JP5287467B2 - Method for manufacturing light emitting device - Google Patents

Description

  The present invention relates to a method for manufacturing a light emitting element and a light emitting element, and more particularly to a method for manufacturing a light emitting element and a light emitting element suitable for extracting light from a light emitting layer of the light emitting element to the outside.

The light-emitting layer portion is formed of (Al _x Ga _1-x ) _y In _1-y P mixed crystal (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1; hereinafter also referred to as AlGaInP mixed crystal or simply AlGaInP). By adopting a double hetero structure in which a thin AlGaInP active layer is sandwiched between an n-type AlGaInP clad layer and a p-type AlGaInP clad layer having a larger band gap than that, for example from green A high-luminance element can be realized in a wide wavelength range up to red.

Here, energization to the light emitting layer portion is performed through a metal electrode formed on the element surface. Since the metal electrode functions as a light shielding body, for example, it is often formed so as to cover only the central portion of the first main surface of the light emitting layer portion, and light is extracted from the surrounding electrode non-formation region.
In this case, reducing the area of the metal electrode as much as possible can increase the area of the light extraction region formed around the electrode, which is advantageous from the viewpoint of improving the light extraction efficiency.

  Conventionally, attempts have been made to increase the light extraction amount by effectively spreading the current in the element by devising the electrode shape, but in this case also, the increase in the electrode area is unavoidable in any case, and therefore the light extraction region. On the other hand, the decrease in the area of the light causes a dilemma where the amount of light extraction is limited.

  In addition, the carrier concentration of the dopant in the clad layer, and thus the conductivity, is kept somewhat low in order to optimize the light emission recombination of carriers in the active layer, and the current tends not to spread in the in-plane direction. is there. As a result, the current density is concentrated in the electrode covering region, and the substantial light extraction amount in the light extraction region is reduced.

Therefore, a method of forming a light extraction layer such as GaP having a low resistivity with a higher dopant concentration than the cladding layer between the cladding layer and the electrode is employed.
If the light extraction layer such as GaP is formed so as to have a thickness increased to a certain level or more, not only the current diffusion effect in the element surface is improved but also the amount of light extraction from the side surface of the layer is increased. Therefore, the light extraction efficiency can be further increased.
The light extraction layer needs to be formed of a compound semiconductor having a band gap energy larger than the photon energy of the emitted light beam so that the emitted light beam can be efficiently transmitted and the light extraction efficiency can be increased. In particular, GaP is widely used as a light extraction layer of an AlGaInP-based light emitting element because it has a large band gap energy and a small absorption of emitted light flux.

Since the GaAs substrate used for forming the light emitting layer is a light absorbing substrate (that is, an opaque substrate), the GaAs substrate is removed by grinding or etching after the light emitting layer is grown, and a GaP transparent substrate layer is attached to the GaP single crystal substrate instead. They are also formed by combination or vapor deposition.
Conventionally, a GaP light emitting layer and a GaP epitaxial layer as an extraction layer of about 30 to 100 μm are vapor-phase grown on a highly transparent GaP substrate to improve the light extraction efficiency.

Similarly, in the AlGaInP light emitting diode, the opaque substrate on the second main surface side of the light emitting layer portion is replaced with a GaP transparent substrate layer, and light can be extracted from the side surface of the transparent substrate. Light can be reflected by the reflective layer or electrode on the second main surface side, and the reflected light can be extracted together with the direct light beam from the first main surface side, so that the light extraction efficiency of the entire element can be increased.
In addition to GaP, GaAsP, GaAlAs, or the like can provide the same effect as GaP.

However, even when such highly transparent crystals are arranged on both the upper and lower sides or one side of the light emitting layer, light may be absorbed inside due to multiple reflections on the surface and the outside may not be emitted.
In order to improve this, Patent Document 1 discloses that light extraction efficiency is obtained by immersing the surface of the light emitting element in an etching solution made of I ₂ + HNO ₃ + HF + CH ₃ COOH to form irregularities on the surface and roughen the surface. A method for manufacturing a light-emitting element that increases the brightness is disclosed.

