconductor layers, the n-type contact layer 3 and the metal distribution electrode As long as the active layer 5, except for 12, the interface electrode 8, and the surface electrode pad 17 satisfy the design of an arrangement positional relationship that does not overlap (do not interfere with each other) on the same axis in the stacking direction, the same as in the first embodiment. In a light emitting device such as visible light such as red or infrared light, it is possible to obtain an LED device with high output, high efficiency, and low operating voltage as an initial object of the present invention without depending on the wavelength. Easy to guess.

[Example 4]
In Example 4, an example of an LED element in which the material of the insulating protective film is changed will be exemplified.

The difference from Example 1 is that in Example 1, the material of the insulating protective film is SiN, but in Example 4, the material of the insulating protective film is SiO ₂ . This film thickness was the same as the SiN film thickness dimension in Example 1 above. Since the etching rate of SiO ₂ by buffered hydrofluoric acid or the like is faster than that of SiN, the etching time when exposing the metal distribution electrode was set to 4 minutes. The remaining configuration and manufacturing method are the same as those in Example 1.

In Example 4, when the refractive index of the formed SiO ₂ film was measured by spectroscopic ellipsometry, it was confirmed to be about 1.45. Further, when the LED characteristics of the LED element when driving at 20 mA were evaluated, the light emission output was 11.5 mW, the operating voltage was 1.98 V, and the light emission efficiency defined by the obtained light output / input power was 29.0%. Although it was a little inferior to the said Example 1, the red LED element of high luminous efficiency was able to be obtained.

Compared with the LED element using SiN in Example 1, the light emission output is low because the refractive index n in the process of light being led out from the side surface other than the first main surface of the semiconductor layer to the air layer is the semiconductor layer (n = about 3.6)> SiO ₂ layer (n = about 1.45) <ITO layer (n = about 1.98)> becomes a relationship of air (n = 1), SiO ₂ layer This is because the refractive index increased when the film was applied to the ITO layer. This is considered to be because light that is reflected toward the semiconductor layer increases in the process in which light emitted from the semiconductor layer is extracted to the air layer.

Therefore, it is preferable to form the SiN layer or the like with a material having a higher refractive index than that of the transparent conductive film so that the refractive index is gradually reduced from the semiconductor layer to the air layer as described below.
Semiconductor layer (n = about 3.6)> SiN layer (n = about 2.22)> ITO layer (n = about 1.98)> Air (n = 1)

[Example 5]
In the fifth embodiment, unlike the first embodiment, an example in which the light extraction surface side of the semiconductor layer is not roughened is illustrated.

The only difference from Example 1 is that no roughening etching process after exposing the n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer is performed. is there. The remaining configuration and manufacturing method are the same as those in Example 1.

  When the LED characteristics of the LED element of Example 5 at 20 mA drive were evaluated, the light emission output was 6.1 mW and the operating voltage was 1.95 V. The light emission efficiency defined by the obtained light output / input power was It was 15.6%.

  Thus, the roughening process of the light extraction surface of the LED element has an effect of remarkably improving the light emission output of the LED element, and the characteristics of the LED element greatly change depending on the presence or absence of the roughening process. Although the output improvement rate varies depending on the rough surface processing method, the importance of the rough surface processing is considered to be obvious as compared with the LED element having a flat light extraction surface in a non-processed state.

  As described above, at least the n-type contact layer 3, the active layer 5, the interface electrode 8, the metal distribution electrode 12, and the surface electrode pad 17 are included. Of these semiconductor layers, the n-type contact layer 3 and the metal distribution electrode If the active layer 5, except for 12, the interface electrode 8, and the surface electrode pad 17 satisfy the design of an arrangement positional relationship in which they do not overlap (do not interfere with each other) on the same axis in the stacking direction, for example, no rough surface processing is performed. Compared with the LED element, it can be inferred that there is an effect of improving the light emission efficiency. However, compared with the above-mentioned Example 1, when viewed only from the viewpoint of obtaining a highly efficient LED element, the light output is poor and the efficiency is high. Is hard to say. Therefore, as a suitable LED element, it is preferable that the semiconductor layer is roughened on the light extraction surface side of the LED element.

[Example 6]
In Example 6, an example of an LED element in which the material of the transparent conductive film is changed will be exemplified.

In Example 1 described above, an example in which ITO is used for the transparent conductive film 21 is shown. However, in Example 6, the material of the transparent conductive film is SnO ₂ (tin oxide), In ₂ O ₃ (indium oxide). Various LED elements using any one of ZnO (zinc oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), and IZO (indium-doped zinc oxide) were produced.

