JPH11233893A - Semiconductor light emitting device and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: A luminous efficiency when a semiconductor light emitting element is further formed on a continuous film semiconductor layer having a lattice constant or a thermal expansion coefficient different from that of a substrate using a partial growth suppressing structure. And reliability are prevented from deteriorating. SOLUTION: In a semiconductor light emitting device formed on a continuous film semiconductor layer including a region above a growth suppressing structure obtained by crystal growth on a growth suppressing structure, light emission which generates light by current injection in an active layer. The region is formed in a region other than the region above the growth suppressing structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device, and more particularly to a highly reliable semiconductor light emitting device formed on a substrate with a semiconductor material having a different lattice constant or thermal expansion coefficient from the substrate.

[0002]

2. Description of the Related Art When a semiconductor light emitting device is formed on a substrate having a lattice constant different from the crystal material by 3% or more, or when a semiconductor crystal is grown on a substrate having a thermal expansion coefficient different by 10% or more, First, a crystal material having a lattice constant and a coefficient of thermal expansion substantially equal to those of the material constituting the semiconductor light emitting device (both within 1% in both the lattice constant and the coefficient of thermal expansion) is grown on the substrate to form a continuous film semiconductor layer. Attempts have been made to form light emitting elements. It has been reported that a semiconductor layer stacked on a continuous film semiconductor layer has reduced crystal defects.
As a typical example of such a light emitting device, FIG. 8 shows that a GaN layer is grown thickly on a sapphire substrate 800 to form a continuous film semiconductor layer, and a blue light emitting diode (L) is formed thereon.
An example according to the prior art in which ED) is formed is shown.

A method of manufacturing this conventional LED will be described. First, a GaN layer 801 is grown to a thickness of 5 μm on the sapphire substrate 800 by a halide vapor deposition method (HVPE method). Next, a selective growth mask 802 made of SiO _{2 is} formed on the surface of the GaN layer 801 in a lattice shape (a shape of SiO ₂ stripes of 200 μm pitch and 20 μm width is orthogonal to each other). FIG. 8A is a cross-sectional view of the process manufactured as described above.

Next, HV is applied on the sapphire substrate 800.
The n-type GaN continuous film semiconductor layer 803 is 300
It is grown to a thickness of μm. At this time, the n-type GaN continuous film semiconductor layer 803 grown by the HVPE process begins to grow from the portion where the sapphire substrate 800 is exposed, but as the thickness increases, the selective growth mask 80 made of SiO _{2 is formed.}
2 Growing to the left and right as if overhanging, eventually reaching 20
The selective growth mask 802 made of SiO _{2 having a} width of μm was covered. Thus, the n-type GaN continuous film semiconductor layer 803 having a flat surface was formed.

Next, a wafer in which an n-type GaN continuous film semiconductor layer 803 is formed on the sapphire substrate 800 is:
N-GaN by metal organic chemical vapor deposition (MOCVD)
Cladding layer 804, InGaN active layer 805, p-Ga
An N contact layer 806 was formed. FIG. 8B shows a cross-sectional view of the process manufactured as described above.

Next, as shown in FIG. 9A, which is a top view of a conventional LED, and FIG. 9B is a cross-sectional view taken along line AA ′ of the conventional LED, a light emitting region 810 of 300 μm square is left. The p-GaN contact layer 8 is formed to surround the p-GaN contact layer 8 by using a usual photolithography technique and a dry etching technique.
06, the InGaN active layer 805, and the n-GaN cladding layer 804 were removed so as to penetrate them, exposing the n-type GaN continuous film semiconductor layer 803. Finally, an n-type electrode 807 was formed on the surface of the n-type GaN continuous film semiconductor layer 803, and a light-transmissive p-type electrode 808 was formed on the surface of a 300 μm square p-GaN contact layer 806. A scribing was performed around the light emitting region 810 from the wafer thus manufactured, and individual LEDs were cut out to be used as elements. A conventional LED manufactured in this manner has been reported.

[0007]

However, as a result of testing the characteristics of the LED fabricated in this way by the inventor, the luminous efficiency (the conversion efficiency of electrons into photons) when a current of 20 mA is injected is different. Varies greatly from 0.3% to 10% depending on the device, and the yield at which a desired luminous efficiency of 5% or more can be obtained is as low as 2%, and the initial reliability of about 100 hours at 80 ° C. In the test, it was newly found that the luminous efficiency of all the devices was drastically reduced to about 30% or less at the start of the test.

