JP5278323B2 - Manufacturing method of high brightness light emitting diode - Google Patents

Description

The present invention relates to a method of manufacturing a high brightness light emitting diode, a light emitting element substrate, and a high brightness light emitting diode.

  In recent years, research on increasing the brightness of light emitting diodes has been conducted, and in order to dramatically improve the light emission in the entire light emitting layer and the light extraction efficiency from the side surface, the current diffusion layer is made thicker. FIG. 11 is a schematic view showing a cross section of a light-absorbing type high-intensity light-emitting diode. This high-intensity light-emitting diode 51 has a quaternary light-emitting layer 53, a connection layer 54 ′, and a current diffusion layer 54 on a GaAs substrate 52, especially when the thickness of the conventional current diffusion layer is about 8 μm. On the other hand, the current diffusion layer 54 of the high-intensity light emitting diode has a thick film of about 50 to 150 μm. As a result, the brightness can be increased by about twice or more compared to the conventional light emitting diode. Further, the light absorption type high-intensity light-emitting diode 51 of FIG. 11 is manufactured as follows.

  First, a light emitting layer 53 composed of a quaternary compound semiconductor (for example, AlGaInP) is epitaxially grown on a GaAs substrate 52 in a reactor of metal-organic chemical vapor deposition (MOCVD), A connection layer 54 ′ for growing the current diffusion layer 54 is heteroepitaxially grown thereon and taken out. Subsequently, it is placed in a reactor of hydride vapor phase epitaxy (HVPE), a current diffusion layer 54 such as GaP as a light extraction window is homoepitaxially grown on the connection layer 54 ', and vacuum deposition is performed. The light extraction side electrode 56 and the back surface electrode 57 are attached by the method to form a chip.

  The high-intensity light-emitting diode 51 manufactured in this way is known as a light-absorption type high-intensity light-emitting diode because the light absorption of the GaAs substrate 52 is large in the emission wavelength region of the quaternary emission layer 53.

  On the other hand, the light transmission type high-intensity light emitting diode is manufactured by the same manufacturing method as the light absorption type high-intensity light emitting diode 51, and after forming the first current diffusion layer 54, the GaAs substrate 52 is removed with an etching solution. A second current diffusion layer is heteroepitaxially grown on the surface from which the GaAs substrate 52 has been removed. Then, an electrode is attached and processed into a chip to obtain a light-transmitting high-intensity light-emitting diode. The light-transmitting high-intensity light-emitting diode manufactured as described above has an effect of extracting light not only from the side surface of the light-emitting element but also from the transparent substrate side (US Pat. No. 5,0087,18).

  However, in such a light transmissive type high-intensity light emitting diode, when the second current diffusion layer is formed on the surface from which the GaAs substrate is removed, due to the stress due to lattice strain that occurs when the amount of lattice displacement increases, There is a problem that the growth film in the epitaxial layer is destroyed.

In addition, when forming the second current diffusion layer on the surface from which the GaAs substrate has been removed, due to lattice mismatch that occurs when the amount of lattice misalignment increases, the interface at the initial stage of growth is substantially spherical and has a diameter of several tens of nanometers. A micro-hole defect of ˜several μm is formed, and this micro-hole defect causes a problem of partial bonding failure.

  The present invention has been made in view of such problems, and in the method of manufacturing a high-intensity light emitting diode, the growth during epitaxial that occurs when the second current diffusion layer is formed on the surface from which the GaAs substrate has been removed. An object of the present invention is to manufacture a high-intensity light-emitting diode capable of preventing film breakage and suppressing micro-hole defects generated at the interface at the initial stage of growth.

