JP2008135787A - Nitride semiconductor light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable nitride base light emitting element having a high large light emitting power, in which the control of etching amount is possible. <P>SOLUTION: The nitride base semiconductor light emitting element comprising a second conductive type nitride semiconductor layer and a first conductive type nitride base semiconductor layer successively formed upwardly on a holding metal plate, and an In containing etching marker layer formed on the first conductive type nitride base semiconductor layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a nitride-based semiconductor light-emitting device capable of emitting light in a blue region to an ultraviolet region, and more particularly to a nitride-based semiconductor light-emitting device capable of controlling an etching amount and having a large light output and high reliability.

  Conventionally, in order to provide an inexpensive nitride-based semiconductor light-emitting device, various nitride-based semiconductor light-emitting devices using Si (silicon) as a substrate have been used. FIG. 11 shows a schematic cross-sectional view of a conventional nitride-based semiconductor light-emitting device using Si as a substrate.

  In the nitride semiconductor light emitting device of FIG. 11, at least a buffer layer 400, a lower cladding layer 300, a light emitting layer 200, and an upper cladding layer 100 are sequentially stacked on a Si substrate 500, and a p-type pad electrode 600 is formed on the upper cladding layer 100. An n-type electrode 700 is formed on the back surface of the Si substrate 500.

  The above-described conventional nitride semiconductor light emitting device has the following problems. That is, light generated from the light emitting layer 200 is emitted to the upper surface and side surfaces of the light emitting element and the Si substrate 500 side, and the light emitted to the Si substrate 500 side is incident on the Si substrate 500. However, since the Si substrate 500 absorbs a large amount of light from the light emitting layer 200 (here, light having a short wavelength), a large light output cannot be expected from the conventional nitride semiconductor light emitting device.

  Therefore, a method has been proposed in which a metal plate that reflects light and can also be used as an electrode is used instead of the Si substrate. However, there is a problem that it is difficult to grow a nitride-based semiconductor layer on a metal plate. In addition, the method of bonding a metal plate and a nitride semiconductor layer using a conductive adhesive has a problem that the light emitting element deteriorates early because the heat dissipation of the conductive adhesive is not excellent. It was.

  Therefore, a buffer layer and a nitride-based semiconductor layer are sequentially stacked on the Si substrate to form a metal plate on the nitride-based semiconductor layer, and then an electrode is formed on the exposed nitride-based semiconductor layer by removing the Si substrate and the buffer layer. It is conceivable to provide a method. In particular, when the buffer layer is highly resistive or nonconductive, it is necessary to remove the buffer layer. However, although the Si substrate can be selectively removed by wet etching, it is difficult to selectively remove the buffer layer.

  That is, since the buffer layer is hardly etched by the wet etching method, the dry etching method is usually used. However, since this dry etching method does not show selectivity as in the wet etching method, the etching amount is controlled. Is difficult. In general, the etching amount is controlled by the etching time, but it is still difficult to control the etching amount.

  Therefore, if the etching amount of the buffer layer becomes too large, the nitride-based semiconductor layer is etched and the film thickness of this layer becomes thin, so that the current does not spread sufficiently in this layer, and the light emitting region of the light emitting element is reduced. There has been a problem that a light-emitting element having a large light output cannot be obtained due to narrowing. On the other hand, if the etching amount is too small, the buffer layer remains on the nitride-based semiconductor layer. If the buffer layer is highly resistive or non-conductive, it is difficult to inject current into the light-emitting element, and the operating voltage is reduced. As a result, the reliability of the light-emitting element is lowered.

  In view of the above circumstances, an object of the present invention is to provide a nitride-based semiconductor light-emitting device that can control the etching amount and has a high light output. Another object of the present invention is to provide a nitride-based semiconductor light-emitting device having high reliability even when a high-resistance or non-conductive buffer layer is stacked on a substrate in the manufacturing process of the light-emitting device. .