As a result of a detailed study by the inventor of these conventional elements, the following facts were found. (1) Light emission at the InGaN active layer 805 located in the region 811 immediately above the selective growth mask 802 where the selective growth mask 802 exists is extremely small. Also, this decrease in luminous efficiency is due to the fact that the light emitting region
It has also been found that this is particularly remarkable when the region 811 immediately above the selective growth mask is located in the central region of. As a result, the luminous efficiency greatly changes depending on the position of the region 811 immediately above the selective growth mask in the light emitting region 810. (2) Even in the case of the above-described device having poor reliability, the region 81 immediately above the selective growth mask after the reliability test run for 100 hours.
In the InGaN active layer 805 having a width of 1 (20 μm), almost no light emission is observed in a region of a total of 80 μm including about 30 μm on both sides in the vicinity thereof.

Further, as a result of crystal analysis of the conventional device, InGa located in the region 811 immediately above the selective growth mask was obtained.
It became clear that crystal transition was concentrated and introduced into the N active layer 805 through the n-type GaN continuous film semiconductor layer 803 having a thickness of 300 μm. FIG. 10 shows the density of crystal transition in the InGaN active layer 805 by using the selective growth mask 8.
The result of measurement using the distance from the 02 end as a parameter is shown. In of the region 811 immediately above the selective growth mask having a width of 20 μm
Crystal transitions having a density of 10 ¹² cm ⁻² are concentrated in the GaN active layer 805, and furthermore, 1 mm from the edge of the selective growth mask 802.
A transition of 10 ¹¹ cm ^-2 was observed even at a position separated by 0 µm. As the distance from the edge of the selective growth mask 802 increases, the crystal transition decreases, and in the InGaN active layer 805 located at a distance of 30 μm or more, the crystal transition decreases to 10 ⁷ to 10 ⁸ cm ⁻³ . Such a tendency was observed in any part of the wafer prepared as described above.

In the same manner, a semiconductor laser is formed on the n-type GaN continuous film semiconductor layer 803 as described above by including a region 811 immediately above a selective growth mask in a light emitting region, having a large oscillation threshold current of 700 mA, and The life was very short at room temperature, about 1 second.

As described above, the following problems have been clarified in the prior art. (1) In a light-emitting element on a continuous film semiconductor layer manufactured by using the selective growth method, a decrease in luminous efficiency is observed in a region 811 immediately above the selective growth mask. The luminous efficiency drops dramatically. (2) The life of the semiconductor laser device formed on the continuous GaN film was short, and no semiconductor laser device was obtained.

For this reason, a continuous film semiconductor layer having a lattice constant and a thermal expansion coefficient different from those of the substrate is grown on the substrate, and a semiconductor light emitting element formed thereon is caused by the lattice constant difference and the thermal expansion coefficient difference. It has not been possible to prevent a decrease in luminous efficiency or poor reliability.

Therefore, utilizing the partial growth suppressing structure,
It is an object of the present invention to prevent a decrease in luminous efficiency and a decrease in reliability when a semiconductor light emitting element is further formed after a continuous film semiconductor layer having a lattice constant or a thermal expansion coefficient different from that of a substrate is formed.

[0014]

A first aspect of the present invention has a continuous film semiconductor layer including a region immediately above a growth suppression structure obtained by crystal growth on a growth suppression structure, and an active layer for generating light. A semiconductor light emitting device, wherein:
The light emitting region that generates light by current injection is formed in a region other than the region immediately above the growth suppressing structure.

According to a second aspect of the present invention, the light emitting region is formed at a position at least 30 μm away from the region immediately above the growth suppressing structure. The region between the regions is formed by removing the active layer.

On the other hand, a fourth step is to form a growth suppressing structure on the substrate, and the substrate and the lattice constant or the thermal expansion coefficient are so set as to continuously cover both the substrate and the growth suppressing structure. A second step of forming a different continuous film semiconductor layer, a third step of forming a multilayer structure including an active layer for generating light on the continuous film semiconductor layer, and excluding a region immediately above the growth suppressing structure portion And a fourth step of forming a structure for defining a light emitting region in the active layer by dividing the semiconductor light emitting element from a wafer into a plurality of semiconductor light emitting elements. A method for manufacturing a semiconductor light emitting device having a step of
A fifth step of dividing the semiconductor light emitting device from the wafer so that the active layer immediately above the growth suppressing structure is not included in the semiconductor light emitting device after the fourth step. In the fifth step, the semiconductor light emitting device is divided so that the active layer remaining in a region within 30 μm from the end immediately above the growth suppressing structure is not included in the semiconductor light emitting device.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments. Embodiment 1 FIG. 1 shows an example of a semiconductor laser device embodying the present invention. This semiconductor laser device is n-GaN
Continuous film semiconductor layer 102, n-GaN buffer layer 103,
n-Al _0.1 Ga _0.9 N cladding layer 104, multiple quantum well active layer 105, p-Al _0.1 Ga _0.9 N cladding layer 10
6, a p-GaN contact layer 107, a mesa stripe 110 for defining a laser emission region as a ridge waveguide, and a p-type current injection p.
It comprises a mold electrode 111 and an n-type electrode 112.

