JP2002246694A - Nitride semiconductor light emitting element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the light emission life and intensity of a nitride semiconductor light emitting element and also to prevent generation of a crack. SOLUTION: The nitride semiconductor light emitting element includes a light emitting element structure having a nitride semiconductor base layer 102 grown on a substrate of a nitride semiconductor or on a nitride semiconductor substrate layer grown on a base substrate other than the nitride semiconductor, n-type layers 103 to 105 and p-type layers 107 to 110 above the nitride semiconductor base layer, and a light emitting layer 106 provided between the n- and p-type layers and including a quantum well layer or a barrier layer adjacent thereto. Even the light emitting element structure after grown is provided in its surface with unflattened recesses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a nitride semiconductor light emitting device having a long high-power operation life and reduced occurrence of cracks, and to an improvement in a manufacturing method thereof.

[0002]

2. Description of the Related Art Ga stacked on a sapphire basic substrate
A nitride semiconductor underlayer is grown using a selective growth technique using a SiO ₂ mask formed in a stripe shape on the N substrate layer as a growth suppressing film, and a semiconductor laser device is formed in a region above the SiO ₂ mask. To improve laser oscillation life by using Journal of Electronic Materials, Vol. 27, N
o.4, 1998.

Further, a nitride semiconductor base layer is grown by using a selective growth technique using a SiO ₂ mask formed in a stripe shape on a GaN substrate as a growth suppressing film.
₍₂₎ By forming a semiconductor laser device in the region above the mask, it is possible to improve the oscillation life at high output.
Japanese Journal of Applied Physics, vol.39 (2000)
Pt.2, No.7A, L647.

[0004]

SUMMARY OF THE INVENTION Even in the nitride semiconductor light emitting device manufactured by the above prior art,
It is desired to further improve the high-output operation life and the production yield. Accordingly, it is a main object of the present invention to further improve the high-output operation life of a nitride semiconductor light-emitting device and to suppress the occurrence of cracks in the device to improve the production yield.

[0005]

In the nitride semiconductor light emitting device according to the present invention, the nitride semiconductor light emitting device is grown on the surface of a nitride semiconductor substrate or on the surface of a nitride semiconductor substrate layer grown on a basic substrate other than the nitride semiconductor. A nitride semiconductor underlayer,
A light emitting element structure including a light emitting layer including a quantum well layer or a quantum well layer and a barrier layer in contact with the quantum well layer or the quantum well layer between the n-type layer and the p-type layer was formed on the underlayer, and the light emitting element structure was grown. It is characterized in that the surface includes a non-planarized depression even afterwards.

Preferably, the growth suppressing film is formed in a stripe pattern. The longitudinal direction of the stripe-shaped growth suppressing film is determined by the <1-100> or <11-2> of the nitride semiconductor crystal included in the mask substrate.
Preferably, it is substantially parallel to the 0> direction.

A depression is formed above the stripe-shaped growth suppression film, and light is emitted from a side end of the depression in the width direction of the growth suppression film by 2 μm or more and above a region within the width of the growth suppression film. It is preferable that a light emitting portion having an element structure is included. A gap may be formed between the growth suppressing film and the depression above it.

Preferably, the width of the growth suppressing film is in the range of 7 to 100 μm, and the thickness thereof is 0.05 to 10 μm.
Is preferably within the range.

The growth suppressing film is made of SiO ₂ , SiO, SiN _x
And a dielectric film of at least one of SiON _x and a metal of W or Mo.

[0010] The nitride semiconductor underlayer preferably contains at least one of Al and In.

The nitride semiconductor underlayer is GaN, and S
It contains at least one or more of i, O, Cl, S, C, Ge, Zn, Cd, Mg and Be impurity groups, and has an addition amount of 1 × 10 ¹⁷ / cm ³ or more and 5 × 10 ¹⁸ /
cm ³ or less.

The nitride semiconductor underlayer is Al _x Ga ₁ -xN
(0.01 ≦ x ≦ 0.15), and Si,
O, Cl, S, C, Ge, Zn, Cd, Mg and Be
It is preferable that at least one of the impurity groups described above is contained, and the added amount is 3 × 10 ¹⁷ / cm ³ or more and 5 × 10 ¹⁸ / cm ³ or less.

The nitride semiconductor underlayer is made of In _x Ga ₁ -xN.
(0.01 ≦ x ≦ 0.15), and Si,
O, Cl, S, C, Ge, Zn, Cd, Mg and Be
It is preferable that at least one of the impurity groups described above is contained, and the added amount is 1 × 10 ¹⁷ / cm ³ or more and 4 × 10 ¹⁸ / cm ³ or less.

Preferably, the electrode is formed on a region including two or more depressions. Similarly, it is preferable that a dielectric film is formed on a region including two or more depressions. The bonding region between the wire bond and the nitride semiconductor light emitting device preferably includes one or more depressions.

The quantum well layer preferably contains at least one of As, P, and Sb.

[0016] The nitride semiconductor light emitting device can be either a laser device or a light emitting diode device. Such a nitride semiconductor light emitting element can be a component of various optical devices or semiconductor light emitting devices.

On the other hand, in the method for manufacturing a nitride semiconductor light-emitting device according to the present invention, the method for growing a nitride semiconductor on a surface of a nitride semiconductor substrate or a surface of a nitride semiconductor substrate layer grown on a basic substrate other than the nitride semiconductor A growth suppressing film is formed partially to form a mask substrate, a nitride semiconductor underlayer is grown on the mask substrate, and an n-type layer and a p-type layer are formed on the nitride semiconductor underlayer. Including a step of growing a light-emitting element structure including a quantum well layer or a light-emitting layer including a quantum well layer and a barrier layer in contact with the quantum well layer. It is characterized in that a non-planarized depression is formed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, various embodiments according to the present invention will be described with reference to the drawings. In the drawings of the present application, dimensional relationships such as length, width, thickness, and depth are appropriately changed for clarification and simplification of the drawings, and do not represent actual dimensional relationships.