  In order to achieve the above object, the present invention includes a second conductivity type nitride-based semiconductor layer, a light emitting layer, and a first conductivity-type nitride-based semiconductor layer sequentially formed above a holding metal plate, The nitride semiconductor light emitting device includes an etching marker layer containing In formed on a conductive nitride semiconductor layer, and an electrode formed on the etching marker layer containing In.

  The present invention also includes a second conductivity type nitride-based semiconductor layer, a light emitting layer, and a first conductivity-type nitride-based semiconductor layer sequentially formed above the holding metal plate, An nitridation comprising an etching marker layer containing In formed on a semiconductor layer, and an electrode formed on the first conductivity type nitride-based semiconductor layer exposed by partially removing the etching marker layer containing In It is a physical semiconductor light emitting device.

  The material of the etching marker layer containing In is preferably any of InN, InGaN, or InGaAlN.

  Moreover, it is preferable that the layer in contact with the etching marker layer containing In in the first conductivity type nitride-based semiconductor layer contains Al.

  As described above, according to the present invention, since the etching amount can be easily controlled, it is possible to provide a highly reliable nitride semiconductor light emitting device having a wide light emitting region and a large light output. In addition, a highly reliable nitride-based semiconductor light-emitting element can be provided even when a high-resistance or non-conductive buffer layer is stacked on a substrate.

Embodiments of the present invention will be described below.
(substrate)
As the material of the substrate used in the present invention, conventionally known materials such as Si, GaAs or GaP are used. Si is preferably used. When Si is used for the substrate, the crystallinity of the nitride-based semiconductor layer stacked on the buffer layer can be improved by providing the buffer layer on the substrate. In addition, since a large-area substrate can be obtained at low cost, a light-emitting element can be manufactured on a large scale, so that the manufacturing cost of the light-emitting element is reduced. Further, the substrate can be easily processed.

(Buffer layer)
The buffer layer used in the present invention is laminated on the substrate. The material of the buffer _{layer, In x Al y Ga 1-} xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1) known nitride-based semiconductor materials conventionally represented by may be employed. AlN or AlGaN is preferably used. When AlN or AlGaN is used for the buffer layer, since the buffer layer does not contain In, the end point detection device of the dry etching apparatus can clarify the distinction from the etching marker layer containing In. In addition, the etching marker layer containing In can sufficiently function as an etching marker layer. The buffer layer may be conductive, high resistance, or non-conductive. However, when the buffer layer is high resistance or non-conductive, the importance of the etching marker layer containing In is important. Increase.

(Etching marker layer containing In)
The etching marker layer containing In used in the present invention is laminated on the buffer layer. As the material of the etching marker layer containing _{In, In x Al y Ga 1} -xy N (0 <x, 0 ≦ y, x + y ≦ 1) known nitride-based semiconductor materials conventionally represented by may be employed. Preferably, it is any of InN, InGaN, or InAlGaN. Further, it is more preferable that the content of In is larger than that of the buffer layer and the first conductivity type nitride-based semiconductor layer. When the content of In is large, the function as an etching marker layer can be exhibited more.

  In addition, since it contains In, this layer tends to be a soft layer, and damage to the light emitting layer during the etching is reduced. Furthermore, the mechanical damage to the light emitting layer at the time of wire bonding to the pad electrode is reduced. Accordingly, the provision of this layer functions as an absorption layer for damage to the light emitting layer, and thus the reliability of the light emitting element can be improved.

  Note that the etching marker layer refers to a layer having a function of detecting an In signal by an end point detection apparatus of an etching apparatus.

(First conductivity type nitride semiconductor layer)
The first conductivity type nitride-based semiconductor layer used in the present invention is stacked on an etching marker layer containing In. As the material of the first conductivity type nitride semiconductor _{layer, In x Al y Ga 1-} xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1) known nitride-based semiconductor materials conventionally represented by the reference Can be.