In order to solve the above-described problems, the present invention provides at least a step of forming a quaternary light emitting layer on the first main surface side of a GaAs substrate by epitaxial growth, and a first current diffusion layer on the quaternary light emitting layer. A step of forming a group III-V compound semiconductor by HVPE growth, a step of removing the GaAs substrate, and forming a group III-V compound semiconductor by HVPE growth as a second current diffusion layer on the surface from which the GaAs substrate has been removed. And a method of manufacturing a high-intensity light-emitting diode that performs a process of processing the obtained substrate into a chip,
The step of forming a group III-V compound semiconductor as a second current diffusion layer on the surface from which the GaAs substrate has been removed by HVPE growth has an initial III / V ratio of 3 or more, and then III / V ratio is changed so as to be relatively low, and a III-V compound semiconductor is formed as a second current diffusion layer by HVPE growth, and the initial III / V ratio is 3 or more in this step. Thus, the growth temperature when forming the second current diffusion layer is 550 ° C. to 700 ° C., which is a lower temperature range than the temperature when growing with a relatively low III / V ratio, and the III / V ratio. When the temperature is 5 or more, the growth is started at a temperature in the range of 550 ° C. to 730 ° C., and then the temperature is raised to the same temperature as that at the time of growth with a relatively low III / V ratio. High To provide a method of manufacturing a degree emitting diode.

  Here, the initial III / V ratio of the source gas to be supplied is made higher than 3, and the growth temperature when forming the second current diffusion layer is set to a temperature within a range of 550 ° C. to 700 ° C. can do.

In the manufacture of light-transmitting high-intensity light-emitting diodes, during growth of the second current diffusion layer on the surface from which the GaAs substrate has been removed, stress due to lattice strain that occurs when the amount of lattice displacement increases causes There is a problem that the growth film is destroyed. In particular, the substrate manufactured at a position away from the supply port of the source gas has a strong tendency to destroy the growth film and cause a microhole defect. Therefore, it is considered that the above problem is caused by the lack of the group III gas that is the source gas of the current diffusion layer in the process of forming the second current diffusion layer.
Therefore, the above problem is solved by setting the III / V ratio at the initial stage to 3 or more, more preferably higher than 3, and making the III / V ratio relatively low in a state where the group III gas is sufficiently distributed to all the substrates. Is solved, and the destruction of the growth film can be prevented.
As described above, according to the manufacturing method of the present invention, it is possible to suppress the destruction of the growth film even on the substrate manufactured at a position away from the supply port of the source gas, and it is possible to manufacture a high-quality high-intensity light-emitting diode. .

Also, in the manufacture of light-transmitting high-intensity light-emitting diodes, when the second current diffusion layer is formed on the surface from which the GaAs substrate is removed, the initial growth is caused by a lattice mismatch that occurs when the amount of lattice displacement increases. A micro-hole defect is formed at the interface at the stage, and this micro-hole defect causes a problem in that a partial bonding failure occurs.
However, with the III / V ratio at the beginning of formation being 3 or more, more preferably 3 or more, the temperature is raised to a temperature (for example, 750 ° C.) for growth with a relatively low III / V ratio. In the middle of 550 to 700 ° C., when the III / V ratio is 5 or more, start growth at a low temperature range of 550 ° C. to 730 ° C., thereby reducing the amount of lattice misalignment and generating micro hole defects. Can be suppressed. Further, the warp due to the difference in linear expansion coefficient can be reduced by lowering the growth start temperature.
As a result, it is possible to form a current diffusion layer that suppresses partial bonding failure, and it is possible to prevent substrate cracking in the chip process. The same effect can be obtained even with a substrate manufactured at a position away from the source gas supply port.

  In this case, the first and second current diffusion layers to be grown can be GaP or GaAsP window layers.

  As described above, the current diffusion layer can be made of GaP or GaAsP and can have high luminance.

  In this case, the method of setting the initial III / V ratio to 3 or more reduces the III / V ratio by lowering the supply amount of the group V source gas than when the III / V ratio is relatively low. Is relatively high.

  By keeping the supply amount of Group III source gas constant and reducing the supply amount of Group V source gas, it is possible to reduce the concentration of the source material and prepare an environment with a high III / V ratio, and prevent the growth film from being destroyed. The occurrence of micro hole defects can be suppressed. Also, after the formation of a current diffusion layer with a high III / V ratio, it is possible to grow at a high speed by increasing the proportion of the group V source gas, which is good in productivity and promotes lattice relaxation by rapid growth. In addition, a high-intensity light emitting diode having a current diffusion layer that has a small warpage and is difficult to break can be manufactured.

  According to the present invention, there is also provided a light emitting element substrate including at least a quaternary light emitting layer and first and second current diffusion layers, and the number of microhole defects having a diameter of 1 μm or more at the interface of the second current diffusion layer. Is less than 200 / cm, preferably less than 80 / cm, and more preferably 0 / cm, whereby a light-emitting element substrate is obtained.