Next, a manufacturing process of the device of this embodiment will be described with reference to FIG. First, the MO was placed on the sapphire substrate 100.
The GaN buffer layer 101 is grown to a thickness of 1 μm by the CVD method. Then, after a SiO ₂ film was 0.4μm thick formed by conventional sputtering method on the surface of the GaN buffer layer 101, typically photo-periodic SiO ₂ pitch 150μm in width 10μm by lithography and etching techniques
Selective growth mask 150 made of
Selective growth mask 15 made of 00 μm periodic SiO ₂
1 and 2 were formed in a shape orthogonal to each other. FIG. 2A is a process sectional view of the semiconductor laser device manufactured as described above.

Subsequently, an n-GaN continuous film semiconductor layer 102 was grown on this wafer by HVPE to a thickness of 150 μm. With the substrate temperature set to 1020 ° C., the growth of 150 μm thickness was completed by the growth for 35 minutes. During this growth, since the selective growth masks 150 and 151 function as a growth suppressing structure, growth occurs only in the region where the GaN buffer film 101 is exposed at the beginning of growth, as described in the conventional example, and gradually the selective growth mask At the stage where the growth progressed in the lateral direction on 150 and 151, and finally the growth of 150 μm in thickness was completed, the n-GaN continuous film semiconductor layer 102 was a continuous film, and the surface was smooth.

Next, an n-GaN buffer layer 103 having a thickness of 0.5 μm and n-Al _0.1 Ga _0.9 N is continuously formed on the n-GaN continuous film semiconductor layer 102 by MOCVD.
The cladding layer 104 is made of 0.2 μm thick, 4 nm thick In _0.25
Two Ga _0.75 N well layers and 3 nm thick In _0.05 Ga _0.95 N
The multiple quantum well active layer 105 composed of three barrier layers, p-
The Al _0.1 Ga _0.9 N cladding layer 106 is 0.2 μm thick,
The GaN contact layer 107 was grown to a thickness of 0.7 μm. FIG. 2B is a process sectional view of the semiconductor laser device manufactured as described above.

Subsequently, a mesa stripe 110 having a width of 2 μm and a height of 0.7 μm is formed in the region 1 directly above the selective growth mask 150.
A region other than 52 was formed substantially parallel to the selective growth mask 150. At this time, the mesa stripe 110 was positioned substantially at the center of the adjacent selective growth mask 150 as viewed from above the element. For the formation of the mesa stripe 110, ordinary photolithography technology and dry etching technology were applied. Thereafter, a stripe-shaped p-type electrode 111 is formed on the mesa stripe 110 on the upper surface, and the wafer thickness is reduced to about 120 μm by polishing the back surface of the wafer.
m (that is, the sapphire substrate 100, the GaN buffer layer 101, and the selective growth masks 150 and 151 are completely removed so that the n-GaN continuous film semiconductor layer 102 is exposed on the back surface of the wafer). Layer 1
The n-type electrode 112 was formed on the entire exposed back surface of the substrate 02. FIG. 2C is a process sectional view of the semiconductor laser device manufactured as described above.

Next, a mirror surface constituting a laser resonator was formed by cleavage. This cleavage step was performed as follows. First, two scratches were made near two corners of the back surface of the wafer (that is, the n-GaN continuous film layer 103 side).
The laser cavity mirror was formed by cleaving at the position of the scratch in a direction parallel to the direction in which the selective growth mask 151 was formed. At this time, the two scratches are formed at positions 50 μm away from the edge portions of the selective growth mask 151 adjacent to each other, and the area 15 directly above the selective growth mask 151 is formed.
3 was not included in the laser element. Therefore, the laser cavity length was 400 μm. Finally, the portion of the region 152 immediately above the selective growth mask 150 was scribed and divided into individual laser chips. Through the above steps, the laser device shown in FIG. 1 is completed.