JP 2005-317664 A

However, although the light emitting element manufacturing method described in Patent Document 1 described above can increase the light extraction efficiency to some extent, there is a limit to the surface roughness that can be reached, and the improvement of the light extraction efficiency has reached its peak.
There has been a demand for light-emitting elements with higher emission intensity, and a new roughening method has been demanded.

  The present invention has been made to solve the above-described problems, and the surface of the light extraction layer can be roughened to such an extent that the reflectance on the surface of the light extraction layer can be reduced. An object of the present invention is to provide a method for manufacturing a light emitting device and a light emitting device capable of improving the light extraction efficiency more than before.

  In order to solve the above problems, in the present invention, a light emitting element substrate is formed by dicing at least a light emitting element substrate whose light extraction layer is made of any one of GaP, GaAsP, and GaAlAs. Provided is a method for manufacturing a light-emitting element, comprising: a roughening etching step in which etching is performed with a second etching solution containing at least hydrofluoric acid after etching with a first etching solution containing iodic acid, thereby roughening the surface. To do.

  In order to improve the light extraction efficiency in this way, the surface of the light-emitting element chip is etched with a first etching solution containing at least iodic acid, and then sequentially etched with a second etching solution containing at least hydrofluoric acid. By doing so, the surface roughness can be increased as compared with the conventional roughening etching, and the light extraction efficiency can be improved as compared with the conventional.

Here, each of the light-emitting element substrates is made of at least a compound represented by a composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1). The light extraction layer is laminated or bonded to a light emitting layer having a double hetero structure in which the first conductive type cladding layer, the active layer, and the second conductive type cladding layer are laminated in this order. Is preferred.
By manufacturing a light-emitting element using the light-emitting element substrate having such a structure, a light-emitting element in which a light-emitting layer with extremely high light extraction efficiency is made of AlGaInP can be manufactured.

Moreover, it is preferable that the first etching solution contains nitric acid and acetic acid in addition to the iodic acid.
Thus, by adding nitric acid and acetic acid to the first etching solution in addition to iodic acid, the surface of the light extraction layer made of GaP, GaAsP, or GaAlAs can be further roughened as compared with the prior art. The extraction efficiency can be further improved.

Then, it is preferable that the second etching solution contains acetic acid in addition to the hydrofluoric acid.
In this way, by adding the second etching solution to the hydrofluoric acid and further containing acetic acid, the surface roughness of the light extraction layer can be further increased, and thus the light extraction efficiency can be further improved.

Furthermore, it is preferable that the roughening etching step has a surface roughness (Ra) of the light emitting element of 1.4 μm or more.
As described above, the surface roughness (Ra) of the light emitting element is set to 1.4 μm or more in the roughening etching step, whereby the reflectance of the light extracted from the light emitting layer on the surface of the light extraction layer is increased. A light-emitting element that can be sufficiently reduced and has a light-emission output stronger than before can be manufactured.

  In the present invention, at least the light extraction layer is a light emitting element made of any one of GaP, GaAsP, and GaAlAs, and the surface roughness (Ra) of the light emitting element is 1.4 μm or more. Provided is a light emitting device.

  Thus, if the surface roughness (Ra) of the surface is 1.4 μm or more, the surface of the light extraction layer is greatly roughened, so that the light from the light emission layer is extracted. The reflectance reflected on the surface of the layer can be greatly reduced compared to the conventional case. Therefore, a light emitting element with higher light emission efficiency than the conventional one can be obtained.

Here, each of the light-emitting elements includes at least a compound represented by a composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1). The light extraction layer is laminated or bonded to a light emitting layer having a double hetero structure in which the first conductivity type cladding layer, the active layer, and the second conductivity type cladding layer are laminated in this order. preferable.
By using a light-emitting element having the above structure, a light-emitting element with extremely high light emission efficiency can be obtained.