  Here, the first conductivity type nitride-based semiconductor layer may be composed of not only one layer but also two or more nitride-based semiconductor layers. In this case, it is preferable that the layer in contact with the etching marker layer containing In contains Al. When etching reaches the first conductivity type nitride-based semiconductor layer containing Al from the etching marker layer containing In, the etching rate is drastically reduced. It is possible to expose the first conductivity type nitride-based semiconductor layer that often contains Al.

  Also, this layer is doped with either an n-type dopant or a p-type dopant.

(Light emitting layer)
The light emitting layer used in the present invention is laminated between the first conductivity type nitride semiconductor layer and the second conductivity type nitride semiconductor layer. As the light emitting layer, any of MQW (multiple quantum well) light emitting layer and SQW (single quantum well) light emitting layer can be used.

(Second conductivity type nitride semiconductor layer)
The second conductivity type nitride semiconductor layer used in the present _{invention, In x Al y Ga 1-} xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1) conventionally known nitride semiconductor represented by Materials can be used.

  Further, the second conductivity type nitride-based semiconductor layer may be composed of not only one layer but also two or more nitride-based semiconductor layers.

  In addition, this layer is doped with either an n-type dopant or a p-type dopant, but is doped with a different type of dopant from the first conductivity type nitride semiconductor layer.

(Nitride semiconductor contact layer)
A nitride semiconductor contact layer can be laminated on the second conductivity type nitride semiconductor layer. The material used in the nitride-based semiconductor contact _{layer, In x Al y Ga 1-} xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1) known nitride-based semiconductor materials conventionally represented by is used obtain.

  Moreover, although this layer is doped with either an n-type dopant or a p-type dopant, it is doped with the same type of dopant as the second conductivity type nitride semiconductor layer.

  In addition, as a method of laminating each of the layers described above, a conventionally known method can be used. For example, VPE method (vapor phase epitaxy method), MOCVD method (metal organic chemical vapor deposition method), MBE method (molecular beam) Epitaxy method) or a combination of these methods can be used.

  Moreover, a conventionally well-known material can be used for the above-mentioned n-type dopant, for example, Si (silicon), O (oxygen), Cl (chlorine), S (sulfur), C (carbon) or Ge (germanium). Etc. can be used.

  Moreover, a conventionally well-known material can be used also for the above-mentioned p-type dopant, for example, Mg (magnesium), Zn (zinc), Cd (cadmium), Be (beryllium), etc. may be used.

(Underlayer)
An underlayer can be formed on the nitride-based semiconductor contact layer. As a method for forming the underlayer, a conventionally known method can be used, and for example, any one or more of a vapor deposition method, a CVD method (chemical deposition method), and a sputtering method can be used.

(Metal plate for holding)
The holding metal plate used in the present invention is used as an electrode and is formed on an underlayer. As a material of the holding metal plate, conventionally known metals can be used, but it is preferable to use a metal mainly composed of Ni (nickel) or Au (gold). A highly reliable light-emitting element that has good heat dissipation and conductivity and does not deteriorate at an early stage can be manufactured.

  In addition, as a method for forming the holding metal plate, a conventionally known method can be used. For example, any one or more of a vapor deposition method, a CVD method, a sputtering method, an electrolytic plating method, and an electroless plating method are used. be able to. The electrolytic plating method is preferable. When the electrolytic plating method is used, a thick-film holding metal plate can be easily produced in a short time, and the holding metal plate produced by the electrolytic plating method has an adhesive force with the base layer. Since it is improved and peeling does not occur, the reliability of the light emitting element tends to be improved.

  The thickness of the holding metal plate is preferably 10 μm or more and 2 mm or less. If the thickness of the holding metal plate is 10 μm or more, the light emitting device can be easily handled even when the substrate is removed, and if it is thicker than 2 mm, it tends to be difficult to divide and cut the holding metal plate. . Further, the light emitting element tends to be too large.