The laser device manufactured as described above is
Laser oscillation was realized with a threshold current of 25 mA. In addition, as a result of performing a reliability test on the laser device under the conditions of 50 ° C. atmosphere and 3 mW output, it was confirmed that the life of most devices was 1000 hours or more, except for the laser device which failed within the initial 50 hours. The resulting median life (time during which half of the devices tested failed) was 1500 hours. This reliability is a sufficient characteristic even when the element is used as a light source for an optical disk. This improvement in reliability can be achieved by the present laser device by the regions 152, 153 directly above where crystal defects are concentrated on the selective growth masks 150, 151 which are growth suppression structures formed for growing the n-GaN continuous film semiconductor layer 102. Is not included in the light emitting region of the laser element (in this case, the portion where the mesa stripe 110 in which the current is selectively injected into the active layer 105 is formed). Mesa stripe 11 for growth mask 150
It can be understood that this is because the relative position of 0 and the relative position for cleavage of the laser resonator mirror with respect to the selective growth mask 151 are set.

In the laser device embodying the present invention, the mesa stripe 110 is located at the center between the regions 152 immediately above the adjacent selective growth masks 150 (ie, at a portion 70 μm away from the edge of the selective growth mask 150). Is formed. With a structure similar to that of the above-described embodiment element, the distance from the end of the mesa stripe 110 directly above the region 152 (that is, the selective growth mask 150) is 0 μm (that is, when the mesa stripe 110 is formed in the region 152 directly above),
Laser elements were manufactured in the conditions of 10 μm, 20 μm, 30 μm, 50 μm, and 70 μm, and the same reliability test as described above was performed. At this time, the scribe position for element isolation is set to the adjacent mesa stripe 11 in any element.
Mesa stripe 1 at the scribe position near the center of 0
The relative distance to the position 10 was constant. The result is shown in FIG. The horizontal axis is the mesa stripe 1 from the center of the area 152 immediately above.
The distance up to 10 and the vertical axis indicate the median life.
From this result, in order to secure a median life of 1000 hours or more required for practical use, the mesa stripe 11
It was found that it was necessary to form 0 at a position 30 μm or more away from the region 152 immediately above.

(Embodiment 2) Next, a case where the present invention is applied to a light emitting diode will be described. FIG. 4 shows a structural view of the device according to the second embodiment. n-GaN continuous film semiconductor layer 401, n-GaN buffer layer 402, In _0.1 Ga _0.9
N strain relaxation layer 403, In _0.5 Ga _0.5 N single quantum well active layer 404, p-Al _0.2 Ga _0.8 N evaporation preventing layer 405,
p-GaN contact layer 406 and n-type electrode 40
7. It is composed of a p-type electrode 408. In the device of this embodiment, the light emitting region is defined by the mesa 410.

Next, a method of manufacturing the present light emitting device will be described. First, a groove structure 450 having a width of 40 μm and a depth of 50 μm is formed on the surface of the sapphire substrate 400 by dicing.
It is formed in a grid at a pitch of μm. FIG. 5A is a process sectional view of the semiconductor device manufactured as described above.

Next, an n-GaN continuous film semiconductor layer 401 having a thickness of 300 μm is grown by HVPE. At this time, since the groove structure 450 is formed in the sapphire substrate 400, the n-GaN continuous film semiconductor layer 40 is initially formed.
1 cannot grow as a flat surface, but as the growth layer thickness increases, the groove structure 45 gradually grows from the left and right walls.
0 was buried, and the groove on the surface was buried flat. That is, the same effect as the slow growth in the trench 450 can be realized effectively, and at the end of the growth of 300 μm, n−
The continuous GaN film layer 401 could be a single continuous layer having a flat surface.

Next, the molecular beam epitaxy method (MBE
N) on the n-GaN continuous film semiconductor layer 401
0.4μm thickness of GaN buffer layer 402, an In _0.2 Ga
_0.8 N strain relaxation layer 403 with a thickness of 0.05 μm, In _0.45 G
a _0.55 N single quantum well active layer 404 is 4 nm thick, p-A
l _0.1 Ga _0.9 N evaporation preventing layer 405 is 0.1 μm thick, p-
The GaN contact layer 406 was grown to a thickness of 0.4 μm.
FIG. 5 is a process sectional view of the light emitting device manufactured up to this point.
(B).