  As described above, according to the present invention, it is possible to roughen the surface to such an extent that the reflectance of the light extraction layer surface of the light emitted from the light emitting layer can be reduced as compared with the conventional case, that is, as compared with the conventional case. Furthermore, a method for manufacturing a light emitting element and a light emitting element capable of improving the light extraction efficiency are provided.

It is the process flow which showed an example of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the board | substrate for light emitting elements in the manufacture process of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the board | substrate for light emitting elements from which the GaAs substrate and the GaAs buffer layer were removed in the manufacture process of the manufacturing method of the light emitting element of this invention. It is the figure which showed the outline of the light emitting element substrate in which the n-type GaP layer was formed in the manufacture process of the manufacturing method of the light emitting element of this invention. FIG. 5 is an enlarged view of a WS portion of the light emitting element substrate as shown in FIG. 4 in the process after the electrode forming process of the light emitting element manufacturing method according to the embodiment of the present invention. It is the schematic which showed an example of the outline of the light emitting element of this invention.

Hereinafter, the present invention will be described more specifically.
As described in Patent Document 1 described above, a method of increasing the light extraction efficiency by roughening the surface of a light emitting element is known. As this effect, an increase in light emission amount of 10% or more is achieved.
However, conventional roughening etching has a limit, and further improvement in light extraction efficiency has been demanded.

  The present inventor has intensively studied the roughening etching method in order to further improve the light extraction efficiency, and it is possible to limit the roughness that can be reached when a conventional roughening etching solution is used. It has been found that when the surface is scraped to some extent, the remaining convex portion is preferentially dissolved, resulting in a dull surface shape.

Therefore, the function is divided into a first etching solution that changes the material surface to iodic acid (HIO ₃ ), which is a component that is easier to dissolve than I _2, and a second etching solution that contains the component to be dissolved, and is divided into two stages. It was found that the surface roughness can be drastically improved by immersion and etching.
Specifically, after first etching with a first etching solution containing iodic acid, performing a two-step etching with a second etching solution containing hydrofluoric acid, the surface roughness is increased to a larger value than before. Thus, it was found that the light extraction efficiency was improved, and the present invention was completed based on this finding.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. FIG. 6 is a diagram showing an example of a schematic of the light emitting device of the present invention.
The light-emitting element 10 of the present invention includes at least an n-type light extraction layer 20 made of, for example, n-type GaP and having a thickness of 50 μm to 500 μm (for example, 200 μm), an n-type connection layer 13 made of AlGaInP, a light-emitting layer 17, For example, the p-type connection layer 18 made of GaP, the p-type light extraction layer 19 made of p-type GaP and having a thickness of 5 μm to 200 μm (for example, 40 μm), and the second main surface of the n-type light extraction layer 20 are formed. A bonding alloying layer 25a, a back electrode 25 covering the same, a bonding alloying layer 24a formed on the first main surface of the p-type light extraction layer 19, and a light extraction region side electrode 24 covering this, A bonding wire 28 connected to the light extraction region side electrode 24 and a mold portion (not shown) made of epoxy resin are formed.

  And at least the main surface and side surface of the p-type light extraction layer 19 and the side surface of the n-type light extraction layer 20 are roughened, and the surface roughness (Ra) of the light emitting element 10 is 1.4 μm or more. is there.

The light emitting device of the present invention having a surface roughness (Ra) of 1.4 μm or more has a significantly rougher surface than a conventional light emitting device (surface roughness (Ra = 0.4 μm or so)).
Therefore, the reflectance at the surface of the light emitted from the light emitting layer is smaller than the conventional one. That is, the light-emitting element has a significantly improved light extraction efficiency as compared with the conventional light-emitting element, that is, a light-emitting element with high luminance.