(etching)
As a substrate etching method, a conventionally known method such as a wet etching method, a dry etching method, or a combination of these methods is used. A wet etching method is preferred. In this case, the buffer layer functions as an etching stop layer, which facilitates the manufacturing process and reduces the manufacturing cost. Further, when the substrate is made of Si, if a mixed solution of hydrofluoric acid, nitric acid, and acetic acid is used as an etchant, the substrate made of Si can be selectively etched.

  As a method for etching the buffer layer, a dry etching method such as a reactive ion etching method or a plasma etching method is used. A reactive ion etching method is preferred. When etching reaches the etching marker layer containing In, since In is detected by the end point detection device, it can be easily determined that the etching reaches the etching marker layer containing In, The etching amount can be easily controlled.

  Therefore, the etching amount becomes too large, the film thickness of the first conductivity type nitride semiconductor layer becomes thin, and the current does not spread to the first conductivity type nitride semiconductor layer, and the light emitting region of the light emitting element becomes small. When the buffer layer is highly resistive or non-conductive, the etching amount becomes too small to leave the buffer layer, and the light emitting element does not emit light.

  Etching marker layers containing In can also be etched. Here, the etching method is preferably the same etching method as that for the buffer layer.

  Further, at the time of the etching, it is possible to control the etching amount with higher accuracy by simultaneously etching a dummy wafer laminated with substantially the same material and film thickness as the wafer to be etched.

  As the dry etching apparatus, a conventionally known apparatus including an end point detection apparatus can be used. Here, as a detection method of the end point detection device, an emission spectroscopic analysis method, a reflected light analysis method, a gas analysis method, a laser interference method, an impedance measurement method, a pressure measurement method, or the like is used. The emission spectroscopic analysis method is preferred. When the emission spectroscopic analysis method is used, there is a tendency that high sensitivity can be obtained directly from a reaction system by etching.

(electrode)
The electrode used in the present invention is formed on an etching marker layer containing In or on a first conductivity type nitride semiconductor layer.

(Pad electrode)
A pad electrode can be formed on the electrode. Au (gold) is preferably used as the material of the pad electrode. A wire made of Au or the like can be bonded on the pad electrode.

  As a method for forming the electrode and the pad electrode, a conventionally known method can be used, and for example, any one or a plurality of evaporation methods, CVD methods, and sputtering methods can be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Example 1)
FIG. 1 shows a schematic cross-sectional view of the nitride-based semiconductor light-emitting device of this example. The nitride-based semiconductor light-emitting device of this example includes an underlayer 8, a nitride-based semiconductor contact layer 7, a second conductivity-type nitride-based semiconductor layer 6, and an MQW light-emitting layer 5 that are sequentially placed on the holding metal plate 9. The first conductive type nitride semiconductor layer 4, the etching marker layer 3 containing In, the electrode 10, the pad electrode 11, and the Au wire 12.

  Hereinafter, the manufacturing process of the nitride-based semiconductor light-emitting device of this example will be described with reference to FIGS.

First, a substrate 1 made of Si is set in a growth apparatus, and a buffer layer 2 made of AlN is formed on the substrate 1 with a thickness of 200 nm and an n-type In _0.2 Ga _0.8 using MOCVD growth, as shown in FIG. The etching marker layer 3 containing In made of N is 100 nm thick, the first conductivity type nitride-based semiconductor layer 4 made of n-type GaN is 400 nm thick, the MQW light emitting layer 5 is 50 nm thick, and p-type Al _0.2 Ga _0.8. A wafer is formed by sequentially laminating a second conductive type nitride semiconductor layer 6 made of N with a thickness of 10 nm and a nitride type semiconductor contact layer 7 made of p-type GaN with a thickness of 200 nm.

  Next, the wafer is taken out from the growth apparatus, and Pd is formed to a thickness of 50 nm and Au is formed to a thickness of 100 nm on the nitride-based semiconductor contact layer 7 as an underlayer 8 as shown in FIG. On top of this, Ni is formed as a holding metal plate 9 to a thickness of 80 μm by electrolytic plating.