  All the methods for producing the transparent conductive film are formed by using the RF magnetron sputtering method. The film thickness was aimed at about 80 nm. The manufacturing method is the same as in Example 1 except that the material of the transparent conductive film is changed and phosphoric acid and a mixed acid of hydrochloric acid are used as the etching solution during the element separation process of the ZnO-based material.

  Table 2 below summarizes the results of the evaluation of characteristics of the produced LED elements at the time of 20 mA energization, the resistivity and the transmittance of various LED elements in the transparent conductive film.

  As apparent from Table 2, a highly efficient LED element was obtained with any transparent conductive film material. Therefore, at least the n-type contact layer 3, the active layer 5, the interface electrode 8, the metal distribution electrode 12, and the surface electrode pad 17 are included, and among these semiconductor layers, the n-type contact layer 3 and the metal distribution are provided. Depending on the material of the transparent conductive film, if the active layer 5, excluding the electrode 12, the interface electrode 8, and the surface electrode pad 17 satisfy the design of an arrangement positional relationship that does not overlap (do not interfere with each other) on the same axis in the stacking direction, There is no particular impact. What is important is the film thickness and resistivity of the transparent conductive film, and the transmittance.

  Next, a comparative example will be described with reference to FIGS. In FIGS. 19 to 22, substantially the same members as those in the first embodiment are denoted by the same member names and symbols. Therefore, the detailed description regarding the substantially same member as the said Example 1 is abbreviate | omitted.

[Comparative Example 1]
In this comparative example 1, an example of the conventional LED element which does not have a metal distribution electrode and a transparent conductive film is illustrated. The LED element of Comparative Example 1 does not have a metal distribution electrode and a transparent conductive film. In Comparative Example 1, the interface electrode and the surface electrode pattern of the LED element are different from those in Example 1 because the transparent conductive film is not included.

  In the LED element of Comparative Example 1, as shown in FIGS. 19 and 20, the interface electrode 8 is formed in a single comb shape instead of a plurality. The distance between the comb-shaped interface electrode 8 and the ohmic surface electrode 23 is maintained at a substantially constant distance. The line width of the comb-shaped interface electrode 8 was designed to be 2 μm.

  The ohmic surface electrode 23 is formed in a shape facing the comb-shaped interface electrode 8 as shown in FIGS. 19 and 20, extending a thin line from the center circle having a diameter of 100 μm in all directions, and from the thin line. The thin line is further extended so as to branch, and the current is uniformly and uniformly injected into the element surface. In this fine wire electrode, the thickness of the fine wire extending in the lateral direction from the center circle is 15 μm, and the thickness of the four fine wires extending in the longitudinal direction of the element is 10 μm.

  As shown in FIGS. 19 and 20, the ohmic surface electrode 23 and the interface electrode 8 are arranged so as not to overlap each other on the axis in the depth direction from the first main surface which is the light extraction surface of the element. The surface electrode pad for wire bonding is disposed so as to overlap the central circular portion of the ohmic surface electrode 23.

  The ohmic surface electrode 23 needs to obtain ohmic contact with the semiconductor layer, similarly to the metal distribution electrode 12 of the first embodiment. For this reason, the electrode structure is formed of AuGe (gold / germanium alloy), Ni (nickel), and Au (gold) sequentially from the semiconductor layer side with thicknesses of 50 nm, 10 nm, and 500 nm, respectively. The LED element of Comparative Example 1 is substantially the same except for the metal distribution electrode and transparent conductive film manufacturing method and electrode pattern of Example 1 above.

  The LED characteristics of the LED element of Comparative Example 1 manufactured in such a configuration are a light emission output of 7.9 mW and an operating voltage of 1.96 V. Compared with the LED element of Example 1 above, the light emission output is particularly about The result was as low as 2 mW. The luminous efficiency defined by the obtained light output / input power is 20.2%, which is 6% lower than the LED element of Example 1 above.

  This is because the loss of the light emitted from the active layer by the surface electrode is increased due to the increase in the area of the surface electrode that cannot transmit light relative to the light emitting area of the LED element. Conceivable.

[Comparative Example 2]
In Comparative Example 2, an LED element having a small surface electrode area as in Example 1 was fabricated in the LED element of Comparative Example 1. The LED element shown in Comparative Example 2 and its electrode pattern are shown in FIGS. 21 and 22, respectively.

  The interface electrode 8 of the comparative example 2 is formed in the single annular | circular shape as shown in FIG.21 and FIG.22. The distance between the annular interface electrode 8 and the ohmic surface electrode 23 is maintained at a substantially constant distance. The line width of the interface electrode 8 is 2 μm.