Further, the light emitting layer 17 has, for example, at least a composition of (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) and a thickness of 0. An n-type clad layer (first conductivity type clad layer) 14 (the n-type dopant is Si) of 8 μm or more and 4 μm or less (for example, 1 μm), and an active layer 15 (thickness of 0.4 μm or more and 2 μm or less (for example, 0.6 μm)) Non-doped) and a p-type cladding layer (second conductivity type cladding layer) 16 having a thickness of 0.8 μm to 4 μm (for example, 1 μm) (p-type dopant is Mg: C from organometallic molecules also contributes as a p-type dopant. Can be made up of.

  As a result, it is possible to obtain a light-emitting element with higher luminance than in the past in a wide wavelength range from green to red.

  Although the case where the light extraction layer is GaP has been described above, the light extraction layer may have a composition of GaAsP or GaAlAs. In this case, the GaP light extraction layer is replaced with GaAsP or GaAlAs. That's fine.

The light emitting device of the present invention as described above can be manufactured by the method for manufacturing the light emitting device of the present invention as shown below, but is not limited thereto.
This will be described below with reference to FIGS.

  FIG. 1 is a process flow showing an example of a method for manufacturing a light emitting device of the present invention, FIG. 2 is a diagram showing an outline of a light emitting device substrate in the manufacturing process of the method for manufacturing a light emitting device of the present invention, and FIG. FIG. 4 is a schematic diagram of a light emitting device substrate from which a GaAs substrate and a GaAs buffer layer are removed in the manufacturing process of the light emitting device of FIG. 4, and FIG. 4 is an n-type in the manufacturing process of the light emitting device manufacturing method of the present invention. FIG. 5 is a schematic view of a light emitting element substrate on which a GaP layer is formed. FIG. 5 is an enlarged view of the WS portion of the light emitting element substrate as shown in FIG. 4 in the process after the electrode forming process of the light emitting element manufacturing method of the present invention. FIG.

  First, as shown in step 1 of FIG. 1, an n-type GaAs single crystal substrate is prepared as a growth substrate.

  Next, as shown in step 2 of FIG. 1 and FIG. 2, an n-type GaAs buffer layer 12 is epitaxially grown on the main surface of the n-type GaAs single crystal substrate 11 by 0.5 μm, for example, and then n-type composed of AlGaInP. The connection layer 13 is epitaxially grown.

After that, the light emitting layer 17 is made of (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) and has a thickness of 0.8 μm to 4 μm (for example, 1 μm). ) N-type cladding layer (first conductivity type cladding layer) 14 (the n-type dopant is Si), an active layer 15 (non-doped) having a thickness of 0.4 μm or more and 2 μm or less (for example, 0.6 μm), and a thickness of 0. 8 μm or more and 4 μm or less (for example, 1 μm) of a p-type cladding layer (second conductivity type cladding layer) 16 (p-type dopant is Mg: C from organometallic molecules can also contribute as a p-type dopant) in this order Epitaxially grow.
Here, it is desirable that the dopant concentration of each of the p-type cladding layer 16 and the n-type cladding layer 14 is, for example, 1 × 10 ¹⁷ / cm ³ or more and 2 × 10 ¹⁸ / cm ³ or less.

  Further, as shown in step 3 of FIG. 1, a p-type connection layer 18 made of, for example, GaP is epitaxially grown on the p-type cladding layer 16.

The epitaxial growth of each of the above layers can be performed by a known MOVPE method.
Moreover, the following can be used as source gas used as each component source of Al, Ga, In (indium), and P (phosphorus).
-Al source gas; trimethylaluminum (TMAl), triethylaluminum (TEAl), etc.
Ga source gas: trimethylgallium (TMGa), triethylgallium (TEGa), etc.
In source gas: trimethylindium (TMIn), triethylindium (TEIn), etc.
P source gas: trimethyl phosphorus (TMP), triethyl phosphorus (TEP), phosphine (PH ₃ ), etc.