First, the “nitride semiconductor substrate” refers to Al _{x
Ga y In z N (0 ≦} x ≦ 1; 0 ≦ y ≦ 1; 0 ≦ z ≦ 1;
x + y + z = 1). However, about 10% or less of the nitrogen element of the nitride semiconductor substrate may be replaced with an element of As, P, or Sb (provided that the hexagonal system of the substrate is maintained). Further, in a nitride semiconductor substrate, Si, O, Cl, S, C,
Ge, Zn, Cd, Mg, or Be may be doped. Among these doping materials, Si, O, and Cl are particularly preferable as the n-type nitride semiconductor. The principal plane orientation of the nitride semiconductor substrate is C plane ｛0
001}, A plane {11-20}, R plane {1-102},
The M plane {1-100} or {1-101} plane can be preferably used. In addition, if the main surface of the substrate has an off angle within 2 ° from these crystal plane directions, the surface morphology may be good.

"Basic substrate" means a substrate other than a nitride semiconductor. As a specific base substrate, a sapphire substrate, a SiC substrate, a Si substrate, a GaAs substrate, or the like can be used.

The "growth suppressing film" is, for example, as shown in FIG.
As shown in FIG. 2, a film formed in a stripe shape on the substrate surface, on which a nitride semiconductor is unlikely to grow. That is, it means that the growth rate of the nitride semiconductor is slow or does not grow directly on the growth suppressing film. As the material of the growth suppressing film, oxides or nitrides of Si or compounds thereof, for example, Si
O ₂ , SiO, SiN _x , SiON _x , or a metal such as W or Mo can be used. Further, the growth suppressing film shown in FIG. 1 has a stripe arrangement along one direction, but may have a mesh arrangement in which these stripes cross each other (see FIG. 2).

The term "nitride semiconductor substrate layer" means a mask substrate or a processed substrate when a basic substrate such as a sapphire substrate other than a nitride semiconductor substrate is used as a substrate for producing a nitride semiconductor light emitting device. a layer according grown nitride semiconductor underlying substrate for, Al _x Ga _y in
_z N (0 ≦ x1 ≦; 0 ≦ y ≦ 1; 0 ≦ z ≦ 1; x + y +
z = 1). However, in this nitride semiconductor substrate layer, Si, O, Cl, S, C, Ge, Zn, C
At least one of the impurity groups of d, Mg, and Be may be doped.

The term "mask substrate" means a substrate in which a growth suppressing film is partially formed on the surface of a nitride semiconductor substrate or on the surface of a nitride semiconductor substrate layer grown on a basic substrate. The width of the growth suppressing film and the width of the portion where the growth suppressing film is not formed may have a fixed period, or may have various different widths. In addition, the thickness of the growth suppressing film may always have a constant thickness, or may have various different thicknesses.

"Groove" means a concave portion processed in a stripe shape on the substrate surface as shown in FIG. 4, for example, and "hill" means a convex portion processed in a stripe shape similarly. . The cross-sectional shapes of the grooves and hills do not necessarily have to be rectangular as shown in FIG. 4, but may be any as long as they cause uneven steps. Although the grooves and hills shown in FIG. 4 have a stripe arrangement processed along one direction, similar to the case of the growth suppression film (FIG. 2), the grooves and hills have a mesh arrangement in which the grooves or hills cross each other. There may be.

The term “worked substrate” means a substrate having grooves and hills formed on the surface of a nitride semiconductor substrate or on the surface of a nitride semiconductor substrate layer grown on a basic substrate. The width of the groove and the width of the hill may have a fixed period, or may have various widths. Regarding the depth of the grooves, all the grooves may have a constant depth or may have various different depths.

[0026] The term "nitride semiconductor underlayer", is a layer that is grown on the uneven surface of the mask substrate or working the _{substrate, Al x Ga y In z N} (0 ≦ x ≦ 1; 0 ≦ y ≦ 1 ; 0
≦ z ≦ 1; x + y + z = 1). However,
In this nitride semiconductor underlayer, Si, O, Cl, S,
At least one of an impurity group of C, Ge, Zn, Cd, Mg, and Be may be doped.

The term “substrate with depression” means an entire substrate including a depression on which a nitride semiconductor base layer is coated on a mask substrate or a processed substrate (see FIGS. 3 and 5).

The term "coating film thickness" refers to the thickness of the nitride semiconductor underlayer on a region where the growth suppressing film is not formed on the mask substrate, or the nitride semiconductor underlayer is grown on the processed substrate. It means the film thickness from the bottom of the groove of the processed substrate to the surface of the nitride semiconductor underlayer excluding the depression.

The term "light emitting layer" means a layer capable of producing a light emitting effect, including one or more quantum well layers or a plurality of barrier layers alternately stacked thereon. However, the light emitting layer having a single quantum well structure is composed of only one well layer or a laminate of barrier layers / well layers / barrier layers.

The “light emitting element structure” means a structure further including an n-type layer and a p-type layer sandwiching the light-emitting layer in addition to the light-emitting layer.

The term “nitride semiconductor multilayer film structure” means a structure including a nitride semiconductor underlayer and a light emitting device structure.

"Dent" means that when a nitride semiconductor underlayer or a nitride semiconductor multilayer film structure is grown and covered on a mask substrate or an uneven surface of a processed substrate, the nitride semiconductor underlayer or the nitride semiconductor It means a portion where the multilayer structure is not buried flat (see FIGS. 3 and 5 in an example in which the depression is on the surface of the nitride semiconductor underlayer). In particular, the depression in the present invention must always exist on the surface of the nitride semiconductor multilayer structure. However, the effect of the present invention cannot be obtained even if a depression is formed by etching or the like after the nitride semiconductor multilayer film structure is coated flat on the mask substrate or the processed substrate. Whether or not the depression is formed by processing after the crystal growth becomes clear by observing the cross section of the nitride semiconductor multilayer film structure. This is because, if a pit is formed by processing after completion of crystal growth, the continuity in the lateral direction in the stack in the light emitting device structure is cut off by the pit,
This is because if a depression is formed along with the crystal growth, the continuity in the lateral direction in the stack in the light emitting device structure is not cut off by the depression but continues along the side wall surface of the depression.