  Thus, for example, in a light emitting element substrate composed of a quaternary light emitting layer and first and second current diffusion layers, the number of microhole defects having a diameter of 1 μm or more at the interface of the second current diffusion layer is less than 200 / A light-emitting element substrate having a cm of preferably less than 80 / cm, more preferably 0 / cm, is a high-quality light-emitting element substrate having no bonding failure.

  Furthermore, the present invention is a light emitting diode element comprising at least a quaternary light emitting layer and first and second current diffusion layers, wherein the number of microhole defects having a diameter of 1 μm or more at the interface of the second current diffusion layer is 200. A high-intensity light-emitting diode element characterized in that the number is less than 80 / cm, preferably less than 80 / cm, more preferably 0 / cm is obtained.

  Thus, for example, in a light emitting diode element composed of a quaternary light emitting layer and first and second current diffusion layers, the number of microhole defects having a diameter of 1 μm or more at the interface of the second current diffusion layer is less than 200 / cm, A high-intensity light-emitting diode element that has a good Vf value and life characteristics without a defective junction, as long as the high-intensity light-emitting diode element is preferably less than 80 / cm, more preferably 0 / cm It becomes.

With such a method of manufacturing a high-intensity light emitting diode of the present invention, when the second current diffusion layer is grown on the surface from which the GaAs substrate has been removed, it is possible to effectively prevent the growth film from being destroyed during the epitaxial process. Micro-hole defects that occur at the interface at the initial stage of growth can be effectively suppressed, and the same effect can be obtained even with a substrate manufactured at a position away from the source gas supply port. A high-intensity light emitting diode can be manufactured with high productivity.

It is the conceptual diagram which showed the manufacturing method of the high-intensity light emitting diode which concerns on this invention in process order. A substrate of a high-intensity light-emitting diode obtained by forming an n-type GaP film at (a) upstream, (b) intermediate flow, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Example 1 It is an observation photograph of the surface. A substrate of a high-intensity light-emitting diode obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 1 It is an observation photograph of the surface. A substrate of a high-intensity light-emitting diode obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 2 It is an observation photograph of the surface. The substrate of the high-intensity light-emitting diode obtained by forming the n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 3 It is an observation photograph of the surface. A substrate of a high-intensity light-emitting diode obtained by forming an n-type GaP film at (a) upstream, (b) intermediate flow, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Example 1 It is the observation photograph of the n layer interface expanded 500 times with the color laser microscope. A substrate of a high-intensity light-emitting diode obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 1 It is the observation photograph of the n layer interface expanded 500 times with the color laser microscope. In Comparative Example 2, the n-layer interface magnified 500 times with a color laser microscope of the substrate of the high-intensity light-emitting diode obtained by forming the n-type GaP film upstream from the source gas supply port of the n-type GaP window layer It is an observation photograph. In Comparative Example 3, the n-layer interface magnified 500 times with a color laser microscope of the substrate of the high-intensity light-emitting diode obtained by forming the n-type GaP film upstream from the source gas supply port of the n-type GaP window layer It is an observation photograph. It is (a) sectional drawing and (b) front view of the apparatus which supplies the source gas used by the Example, the comparative example, and the experiment example. It is the schematic which showed the cross section of the high-intensity light emitting diode of a light absorption type.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.
In the method of manufacturing a high-intensity light-emitting diode, the inventor prevents the growth film from being destroyed during the growth of the second current diffusion layer on the surface from which the GaAs substrate has been removed, so that the interface at the initial stage of growth is prevented. In order to develop a manufacturing method of a high-intensity light-emitting diode that can suppress the micro-hole defect that has occurred, intensive studies were conducted.

  As a result, the present inventor consumes Group III raw materials because the growth film is more likely to be destroyed and micro-hole defects are generated, particularly in a substrate manufactured at a position farther from the supply port of the raw material gas. It was considered that the growth film was destroyed when the III / V ratio was lowered. If the III / V ratio is an environment of 3 or more at the beginning of formation, it is possible to prevent the growth of the epitaxially grown film from being destroyed, and by changing the molar ratio of the source gas introduced into the furnace, In a state where the V ratio is 3 or more, the temperature is increased from 550 to 700 ° C. while the temperature is increased to a temperature (for example, 750 ° C.) when the later III / V ratio is relatively lowered, and the III / V ratio is 5 In the case of the above, by starting the growth at a low temperature range of 550 ° C. to 730 ° C., it is possible to suppress the occurrence of microhole defects and to prevent substrate cracking in the chip process. The inventors have found that the same effect can be obtained with a substrate manufactured at a position away from the supply port, and completed the present invention.