  Next, the process proceeds to step 4 in FIG. 1, and a p-type light extraction layer 19 made of p-type GaP and having a thickness of 5 μm to 200 μm (for example, 40 μm) is grown by HVPE.

Specifically, this HVPE method is based on the reaction of the following formula (1) by introducing hydrogen chloride onto Ga while heating and maintaining the Group III element Ga at a predetermined temperature in the container. GaCl is generated and supplied onto the substrate together with H ₂ gas which is a carrier gas.
Ga (liquid) + HCl (gas) → GaCl (gas) + 1 / 2H ₂ (1)
The growth temperature is set to, for example, 640 ° C. or more and 860 ° C. or less. Further, P which is a group V element supplies PH ₃ onto the substrate together with H ₂ which is a carrier gas. Furthermore, when Zn is used as the p-type dopant, Zn is supplied in the form of DMZn (dimethyl Zn). GaCl is excellent in reactivity with PH _3, and a GaP light extraction layer can be efficiently grown by the reaction of the following formula (2).
GaCl (gas) + PH ₃ (gas)
→ GaP (solid) + HCl (gas) + H ₂ (gas) (2)
At this stage, the light emitting element substrate shown in FIG. 2 is obtained.

  When the growth of the p-type light extraction layer 19 is completed, the process proceeds to step 5 in FIG. 1, and the n-type GaAs single crystal substrate 11 and the n-type GaAs buffer layer 12 are mixed with, for example, an ammonia / hydrogen peroxide mixture as shown in FIG. It is removed by chemical etching using an etching solution such as a solution.

Then, the process proceeds to step 6 in FIG. 1, and, as shown in FIG. 4, the second main surface side (n-type connection layer 13) of the light emitting layer 17 from which the n-type GaAs single crystal substrate 11 and the n-type GaAs buffer layer 12 have been removed. A separately prepared n-type GaP single crystal substrate having a thickness of 50 μm or more and 500 μm or less (for example, 200 μm) is bonded to the second main surface side to form an n-type light extraction layer 20.
Note that the n-type light extraction layer 20 can also be formed by epitaxial growth instead of bonding the GaP single crystal substrate.
The light emitting element substrate 21 is manufactured by the process as described above.

When the above steps are completed, the first main surface of the p-type light extraction layer 19 and the n-type light extraction are performed by sputtering or vacuum evaporation as shown in step 7 of FIG. 1, FIG. 5A, or FIG. Metal layers for forming a bonded alloying layer are formed on the second main surface of the layer 20, respectively, and heat treatment for alloying (so-called sinter treatment) is performed to form bonded alloyed layers 24a and 25a.
And the light extraction area | region side electrode 24 and the back surface electrode 25 are formed so that these joining alloying layers 24a and 25a may be covered, respectively, and it is set as the wafer for light emitting elements.

  FIG. 5 is an enlarged view of the WS portion of FIG. 4, and FIG. 5A shows a state in which the light extraction region side electrode 24 is formed.

Next, the process proceeds to step 8 in FIG. 1, and as shown in FIG. 5B, dicing is performed in accordance with the light emitting element chip size to obtain a light emitting element chip.
For example, in this dicing step, after half dicing, the electrical characteristics are inspected with a probe, and then the full dicing is performed to hold the chip on the sheet.
There is also a method in which full dicing is not performed after half dicing. However, by performing full dicing, not only the side surface portion of the p-type light extraction layer of the light emitting device but also the side surface of the n-type light extraction layer can be roughened by subsequent roughening etching. Full dicing is more desirable because the luminous efficiency can be increased as compared with it.

At the time of dicing, a processing damage layer having a relatively high crystal defect density is formed on the side surface exposed by dicing.
Since a large number of crystal defects included in the processing damage layer cause current leakage and scattering during light-emission energization, the processing damage layer is used as an etching solution for damage layer removal as shown in step 9 of FIG. It is desirable to remove by chemical etching.