[Embodiment 1] First, the present inventors examined the difference in device characteristics between a case where a nitride semiconductor laser device was manufactured according to the prior art and a case where a nitride semiconductor laser device was manufactured according to the present invention. .

FIG. 1A shows a case A according to the present invention.
On a mask substrate on which a growth suppressing film is formed on a nitride semiconductor substrate (for example, a GaN substrate) shown in (1), a nitride semiconductor multilayer film structure in which a depression is formed without being completely buried is grown and nitrided. When a semiconductor laser device was formed, the oscillation life of the laser device was about 18,000 hours under the conditions of a laser output of 30 mW and an ambient temperature of 60 ° C.

As another case B according to the present invention,
On a mask substrate having a growth suppressing film formed above a basic substrate (for example, a sapphire substrate) shown in FIG. 1B, a nitride semiconductor multilayer film structure in which a depression is formed without being completely buried is grown. When the nitride semiconductor laser device is formed by the
The oscillation life of the laser device under the condition of
It was about 0 hours.

Next, as a case C according to the prior art, a recess is formed by completely flattening the surface on a mask substrate having a growth suppressing film formed on the nitride semiconductor substrate shown in FIG. When a nitride semiconductor laser device was formed by growing a nitride semiconductor multilayer film structure that was not formed, the oscillation life of the laser device was about 1500 hours under the conditions of a laser output of 30 mW and an ambient temperature of 60 ° C.

Further, as another case D according to the prior art, the surface is completely buried and no depression is formed on the mask substrate having the growth suppressing film formed above the basic substrate shown in FIG. 1B. When a nitride semiconductor laser device was formed by growing a nitride semiconductor multilayer structure, the oscillation life of the laser device was about 500 hours under the conditions of a laser output of 30 mW and an ambient temperature of 60 ° C.

The results of these surveys are plotted in the graph of FIG. As will be described in detail in the following embodiment, it can be seen that in the case A and the case B (particularly in the case A), a nitride semiconductor laser device having an extremely long oscillation life can be obtained. This result is presumed to be caused by differences in the magnitude and distribution of crystal lattice strain present in the nitride semiconductor film in each case.

In the case A and the case B, the light emitting element is formed in a state where the surface is depressed. On the other hand, case C
In the case D and the case D, the laser element is manufactured by a conventional technique that does not cause a depression on the surface. If no depression is formed on the surface, the lateral growth of the nitride semiconductor multilayer film structure proceeds on both sides of the growth suppressing film and finally merges near the center of the growth suppressing film. Lattice distortion will occur.

FIG. 6C shows a crystal growth mode in case C in which a nitride semiconductor multilayer structure is grown using the mask substrate of FIG. 1A. In this case, first, crystal growth of the nitride semiconductor multilayer structure starts from the window region of the GaN substrate that is not covered with the growth suppressing film. The nitride semiconductor multilayer structure growing in the window region grows in a normal crystal growth direction (a direction perpendicular to the main surface of the substrate). If the nitride semiconductor multilayer structure grows thicker than the growth suppressing film, the growth in the horizontal direction parallel to the main surface of the substrate (lateral growth) proceeds on the growth suppressing film, and the nitride also grows on the growth suppressing film. An object semiconductor multilayer structure is formed.
Then, the nitride semiconductor multilayer structures laterally grown from both sides of the growth suppressing film to the vicinity of the center are united with each other, and the entire surface of the growth suppressing film is covered. At this time, the combination of the films causes crystal lattice distortion.
On the other hand, the crystal growth form of the nitride semiconductor multilayer structure in Case A is shown in FIG. 6 (a). In this case, the surface portion of the nitride semiconductor multilayer structure has a depression due to the lateral growth. The formation does not completely occur, so that it is possible to reduce crystal lattice distortion due to coalescence. Such a difference affects the oscillation life of the laser element. Case A has a longer oscillation life than case C, and case B has a longer oscillation life than case D. Conceivable.

In both cases A and B, there is a depression on the surface of the nitride semiconductor multilayer structure, but the laser oscillation life is longer in case A. In case A, a nitride semiconductor substrate is used. Therefore, there is no significant difference in the coefficient of thermal expansion between the substrate and the nitride semiconductor multilayer structure laminated thereon as compared with the case where the basic substrate is used. In particular, in the light emitting device structure, there are nitride semiconductor layers of various mixed crystal compositions included in the laser device structure, and there is a problem of a difference in thermal expansion coefficient between these layers. It is considered that the crystal lattice distortion caused by this difference in the thermal expansion coefficient affects the oscillation life. On the other hand, in case B, since the sapphire substrate is used as the base substrate in addition to the factor of the crystal lattice distortion described in case A, the difference in thermal expansion coefficient between sapphire and the nitride semiconductor is large, and the nitride semiconductor multilayer film There is also a large crystal distortion component due to this in the structure. The crystal growth mode in this case is shown in FIG.
Even if pits are formed to completely prevent lateral growth from coalescing and crystal lattice distortion due to lateral growth coalescence is reduced, the crystal lattice distortion due to the use of the base substrate is large, and a nitride semiconductor substrate is used. The crystal lattice distortion cannot be reduced as much as in the case. As a result, it is considered that the laser oscillation life of Case A was longer than that of Case B.

In the case A and the case B, the effect of alleviating the crystal lattice distortion is obtained by forming a depression on the surface. It is more preferable to grow the nitride semiconductor multilayer film structure such that voids are formed in the voids, because the effect of alleviating the crystal lattice distortion can be obtained even in the voids. However, also in this case, it is necessary that the nitride semiconductor multilayer film structure is continuously grown at least partially.