Hereinafter, the manufacturing method of the high-intensity light emitting diode of this invention is demonstrated.
The manufacturing method of the high-intensity light-emitting diode according to the present invention includes at least a step of forming a quaternary light-emitting layer on the first main surface side of the GaAs substrate by epitaxial growth, and a first current diffusion layer on the quaternary light-emitting layer. A step of forming a group III-V compound semiconductor by HVPE growth, a step of removing the GaAs substrate, and forming a group III-V compound semiconductor by HVPE growth as a second current diffusion layer on the surface from which the GaAs substrate has been removed. And a step of processing the obtained substrate into a chip, wherein a III-V group compound semiconductor is provided as a second current diffusion layer on the surface from which the GaAs substrate has been removed. In the process of forming by HVPE growth, the initial III / V ratio of the raw material gas to be supplied is set to 3 or more, and then the III / V ratio is relatively And forming a group III-V compound semiconductor by HVPE growth as the second current spreading layer, and in this step, the initial III / V ratio is set to 3 or more to form the second current spreading. When the growth temperature at the time of forming the layer is set to 550 ° C. to 700 ° C., which is a lower temperature range than the temperature at which the III / V ratio is relatively lowered, and the III / V ratio is 5 or more A high-luminance light-emitting diode characterized by starting growth at a temperature in the range of 550 ° C. to 730 ° C. and then raising the temperature to the same temperature as the temperature at which the III / V ratio is relatively lowered. It is a manufacturing method.
FIG. 1 is a conceptual diagram illustrating a method of manufacturing a high-intensity light emitting diode according to the present invention in the order of steps. Hereinafter, each step will be described in more detail.

  In step 101 of FIG. 1, an n-type GaAs substrate 2 is prepared as a growth single crystal substrate, cleaned, and then placed in a MOCVD reactor.

Next, in step 102, the quaternary light emitting layer 3 made of AlGaInP is epitaxially grown on the first main surface side of the n-type GaAs substrate 2 by metal organic vapor phase epitaxy (MOCVD) to form about 5 μm. The quaternary light emitting layer 3 is made of (Al _x Ga _1-x ) _y In _1-y P (0 <x, y <1), and an n-type cladding layer, an active layer, and a p-type cladding layer are arranged in this order. Form with.

As source gases used as component sources of Al, Ga, In (indium), and P (phosphorus) used in the epitaxial growth of these layers, an Al source gas (for example, trimethylaluminum (TMAl), triethylaluminum (TEAl)), Ga Source gas (for example, trimethylgallium (TMGa), triethylgallium (TEGa)), In source gas (for example, trimethylindium (TMIn), triethylindium (TEIn)), P source gas (for example, trimethylphosphorus (TMP), triethyl) Phosphorus (TEP), phosphine (PH ₃ )) and the like.

  Next, in Step 103, a first current diffusion layer is formed on the quaternary light emitting layer 3. The current spreading layer 4 is preferably a GaP or GaAsP window layer. Hereinafter, the GaP window layer will be described as an example of the current spreading layer 4.

  The connection layer 6 made of p-type GaP is heteroepitaxially grown to a thickness of several μm by the MOCVD method. Then, the substrate is placed in an HVPE reactor, doped with Zn, and the p-type GaP current diffusion layer 4 is homoepitaxially grown on the connection layer 6 to form a p-type GaP window layer with a thickness of 30 to 200 μm.