As this damage layer removing etching solution, for example, a sulfuric acid-hydrogen peroxide aqueous solution can be used.
Also, for example, a sulfuric acid: hydrogen peroxide: water mass blending ratio of 3: 1: 1 can be used, and the liquid temperature is adjusted to 40 ° C. or higher and 60 ° C. or lower, and requires about 6 minutes of etching. can do.

  Thereafter, as shown in Step 10 of FIG. 1 and FIG. 5C, a roughening etching solution is brought into contact with the main surface and side surfaces of the light emitting element chip from which the processing damage layer has been removed, and the p-type light extraction layer 19 is contacted. Roughening etching is performed to roughen the main surface, side surfaces, and side surfaces of the n-type light extraction layer 20.

  This roughening etching process is a process in which etching is first performed with a first etching solution containing at least iodic acid, and then sequentially etched with a second etching solution containing at least hydrofluoric acid.

  By performing such a roughening etching step, the surface roughness of the light emitting element becomes Ra = 1.4 μm or more, and the surface roughness achieved by the conventional roughening etching (Ra = 0.4 μm) is achieved. It can be made much rougher than that. That is, the amount of light reflected from the light-emitting layer on the surface can be reduced as compared with the conventional case, the light extraction efficiency can be increased as compared with the conventional case, and a high-luminance light-emitting element can be manufactured.

Here, the first etching solution containing at least iodic acid can contain nitric acid and acetic acid in addition to iodic acid. Moreover, the mixing ratio can make 30-1300 mol of nitric acid, 90-120000 mol of acetic acid, and 50-3300 mol of water with respect to 1 mol of iodic acid. Further, hydrogen peroxide may be contained instead of nitric acid.
By setting the first etching solution to the composition as described above, the surface of the light extraction layer can be made rougher by etching with the second etching solution later, and thus a light-emitting element with higher brightness can be manufactured. Can do.

The second etchant preferably contains acetic acid in addition to hydrofluoric acid.
Furthermore, the mixing ratio can be 0 to 20 mol, preferably 2 to 4 mol, relative to 1 mol of hydrofluoric acid. Moreover, water can be 1-2 mol.
By using the second etching solution having such a composition, the surface of the light extraction layer after being immersed in the first etching solution can be further roughened as compared with the conventional one, and thus the light extraction efficiency is further improved. The light emitting element made can be manufactured.

  Thereafter, the second main surface side (the surface of the back electrode 25) is bonded to the metal stage via the Ag paste layer with respect to the separated light emitting element chip, and the bonding wire 28 is attached to the light extraction region side electrode 24. When a connection is made and a mold part (not shown) made of epoxy resin is formed, the light emitting element 10 as shown in FIG. 6 is completed.

  According to the method for manufacturing a light emitting device of the present invention as described above, the reflectance at the surface of the light emitted from the light emitting layer can be reduced as compared with the conventional light emitting device. Can be manufactured.

Although the case where the GaP layer is formed as the light extraction layer has been described above, this light extraction layer may be GaAsP or GaAlAs.
In this case, the step of forming the GaP layer may be a step of forming a GaAsP layer or a GaAlAs layer.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
Example 1
A light emitting device substrate as shown in FIG. 4 was manufactured according to the steps as shown in FIG.
Then, after dicing, the light-emitting element chip was immersed in a first etching solution having a composition of iodic acid: nitric acid: acetic acid: water = 1: 120: 520: 200 (mol ratio), and the temperature was 40 ° C. Held for 10 minutes. Thereafter, the surface of the light-emitting element chip is roughened by immersing the light-emitting element chip in a second etching solution having a composition of hydrofluoric acid: acetic acid = 1: 2.8 (mol ratio) at room temperature for 5 minutes to manufacture a light-emitting element. did.

(Example 2)
A light emitting device was manufactured under the same conditions as in Example 1 except that the composition of the first etching solution was iodic acid: nitric acid: acetic acid: water = 1: 60: 260: 100 (mol ratio).