As described above, when each type of substrate is used, a difference appears in the distribution and magnitude of the crystal lattice strain inside the nitride semiconductor multilayer structure, and as a result, there is a difference in the life of the semiconductor laser device. It is presumed to have appeared.

By the way, the effect of reducing the lattice distortion described above can be expected even when a processed substrate is used. FIGS. 7A and 7B show crystal growth modes when a nitride semiconductor multilayer structure is grown on a processed substrate. The growth of the nitride semiconductor multilayer film structure starts in the lateral direction from the side wall of the groove formed in the processing substrate, and the crystals grown from the side walls of the groove unite at the center of the groove, and thereafter proceed in the normal crystal growth direction. . However, in the crystal growth mode shown in FIG. 7A, a dent that does not completely fill the nitride semiconductor multilayer film structure above the hill occurs, so that horizontal crystal distortion parallel to the main surface of the substrate causes the dent. Can be mitigated through. That is, the depression can reduce the crystal strain concentrated at the center of the groove in the crystal growth mode shown in FIG. 7A, and can alleviate the crystal strain of the entire nitride semiconductor multilayer structure. However,
If the growth of the nitride semiconductor multilayer structure is further advanced, FIG.
As shown in (b), all the depressions are buried flat, and the stress in the crystal generated at the portion where the lateral growth is united in the groove cannot be reduced.

More preferably, in the form of crystal growth using a processing substrate, as shown in FIG.
A depression is formed not only in the center of the hill but also in the center of the groove. By utilizing such a crystal growth form,
Since there is no portion where crystal strain is concentrated, it is possible to form a nitride semiconductor multilayer film structure in which crystal strain is remarkably reduced.

Since the growth suppressing film is not used when the processing substrate is used, there is an advantage that the growth suppressing film in the mask substrate is not affected by the difference in thermal expansion coefficient or the impurity.

The present inventors have also found that the use of the crystal growth mode according to the present invention can also suppress the occurrence of cracks in the nitride semiconductor multilayer film structure. As a result, the production yield of the nitride semiconductor laser device is improved.

For example, FIG.
When a nitride semiconductor laser device including a structure having a depression on the surface is formed using the nitride semiconductor substrate (for example, a GaN substrate) shown in FIG.
cm ² . On the other hand, when a nitride semiconductor light emitting device having no recess on the surface is formed on the conventional GaN substrate shown in FIG. 6C as case C, it has been thought that cracks hardly occur conventionally. However, many cracks occurred in the epiwafer plane after the light emitting element was actually grown. This is considered to be because the light-emitting element has various laminated structures (for example, the AlGaN layer has a smaller lattice constant than the GaN layer, and the InGaN layer has a larger lattice constant than the GaN layer). Furthermore, in the GaN substrate obtained by the current technology, it is considered that the substrate itself has latent distortion. Therefore, when a nitride semiconductor laser device is formed on a conventional GaN substrate, the crack density is about 5 to 8
Book / cm ² . From this, it was found that the crack density can be reduced by using the crystal growth morphology according to the present invention.

On the other hand, in the case B, when a nitride semiconductor laser device is formed using a different substrate (for example, a sapphire substrate) shown in FIG. It was 3 to 5 wires / cm ² . However, in the case D, when the nitride semiconductor laser device is formed using the sapphire substrate shown in FIG. ^{Was 2} .

From the above, it has been found that cracks can be suppressed when the nitride semiconductor laser device is formed in such a manner that the surface is depressed. The effect of suppressing the occurrence of cracks due to such pits was greater as the pits were deeper, and as the distribution density of the pits was higher. In addition, in order to change the depth and density of the depression, the structure can be controlled by changing the structure of the growth suppressing film when using a mask substrate and by changing the structure of grooves and hills when using a processed substrate. .

Further, it was found that the crack suppressing effect due to the depression in the present invention has the following characteristics. Since two or more dents are included in one nitride semiconductor light-emitting device divided into chips, the crack generation rate is reduced by about 30% as compared with one device. Moreover, when a ridge stripe portion is provided between the depressions 1 and 2 as in a nitride semiconductor light emitting device (laser device) having a ridge stripe structure shown in FIG. Yield improved. As a result of investigating this in detail, it was found that cracks crossing the longitudinal direction of the ridge stripe were reduced. This is considered to be because cracks could be prevented from penetrating into the ridge stripe portion of the nitride semiconductor light emitting device by having the depressions on both sides of the ridge stripe portion.

Further, it has been found that the depression in the present invention has the following effects in the electrode of one nitride semiconductor light emitting device divided into chips. When two or more dents according to the present invention are included in one nitride semiconductor light emitting element, the element defect rate due to electrode peeling is reduced by about 20% as compared with one element. Moreover, for example, as in a nitride semiconductor light emitting device (laser device) having a ridge stripe structure shown in FIG.
When a ridge stripe portion is provided between the dent 1 and the dent 2, especially the p-electrode 112 in the ridge stripe portion
Peeling (including the pad electrode) was prevented, and the yield of the light emitting device was improved. For this reason, it is preferable that the electrode is formed on a region including two or more depressions,
It has been found that a ridge stripe portion is more preferably provided between the depressions, and the electrode is preferably formed on a region including these depressions. The effect of preventing the electrode peeling at the ridge stripe portion was the same for the peeling of the dielectric film. For example, The same applies to the SiO ₂ dielectric film 113 of the method shown in FIG. 19.
Note that, instead of the SiO ₂ dielectric film 113, another dielectric film such as SiN _x may be used.

Further, it has been found that the depression in the present invention has the following effects in wire bonding of one nitride semiconductor element divided into chips. Since one or more dents according to the present invention are included in the bonding region between the wire bond and the nitride semiconductor light emitting device, the peeling of the wire bond itself or the peeling of the electrode including the wire bond is reduced by about 20%. . From this, it was found that it is preferable that one or more dents in the present invention be included in the bonding region between the wire bond and the nitride semiconductor light emitting device.