  Next, as shown in FIG. 4, the substrate 1 is removed by a wet etching method using a hydrofluoric acid-based etching solution to expose the buffer layer 2.

  Next, as shown in FIG. 5, the buffer layer 2 is removed by a dry etching method using chlorine gas, here a reactive ion etching method, and the etching marker layer 3 containing In is exposed. Here, in order to completely expose the etching marker layer 3 containing In, the etching is continued for 20 seconds after the In signal is detected by the end point detection device of the dry etching device. Dry etching is completed with the etching marker layer 3 containing In being completely exposed. In addition, the emission spectroscopic analysis was used as the end point detection method.

  Next, as shown in FIG. 6, using an evaporation method, an electrode 10 is formed on the etching marker layer 3 containing In serving as a light emitting surface, and Ti is formed into a substantially quadrangular shape with a side of 150 μm square with a thickness of 5 nm and Al. Is formed to a thickness of 5 nm, and Au is formed as a pad electrode 11 thereon to a thickness of 0.5 μm.

  Thereafter, the wafer is divided into a substantially square shape with a side of 350 μm square, the holding metal plate 9 side is mounted on the bottom of the cup of the lead frame, and the Au wire 12 is bonded onto the pad electrode 11.

  The nitride-based semiconductor light-emitting device of this example obtained as described above is an etching containing In between the buffer layer 2 made of AlN and the first-conductivity-type nitride-based semiconductor layer 4 made of n-type GaN. By forming the marker layer 3, In can be clearly detected by the end point detection device, the etching amount of the non-conductive buffer layer 2 can be easily controlled.

  Therefore, in this embodiment, a nitride-based semiconductor light-emitting device having a large light output and high reliability can be obtained.

(Example 2)
FIG. 7 shows a schematic cross-sectional view of the nitride-based semiconductor light-emitting device of this example. The nitride-based semiconductor light-emitting device of this example includes an underlayer 28, a nitride-based semiconductor contact layer 27, a second conductivity-type nitride-based semiconductor layer 26, and an MQW light-emitting layer 25 that are sequentially placed on a holding metal plate 29. The first conductivity type nitride semiconductor layer 24, the etching marker layer 23 containing In, the electrode 210, the pad electrode 211, and the Au wire 212 are included.

  Here, the present embodiment is characterized in that the etching marker layer 23 containing In is made of InN not containing Ga, so that the function as an etching marker layer is more exhibited.

Hereinafter, a manufacturing process of the nitride-based semiconductor light-emitting element of this example will be described. First, as shown in FIG. 8, a buffer layer 22 made of AlN is 150 nm thick on a substrate 21 made of Si, and an etching marker layer 23 containing In made of n-type InN is 50 nm thick. One conductivity type nitride semiconductor layer 24 is 500 nm thick, MQW light emitting layer 25 is 40 nm thick, second conductivity type nitride semiconductor layer 26 made of p-type Al _0.2 Ga _0.8 N is 5 nm thick, p-type GaN. A wafer is formed by sequentially laminating nitride semiconductor contact layers 27 made of the above to a thickness of 150 nm.

  Next, Pd is formed as a base layer 28 to a thickness of 30 nm on the nitride semiconductor contact layer 27 by vapor deposition, and Au is formed as a holding metal plate 29 to a thickness of 100 μm by electrolytic plating on the nitride semiconductor contact layer 27.

  Next, using a normal photo process, the substrate 21 is removed with a hydrofluoric acid etching solution to expose the buffer layer 22.

  Next, the buffer layer 22 is removed by a dry etching method using chlorine gas, here a reactive ion etching method, and the etching marker layer 23 containing In is exposed. Here, in order to completely expose the etching marker layer 23 containing In, the etching is continued for 20 seconds after the In signal is detected by the end point detection device of the dry etching device. Etching is completed in a state where the etching marker layer 23 containing In is completely exposed.

