JP2005197414A - Semiconductor light emitting device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light emitting device which has a plurality of semiconductor light emitting elements different in luminescence wavelength bands, in which guide wave loss of oscillation light is reduced and high power output is realized, and the number of processes is reduced and yield is improved in manufacture, and to provide a manufacturing method of the device. <P>SOLUTION: In index guide-type lasers 2 and 3 which constitute the semiconductor light emitting device 1, for example, compositions of buried layers 29 and 39 are set to be identical, and optical guide layers 22, 26, 32 and 36 are formed in upper and lower clad layers 21, 24, 31 and 34 which are confronted each other across active layers 23 and 33 of the respective elements so that optical characteristics of oscillation light of the elements become desired ones. Since the compositions of the embedded layers in a plurality of index guide-type laser elements are made identical, the number of processes in an epitaxy process can be reduced in manufacture of the semiconductor light emitting device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor light emitting device and a method for manufacturing the semiconductor light emitting device.

Conventionally, a plurality of semiconductor light emitting elements such as semiconductor laser elements are used for reading from an optical recording medium, such as reading from a CD-ROM (Compact Disc-Read Only Memory) or DVD-ROM (Digital Versatile Disc-Read Only Memory). A semiconductor light emitting device is configured. In general, a semiconductor laser element having a light emission wavelength of 780 nm is used for reading a CD-ROM, and a semiconductor laser element having a light emission wavelength of 650 nm is used for reading a DVD-ROM.
When a multi-wavelength semiconductor light-emitting device is formed by forming a plurality of semiconductor laser elements having different emission wavelength bands on one substrate, an assembly of single-wavelength semiconductor light-emitting devices composed of a single semiconductor laser element As compared with the case where a multi-wavelength semiconductor light-emitting device is configured, a multi-wavelength semiconductor light-emitting device having a small size and high emission point accuracy can be configured.

Semiconductor laser elements as semiconductor light emitting elements used in semiconductor light emitting devices are roughly classified into index guide types and gain guide types according to their waveguide structures.
In general, as shown in FIG. 5, the index guide type laser element has a first conductivity type (for example, n-type) (Al _0.7 Ga _0.3 ) _0.5 In ₀ on a semiconductor substrate 104 made of GaAs, for example. a first conductive type cladding layer 121 made of _.5 P, a multiple quantum well with _{(Al 0.45 Ga 0.55) 0.5 in} 0.5 P and GaInP; active layer by (MQW multi quantum well) structure 123, a second conductivity type cladding layer 124 made of (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P of the second conductivity type (for example, p-type), and the second conductivity type cladding layer 124 The second conductivity type GaInP etching stop layer 125 provided at a predetermined position of the second conductivity type cladding layer 124 and the second conductivity type GaAs contact layer 127 formed on the opposite side of the active layer 123. Has become element main portion 128 has a buried layer 129 by _{Al 0.5 In} 0.5 P defining a main current path in the device main unit 128. Electrodes 105 and 106 are deposited on the opposite sides of the base 104 and the contact layer 127 from the active layer 123, respectively.

  With this configuration, in the index guide type laser element, a refractive index difference is formed in the crystal growth direction of each layer of the element main part, for example, in the vertical direction. Then, the etching mode for the second conductivity type clad layer 124 is determined by the etching stop layer 125, so that the shape of the second conductivity type clad layer 124 and the buried layer 128 can be specified, and the main part of the device can be determined by this specification. For example, the effective refractive index difference in the horizontal direction is formed. By forming the effective refractive index difference between the vertical direction and the horizontal direction, in the index guide type laser element, the radiation shape of the oscillation light is controlled, and the light confinement efficiency is improved and the waveguide loss is suppressed. .

  On the other hand, as shown in FIG. 6, in the gain guide type laser element, the first conductive type cladding layer 221, the active layer 223, and the second conductive type cladding layer 224 are sequentially formed on one main surface of the substrate 204. The device main portion 228 is laminated, and an insulating layer 207 that defines a main current path in the device main portion 228 is provided. Electrodes 205 and 206 are deposited on the opposite side of the base 204 and the second conductivity type cladding layer 224 from the active layer 223, respectively.

In this gain guide type laser element, in general, the main current path is defined regardless of the buried layer in consideration of the optical characteristics of the element. That is, an insulating layer 207 formed by, for example, oxygen ion implantation is formed as an insulating layer that defines a main path of a current generated by applying a forward voltage between the electrodes 206 and 205.
In the gain guide type laser element, unlike the index guide type laser element, the current path is defined by, for example, the insulating layer 207 described above, and therefore, the optical confinement in the horizontal direction due to the formation of the refractive index is not sufficiently performed. Therefore, in the gain guide type laser element, compared with the index guide type laser element, the control of the radiation shape and transverse mode of the light oscillated from the active layer is weak, and the waveguide loss of the oscillation light is increased.