Further, a 300 μm square mesa 410 including an In _0.45 Ga _0.55 N single quantum well active layer 404 is periodically left using a normal photolithography technique and a dry etching technique, and a region therebetween is etched with a width of 100 μm. Then, the n-GaN continuous film semiconductor layer 401 was exposed on the etching bottom surface. That is, the etched region has a lattice shape with a pitch of 400 μm,
A region 451 immediately above the trench structure 450 containing many defects grown by MBE on the trench structure 450 and In contained in the periphery thereof.
_{The 0.45} Ga _0.55 N single quantum well active layer 404 was completely removed. In this embodiment, the groove structure 450 is a growth suppressing structure. FIG. 5C is a process sectional view of the light-emitting element manufactured as described above.

Next, the back surface of the wafer is polished, the sapphire substrate 400 is completely removed, and the n-GaN continuous film semiconductor layer 401 is exposed on the back surface of the wafer.
An n-type electrode 407 is formed on the continuous film semiconductor layer 401,
A light transmissive p-type electrode 408 was formed on the surface of. Finally, individual light emitting diode chips were obtained by scribing in the region 451 immediately above the groove structure 450. FIG. 4 is a process cross-sectional view of the light-emitting element manufactured as described above.

When the conversion efficiency of electrons to photons of the light emitting diode thus manufactured was measured, the yield of devices having a conversion efficiency of 5% or more, which can be regarded as having no practical problem, was as high as 85%. Was. Further, a reliability test was performed on the device of this example under the same conditions as those of the device of the related art.
A luminescence intensity of 5 to 103% was obtained, and reliability without practical problems was secured.

The light emitting region in the light emitting device of this embodiment corresponds to the mesa 410 where the In _0.45 Ga _0.55 N single quantum well active layer 404 remains. A mesa 410 is formed in a region excluding a region 451 immediately above a trench structure 450 used as a growth suppressing structure when growing the n-GaN continuous film semiconductor layer 401.
Is formed, the light-emitting region does not include the region 451 immediately above the groove structure 450 in all of the manufactured light-emitting elements. Further, by etching, In _0.45 Ga _0.55
The width from which the N single quantum well active layer 404 is removed is 100 μm.
m, and the light emitting region of the mesa 410 is formed at a distance of 30 μm from the end of the groove structure 450 having a width of 40 μm. As described above, an element having high luminous efficiency can be obtained with good yield and reliability without any problem can be realized because the crystal growth process by the HVPE method and the MOCVD method concentrates on the region 451 directly above the groove structure 450. The effect of the introduced crystal defects does not adversely affect the light emission in the In _0.45 Ga _0.55 N single quantum well active layer 404, and the light emitting region can be arranged with good controllability in a portion having relatively few crystal defects. It is thought that it became.

In the light emitting device of the above embodiment, the light emitting device manufacturing process and the structure are almost the same, and only the pitch of the groove structure 450 is changed from 400 μm of the above example to 50 μm.
Light emitting devices were manufactured on a trial basis when the thickness was changed to 0 μm and 300 μm. Also in this case, the size and the manufacturing pitch of the mesa 410 were 300 μm and 400 μm, respectively, which were the same as those of the above-described embodiment. When the light-emitting characteristics of these light-emitting elements were measured, the yield at which luminous efficiency of 5% or more was obtained was reduced to 16% in the element in which the pitch of the grooves 450 was reduced to 300 μm. On the other hand, it was 38% for the light emitting element expanded to 500 μm. This indicates that it is important that the pitch of the groove structure 450 is the same as the production pitch of the mesas 410 forming the individual light emitting diodes. Therefore, in order to manufacture more light emitting elements from a wafer having the same area, the region 451 immediately above the groove structure should not be included in the light emitting area in all the light emitting elements. In this sense, it goes without saying that the pitch of the groove structure 450 may be an integral multiple of the pitch of the mesa 410.

(Embodiment 3) Next, an embodiment in which the growth suppressing structure itself is left in the laser device will be described. FIG. 6 shows an element structure diagram of the present embodiment. The device structure of the present embodiment includes an n-SiC substrate 600 and a GaN buffer layer 60.
1. n-GaN continuous film semiconductor layer 602, n-GaN buffer layer 603, n-Al _0.1 Ga _0.9 N cladding layer 60
4, 3 nm thick In _0.1 Ga _0.85 Al _0.05 N barrier layer 3
A multi-quantum well active layer 605 composed of two layers of In _0.2 Ga _0.8 N quantum well layers having a thickness of 3 nm, a p-Al _0.1 Ga _0.9 N cladding layer 606, and a p-GaN contact layer 607; Type electrode 611, n-type electrode 61
2. Further, a mesa stripe 610 for defining a waveguide and a current path, and an etched mirror 613 serving as a resonator mirror
have.