(Regarding Mask Substrate) The mask substrate in the present invention is composed of a nitride semiconductor substrate and a patterned growth suppressing film when a nitride semiconductor substrate is used, and is formed when a basic substrate is used. It comprises a base substrate, a nitride semiconductor substrate layer thereon, and a patterned growth suppression film thereon. However, since the nitride semiconductor substrate has a small difference in thermal expansion coefficient from the nitride semiconductor film formed thereon, the warpage of the substrate is much smaller than when a basic substrate is used. Therefore, the growth suppressing film formed on the nitride semiconductor substrate, and thus the position of the depression, can be formed with higher precision than those formed on the nitride semiconductor substrate layer on the base substrate. In addition, since the warpage of the substrate is very small, it will be described in detail in “(Position of formation of light emitting portion)” described later. The structure can be manufactured with high accuracy. Furthermore, the small warpage of the substrate itself acts to prevent the occurrence of new distortion and cracks, and also has the effect of extending the life of the semiconductor laser device and reducing other device characteristic defects. Therefore, it is more preferable to use a nitride semiconductor substrate than to use a basic substrate.

(Regarding the Film Thickness of the Nitride Semiconductor Underlayer Covering the Mask Substrate) In the present invention, in order to form a recess which is not flatly covered with the nitride semiconductor multilayer structure on the mask substrate, the mask substrate must be formed. What is necessary is just to grow the nitride semiconductor underlayer to be covered thinly. However, a depression is formed in the underlying layer above the growth suppression film region of the mask substrate,
In order to form a semiconductor laser device, a flat portion of the underlayer is also required. Therefore, it is preferable that the coating thickness of the nitride semiconductor underlayer is 2 μm or more and 20 μm or less. If the coating thickness is smaller than 2 μm, it depends on the width and thickness of the growth suppressing film on the mask substrate, but it is flat below the growth suppressing film so that the light emitting portion of the semiconductor laser element can be manufactured. Getting the formation area begins to be difficult. On the other hand, if the coating thickness is larger than 20 μm, the thermal expansion between the mask substrate and the nitride semiconductor underlayer (or the nitride semiconductor multilayer film structure) is more effective than the effect of alleviating the crystal distortion due to the depression and the effect of suppressing the crack. There is a high possibility that the stress distortion due to the coefficient difference becomes too strong and the effect of the present invention is not sufficiently exhibited.

(Regarding Mask Width) The growth suppressing film of the mask substrate is easily buried in the nitride semiconductor base layer if the mask width is relatively small, and is hard to be buried if it is wide. According to the study results of the present inventors, the mask width M1 for forming a depression without completely covering the upper part of the growth suppression film of the mask substrate with the nitride semiconductor base layer is not less than 7 μm and not more than 75 μm.
Or less, and may be 7 μm or more and 100 μm or less. However, the appropriate mask width M1 depends on the thickness of the nitride semiconductor base layer or the nitride semiconductor multilayer film structure covering the mask substrate. It is necessary to adjust the coating thickness of the nitride semiconductor underlayer together with M1.

The lower limit and upper limit of the mask width M1 were estimated from the following viewpoints. The lower limit of the mask width M1 of the growth suppressing film depends on the size of the light emitting portion in the light emitting device. For example, when a nitride semiconductor laser device is manufactured above a growth suppressing film having a mask width M1 that causes a depression, a light emitting portion below a ridge stripe portion of the laser device is formed in a region I in FIG. It preferably belongs to Since the ridge stripe width is formed in the range of 1 to 3 μm and the minimum depression width can be estimated to be 1 μm, the lower limit of the mask width M1 is the area II including the depression.
Width = recess width (1 μm) +2 μm × 2 (see FIG. 8) and stripe width (1 μm) × 2 plus 7 μm or more.

On the other hand, the upper limit of the mask width M1 is not particularly limited. However, if M1 is too wide, the density of the dents per unit area of the wafer decreases, and the effect of alleviating crystal distortion and suppressing cracks is reduced. Will be reduced. Also, the chip yield per wafer is reduced. Therefore, it is desired that the upper limit value of the mask width M1 is 100 μm or less.

In the above description, the mask substrate in which only the mask width is changed has been described. However, the mask substrate may be formed by changing not only the mask width but also the mask thickness and / or space width described below. Needless to say. This is the same for the mask substrate in other embodiments.

The above-mentioned depression width is defined as follows. The shape of the depression may change depending on the growth conditions of the nitride semiconductor base layer and the alignment direction of the growth suppressing film, and the width of the depression may not be constant. In this case, the width of the depression is defined at the widest part in parallel with the width direction of the ridge stripe of the nitride semiconductor laser device.

(Regarding Mask Thickness) A mask formed on a nitride semiconductor substrate is easily buried in a nitride semiconductor underlayer if its thickness is relatively small, and is hard to be buried if it is thick. According to the study results of the present inventors, the mask thickness T1 for forming a depression without completely covering the growth suppressing film of the mask substrate with the nitride semiconductor underlayer may be 0.05 μm or more. More preferably, it is more preferably 0.01 μm or more. The reason is that if the mask thickness T1 is smaller than 0.05 μm, the growth suppressing film may be deteriorated at the time of raising the temperature before the growth of the nitride semiconductor underlayer, and the nitride semiconductor substrate may be exposed. This makes it difficult to control the mask thickness. If the lower limit of the mask thickness T1 is 0.1 μm or more, such a problem is almost eliminated.

Regarding the upper limit of the mask thickness T1, if the growth suppressing film is too thick, the mask substrate is easily broken due to a difference in thermal expansion coefficient between the growth suppressing film and the nitride semiconductor underlayer. It is desirable that T1 be 10 μm or less. Further, the appropriate mask thickness T1 depends on the thickness of the nitride semiconductor underlayer or nitride semiconductor multilayer film structure covering the mask substrate. It is necessary to adjust the coating thickness of the nitride semiconductor underlayer together with the thickness T1.