Thus, the gain guide type laser element has many disadvantages in optical characteristics as a laser element compared to the index guide type laser element. However, as described above, in comparison with the manufacture of an index guide type laser element that requires an epitaxy process for forming an embedded layer, the manufacture of a gain guide type laser element requires the formation of an embedded layer, that is, an embedded semiconductor layer. Since it is not required, an increase in the number of epitaxy steps can be suppressed.
In general, since an increase in the number of epitaxy steps is always accompanied by a decrease in yield, in the manufacture of semiconductor laser devices, the number of times of epitaxy should be reduced as much as possible to suppress an increase in the number of defective products due to a decrease in yield. desirable. For this reason, in manufacturing a multi-wavelength semiconductor light emitting device having a plurality of semiconductor laser elements different from each other, at least one laser element is configured to be a gain guide type laser element unless an improvement in output of each element is particularly required. Accordingly, priority has been given to reducing the number of epitaxy steps in manufacturing and improving yield.

  However, in recent years, with the advent of write-once or rewritable optical recording media such as CD-R (Compact Disc-Recordable), DVD-R (Digital Versatile Disc-Recordable), etc., higher output of semiconductor laser elements is required. It became so. As described above, the gain guide type laser element has a large waveguide loss, and the transverse mode becomes unstable in the high output region, so that it is difficult to increase the output in practical use. Therefore, in this case, a multi-wavelength semiconductor light emitting device is configured by using, as an index guide type laser element, a larger number of semiconductor laser elements, that is, all the semiconductor laser elements unless inconvenience occurs. Is desirable.

On the other hand, a two-wavelength semiconductor light-emitting device having a schematic configuration shown in FIG. 7 is configured only by index guide type laser elements, and only the active layer is different from each other in each element main part of each laser element. Thus, a two-wavelength semiconductor light-emitting device in which the emission wavelength bands of the semiconductor laser elements are different from each other has been proposed (for example, see Patent Document 1).
In the two-wavelength semiconductor light emitting device according to this proposal, in two semiconductor light emitting elements having different emission wavelength bands, the material composition other than the active layer in the main part of the element, that is, the material composition of the cladding layer and the light guide layer is the same material system. With this configuration, light emission by a plurality of laser elements having different emission wavelength bands and a reduction in the number of times of epitaxy in the manufacturing process are achieved.
Japanese Patent Laid-Open No. 2002-223038

  However, in a semiconductor light emitting device having a plurality of semiconductor light emitting elements having different emission wavelength bands, the material composition other than the active layer of each element main part of the plurality of semiconductor light emitting elements, that is, the composition of the cladding layer and the light guide layer, When the composition is made of the same material system, for example, it becomes difficult to control the radiation shape (FFP: Far Field Pattern) of the laser-oscillated light from the active layer, and the optical system using this semiconductor light emitting device is optical. This also hinders design.

  That is, when a multi-wavelength semiconductor light-emitting device is configured using a plurality of index guide type laser elements having different emission wavelength bands, a plurality of index guide type laser elements having different active layers only are configured. Forming a semiconductor light emitting device by forming a plurality of semiconductor laser elements having different bands from each other causes a problem in the light emission characteristics of the element, and is not necessarily optimal as a configuration of a multiwavelength semiconductor light emitting device.

  In manufacturing such an index guide type laser element, epitaxy for forming the main part of the element and epitaxy for forming the buried layer are required. Therefore, at least twice for manufacturing one laser element. An epitaxy process is required. That is, in order to form a plurality of semiconductor laser elements having different emission wavelength bands by using an index guide type laser element, as long as the structure of each element is the same as that in the case of manufacturing each element alone, at least for each element. Two epitaxies are required. Therefore, for example, in the case of manufacturing a two-wavelength semiconductor light-emitting device, at least four times of epitaxy is necessary, and the yield is lowered due to an increase in the number of times of epitaxy, and the manufacturing work is complicated.

  The present invention aims to solve the above-mentioned problems in a semiconductor light-emitting device having a plurality of semiconductor light-emitting elements having different emission wavelength bands and the manufacture of this semiconductor light-emitting device.

  A semiconductor light emitting device according to the present invention is a semiconductor light emitting device having at least a plurality of semiconductor light emitting elements having different emission wavelength bands on a substrate, and each of the plurality of semiconductor light emitting elements is at least a first conductivity type cladding. A plurality of semiconductor light emitting devices as described above, comprising: a device main portion comprising a layer, an active layer, a second conductivity type cladding layer, and a light guide layer; and a buried layer defining a main current path for the active layer. The buried layers have the same composition.

The semiconductor light-emitting device according to the present invention is characterized in that the configuration of the light guide layer is different in at least some of the semiconductor light-emitting elements.
The semiconductor light-emitting device according to the present invention is characterized in that at least one of the plurality of semiconductor light-emitting elements has an etching stop layer that defines the depth of the buried layer.
The semiconductor light emitting device according to the present invention is characterized in that at least one of the plurality of semiconductor light emitting elements is AlGaAs-based.
The semiconductor light emitting device according to the present invention is characterized in that at least one of the plurality of semiconductor light emitting elements is AlGaInP-based.