Hereinafter, a method for fabricating the laser device of this embodiment will be described. (Process drawing is omitted here because it is similar to FIG. 2.) First, the period over n-SiC substrate 600, a selective growth mask 650 period of 100μm in width 10μm consisting of SiN _x, a width of 10μm Is 400
The μm selective growth masks 651 were formed so as to be orthogonal to each other. GaN is deposited on this wafer by MOCVD.
The buffer layer 601 has a thickness of 30 nm, the n-GaN continuous film semiconductor layer 602 has a thickness of 100 μm, and the n-GaN buffer layer 60 has a thickness of 100 μm.
3 is 0.1 μm, the n-AlGaN cladding layer 604 is 0.3 μm thick, the multiple quantum well active layer 605, p-AlG
The aN cladding layer 606 and the p-GaN contact layer 607 are continuously grown with a thickness of 0.3 μm and a thickness of 1.0 μm, respectively. At this time, in the growth of the n-GaN continuous film semiconductor layer 602, when the thickness is 30 μm or less, an ungrown portion remains on the selective growth masks 650 and 651, and the crystal does not exhibit a continuous film. However, at the stage where the growth is further continued and the thickness reaches 100 μm, the surface of the n-GaN continuous film semiconductor layer 602 exhibits a flat and continuous single film as in the first embodiment, and the continuous Each of the layers 603 to 607 included in the stacked structure formed as described above was also grown as a flat layer.

Next, a mesa stripe 610 having a height of 0.8 μm and a width of 2 μm was formed in parallel with the selective growth mask 651 by using ordinary photolithography and etching techniques. The mesa stripe 610 not only forms a laser waveguide in the active layer 605, but also regulates the path of a current injected into the active layer 605 in a portion immediately below the mesa stripe 610, thereby efficiently converting electrons into laser light. do. In this step, the mesa stripe 610 is formed at the center of the region 653 immediately above the selective growth mask 651 on both sides, that is, the end of the selective growth mask 651 and the mesa stripe 610.
Was formed so that the distance between the ends of the pattern was 39 μm.

Next, an etched mirror 613 serving as a laser resonator mirror was formed by using a photolithography technique and a dry etching technique for forming an ordinary etched mirror. At this time, the etched mirror 613 is parallel to the selective growth mask 650 and the entire width centering on the region 652 immediately above the selective growth mask 650 is centered so that the active layer 605 in the region 652 immediately above the selective growth mask 650 is removed by etching. Etching is performed on a 100 μm area, and n
The etching was performed until the -GaN continuous film semiconductor layer 602 was exposed on the etching bottom surface. By this step, a set of cavity mirrors to be a laser cavity was formed, and the cavity length of the laser device of the present embodiment was 300 μm. That is, 40, which is the same as the cycle of the selective growth mask 650,
This means that etching for forming an etched mirror was performed at a period of 0 μm.

Finally, after forming a p-type electrode 611 on the upper surface of the mesa stripe 610 and an n-type electrode 612 on the entire back surface of the n-SiC substrate 600, selective growth masks 650 and 651 are formed.
Are divided into individual laser elements by scribing in the areas 652 and 653 immediately above the laser elements.

The laser device of the present embodiment is replaced with the laser device of the second embodiment 6
A reliability test was performed under an atmosphere of 0 ° C. and a light output of 5 mW. As a result, it was confirmed that all the devices had a lifetime of 1,000 hours or more, except for the devices that showed abnormal deterioration for the first 24 hours. The median life in this case was about 1600 hours. As described above, a highly reliable laser can be realized only in a region where the region 652 directly above the selective growth mask 650 is not included in the mesa stripe 610 which is a light emitting region and there are few crystal defects causing deterioration of the laser element. It is assumed that the active layer 605 contributes to light emission.