  Next, Ti is formed to a thickness of 5 nm as an electrode 210 on the etching marker layer 23 containing In serving as a light-emitting surface by vapor deposition, and the pad electrode 211 is formed thereon. As a result, Au is formed to a thickness of 0.5 μm.

  Thereafter, the wafer is divided into a substantially quadrangular shape with a side of 350 μm square, the holding metal plate 29 side is mounted on the cup bottom of the lead frame, and an Au wire 212 is bonded onto the pad electrode 211.

  The nitride semiconductor light emitting device of this example obtained as described above does not contain Ga between the buffer layer 22 made of AlN and the first conductivity type nitride semiconductor layer 24 made of n-type GaN. By forming the etching marker layer 23 containing In consisting of InN, In can be clearly detected by the end point detection device, the buffer layer 22 that is nonconductive can be more easily formed than the first embodiment. The etching amount can be controlled.

  Therefore, in this example, a nitride-based semiconductor light-emitting element with higher reliability than that in Example 1 can be obtained.

(Example 3)
FIG. 9 shows a schematic cross-sectional view of the nitride-based semiconductor light-emitting device of this example. The nitride-based semiconductor light-emitting device of this example includes an underlayer 38, a nitride-based semiconductor contact layer 37, a second conductivity-type nitride-based semiconductor layer 36, an MQW light-emitting layer 35, which are placed on a holding metal plate 39. A first conductivity type nitride semiconductor layer 34, a first conductivity type nitride semiconductor layer 341 containing Al, an etching marker layer 33 containing In, a buffer layer 32, an electrode 310, a pad electrode 311 and an Au wire 312 are included. ing.

  Here, in this embodiment, a part of the etching marker layer 33 including the buffer layer 32 and In is etched, and the electrode 310 is formed on the first conductivity type nitride-based semiconductor layer 341 including Al exposed thereby. It is characterized by being formed.

Hereinafter, a manufacturing process of the nitride-based semiconductor light-emitting element of this example will be described. First, on a substrate (not shown) made of Si, a buffer layer 32 made of AlN has a thickness of 200 nm, an etching marker layer 33 containing In made of n-type In _0.3 Ga _0.7 N has a thickness of 100 nm, and an n-type Al _0.1 Ga. The first conductive nitride-based semiconductor layer 341 containing Al composed of _0.9 N is 100 nm thick, the first conductive nitride-based semiconductor layer 34 composed of n-type GaN is 400 nm thick, and the MQW light emitting layer 35 is 40 nm thick. Then, a second conductive nitride semiconductor layer 36 made of p-type Al _0.1 Ga _0.9 N and a nitride semiconductor contact layer 37 made of p-type GaN are sequentially stacked to a thickness of 5 nm and 150 nm.

  Next, using a vapor deposition method, Pd is formed to a thickness of 30 nm as an underlayer 38 on the nitride semiconductor contact layer 37, and Ni is formed as a holding metal plate 39 to a thickness of 80 μm thereon by electrolytic plating. To do.

  Next, the substrate (not shown) is removed using a hydrofluoric acid etching solution over the entire surface using a normal photo process, and the buffer layer 32 is exposed.

  Next, in order to form the electrode 38 at substantially the center of the main light emitting surface, the buffer marker 32 and the etching marker layer 33 including In are etched by a reactive ion etching method using chlorine gas. Here, in order to completely expose the etching marker layer 33 containing In, the etching is continued for 20 seconds after the In signal is detected by the end point detection device of the dry etching device. Next, even if the etching marker layer 33 containing In is completely exposed, the etching is further continued. After the In signal is detected by the end point detection device of the dry etching apparatus, etching is performed until the In signal disappears completely. The first conductivity type nitride-based semiconductor layer 341 containing Al is exposed.

  Next, using an evaporation method, Ti is formed to a thickness of 5 nm and Al is formed to a thickness of 5 nm as an electrode 310 on the exposed surface of the first conductivity type nitride semiconductor layer 341 containing Al, and a pad is formed thereon. As the electrode 311, Au is formed to a thickness of 0.6 μm.