  A method of manufacturing a semiconductor light emitting device according to the present invention is a method of manufacturing a semiconductor light emitting device having at least a plurality of semiconductor light emitting elements having different emission wavelength bands on a substrate, and includes at least a first conductivity type cladding layer, an active type Epitaxial growth for forming a laminated semiconductor layer having a layer, a second conductivity type cladding layer, and a light guide layer, and etching to form the second conductivity type cladding layer in a desired shape are performed a plurality of times as described above, A main part forming step for forming each main part of each semiconductor light emitting element, and a buried layer forming step for forming a buried layer for defining a main current path in each semiconductor light emitting element finally obtained in each main part; In the buried layer forming step, the buried layer is simultaneously formed on the main part of at least two semiconductor light emitting elements of the plurality of semiconductor light emitting elements.

The method of manufacturing a semiconductor light emitting device according to the present invention is characterized in that, in the main part forming step, the light guide layer has a different structure in at least some of the semiconductor light emitting elements. .
The method for manufacturing a semiconductor light emitting device according to the present invention is characterized in that an etching stop layer for etching is formed on at least one of the plurality of semiconductor light emitting elements in the main part forming step.
The method for manufacturing a semiconductor light emitting device according to the present invention is characterized in that at least one of the plurality of semiconductor light emitting elements is AlGaAs-based.
The method for manufacturing a semiconductor light emitting device according to the present invention is characterized in that at least one of the plurality of semiconductor light emitting elements is AlGaInP-based.

In the semiconductor light-emitting device and the method for manufacturing the semiconductor light-emitting device according to the present invention, even when the same composition, that is, the common buried layer is formed in a plurality of semiconductor light-emitting elements constituting the device, the characteristics of each element that change due to this Can be corrected by the configuration of the light guide layer.
That is, when at least two of the plurality of semiconductor light emitting elements constituting the device are index guide type laser elements, the light guide layer is also provided in the first conductivity type cladding layer, for example, so that each element emits light. The characteristics can be controlled well.
In the present invention, the configuration of the light guide layer is not limited to the configuration in the sense that the light guide layer is provided in both the first conductivity type cladding layer and the second conductivity type cladding layer, for example. Layer structure when the layer is a multi-layer structure, that is, a two-layer structure or a three-layer structure, a stack structure as a stacking order thereof, an arrangement structure by adjusting a distance from the active layer, a material structure as a composition of each guide layer, etc. Is also referred to.
When at least two semiconductor light emitting elements are index guide type laser elements, it is desirable that the buried layer be formed of a material that does not absorb oscillation light from the active layer, such as AlInP.

According to the semiconductor light emitting device of the present invention, when at least a part of a plurality of semiconductor light emitting elements constituting the device, for example, two or more semiconductor light emitting elements are index guide type laser elements, these index guide type laser elements are common. The buried layer is formed, and the change in the optical characteristics of each element caused by the buried layer is corrected by the configuration of the light guide layer.
Thus, a multi-wavelength semiconductor light emitting device having a plurality of semiconductor light emitting elements formed of different material systems, for example, index guide type laser elements, as high efficiency and high output elements is configured.
In addition, according to the configuration of the light guide layer, not only the light emission wavelength band and the change caused by the composition of the buried layer, but also the light guide layer corresponding to the demands on the element in various optical characteristics Can be formed. Accordingly, since the degree of freedom in optical design including the light emission characteristics of the semiconductor light emitting element such as a semiconductor laser element such as the radiation shape is expanded, the present invention can be applied more flexibly to provide a multiwavelength semiconductor light emitting device and the same. The optical device used can be designed.

  Furthermore, according to the semiconductor light emitting device of the present invention, when the semiconductor light emitting element is an index guide type laser element, the buried layer is made of a material such as AlInP that does not absorb oscillation light from the active layer, thereby embedding. Waveguide loss based on absorption of oscillation light by the buried layer and the influence on the optical characteristics of the laser element can be further reduced.

Further, according to the method for manufacturing a semiconductor light emitting device according to the present invention, the step of forming the plurality of elements by making the composition of the buried layers of the plurality of semiconductor light emitting elements, for example, index guide type laser elements, the same. The steps can be different from the case of manufacturing each element alone. Therefore, the number of epitaxy steps can be reduced, and the complexity of the manufacturing operation is reduced.
In addition, since the number of steps of epitaxy can be reduced, the yield in manufacturing can be improved, and the configuration of the present invention can bring important and many effects.