Here, with respect to the HVPE method, specifically, the reaction of the following formula (1) is performed by introducing hydrogen chloride onto the Ga while maintaining the group III element Ga at a predetermined temperature in the container. Then, GaCl is generated and supplied onto the substrate together with H ₂ gas which is a carrier gas. The growth temperature is set to 600 ° C. or higher and 800 ° C. or lower, for example.
Ga (g) + HCl (g) → GaCl (g) + 1 / 2H ₂ (g) (1)

Further, P, which is a group V element, supplies PH ₃ together with H ₂ which is a carrier gas onto the substrate, and Zn, which is a p-type dopant, is supplied in the form of DMZn (dimethyl Zn). GaCl is excellent in reactivity with PH _3, and the current diffusion layer can be efficiently grown by the reaction of the following formula (2).
GaCl (g) + PH ₃ (g) → GaP (s) + HCl (g) + H ₂ (g) (2)

  Next, in step 104, the second main surface side of the GaAs substrate is polished to remove peripheral nodules, and then etching is performed to remove the GaAs substrate. As an etchant, for example, a sulfuric acid / hydrogen peroxide mixture can be used.

Next, in Step 105a and Step 105b, the second current diffusion layer 5 is formed on the surface from which the GaAs substrate has been removed by epitaxial growth using the HVPE method described above. The current spreading layer 5 is preferably an n-type GaP window layer or an n-type GaAsP window layer. In step 105a, the initial III / V ratio is set to 3 or more, more preferably higher than 3, and the second current diffusion layer 5a having a high III / V ratio is formed to have a thickness of several μm. On the other hand, in step 105b, the III / V ratio is changed to be relatively low, and the second current spreading layer 5b having a low III / V ratio is formed.
Thus, by making the III / V ratio at the initial stage of epitaxial growth 3 or more, more preferably higher than 3, it is possible to effectively prevent the destruction of the epitaxial film caused by the shortage of the group III material.

Here, in the method of setting the III / V ratio to 3 or more in the step 105a, the III / V ratio is relatively increased by reducing the supply amount of the group V source gas compared to the step 105b. preferable. By doing so, waste due to unreacted group III raw materials can be eliminated. Further, when the reaction temperature at the initial stage of growth is lowered, the raw material becomes excessive and the quality of the epitaxial film does not deteriorate.
At this time, the III / V ratio set to 3 or more in the step 105a can be preferably 5 or more. By setting it as this range, the destruction of the growth film during the epitaxial can be effectively suppressed even in the substrate located further downstream. The III / V ratio is desirably 10,000 or less. If it is smaller than 10,000, it can suppress that the V group element runs short and the quality of the epitaxial film deteriorates.
On the other hand, the relatively low III / V ratio in step 105b can be set to 1.0 or more, more preferably 1.2 or more.

Furthermore, the growth start temperature in the step 105a is in the range of 550 ° C. to 700 ° C., which is a low temperature region in the middle of raising the temperature to the growth temperature of the step 105b, and in the range of 550 ° C. to 730 ° C. when the III / V ratio is 5 or more. Then, the temperature is raised to the same temperature as the growth temperature in step 105b.
As described above, when the temperature is increased from 550 ° C. to 700 ° C. and the III / V ratio is 5 or more, the growth is started at a low temperature range of 550 ° C. to 730 ° C. It is because it can do.

Finally, in step 106, the substrate is cut, processed into chips, and electrodes are attached, so that a high-intensity light emitting diode is obtained.

Example 1
In the environment of 600 to 800 ° C. on the first main surface side of the GaAs substrate having the thickness of 280 μm and the orientation flat (OF) formed on the outer periphery in accordance with the process of FIG. 1 of the present invention described above, (CH ₃ ) ₃ Using Al, (CH ₃ ) ₃ Ga, (CH ₃ ) ₃ In, and PH ₃ as source gases, an MOGa method is used to form an AlGaInP quaternary light-emitting layer having a thickness of 8 μm. At that time, a MOP method is used as the surface layer to form a GaP film of several μm. A p-type GaP window layer having a thickness of 150 μm was formed as a first current diffusion layer using the HVPE method, and then the GaAs substrate was removed by etching.
Next, a second current spreading layer is formed by the HVPE method. The formation start temperature at the beginning of the formation is set to 614 ° C., and the growth is started from 614 ° C. in a low temperature region in the middle of raising the temperature to 750 ° C. which is a predetermined growth temperature. Further, by changing the molar ratio of hydrogen chloride and phosphine, which is a raw material gas for the n-type GaP window layer introduced into the furnace, the raw material gas is supplied to the substrate with a III / V ratio of 6.0, and the n-type GaP window layer Is formed to 2.5 μm. Thereafter, the III / V ratio was changed to 1.2 to 3.0, and an n-type GaP window layer was formed to 150 μm.