Incidentally, in the first embodiment, the cleavage position of the laser element is set in the region 15 directly above the selective growth mask 150.
It was limited to two outside parts. This is the selective growth mask 1
When cleaved at the region 152 directly above the region 50, the region 152 directly above the selective growth mask, which contains many crystal defects near the easily broken cleavage plane in the mesa stripe 110, which becomes the laser emission region, is included, and the device is operated. This is to avoid instantaneous deterioration when the battery is damaged. However, when cleaving is performed in the vicinity of the region 152 directly above the selective growth mask 150 in parallel with the region 152 directly above the selective growth mask 150 as in the first embodiment, a step is partially generated in the cleavage plane, and as a result, a step is generated. In some devices, the region 152 directly above the selective growth mask 150 may be included in the mesa stripe 110. This is because the region 152 directly above the selective growth mask 150
Contains many crystal defects, and is considered to be a cause of being weak as a crystal and more easily broken. That is, regardless of the fact that the crystal has the property of being easily cleaved in the region 152 directly above the selective growth mask 150, the vicinity is cleaved in the first embodiment. This phenomenon is observed not only when the element is divided by cleavage but also when the element is divided by scribing. The same phenomenon is observed in the case where the selection mask 151 is scribed in the region 153 immediately above the selection mask 151. In the case where the scribe was performed with good controllability in the vicinity of the region 153 directly above and in parallel with the region 153 directly above the selection mask 151, the yield was low.

On the other hand, in the device of the present embodiment, the device dividing position by scribing all four surfaces when dividing the device can be limited to the regions 652 and 653 immediately above the selective growth masks 650 and 651. No scribing occurred, and the mesa stripe 610 did not include the region 652 immediately above the selection mask, and the element shape did not deviate from a predetermined shape (a rectangular shape as viewed from above as shown in FIG. 6). As a result, errors can be reduced even in recognition of the element shape when mounting the element, and the element mounting yield can be improved. This point is also a great advantage of the device of the present embodiment.

(Embodiment 4) Next, an embodiment of the present invention in which the active layer in the region immediately above the growth suppressing structure remains in the device will be described using an example of a light emitting diode. In FIG.
FIG. 2 shows a structural view of the light emitting device of the present embodiment as viewed from above. The method of forming the GaN continuous film layer and the semiconductor multilayer structure are the same as those of the second embodiment (the description of the present embodiment assumes that the common layers are the same as those of the second embodiment). The difference from the second embodiment is that the shape of the mesa 710 including the In _0.45 Ga _0.55 N single quantum well active layer 404 has a shape as shown in FIG. 7 and the size is increased to 390 μm square. is there. Therefore, in the light emitting device of the present embodiment, n
-In _0.45 Ga _0.55 located in the region 751 directly above the groove structure 450 as the growth suppressing structure during the growth of the -GaN continuous film layer 401
The N single quantum well active layer 404 is included in the mesa 710.

However, in the light emitting device of the present embodiment, the p-type electrode 711 is 300 μm square and arranged in the center region of the mesa 710. That is, the region 75 immediately above the groove structure 450
No p-type electrode was formed in the region 30 μm from the end of the region 1 and the region 751 directly above. On the other hand, the n-type electrode 712 is composed of the In _0.45 Ga _0.55 N single quantum well active layer 40.
4 was formed at one corner of the light emitting element from which the light emitting element 4 was removed, as shown in FIG.

With such a configuration, the current injected from the p-type contact layer 406 and the p-type electrode 711 is such that the p-GaN contact layer 406 is made of p-GaN having a relatively high resistivity. In addition, since the thickness is as small as 0.4 μm, almost no current is diffused in the p-type contact layer 406 in the lateral direction, and I
Current can be injected only into the n _0.45 Ga _0.55 N single quantum well active layer 404.

As a result of evaluating the characteristics of the light emitting device of this embodiment, the number of chips having an electron-photon conversion efficiency of 5% or more reached 79% of the inspected devices, which is much higher than the light emitting device constructed by the conventional technology. Improvement was noted. In addition, reliability tests of these light emitting elements (the conditions are the same as in the second embodiment)
Was performed, the emission luminance after 1000 hours was in the range of 85 to 99% of the emission luminance at the beginning of the test, and it was confirmed that all the light emitting elements had no practical problem.

As described above, in the light emitting device of the embodiment, G
Although an example in which a gallium nitride-based light emitting element is manufactured using an aN continuous film semiconductor layer has been described, it goes without saying that the present invention can be applied to the following cases. (1) When the material of the substrate, the material of the continuous film semiconductor layer, and the material constituting the light emitting element are different (for example, the substrate is Si,
When the continuous film semiconductor layer is GaAs, or when the substrate is Si, Ga
As, when the continuous film layer is GaN, etc.). (2) When the material of the selective growth mask which is the growth suppressing structure is different (SiN _x , SiO _x , AlO _x , etc.) or when the structure itself is other than the selective growth mask or the groove structure (for example, formed on a sapphire substrate) Ridge stripes and other irregular structures, etc.). (3) When the order of the steps is changed so that the substrate is completely removed after the formation of the continuous film semiconductor layer and before the formation of the light emitting layer.