  Thereafter, the wafer is divided into a substantially square shape with a side of 300 μm square, the holding metal plate 39 side is mounted on the cup bottom of the lead frame, and an Au wire 312 is bonded onto the pad electrode 311.

The nitride-based semiconductor light-emitting device of this example obtained as described above has a buffer layer 32 made of AlN, a first conductivity-type nitride-based semiconductor layer 341 containing Al made of n-type Al _0.1 Ga _0.9 N, By forming the etching marker layer 33 containing In between the In, it is possible to detect In clearly by the end point detection device, so that the first conductivity type nitride-based semiconductor layer 341 containing Al is exposed with good reproducibility. Can be made.

  In the nitride semiconductor light emitting device of this example, since the electrode 310 is in contact with the first conductivity type nitride semiconductor layer 341 containing Al, the etching marker layer 33 containing In is an n-type. It does not need to have conductivity, and may have high resistance, non-conductivity, or p-type conductivity.

Example 4
FIG. 10 shows a schematic cross-sectional view of the nitride-based semiconductor light-emitting device of this example. The nitride-based semiconductor light-emitting device of this example includes an underlayer 48, a nitride-based semiconductor contact layer 47, a second conductivity-type nitride-based semiconductor layer 46, an MQW light-emitting layer 45, which are installed on a holding metal plate 49. A first conductivity type nitride semiconductor layer 44, a first conductivity type nitride semiconductor layer 441 containing Al, an etching marker layer 43 containing In, a buffer layer 42, an electrode 410, a pad electrode 411, and an Au wire 412 are included. ing.

  Here, in this embodiment, the buffer layer 42 and a part of the etching marker layer 43 including In are etched, and the etching is terminated in the middle of the etching marker layer 43 including In. The electrode 410 is formed on the etching marker layer 43 containing In.

Hereinafter, a manufacturing process of the nitride-based semiconductor light-emitting element of this example will be described. First, on a substrate (not shown) made of Si, a buffer layer 42 made of AlN has a thickness of 200 nm, an etching marker layer 43 containing In made of n-type In _0.3 Ga _0.7 N has a thickness of 100 nm, and an n-type Al _0.15 Ga. The first conductivity type nitride-based semiconductor layer 441 containing Al composed of _0.85 N has a thickness of 100 nm, the first conductivity-type nitride-based semiconductor layer 44 composed of n-type GaN has a thickness of 300 nm, and the MQW light emitting layer 45 has a thickness of 40 nm. Then, a wafer is formed by sequentially laminating a second conductive nitride semiconductor layer 46 made of p-type Al _0.15 Ga _0.85 N to a thickness of 5 nm and a nitride semiconductor contact layer 47 made of p-type GaN to a thickness of 150 nm.

  Next, an evaporation method is used to form Pd with a thickness of 30 nm and Au with a thickness of 200 nm on the nitride-based semiconductor contact layer 47 as an underlayer 48, and as a holding metal plate 49 thereon by electrolytic plating. Ni is formed to a thickness of 80 μm.

  Next, the substrate (not shown) is removed using a hydrofluoric acid etching solution over the entire surface using a normal photo process, and the buffer layer 42 is exposed.

  Next, in order to form the electrode 410 at substantially the center of the main light emitting surface, the etching marker layer 43 including the buffer layer 42 and In is partially removed by a dry etching method using chlorine gas, here, a reactive ion etching method. To do. Here, the In signal is detected by the end point detection device of the dry etching device, and the etching is finished with the etching marker layer 43 containing In exposed.

  Next, as shown in FIG. 10, on the etching marker layer 43 containing In exposed at almost the center of the main light emitting surface, the electrode 410 is made of Hf with a thickness of 3 nm and Al with a thickness of 4 nm by vapor deposition. 200 nm and Ti are formed to a thickness of 50 nm, and Au is formed as a pad electrode 411 thereon to a thickness of 0.6 μm.