  The source gas was supplied using an apparatus shown in FIG. (A) of FIG. 10 is sectional drawing of an apparatus, (b) is a front view. The source gas supplied from the upstream side of the susceptor 21 to the front side can sufficiently come into contact with the front side of the substrate 24 held by the counterbore part 22. The support shaft 25 rotates at a constant speed so that the source gas is supplied evenly. In all of the following Examples, Comparative Examples, and Experimental Examples, the raw material gas was supplied using this apparatus.

FIG. 2 shows high brightness obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream from the source gas supply port of the n-type GaP window layer in Example 1. It is an observation photograph of the substrate surface of a light emitting diode.
Further, FIG. 6 was obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Example 1. It is the observation photograph of the n layer interface expanded 500 times with the color laser microscope (product made from VK-9710 Keyence) of the board | substrate of a high-intensity light emitting diode. The n-layer interface was observed at two points (OF side (OF) and opposite side of the OF side (anti-OF)) at 5 mm from the center (Center) and the outer periphery of each wafer. No micro-hole defects were observed in any wafer, and the generation of defects could be suppressed.

(Comparative Example 1)
The same process as in the previous embodiment is performed until the GaAs substrate is removed by etching.
Next, a second current spreading layer is formed by the HVPE method. The growth temperature is kept constant at 750 ° C., and the source gas is supplied to the substrate at the initial III / V ratio of 6.0 for forming the source gas for the n-type GaP window layer, and the n-type GaP window layer is 2.5 μm. Form. Thereafter, the III / V ratio was changed to 1.2 to 3.0, and an n-type GaP window layer was formed to 150 μm.

FIG. 3 shows high brightness obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 1. It is an observation photograph of the substrate surface of a light emitting diode.
Further, FIG. 7 was obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 1. It is the observation photograph of the n layer interface expanded 500 times with the color laser microscope (product made from VK-9710 Keyence) of the board | substrate of a high-intensity light emitting diode. Note that (a) upstream is the center of the wafer only (Center), (b) is the middle stream, (c) the downstream is the center (Center) of each wafer and two positions 5 mm from the outer periphery (OF side (OF) and The n layer interface on the opposite side of the OF side (anti-OF) was observed. From the observation photograph of the n-layer interface in FIG. 7, microhole defects were observed at the interface portion of Comparative Example 1.

(Comparative Example 2)
The same process as in the previous embodiment is performed until the GaAs substrate is removed by etching.
Next, a second current diffusion layer is formed by a vapor deposition method. While maintaining the growth temperature constant at 750 ° C. and maintaining the III / V ratio of the source gas of the n-type GaP window layer constant at 3.0, the n-type GaP window layer was formed to 150 μm.

FIG. 4 shows high brightness obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream as viewed from the source gas supply port of the n-type GaP window layer in Comparative Example 2. It is an observation photograph of the substrate surface of a light emitting diode.
8 shows a color laser microscope (VK−) of the substrate of the high-intensity light-emitting diode obtained by forming the n-type GaP film upstream from the source gas supply port of the n-type GaP window layer in Comparative Example 2. 9710 Keyence)) is an observation photograph of the n-layer interface magnified 500 times. It should be noted that the n-layer interface was observed at two points (OF side (OF) and opposite side of the OF side (anti-OF)) 5 mm from the center and the outer periphery of each wafer. From the observation photograph of the n-layer interface in FIG. 8, microhole defects were observed at the interface portion of Comparative Example 2.

(Comparative Example 3)
The same process as in the previous embodiment is performed until the GaAs substrate is removed by etching.
Next, a second current diffusion layer is formed by a vapor deposition method. The n-type GaP window layer was formed to 150 μm while the growth temperature was kept constant at 750 ° C. and the III / V ratio of the source gas of the n-type GaP window layer was kept constant at 1.2.