Hereinafter, an embodiment of a semiconductor light emitting device according to the present invention will be described together with an embodiment of a manufacturing method thereof with reference to FIG. 1 and FIGS. 2 to 4. It goes without saying that it is not limited to this.
First, an embodiment of a semiconductor light emitting device according to the present invention will be described with reference to FIG.
This embodiment is an example in which a plurality of semiconductor light emitting elements constituting the semiconductor light emitting device according to the present invention are two index guide laser elements having different emission wavelength bands.

In this embodiment, a semiconductor light-emitting device 1 according to the present invention includes a plurality of semiconductor light-emitting elements having different emission wavelength bands on one main surface of a substrate 4 of a first conductivity type (for example, n-type) GaAs, that is, a substrate, In this example, the first semiconductor light emitting element 2 and the second semiconductor light emitting element 3 are provided.
An electrode 5 made of, for example, a metal multilayer film of Au / Ge / Ni / Au is deposited on the back surface of the substrate 4, and the upper surface of each of the first semiconductor light emitting element 2 and the second semiconductor light emitting element 3 is, for example, Electrodes 6a and 6b made of a metal multilayer film of Au / Pt / Ti are deposited.
In this example, the first semiconductor light emitting element 2 is an AlGaAs semiconductor light emitting element having a light emission wavelength band of 780 nm, and includes a first element main portion 28 formed by stacking semiconductor layers constituting the light emitting element, and AlInP. And a buried layer 29.
The first element main portion 28 includes, for example, a first first conductivity type cladding layer 21 made of Al _0.47 GaAs of the first conductivity type, Al _0.1 GaAs, and Al _{0 on} one main surface of the substrate 4. _.3 first active layer 23 with multiple quantum well (MQW) structure with GaAs, first second conductivity type cladding layer 24 with second conductivity type (for example, p-type) Al _0.47 GaAs, A contact layer 27 made of two-conductivity type GaAs is sequentially stacked by, for example, epitaxial growth.

Then, according to the light emission wavelength band and the light emission characteristics required for the first semiconductor light emitting element 2, the light guide layer made of Al _0.3 GaAs of the first conductivity type is provided in the first first conductivity type cladding layer 21. 22 and a light guide layer 26 made of Al _0.3 GaAs of the second conductivity type is provided in the first second conductivity type cladding layer 24.
In this embodiment, the above-mentioned buried layer 29 constituting the first semiconductor light emitting element is laminated in the second conductivity type cladding layer 24. An etching stop layer 25 made of Al _0.6 GaAs that defines a direction, that is, a dimension in the vertical direction, that is, a depth, may be provided.

On the other hand, the second semiconductor light emitting element 3 is an AlGaInP-based semiconductor light emitting element having a light emission wavelength band of 650 nm in this example, and includes a second element main part 38 formed by laminating each semiconductor layer constituting the light emitting element, and And a buried layer 39 made of AlInP.
The second element main portion 38 includes, for example, a first first conductivity type cladding layer 31 made of (Al _0.7 Ga) _0.52 InP of the first conductivity type on one main surface of the substrate 4, GaInP, and the like. A second active layer 33 having a multiple quantum well (MQW) structure with (Al _0.45 Ga) _0.52 InP, and a second second layer having a second conductivity type (Al _0.7 Ga) _0.52 InP. A two-conductivity-type cladding layer 34 and a contact layer 37 made of second-conductivity-type GaAs are sequentially stacked by, for example, epitaxial growth.

Then, according to the emission wavelength band and the emission characteristics required for the second semiconductor light emitting element 3, the first conductivity type, for example, n-type GaInP and (Al _{0. 7} Ga) _0.52 A light guide layer 32 having a multiple quantum well (MQW) structure with InP is provided, and the second conductivity type GaInP and (Al _0.7 Ga) are provided in the second second conductivity type cladding layer. A light guide layer 36 having a multiple quantum well (MQW) structure with _0.52 InP is provided.

  In this embodiment, the light guide layer 36 in the second second-conductivity-type cladding layer is formed in the above-described buried layer 39 in the stacking direction of the second element main portion 38, that is, in the vertical direction. It plays the role of an etching stop layer that defines the dimension, that is, the depth. That is, it is not always necessary to form the etching stop layer separately from the light guide layer for all of the semiconductor light emitting elements constituting the semiconductor light emitting device according to the present invention.

  For example, in the formation of the first semiconductor light emitting element 2, the etching stop layer 25 can be made of a material having characteristics as a light guide layer. In this case, the etching stop layer not only serves as an etching stop layer in epitaxy, but also acts to attract the emission point and emission distribution of oscillation light from the active layer. Therefore, in this case, it is desirable that the etching stop layer itself has a refractive index capable of absorbing light from the active layer to some extent.