  Thereafter, the wafer is divided into a substantially square shape with one side of 300 μm square, the holding metal plate 49 side is mounted on the bottom of the cup of the lead frame, and Au wire 412 is bonded onto the pad electrode 411.

  The nitride-based semiconductor light-emitting device of this example obtained as described above terminates the etching of the etching marker layer 43 containing In midway. Therefore, the etching marker layer 43 containing In, which is a soft layer, not only can reduce damage to the MQW light emitting layer 45 that occurs during the etching, but also has good ohmic resistance on the etching marker layer 43 containing In. It is possible to reduce mechanical damage to the MQW light emitting layer 45 caused by strain or the like when forming the electrode 410 having the property.

  Therefore, also in this example, a highly reliable nitride-based semiconductor light-emitting element that emits light can be obtained.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

3 is a schematic cross-sectional view of the nitride-based semiconductor light-emitting element of Example 1. FIG. FIG. 3 is a schematic conceptual diagram of the nitride-based semiconductor light-emitting element of Example 1 during manufacture. It is a typical conceptual diagram of the nitride-based semiconductor light-emitting element of Example 1 during manufacture. It is a typical conceptual diagram of the nitride-based semiconductor light-emitting element of Example 1 during manufacture. It is a typical conceptual diagram of the nitride-based semiconductor light-emitting element of Example 1 during manufacture. It is a typical conceptual diagram of the nitride-based semiconductor light-emitting element of Example 1 during manufacture. 6 is a schematic cross-sectional view of a nitride-based semiconductor light-emitting element of Example 2. FIG. It is typical sectional drawing of the nitride type semiconductor light-emitting device of Example 2 before removing a board | substrate. 6 is a schematic cross-sectional view of a nitride-based semiconductor light-emitting element of Example 3. FIG. 6 is a schematic cross-sectional view of a nitride-based semiconductor light-emitting element of Example 4. FIG. It is typical sectional drawing of the conventional nitride semiconductor light-emitting device which used Si for the board | substrate.

Explanation of symbols

  1,21 Substrate, 2,22,32,42 Buffer layer, 3,23,33,43 In-containing etching marker layer, 4,24,34,44 First conductivity type nitride semiconductor layer, 5,25, 35, 45 MQW light emitting layer, 6, 26, 36, 46 Second conductivity type nitride semiconductor layer, 7, 27, 37, 47 Nitride semiconductor contact layer, 8, 28, 38, 48 Underlayer, 9, 29, 39, 49 Holding metal plate, 10, 210, 310, 410 electrode, 11, 211, 311, 411 Pad electrode, 12, 212, 312, 412 Au wire, 341, 441 Al containing 341 Al Physical semiconductor layer, 100 upper clad layer, 200 light emitting layer, 300 lower clad layer, 400 buffer layer, 500 Si substrate, 600 p-type pad electrode, 700 n-type electrode.

Claims (4)

  A second conductive type nitride semiconductor layer, a light emitting layer, and a first conductive type nitride semiconductor layer sequentially formed above the holding metal plate are formed on the first conductive type nitride semiconductor layer. A nitride-based semiconductor light emitting device comprising an etching marker layer containing In, and an electrode formed on the etching marker layer containing In.   A second conductive type nitride semiconductor layer, a light emitting layer, and a first conductive type nitride semiconductor layer sequentially formed above the holding metal plate are formed on the first conductive type nitride semiconductor layer. A nitride comprising: an etching marker layer containing In, wherein an electrode is formed on a first conductivity type nitride-based semiconductor layer exposed by removing a part of the etching marker layer containing In -Based semiconductor light emitting device.   The nitride-based semiconductor light-emitting element according to claim 1 or 2, wherein a material of the etching marker layer containing In is any one of InN, InGaN, or InGaAlN.   4. The nitride semiconductor light emitting device according to claim 1, wherein the layer in contact with the etching marker layer containing In in the first conductivity type nitride semiconductor layer contains Al. 5.

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