  One ohmic surface electrode 23 is formed in a circular shape with a diameter of 100 μm, as shown in FIGS. 21 and 22. This shape is the same as the shape of the surface electrode pad 17 of the first embodiment. The ohmic surface electrode 23 and the interface electrode 8 are arranged so as not to overlap each other on the axis in the depth direction from the first main surface which is the light extraction surface of the element. The surface electrode pad for wire bonding is disposed so as to overlap the ohmic surface electrode 23. Even in the ohmic surface electrode 23 of Comparative Example 2, as in Comparative Example 1, it is necessary to obtain ohmic contact with the semiconductor layer, so that the surface electrode structure is the same as that of Comparative Example 1. The remaining configuration and manufacturing method are the same as those in Example 1.

  The LED characteristics of the LED element of Comparative Example 2 manufactured in such a configuration are a light emission output of 8.3 mW and an operating voltage of 2.65 V. Compared with the LED element of Example 1, the light emission output is particularly about The result was 2 mW lower, and in particular, the operating voltage was higher than 600 mV. The luminous efficiency defined by the obtained light output / input power is 15.5%, which is about 10% lower than that in Example 1.

  The reason why the output of the LED element of Comparative Example 2 is higher than that of Comparative Example 1 is considered to be that the effect of shielding light by the surface electrode is somewhat low, but is not so high. The reason why the operating voltage is increased is that current is injected only to a part of the light emitting surface of the element as compared with Example 1 and Comparative Example 1 above, so that the current density per light emitting area is increased and the current is applied. It is considered that the operating voltage has increased as a result of the increase in the resistance component. Further, it is considered that the increase in the operating voltage increased the temperature of the element, and the light output was not so high.

  From the result of Comparative Example 2, in order to increase the light emission efficiency of the LED element (light emission amount with respect to the input power), it is important to uniformly inject current into the LED element surface and reduce the operating voltage of the element. I understand that.

  As is apparent from the above description, the semiconductor light emitting device of the present invention has been described based on the above embodiments, but the present invention is not limited to the above embodiments and illustrated examples, and does not depart from the gist thereof. It can be implemented in various ways. In the present invention, the following modifications are possible.

[Modification 1]
The materials and thicknesses of the front electrode pad 17 and the back electrode 13 according to the above embodiment are not limited. Since there is no particular influence on the initial target configuration of the present invention, the materials and thicknesses of the front surface electrode pad 17 and the back surface electrode 13 can be appropriately changed.

[Modification 2]
In the above-described embodiments, the red and infrared LED elements have been described. However, the present invention is not limited thereto. For example, the LED element is a short wavelength LED element having an emission wavelength of 610 nm and an emission wavelength of 595 nm. Also good.

[Modification 3]
In the above embodiment, the circular surface electrode pad 17 is used, but the surface electrode pad 17 is not limited to this, and may be formed in various shapes such as a square, a rhombus, and a polygon. Even the interface electrode 8 and the metal distribution electrode 12 can be formed in various shapes.

[Modification 4]
In the above embodiment, the material of the metal reflective layer 9 is uniformly Au, but is not limited to this. As a material of the metal reflection layer 9, for example, even if it has a slightly different kind of metal and has a reflectance slightly inferior to the reflectance of high-purity Au, There is no particular relationship, and it can be easily assumed that similar effects can be obtained. Au is preferable as a material for the reflective layer because it has an excellent reflectance with respect to red and infrared light emitted from the light emitting layer of the semiconductor layer. There are other materials such as Ag and Al as materials having excellent reflectivity, but Ag is particularly brittle and resistant to acid and alkali chemicals for manufacturing LED elements, and the reflective layer is abnormal. Since there is a problem that it becomes difficult to manufacture an element by etching, it is not practically used.

  In addition, Ag may cause a problem that electromigration occurs when a current is applied to the LED element, causing a short circuit in the element, which is not preferable. Since Al is easily alloyed with the Au-based material of the interface electrode 8, an increase in contact resistance at the interface electrode portion of the LED element becomes a problem, and it is difficult to obtain a high-efficiency LED element. For these reasons, the metal reflective layer 9 is preferably formed of Au or a material that is Au as a main component containing inevitably mixed foreign metals.

[Modification 5]
In the said Example, the example which used Si uniformly as a material of the support substrate 10 was shown. Even if a material such as Ge or GaP is used as the material of the support substrate, the effect intended by the present invention can be obtained. However, the merit of Si is that it is particularly inexpensive as compared with other substrate materials and has excellent thermal conductivity as a readily available material. For example, the thermal conductivity is superior to materials such as Ge and GaP, and of course, it is naturally superior to GaAs as a starting substrate. It is obvious that the low cost of the substrate is directly related to the cost of the LED element and is important for price competitiveness. Further, the thermal conductivity of the support substrate has a particularly strong influence on a large current drive LED element having a large rated current, which is also important. From the above, Si is preferable as the material of the support substrate.