Also, there is a difference in the refractive index of the materials constituting the active layer, the first conductivity type cladding layer, and the second conductivity type cladding layer between the AlGaAs semiconductor light emitting device and the AlGaInP semiconductor light emitting device. Therefore, it is difficult to make both the emission characteristics desirable by simply making the composition of the buried layer the same.
For example, in the first semiconductor light emitting device 2, the first active layer 23 having a multiple quantum well (MQW) structure of Al _0.1 GaAs and Al _0.3 GaAs and the clad layers 21 and 24 made of Al _0.47 GaAs. For example, it is difficult to suitably realize formation of an effective refractive index difference and optical confinement by the buried layer 29 made of AlInP for oscillation light having a center wavelength of 780 nm.

In this example, the buried layer 39 in the second semiconductor light emitting element 3 has the same composition as the buried layer 29, that is, a composition of AlInP. This composition is a buried layer suitable for oscillation light having a central wavelength of 650 nm, for example, from the second active layer 33 having a multiple quantum well (MQW) structure of GaInP and (Al _0.45 Ga) _0.52 InP. Therefore, in the second semiconductor light emitting device 3, the configuration of the light guide layers 32 and 36 need not be strictly adjusted.
On the other hand, in the first semiconductor light emitting element 2 having the element main portion 28 suitable for light emission in the central wavelength band of 780 nm, the configuration of the light guide layer needs to be strictly adjusted.

In this embodiment, in the first semiconductor light emitting device 2, a light guide layer 22 of a first conductivity type, for example, n-type Al _0.3 GaAs is provided in the first first conductivity type cladding layer 21. Since the light guide layer 26 made of Al _0.3 GaAs of the second conductivity type is provided in the first second conductivity type cladding layer 24, the distribution of the oscillation light from the active layer is controlled.
That is, in the semiconductor light emitting device 1 according to the present invention, by adjusting, for example, the thickness, the number of layers, the distance from the active layer, and the like of each light guide layer in the plurality of semiconductor light emitting elements constituting the device, each semiconductor light emitting element. For example, the characteristic change caused by the composition of the buried layer can be corrected with respect to the oscillation light from, so that the light emission characteristics such as FFP can be suitably realized.

An example of the configuration of the light guide layer of the first semiconductor light emitting element in this embodiment will be described.
For example, when the thickness of the light guide layer 22 is in the range of 62 nm to 82 nm, the thickness of the light guide layer 26 is 59 nm, and the distance between the active layer 23 and the light guide layer 22 is 800 nm to 900 nm. By setting the distance between the active layer 23 and the light guide layer 26 to 200 to 250 nm (for example, 220 nm) as (for example, 900 nm), the light emitting characteristics of the device are made favorable even when the buried layer 29 is made of GaInP. Can do.
Each of the light guide layers 22 and 26 has a structure in which each light guide layer has a multi-layer structure, that is, a two-layer structure or a three-layer structure, as well as a change in their stacking order or material composition. The plurality of semiconductor light emitting elements can be different from each other.

Next, an example of the control of the light emission characteristics of the element caused by the configuration of each light guide layer of the first semiconductor light emitting element in this embodiment will be described with reference to Table 1.
Table 1 shows a conventional semiconductor light-emitting element A having a configuration described in Patent Document 1 and a general single-wavelength light-emitting element with respect to an AlGaAs-based semiconductor light-emitting element for light oscillation in a light emission wavelength band having a central wavelength of 780 nm. The comparison result regarding the light emission characteristic of the conventional semiconductor light emitting element B and the semiconductor light emitting element, ie, the 1st semiconductor light emitting element 2 in the Example of the semiconductor light-emitting device by this invention is shown.

Here, Δn is the effective refractive index difference in the horizontal direction between the active layer and its periphery, and θ⊥ and θ // are the vertical radiation angle and horizontal radiation angle of the FFP (Far Field Pattern) of the oscillation light.
If the value of Δn is too large, the light density around the active layer becomes too high, and the deterioration of the device is promoted. Here, it is desirable that the value of Δn be within a range of 0.002 to 0.006.
On the other hand, if the values of θ⊥ and θ // are too large, when the semiconductor light emitting device is put into practical use as an optical device, it becomes impossible to couple with other optical systems such as lenses, and the light use efficiency decreases. End up. Here, it is desirable that θ⊥ be 20 ° or less and θ // be 10 ° or less.

In Table 1, in the results relating to the conventional semiconductor light emitting device A, that is, the semiconductor light emitting device described in Patent Document 1, all the values of Δn, θ⊥, and θ // are large, and a part of the configuration is changed. It is considered difficult to make it suitable for practical use with an optical design by correcting the above.
Further, according to the conventional semiconductor light emitting device B, the value of θ⊥ is not suppressed within a suitable range.
On the other hand, in the semiconductor light emitting element constituting the semiconductor light emitting device according to the present invention, in particular, by forming the light guide layer in the first conductivity type cladding layer and further controlling the thickness, the distance from the active layer, etc. It is considered that the result of keeping all the values of Δn, θ⊥ and θ // within a desired range was obtained.