[0047]

As described above, by applying the present invention, when a semiconductor light emitting device is manufactured on a continuous film semiconductor layer having a lattice constant and a thermal expansion coefficient different from those of a substrate, a decrease in luminous efficiency is prevented. As a result, a light emitting diode or a semiconductor laser having a high luminous efficiency with a high yield can be realized. Further, according to the present invention, it is possible to secure practically sufficient reliability in these light emitting elements.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the semiconductor laser device according to the first embodiment of the present invention;

FIG. 3 is a diagram showing a median life with respect to a distance from a region immediately above a growth mask to a mesa stripe.

FIG. 4 is a sectional view of a semiconductor light emitting device according to a second embodiment of the present invention.

FIG. 5 is a manufacturing process diagram of the semiconductor light emitting device according to the second embodiment of the present invention.

FIG. 6 is a sectional view of a semiconductor laser device according to a third embodiment of the present invention.

FIG. 7 is a top view of a semiconductor light emitting device according to a fourth embodiment of the present invention.

FIG. 8 is a manufacturing process diagram of a conventional semiconductor light emitting device.

FIG. 9 is a view showing a structure of a conventional semiconductor light emitting device.

FIG. 10 is a diagram showing a surface density of crystal transition with respect to a distance from a growth suppressing structure.

[Explanation of symbols]

Reference Signs List 100 sapphire substrate 101, 601 GaN buffer layer 102, 602, 401 n-GaN continuous film layer 103, 603, 402 n-GaN buffer layer 104, 604 n-Al _0.1 Ga _0.9 N cladding layer 105, 605 Multiple quantum well active layer 106, 606, 405 p-Al _0.1 Ga _0.9 N cladding layer 107, 607 406 p-GaN contact layer 110, 610 mesa stripe 111, 611, 408, 711 p-type electrode 112, 612, 407, 712 n-type electrode 150, 151, 650, 651 Selective growth mask 152, 153, 652, 653 Immediately above region 400 Sapphire substrate 403 In _0.2 Ga _0.8 N strain relaxation layer 404 In _0.45 Ga _0.55 N single quantum well active layer 410 Mesa 450 Groove structure 451, 751 Area 600 SiC Substrate 710 mesa

Claims (6)

[Claims] 1. A semiconductor light emitting device comprising: a continuous film semiconductor layer including a region immediately above a growth suppression structure obtained by growing a crystal on a growth suppression structure; and an active layer for generating light. A semiconductor light-emitting element, wherein a light-emitting region for generating light by current injection is formed in a region other than a region immediately above the growth suppressing structure. 2. The semiconductor light emitting device according to claim 1, wherein the light emitting region is formed at a position separated from the region immediately above the growth suppressing structure by 30 μm or more. 3. The semiconductor light emitting device according to claim 1, wherein said active layer is removed in a region between said light emitting region and a region immediately above said growth suppressing structure. 4. A first step of forming a growth suppressing structure on a substrate, and a continuous film semiconductor layer having a different lattice constant or thermal expansion coefficient from the substrate so as to continuously cover both the substrate and the growth suppressing structure. A second step of forming a multilayer structure including an active layer that generates light on the continuous film semiconductor layer; and a third step of forming a multilayer structure including an active layer that generates light on the continuous film semiconductor layer. A fourth step of forming a structure for defining a light emitting region. 5. A method for manufacturing a semiconductor light emitting device, comprising: dividing a semiconductor light emitting device from a wafer into a plurality of semiconductor light emitting devices, wherein after the fourth step, the active layer immediately above the growth suppressing structure is a semiconductor. 5. The method according to claim 4, further comprising: dividing the semiconductor light emitting device from the wafer so as not to be included in the light emitting device. 6. The semiconductor light emitting device according to claim 5, wherein in the fifth step, the semiconductor light emitting device is divided such that the active layer remaining in a region within 30 μm from an end immediately above the growth suppressing structure is not included in the semiconductor light emitting device. A method for manufacturing a semiconductor light emitting device according to claim 5.