(Regarding Space Width) In a space portion of the mask substrate where the growth suppressing film is not formed, the space width is desirably 2 μm or more and 30 μm or less. This is because if the space width is too narrow, the crystallinity of the crystal portion growing in the direction perpendicular to the main surface of the substrate in the initial stage of the growth of the nitride semiconductor underlayer deteriorates, and adversely affects the crystal portion growing later in the lateral direction. This is not preferred. On the other hand, if the space width is too wide, the area of the underlayer in which a laser element can be manufactured becomes small, and the yield of laser chips per wafer decreases, which is not preferable.

(Longitudinal direction of the growth suppressing film) The longitudinal direction of the stripe-shaped growth suppressing film formed on the nitride semiconductor substrate having the {0001} C plane as the main surface or the nitride semiconductor substrate layer on the basic substrate is as follows. Most preferably, it is parallel to the <1-100> direction of the nitride semiconductor crystal,
Next, it was preferable to be parallel to the <11-20> direction. Even if the longitudinal direction of the growth suppressing film in these specific directions had an opening angle of about ± 5 ° in the {0001} C plane, there was no substantial effect.

The advantage of forming the growth suppressing film along the <1-100> direction of the nitride semiconductor crystal is that the depression is hard to fill and the effect of suppressing crystal distortion and crack generation is extremely high. . When the nitride semiconductor underlayer grows on the growth suppressing film formed along this direction, the {11-20} plane is likely to be mainly formed as the side wall surface of the depression. Since the {11-20} side wall surface is perpendicular to the main surface of the substrate as shown in FIG. 9A, the depression tends to have a substantially rectangular cross section. When the cross section of the depression is close to a rectangular shape, it is difficult for the raw material constituting the nitride semiconductor to be supplied to the depth of the depression, and the growth suppressing film is unlikely to be buried in the nitride semiconductor underlayer. For this reason, even if the mask substrate is relatively thickly covered with the nitride semiconductor base layer, there is no fear that the depressions will be buried. In addition, the crystal distortion of the nitride semiconductor underlayer grown on the mask substrate is alleviated by the deep depression, and the generation of cracks can be effectively suppressed.

On the other hand, the nitride semiconductor crystal <11-20>
The advantage of forming the stripe-shaped growth suppressing film along the direction is that the shape of the depression is steep and the fluctuation of the position of the depression is small. When the nitride semiconductor underlayer grows on the growth suppressing film formed along this direction,
The {1-101} plane is likely to be formed mainly on the side wall surface of the depression. Since the {1-101} side wall surface is very flat and the edge portion (see FIG. 5) is steep and does not meander, it is preferable to use the <11-
The dents along the 20> direction are also straight and are not likely to meander. Therefore, a region I for forming a light-emitting element having a long operating life, which will be described later, can be widened (improvement of the yield rate of the light-emitting element), and a reduction in the yield of the light-emitting element due to an irregular formation position of the light-emitting element can be prevented. Can be.

Although the above-mentioned growth suppressing films are all stripe-shaped, they are preferably formed in the following points. That is, the portion contributing to the oscillation of the nitride semiconductor laser device (below the ridge stripe portion) is in a stripe shape, and a preferable ridge stripe portion formation region I described later is also in a stripe shape. It can be easily formed in the preferable region I. However, for example, as shown in FIG. 2, the growth suppressing film may be formed in a mesh shape.

FIG. 2A is a top view of a mask substrate in a case where stripe-like growth suppressing films in two different directions are formed so as to be orthogonal to each other. FIG.
(B) shows that two different types of stripe directions are 60
FIG. 4 shows a top view of the mask substrate when formed at an angle of degrees. FIG. 2C is a top view of the mask substrate when three different types of mask directions are formed so as to form an angle of 60 degrees with each other.

(Regarding Nitride Semiconductor Underlayer Covering Mask Substrate) As the underlayer made of the nitride semiconductor film covering the mask substrate, for example, a GaN film, an AlGaN
A film, an InGaN film, or the like can be used. Further, in the nitride semiconductor underlayer, Si, O, Cl, S,
At least one type of impurity can be added from the impurity group of C, Ge, Zn, Cd, Mg, and Be.

If the nitride semiconductor underlayer is a GaN film,
It is preferable in the following points. That is, since the GaN film is a binary mixed crystal, the controllability of crystal growth is good. Also, since the surface migration length of the GaN film is longer than that of the AlGaN film and shorter than that of the InGaN film, the portion where the growth suppression film is to be buried and flattened is appropriately covered with the GaN film, and the portion where the depression is to be formed is GaN. Coating with the membrane is moderately limited. The impurity concentration in the GaN film used as the nitride semiconductor underlayer is preferably 1 × 10 ¹⁷ / cm ³ or more and 5 × 10 ¹⁸ / cm ³ or less. If the impurity is added in such a concentration range, the surface morphology of the nitride semiconductor underlayer becomes good, and as a result, the thickness of the light emitting layer can be made uniform and the device characteristics can be improved.