FIG. 5 shows a high brightness obtained by forming an n-type GaP film at (a) upstream, (b) midstream, and (c) downstream from the source gas supply port of the n-type GaP window layer in Comparative Example 3. It is an observation photograph of the substrate surface of a light emitting diode.
9 shows a color laser microscope (VK−) of a substrate of a high-intensity light-emitting diode obtained by forming an n-type GaP film upstream from the source gas supply port of the n-type GaP window layer in Comparative Example 3. 9710 Keyence)) is an observation photograph of the n-layer interface magnified 500 times. Note that the n-layer interface was observed at two points (OF side (OF) and opposite side of the OF side (anti-OF)) at a position 5 mm from the center and the outer periphery of the wafer. From the observation photograph of the n-layer interface in FIG. 9, microhole defects were observed at the interface portion of Comparative Example 3.

4 and 5, when the III / V ratio was 3.0 or less and the substrate temperature was high, the growth film was broken on the downstream substrate. When the III / V ratio was 1.2, the growth film was broken not only on the downstream substrate but also on the midstream substrate.

(Experimental example)
The same process as in Example 1 is performed until the GaAs substrate is removed by etching.
Next, a second current diffusion layer is formed by a vapor deposition method. The formation start temperature at the beginning of formation was set to 5 levels, the III / V ratio at the beginning of formation of the source gas for the n-type GaP window layer was set to 5 levels, and each was changed to form the second current diffusion layer. The formation start temperatures were 500 ° C., 550 ° C., 700 ° C., and 730 ° C., respectively, and the growth was started from a temperature in the low temperature region while the temperature was raised to 750 ° C., which is a predetermined growth temperature. The remaining one level was constant at 750 ° C. The source gas of the n-type GaP window layer was initially formed with a III / V ratio of 1.2, 3, 6, 20, and 80, respectively, and the source gas was supplied to the substrate to form an n-type GaP window layer of 2.5 μm. . Thereafter, the III / V ratio was changed to 1.2 to 3.0, and an n-type GaP window layer was formed to 150 μm.

  In the above experimental examples, when the formation start temperature is 700 ° C., the initial III / V ratio of the source gas for forming the n-type GaP window layer is set to 6, and the case where the examples are set to Examples 2 and 20. , 80 is Example 4, and when the formation start temperature is 550 ° C., the initial III / V ratio is 6 and Examples 5 and 20 are Examples 6 and 80. Example 7 and Comparative Example 4 (formation start temperature = 500 ° C., III / V ratio at the beginning of formation = 1.2), Comparative Example 5 (formation start temperature = 500 ° C., III / V at the beginning of formation) V ratio = 3), Comparative Example 6 (formation start temperature = 500 ° C., initial III / V ratio = 6), Comparative Example 7 (formation start temperature = 500 ° C., initial III / V ratio = 20), Comparative example 8 (formation start temperature = 500 ° C., initial III / V ratio = 80), comparative example (Formation start temperature = 550 ° C., III / V ratio at the beginning of formation = 1.2), Example 8 (Formation start temperature = 550 ° C., III / V ratio at the beginning of formation = 3), Comparative Example 10 (Formation start temperature) = 700 ° C, III / V ratio at the beginning of formation = 1.2), Example 9 (formation start temperature = 700 ° C, III / V ratio at the beginning of formation = 3), Comparative Example 11 (formation start temperature = 730 ° C, III / V ratio at the beginning of formation = 1.2), Comparative Example 12 (formation start temperature = 730 ° C., III / V ratio at the beginning of formation = 3), Example 10 (formation start temperature = 730 ° C., III at the beginning of formation) / V ratio = 6), Example 11 (formation start temperature = 730 ° C., initial III / V ratio = 20), Example 12 (formation start temperature = 730 ° C., initial III / V ratio = 80) Comparative Example 13 (constant at 750 ° C., initial III / V ratio = 1.2), Comparative Example 1 (Constant 750 ° C., III / V ratio at the beginning of formation = 3), Comparative Example 15 (Constant 750 ° C., III / V ratio at the beginning of formation = 6), Comparative Example 16 (Constant 750 ° C., III / V ratio at the beginning of formation) = 20) and Comparative Example 17 (constant at 750 ° C, III / V ratio at the beginning of formation = 80)).

  Table 1 shows the results of the number of bonding defects and micro-hole defects (diameter of 1 μm or more) in the wafer in which the second current diffusion layer is formed using each level. The micro hole defect counting method is to count the number of defects of 1 μm or more in the range of 50 μm along the interface from a photograph magnified 500 times with a color laser microscope (manufactured by VK-9710 Keyence). By multiplying by 200, the number per 1 cm was calculated, and the average value of a total of 3 points, 2 points at 5 mm from the center and outer periphery of the wafer (on the opposite side of the OF side and the OF side (anti-OF side)), was calculated.