  The selected values of thickness and interlayer distance in the above description can vary depending on the scale and size of the element, or the required specifications such as the emission wavelength band and output required for the apparatus.

Next, as an example of a method for manufacturing a semiconductor light emitting device according to the present invention, an embodiment of a method for manufacturing a semiconductor light emitting device having a first semiconductor light emitting element and a second semiconductor light emitting element will be described with reference to FIGS. Will be described with reference to FIG.
This embodiment is an example in which a plurality of semiconductor light emitting elements constituting the semiconductor light emitting device according to the present invention are two index guide laser elements having different emission wavelength bands.

First, a base 4 made of GaAs of the first conductivity type (for example, n-type) is prepared as a common substrate on which a plurality of (two in this example) semiconductor light emitting elements having different emission wavelength bands are formed.
Then, although not shown, a first laminated semiconductor layer is formed on the entire surface of the substrate 4, and the other portions are etched off while leaving the first laminated semiconductor layer 8a as shown in FIG. 2A.
That is, for example, the first conductivity type cladding layer 21 made of the first conductivity type Al _0.47 GaAs having the light guide layer 22 made of the first conductivity type Al _0.3 GaAs, the Al _0.1 GaAs, A first active layer 23 having a multiple quantum well (MQW) structure with Al _0.3 GaAs, an etching stop layer 25 having Al _0.6 GaAs, and a second conductivity type (for example, p-type) Al _0.3 GaAs The first conductive semiconductor clad layer 24 of the second conductivity type Al _0.47 GaAs having the light guide layer 26 and the contact layer 27 made of the second conductivity type GaAs are combined into the first laminated semiconductor layer. 8a is sequentially formed by, for example, epitaxial growth. Thereafter, this laminated semiconductor layer 8a is subjected to pattern etching to etch off portions other than the first semiconductor light emitting element forming portion, thereby forming the first laminated semiconductor layer 8a as shown in FIG. 2A.

Next, a second laminated semiconductor layer 8b to be a second semiconductor light emitting element is laminated on the base 4. Then, as shown in FIG. 2B, the first laminated semiconductor layer 8a is exposed and etched off so as to leave the second laminated semiconductor layer 8b.
That is, for example, on the surface of the base 4 remaining after the formation of the first semiconductor light emitting element 8a, the second first conductivity type cladding layer 31 of (Al _0.7 Ga) _0.52 InP of the first conductivity type, A light guide layer 32 having a first quantum conductivity (MQW) structure of n-type GaInP and (Al _0.7 Ga) _0.52 InP, GaInP and (Al _0.45 Ga) _0.52 InP, for example. And a second active layer 33 having a multiple quantum well (MQW) structure, and a light guide layer 36 having a multiple quantum well (MQW) structure of GaInP and (Al _0.7 Ga) _0.52 InP of the second conductivity type. Then, the second conductivity type cladding layer 34 made of the second conductivity type (Al _0.7 Ga) _0.52 InP and the contact layer 37 made of the second conductivity type GaAs are sequentially formed as the laminated semiconductor layer 8b. For example Laminated formed by epitaxial growth.
Thereafter, the area of the contact layer 37 opposite to the active layer 33, that is, the area where the second semiconductor light emitting element on the upper surface is formed is protected by, for example, an etching mask layer (not shown). Then, etch-off is performed to etch away the stacked semiconductor layers other than the etching mask layer forming portion and the first stacked semiconductor layer 8a. In this manner, as shown in FIG. 2B, the first laminated semiconductor layer 8a and the second laminated semiconductor layer 8b are left and formed.

Subsequently, as shown in FIG. 3A, an etching mask layer (not shown) is formed on the contact layer 37 constituting the second stacked semiconductor layer 8b on the side opposite to the active layer 33, that is, in the center of the upper surface in this example, for example. The second semiconductor light emitting element 3 finally formed is selectively etched by a depth that does not reach the second active layer 33 from the contact layer 37 to the light guide layer 36. A stripe-shaped ridge 9b constituting a current path is formed to obtain the second element main portion 38.
Thereafter, as shown in FIG. 3B, an etching mask layer (not shown) is formed on the contact layer 27 constituting the first stacked semiconductor layer 8a on the side opposite to the active layer 23, that is, in the center of the upper surface in this example, for example. The first semiconductor light emitting device 2 is finally formed by performing selective etching at a depth not reaching the first active layer 23 from the contact layer 27 to the light guide layer 26. A stripe-shaped ridge 9a constituting a main current path is formed to obtain the first element main portion 28. In this way, the main part forming step for forming the first and second element main parts 28 and 38 is performed.
In this embodiment, since the main part forming step is performed as described above, the main part forming step of forming the main parts of the plurality of semiconductor light emitting elements having different emission wavelength bands is performed by the semiconductor light emitting device according to the present invention. The number of steps is the same as the number of the plurality of semiconductor light emitting elements constituting one.