(Comparative Example 1)
In Example 1, a light-emitting element substrate as shown in FIG. 4 was made into a light-emitting element chip by dicing, and then a light-emitting element was manufactured without performing roughening etching.

(Comparative Example 2)
In Example 1, as an etchant used in the roughening etching step, an etchant mixed so that the composition is iodine: hydrofluoric acid: nitric acid: acetic acid: water = 1: 190: 60: 970: 310 (mol ratio) Was prepared, and the surface of the light-emitting element chip was roughened by etching at a liquid temperature of 50 ° C. for 2 minutes, whereby a light-emitting element was manufactured.

The surface roughness of the light emitting elements of Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated. The light emission output was evaluated by measuring the omnidirectional light output with an integrating sphere when a direct current of 20 mA was passed.
The results are summarized in Table 1. In addition, the light emission output was shown by the relative value which set the light emission output of the light emitting element of the comparative example 1 which did not perform roughening etching to 1.0.

The light emitting element of Example 1 had a surface roughness Ra of 1.4 μm, which was much larger than the light emitting elements of Comparative Examples 1 and 2. Further, the light emission output is improved by 32% compared to the light emitting element of Comparative Example 2 subjected to the conventional roughening etching, and is 2.5 times the output of the light emitting element of Comparative Example 1 which is not roughened. there were.
Further, the surface roughness of the chip of Example 2 was Ra = 1.6 μm, which was further rougher than Example 1. Thus, the light emission output was improved by 37% compared with the light emitting element of Comparative Example 2 in which the conventional roughening etching was performed.
On the other hand, the surface roughness of the light emitting element of Comparative Example 2 was Ra = 0.4 μm, and the light emission output was about 1.9 times that of Comparative Example 1 in which roughening etching was not performed. , 2 is 80% or less of the light emission output, and did not reach.

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

10: Light emitting element,
DESCRIPTION OF SYMBOLS 11 ... Growth substrate (n-type GaAs single crystal substrate), 12 ... n-type GaAs buffer layer, 13 ... n-type connection layer, 14 ... First conductivity type cladding layer (n-type cladding layer), 15 ... Active layer, 16 ... second conductivity type cladding layer (p-type cladding layer), 17 ... light-emitting layer, 18 ... p-type connection layer,
19 ... p-type light extraction layer (p-type GaP layer), 20 ... n-type light extraction layer (n-type GaP layer), 21 ... light-emitting element substrate,
24 ... (light extraction region side) electrode, 24a ... bonded alloying layer,
25 ... back electrode, 25a ... bonded alloying layer,
28: Bonding wire.

Claims (5)

at least,
A light emitting element substrate is formed by dicing a light emitting element substrate whose light extraction layer is made of any of GaP, GaAsP, and GaAlAs,
The surface of the light emitting device chip, look containing at least iodate, and, after etching the first etching solution containing no hydrofluoric acid, which is a component to dissolve, are sequentially etched by the second etching solution containing at least hydrofluoric acid A method for manufacturing a light-emitting element, comprising a roughening etching step for roughening a surface. The light emitting element substrate;
First conductivity type cladding layers each composed of at least a compound represented by the composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) The light extraction layer is laminated or bonded to a light emitting layer having a double hetero structure in which an active layer and a second conductivity type cladding layer are laminated in this order. Of manufacturing the light-emitting device.   The method for manufacturing a light-emitting element according to claim 1, wherein the first etching solution includes nitric acid and acetic acid in addition to the iodic acid.   4. The method of manufacturing a light emitting element according to claim 1, wherein the second etching solution contains acetic acid in addition to the hydrofluoric acid. 5. 5. The surface-roughening etching step is performed so that the surface roughness (Ra) of the light emitting element is 1.4 μm or more and 1.6 μm or less. 6. The manufacturing method of the light emitting element of description.

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