If the nitride semiconductor underlayer is an AlGaN film, it is preferable in the following points. Since the AlGaN film contains Al, the surface migration length is shorter than that of the GaN film or the InGaN film. The fact that the surface migration length is short means that the cross-sectional shape of the depression is kept steep (for example, the edge in FIG. 5 is not dropped), and the nitride semiconductor does not easily flow into the bottom of the depression (the depression is not easily filled). ) Means that. Also, when the growth suppressing film is coated, the nitride semiconductor is unlikely to flow into the bottom of the groove, and the crystal growth from the side wall of the groove is promoted, so that the lateral growth becomes remarkable and the crystal distortion is further reduced. It is possible to do. The Al composition ratio x of the Al _x Ga ₁ -xN film is preferably 0.01 or more and 0.15 or less,
More preferably, it is 0.01 or more and 0.07 or less. If the composition ratio x of Al is smaller than 0.01, the above-mentioned surface migration length may be increased. On the other hand, if the composition ratio x of Al is larger than 0.15, the surface migration length becomes too short, and the crystallinity of the underlayer may not be good. In addition, an effect equivalent to that of the AlGaN film is obtained as long as the nitride semiconductor underlayer contains Al. The impurity concentration in the AlGaN film used as the nitride semiconductor underlayer is 3 × 10 ¹⁷ / cm ³ or more and 5 × 10 ¹⁷ / cm ³ or more.
^It is preferably ¹⁸ / cm ³ or less. In such a concentration range, Al
At the same time, if an impurity is added, the surface migration length of the nitride semiconductor underlayer is preferably reduced. This makes it possible to further reduce crystal distortion.

If the nitride semiconductor underlayer is an InGaN film, it is preferable in the following points. Since the InGaN film contains In, it is more elastic than a GaN film or an AlGaN film. Therefore, the InGaN film covers the growth suppressing film of the mask substrate, diffuses crystal strain from the substrate throughout the nitride semiconductor multilayer film structure, and has a function of effectively relaxing crystal distortion. In _x Ga _1-x N
The In composition ratio x of the film is preferably 0.01 or more and 0.15 or less, and more preferably 0.01 or more and 0.1 or less. If the composition ratio x of In is smaller than 0.01, the elasticity effect by including In may not be easily obtained. Further, when the composition ratio x of In is 0.1
If it is larger than 5, the crystallinity of the InGaN film may be reduced. In addition, not limited to the InGaN film,
The same effect as this film can be obtained if the nitride semiconductor underlayer contains In. The impurity concentration in the InGaN film used as the nitride semiconductor underlayer is 1 × 10
¹⁷ / cm ³ or more at 4 × 10 ^{1 8} / cm ³ or less. It is preferable that an impurity be added simultaneously with In in such a concentration range, since the surface morphology of the nitride semiconductor underlayer becomes good and elasticity can be maintained.

(Position of formation of light-emitting portion) As a result of detailed studies by the present inventors, where the light-emitting portion (below the ridge stripe portion) of the nitride semiconductor laser device is formed on the recessed substrate. It has been found that the laser oscillation lifetime varies depending on the laser oscillation lifetime. Here, the light emitting portion is a portion of the light emitting layer which substantially contributes to light emission when a current is injected into the light emitting element. For example, in the case of a nitride semiconductor laser device having a ridge stripe structure, it is a light-emitting layer portion below a ridge stripe portion into which current is confined and injected.

In FIG. 10, the horizontal axis of the graph represents the distance from the center c of the mask of the recessed substrate to the edge a of the ridge stripe in the width direction thereof, and the vertical axis represents the laser output of 30 mW and the ambient temperature of 60 ° C. It shows the laser oscillation life. Here, the distance from the center c of the mask to the edge a of the ridge stripe (hereinafter referred to as c-a distance) is indicated such that the right side in the width direction from the mask center c is positive and the left side is negative. In the nitride semiconductor laser device of Case A measured in FIG. 10, a mask substrate made of a GaN substrate was used, the ridge stripe width was 2 μm, the mask width was 18 μm, the space width was 15 μm, and The mask thickness was 0.2 μm.

As can be seen from Case A of FIG. 10, the laser oscillation life of the nitride semiconductor laser device having the ridge stripe formed above the growth suppressing film is longer than that of the nitride semiconductor laser device having the ridge stripe formed above the space. They tended to be longer. Further investigation revealed that, even in the region above the growth suppressing film, if the ridge stripe portion was formed in a region where the ca distance was larger than −5 μm and smaller than 3 μm, the laser oscillation life was significantly shortened. It was found that it decreased. Here, considering that the width of the ridge stripe portion is 2 μm, the ca distance −5 μm is the distance from the mask center c to the ridge stripe end b (hereinafter, c−b
When converted to c), the c-b distance is -3 [mu] m. That is, when at least a part of the ridge stripe portion of the nitride semiconductor laser element is formed so as to be included within a range of less than 3 μm in the width direction from the center c of the mask, the laser oscillation life is dramatically reduced. I understand.

This can be understood as follows. In this case, the dent ends d and e are 1 μm from the center c of the mask to the left and right.
It will be located m meters away. Therefore, when the ridge stripe portion is formed so as to include at least a part of the ridge stripe portion within a range of less than 2 μm from the edge of the dent to the outside of the dent, the laser oscillation life is dramatically reduced.

The region where the laser oscillation life is drastically reduced (from the edge d, e to the outer side of the cavity, 2 μm
Is referred to as a region II. Therefore, the ridge stripe portion of the nitride semiconductor laser device is
In the mask width range, excluding the region II, the whole (a
-B width).
Here, within the mask width range, a range apart from the dent ends d and e by 2 μm or more in the left-right direction outside the dent is referred to as a region I. This area I is the area I above the space part.
This is a region where a nitride semiconductor laser device having a longer laser oscillation life can be formed than that of II, and is the most preferable region among the recessed substrates.

In FIG. 8, the above-mentioned regions I to III are shown in a schematic cross-sectional view of a substrate having a depression. That is, it is desirable that the light emitting portion of the nitride semiconductor laser device fabricated on the recessed substrate is formed in the region I above the growth suppressing film. Note that the same tendency as in FIG. 10 was shown even when the mask width, the space width, and the ridge stripe width were variously changed. In addition, even when the mask substrate was changed from one including the GaN substrate to one including the base substrate, the laser oscillation life was shorter than that when the GaN substrate was included, but showed the same tendency as in FIG. Therefore, also in these cases, it is considered that the light emitting portion forming region of the light emitting element to be formed on the recessed substrate has the relationship shown in FIG.