  Subsequently, as shown in FIG. 4A, buried layers 29 and 39 having the same composition of AlInP, for example, are entirely formed on the upper surfaces of the first and second element main portions 28 and 38 by, for example, epitaxial growth. Then, a predetermined part of the buried layers on the upper surfaces of the contact layers 27 and 37, that is, the buried layers 29 and 39 is selectively removed. After that, as shown in FIG. 4B, an electrode 5 made of, for example, an Au / Ge / Ni / Au multilayer metal film is ohmicly deposited on the back surface of the substrate 4, and Au / Pt / Electrodes 6a and 6b made of a multilayer metal film of Ti are respectively deposited ohmically. In this way, the buried layer forming step for forming the buried layer that defines the main current path in each element is performed, and the semiconductor light emitting device 1 according to the present invention shown in FIG. 1 is obtained.

  In the embodiment of the method for manufacturing the semiconductor light emitting device, in forming the first semiconductor light emitting element 2, an etching stop layer 25 is separately formed in addition to the light guide layer 26. It was set as the structure which prescribes | regulates the etching depth in a part formation process. On the other hand, in the formation of the second semiconductor light emitting element 3, the light guide layer 36 plays a role of regulating the etching depth, and is defined so that the etching does not reach at least the second active layer 33. did.

  In the formation of the first semiconductor light emitting element 2, the etching stop layer 25 can be made of a material having suitable characteristics as a light guide layer. In this case, the etching stop layer not only plays a role of regulating the etching depth in the main part forming step, but also acts to attract the emission point and emission distribution of the oscillation light from the active layer. Therefore, in this case, it is desirable that the etching stop layer itself has a refractive index that can absorb light from the active layer to some extent.

  As described above, in the method for manufacturing a semiconductor light emitting device according to the present invention, each of the light guide layers 22, 26, 32, and 36 has, for example, a structure in which each light guide layer has a multilayer structure, that is, a two-layer structure or a three-layer structure. In addition, by changing the distance from the active layer, the composition structure of each guide layer, the structure as the stacking order, and the like, the semiconductor light emitting elements can have different structures. Thus, the etching mode can be controlled. That is, for each semiconductor light emitting element, an etching stop layer is not necessarily provided separately from the light guide layer.

  Although the embodiments of the semiconductor light emitting device and the method for manufacturing the semiconductor light emitting device according to the present invention have been described above, the semiconductor light emitting device and the method for manufacturing the semiconductor light emitting device according to the present invention are not limited to this embodiment. Needless to say.

For example, in the above-described embodiment, as an example of a method for manufacturing a semiconductor light emitting device according to the present invention, a method for manufacturing a two-wavelength semiconductor light emitting device composed of two semiconductor light emitting elements having different emission wavelengths has been described. According to the above-described method for manufacturing a semiconductor light emitting device according to the present invention, a multi-wavelength semiconductor light emitting device composed of a plurality of three or more semiconductor light emitting elements is formed by the main part forming step and the buried layer forming step. It can be manufactured.
That is, the semiconductor light-emitting device according to the present invention is not limited to the configuration composed of two semiconductor light-emitting elements having different emission wavelengths, and can be a multi-wavelength semiconductor light-emitting device composed of three or more semiconductor light-emitting elements.

In the above-described embodiment, the first conductivity type is n-type and the second conductivity type is p-type, but both may be opposite conductivity types.
The semiconductor light emitting device according to the present invention can also be applied to a so-called pulsation laser, and each element can also be configured to have a buffer layer as required.
And the semiconductor light-emitting device by this invention can be set as the structure by which the several element was formed in one main surface from which a base | substrate differs.

In the method for manufacturing a semiconductor light emitting device according to the present invention, the stripe ridge 9b of the second semiconductor light emitting element 3 is formed in the above-described embodiment, and the stripe ridge 9a of the first semiconductor light emitting element 2 is formed. However, it is also possible to reverse the order of both processes.
According to the method for manufacturing a semiconductor light-emitting device according to the present invention, a plurality of semiconductor light-emitting devices having a plurality of, for example, two semiconductor light-emitting elements can be manufactured by simultaneously forming a large number of semiconductor light-emitting elements and dividing them. In addition, it goes without saying that various modifications and changes can be made, such as a semiconductor integrated circuit.