  In the description of Table 1 above, ◎ and ○ indicate no bonding failure, □ indicates a slight bonding failure but good product of 95% or more, Δ indicates a partial bonding failure, and × indicates that epitaxial growth is not possible. From Table 1, in Example 2-7, there was no joining defect and the micro hole defect of 1 micrometer or more was 0 piece / cm. On the other hand, in Comparative Examples 4-11 and 13 in which the initial III / V ratio was 1.2, epitaxial growth could not be performed, and in other Comparative Examples (Comparative Examples 12 and 14-17), partial bonding failure was observed. Many micro hole defects of 1 μm or more were observed. From this, the temperature (750 ° C.) when growing with the III / V ratio at the beginning of the second current diffusion layer formation being 3 or more and the later III / V ratio being relatively low is grown. When the temperature is increased from 550 to 700 ° C. and the III / V ratio is 5 or more, by starting the growth at a low temperature range of 550 ° C. to 730 ° C., it is possible to suppress the bonding failure, and the micro hole defect It became clear that generation | occurrence | production of can be suppressed.

  As can be seen from these results, according to the manufacturing method of the high-intensity light-emitting diode of the present invention, when the second current diffusion layer is grown on the surface from which the GaAs substrate is removed, the growth film in the epitaxial layer is effectively destroyed. It is possible to effectively prevent micro-hole defects that occur at the interface at the initial stage of growth, and the same effect can be obtained even with a substrate manufactured downstream from the source gas supply port. High-quality high-intensity light-emitting diodes could be manufactured.

  According to the present invention, the film breakage is eliminated and the production of high-quality high-intensity light-emitting diodes by double-sided growth epitaxial growth of the window layer can be stably produced in multiple stages, and the productivity of double-sided growth is greatly improved. In addition, by suppressing the occurrence of interface hole defects, the Vf value and life characteristics are improved, and by suppressing defective bonding, it is possible to reduce yield reduction and reduce man-hours by removing defective bonding parts in the chip manufacturing process. This has been achieved and the productivity of high-intensity light-emitting diodes has been dramatically improved.

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

Claims (4)

At least a step of forming a quaternary light emitting layer by epitaxial growth on the first main surface side of the GaAs substrate, and forming a III-V group compound semiconductor as a first current diffusion layer on the quaternary light emitting layer by HVPE growth. A step, a step of removing the GaAs substrate, a step of forming a group III-V compound semiconductor as a second current diffusion layer on the surface from which the GaAs substrate has been removed by HVPE growth, and processing the obtained substrate into a chip In the method of manufacturing a high-intensity light emitting diode,
The step of forming a group III-V compound semiconductor as a second current diffusion layer on the surface from which the GaAs substrate has been removed by HVPE growth has an initial III / V ratio of 3 or more, and then III / V ratio is changed so as to be relatively low, and a III-V compound semiconductor is formed as a second current diffusion layer by HVPE growth, and the initial III / V ratio is 3 or more in this step. Thus, the growth temperature when forming the second current diffusion layer is 550 ° C. to 700 ° C., which is a lower temperature range than the temperature when growing with a relatively low III / V ratio, and the III / V ratio. When the temperature is 5 or more, the growth is started at a temperature in the range of 550 ° C. to 730 ° C., and then the temperature is raised to the same temperature as that at the time of growth with a relatively low III / V ratio. High Method for producing a degree-emitting diodes.   The initial III / V ratio of the source gas to be supplied is made higher than 3, and the growth temperature when forming the second current diffusion layer is set to a temperature within the range of 550 ° C. to 700 ° C. The method for manufacturing a high-intensity light-emitting diode according to claim 1.   3. The method for manufacturing a high-intensity light emitting diode according to claim 1, wherein the first and second current diffusion layers to be grown are GaP or GaAsP window layers. In the method of setting the initial III / V ratio to 3 or more, the III / V ratio is relatively reduced by reducing the supply amount of the group V source gas than when the III / V ratio is relatively low. The method for manufacturing a high-intensity light-emitting diode according to any one of claims 1 to 3, wherein the manufacturing method is high.

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