[Modification 6]
According to the above embodiment, an example in which SiO ₂ is used as the material of the dielectric layer 15 is illustrated, but the present invention is not limited to this. As a material of the dielectric layer 15, for example, SiN having a refractive index of around 2.2 can be substituted. However, the dielectric layer 15 provided between the metal reflection layer 9 and the light emitting layer 5 has an influence on the reflectivity of reflecting light toward the light extraction surface depending on the refractive index.

  In FIG. 23, the calculation result of the average reflectance in the metal reflective layer 9 at the time of using the material of refractive index 1.45 for the dielectric material layer 15 is shown. FIG. 24 shows the calculation result of the average reflectance in the metal reflective layer 9 when a material having a refractive index of 2.0 is used for the dielectric layer 15. 23 and 24 show the calculation results for the case where the light extraction surface of the LED element is roughened and the case where the light extraction surface is a smooth surface that is not roughened. Furthermore, the calculation is performed even when the metal reflective layer 9 uses a material other than Au.

  As is apparent from the result of this calculation, when the refractive index of the dielectric layer 15 is increased, the average reflectance of the metal reflective layer 9 is lower than that of the refractive index of 1.45. Since this reflectance is closely related to the light emission output of the LED element, the refractive index of the material of the dielectric layer 15 is preferably as low as possible.

Also, in terms of manufacturing, SiO ₂ is easy to form and has a high film forming speed compared to materials such as SiN. In addition, processing such as etching is easy and patterning accuracy is good. Furthermore, since SiO ₂ has extremely low absorption loss in visible light and near infrared light, there is an advantage that a high-power LED element can be easily obtained. For these reasons, the material of the dielectric layer 15 is preferably SiO ₂ .

1 n-type GaAs substrate 2 n-type etching stop layer 3 n-type contact layer 4 n-type cladding layer 5 light emitting layer (active layer)
6 p-type cladding layer 7 p-type contact layer 8 interface electrode 9 metal reflective layer 10 support substrate 11a, 11b metal bonding layer 12 metal distribution electrode 13 back electrode 14 compound semiconductor layer 15 dielectric layer 16 alloying barrier layer 17 surface electrode pad 18 Anti-alloying barrier layer 20 Resist mask 21 Transparent conductive film 22 Rough surface structure 23 Ohmic surface electrode 24 Insulating protective film

Claims (7)

A support substrate;
A semiconductor layer including a light emitting layer;
A metal reflective layer provided between the support substrate and the light emitting layer;
An insulating protective film formed on the first main surface of the semiconductor layer;
A transparent conductive film formed on the first main surface of the insulating protective film;
A distribution electrode provided through the insulating protective film between the semiconductor layer and the transparent conductive film;
An interface electrode for electrically connecting the metal reflective layer and the second main surface of the semiconductor layer;
The interface electrode is not provided in a region immediately below in the depth direction of the distribution electrode, and the light emitting layer of the semiconductor layer is not provided in a region immediately above in the depth direction of the interface electrode. A semiconductor light emitting device characterized. The insulating protective film is formed such that only a region where the distribution electrode is formed is removed by etching on the first main surface of the semiconductor layer, and covers the exposed side surface portion other than the first main surface of the semiconductor layer. Formed,
The semiconductor light emitting element according to claim 1, wherein the transparent conductive film is in contact with the distribution electrode, the first main surface of the semiconductor layer, or both. A surface electrode is formed on the transparent conductive film,
The semiconductor light emitting element according to claim 1, wherein the distribution electrode is not provided in a region immediately below the interface electrode in the depth direction.   The interface electrode is not formed in a region immediately below the second electrode in the depth direction, and the second electrode, the distribution electrode, and the interface electrode are all on the same axis in the depth direction. 3. The semiconductor light emitting device according to claim 1, wherein no interference occurs. A contact layer made of Al _X Ga _1-X As (where 0 ≦ X ≦ 0.3) is formed between the second main surface of the semiconductor layer and the distribution electrode, and the contact layer includes the distribution electrode 5. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device is not formed on a surface other than a region immediately below.   The second main surface of the semiconductor layer in contact with the transparent conductive film is a rough surface having an uneven shape on a surface other than a region where the second electrode and the distribution electrode are formed. Item 6. The semiconductor light emitting device according to any one of Items 1 to 5. A dielectric layer is provided between the dielectric layer and the metal reflective layer;
The semiconductor light emitting element according to claim 1, wherein the interface electrode is provided so as to penetrate the dielectric layer.

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