It is a schematic sectional drawing of the principal part of an apparatus which shows the structure of an example of the semiconductor light-emitting device by this invention. 2A and 2B are schematic cross-sectional views showing one step in an example of a method for manufacturing a semiconductor light emitting device according to the present invention. 3A and 3B are schematic cross-sectional views showing one process in an example of a method for manufacturing a semiconductor light emitting device according to the present invention. 4A and 4B are schematic cross-sectional views showing one step in an example of a method for manufacturing a semiconductor light emitting device according to the present invention. It is a schematic sectional drawing which shows the structure of the index guide type | mold laser element which comprises the conventional single wavelength semiconductor light-emitting device. It is a schematic sectional drawing which shows the structure of the gain guide type | mold laser element which comprises the conventional single wavelength semiconductor light-emitting device. It is a schematic sectional drawing which shows the structure of the conventional 2 wavelength semiconductor light-emitting device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor light-emitting device, 2 ... 1st semiconductor light-emitting device, 3 ... 2nd semiconductor light-emitting device, 4 ... Base | substrate (board | substrate), 5 ... Electrode, 6a ... Electrode , 6b ... electrodes, 8a ... laminated semiconductor layer, 8b ... laminated semiconductor layer, 9a ... ridge (stripe), 9b ... ridge (stripe), 21 ... first first Conductive cladding layer, 22 ... light guide layer, 23 ... first active layer, 24 ... first second conductive cladding layer, 25 ... etching stop layer, 26 ... light Guide layer, 27 ... contact layer, 28 ... first element main part, 29 ... buried layer, 31 ... second first conductivity type cladding layer, 32 ... light guide layer 33 ... second active layer, 34 ... second second conductivity type cladding layer, 36 ... light guide layer, 37 ... co Tact layer, 38 ... second element main part, 39 ... buried layer, 101 ... index guide type laser element, 104 ... substrate (substrate), 105 ... electrode, 106 ... -Electrode, 121 ... 1st conductivity type cladding layer, 123 ... Active layer, 125 ... Etching stop layer, 127 ... Contact layer, 128 ... Element main part, 129 ... Embedding Layer 201, gain guide laser, 204, substrate (substrate), 205, electrode, 206, electrode 207, insulating layer, 221, first conductivity type cladding layer, 223, ..Active layer, 224... Second conductivity type cladding layer, 228... Element main part, 301... Conventional semiconductor light emitting device, 302. 2 semiconductor light emitting device, 304... Substrate ( Plate), 305 ... electrode, 306a ... electrode, 306b ... electrode, 321a ... first first conductivity type cladding layer, 321b ... first first conductivity type cladding layer, 322a ... light guide layer, 322b ... light guide layer, 323 ... first active layer, 324a ... first second conductivity type cladding layer, 324b ... first second conductivity type Cladding layer, 325 ... Etching stop layer, 326a ... Light guide layer, 326b ... Light guide layer, 327a ... Contact layer, 327b ... Contact layer, 328 ... Main element of first element , 329... Buried layer, 333... Second active layer, 338... Second element main part, 339.

Claims (10)

A semiconductor light emitting device having at least a plurality of semiconductor light emitting elements having different emission wavelength bands on a substrate,
Each of the plurality of semiconductor light emitting elements is
An element main portion comprising at least a first conductivity type cladding layer, an active layer, a second conductivity type cladding layer, and a light guide layer;
A buried layer defining a main current path for the active layer,
In the plurality of semiconductor light emitting elements, the composition of the buried layer is the same as each other.   2. The semiconductor light emitting device according to claim 1, wherein at least some of the plurality of semiconductor light emitting elements have different configurations of the light guide layer.   The semiconductor light-emitting device according to claim 1, wherein at least one of the plurality of semiconductor light-emitting elements has an etching stop layer that defines a depth of the buried layer.   2. The semiconductor light emitting device according to claim 1, wherein at least one of the plurality of semiconductor light emitting elements is AlGaAs-based.   The semiconductor light emitting device according to claim 1, wherein at least one of the plurality of semiconductor light emitting elements is AlGaInP-based. A method of manufacturing a semiconductor light emitting device having at least a plurality of semiconductor light emitting elements having different emission wavelength bands on a substrate,
Epitaxial growth for forming a laminated semiconductor layer having at least a first conductivity type cladding layer, an active layer, a second conductivity type cladding layer, and a light guide layer, and making the second conductivity type cladding layer a desired shape Etching is performed a plurality of times, and a main part forming step of forming each main part of each of the plurality of semiconductor light emitting elements,
An embedded layer forming step for forming an embedded layer that defines a main current path in each of the semiconductor light-emitting elements finally obtained in each of the main parts;
In the buried layer forming step, a buried layer is simultaneously formed on a main part of at least two semiconductor light emitting elements of the plurality of semiconductor light emitting elements.   7. The semiconductor light emitting device according to claim 6, wherein, in the main part forming step, the light guide layer has a different structure in at least some of the plurality of semiconductor light emitting elements. Production method.   7. The method of manufacturing a semiconductor light emitting device according to claim 6, wherein, in the main part forming step, an etching stop layer for the etching is formed on at least one of the plurality of semiconductor light emitting elements.   7. The method of manufacturing a semiconductor light emitting device according to claim 6, wherein at least one of the plurality of semiconductor light emitting elements is AlGaAs.   7. The method of manufacturing a semiconductor light emitting device according to claim 6, wherein at least one of the plurality of semiconductor light emitting elements is AlGaInP-based.

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