Further, although the nitride semiconductor laser device in FIG. 10 has a ridge stripe structure, a nitride semiconductor laser device having a current blocking structure has the same relationship as FIG. In the case of the blocking structure, the width of the ridge stripe in FIG. 10 corresponds to the width of the current constriction). That is, in the nitride semiconductor laser device, it is sufficient that the region I shown in FIG. 8 exists below the portion where current is confinedly injected into the light emitting layer and contributes to laser oscillation.

However, in the case of the nitride semiconductor laser device having the current blocking structure, the laser oscillation life is about 2 times as compared with the device having the ridge stripe structure described above.
It was about 0-30% lower. In addition, the nitride semiconductor laser device having the current blocking structure has a large decrease in yield due to crack generation, as compared with the device having the ridge stripe structure. Although the causes of these are not clear, there is probably a problem in the process of forming a current confined portion in the current blocking layer and in the process of growing a nitride semiconductor crystal again on the current blocking layer in which the current confined portion is formed. It is thought that there is. For example, a mask material such as a resist material is used in a process in which a current confinement portion is formed in the current blocking layer. However, these mask materials adhere to the recesses of the nitride semiconductor light emitting device according to the present invention and remain as they are. It is considered that the regrowth adversely affected the light emitting element characteristics. Also, for example,
In the step of crystal-growing the nitride semiconductor again on the current blocking layer in which the current blocking portion has been formed, the nitride semiconductor is once taken out of the crystal growth apparatus during the fabrication of the light emitting element structure in order to form the current blocking portion in the current blocking layer (at room temperature). ), And loaded again into the crystal growth apparatus to grow the remaining light emitting element structure in a crystal (about 1000 ° C.). If a thermal history having a sharp temperature difference is given in the middle of the light emitting element structure as described above, even if the nitride semiconductor light emitting element according to the present invention has a dent, the crystal distortion in the light emitting element structure is reduced by the dent. It is considered that cracking does not occur sufficiently and cracks occur.

As in the case of the laser device, the effect of the present invention can be obtained in the light emitting diode (LED) device as long as the region I shown in FIG. Can get enough.

Next, a case where a processed substrate is used in the present invention will be described. (Processing substrate) As a processing substrate that can be used in the present invention, there are a case where a nitride semiconductor substrate is processed and a case where a nitride semiconductor substrate layer is grown on a basic substrate and the substrate layer is processed. However, for the same reason as described in the description of the mask substrate, it is preferable to use a nitride semiconductor substrate rather than use a base substrate.

(Regarding the Covered Film Thickness of the Nitride Semiconductor Underlayer Covering the Worked Substrate) In the present invention, in order to form a recess which is not flattened by the nitride semiconductor multilayer structure of the work substrate, for example, a nitride semiconductor The base layer may be grown thin. However, apart from the case where a recess is also formed in the region above the groove, unless the groove formed in the processing substrate is buried flat enough to form a laser device, a light emitting element should be formed in the region above the groove. Becomes difficult. Therefore,
The coating thickness of the nitride semiconductor underlayer is about 2 μm or more and 20
It is preferably not more than μm. When the coating film thickness is smaller than 2 μm, it becomes difficult to completely and flatly bury the groove in the nitride semiconductor base layer, although it depends on the groove width and the groove depth formed in the processed substrate. . On the other hand, if the coating film thickness is more than 20 μm, especially when the processing substrate includes the base substrate, the effect of reducing the crystal distortion due to the depression and the effect of suppressing the cracks are more significant than the processing substrate and the nitride semiconductor underlayer (or the nitride semiconductor). The stress distortion due to the difference in thermal expansion coefficient between the substrate and the semiconductor multilayer structure is too strong, and the effect of the present invention may not be sufficiently exhibited.

(Regarding Groove Width) A groove formed in the nitride semiconductor substrate is easily buried in the nitride semiconductor base layer if the groove width is relatively small, and is difficult to be buried if it is wide. This is the same as the relationship with the mask width in the mask substrate. According to the study results of the present inventors, a groove width G1 for completely and flatly covering a groove formed on a processed substrate with a nitride semiconductor underlayer is preferably 4 μm or more and 30 μm or less, and preferably 4 μm. Above, it was more preferable that the thickness be 25 μm or less. On the other hand, the groove width G2 for forming the depression without completely covering the groove formed on the processing substrate with the nitride semiconductor base layer is preferably 7 μm or more and 75 μm or less, but is preferably about 7 μm or more and about 75 μm or less. It may be 100 μm or less. However, whether or not a dent is formed above the groove of the processed substrate strongly depends on the coating thickness of the nitride semiconductor underlayer. Therefore, when the groove is completely and flatly covered or a dent is formed in the region above the groove. In doing so, it is necessary to adjust the coating thickness of the nitride semiconductor underlayer together with the groove widths G1 and G2.

The lower limit and the upper limit of the groove width G1 were estimated from the following viewpoints. Groove 1 in which no depression is formed above the groove
The lower limit value of the groove width G1 depends on the size of the light emitting portion in the light emitting element. Regarding the formation position of the light emitting portion in the light emitting element,
This will be described in more detail with reference to FIG. 12 in the item “(About the formation position of the light emitting unit)” described later. For example, when a nitride semiconductor laser element is formed in a region above a groove which is flatly covered in a recessed substrate, a light emitting portion below a ridge stripe portion of the nitride semiconductor laser element is formed as shown in FIG. It preferably belongs to region I in (a). Therefore, at least the lower limit value of the groove width G1 needs to be wider than twice the ridge stripe width. Ridge stripe width is approximately 1 μm to 3 μm
It is estimated that the groove width G1 must be at least 4 μm, which is the sum of the width of the region III in FIG. 11A, 2 μm, and the stripe width (1 μm) × 2.

On the other hand, the reason that the groove width G1 has an upper limit value is as follows.
If the groove width G1 exceeds 25 μm, it becomes difficult to completely bury the groove 1 having the groove width G1 by laminating the nitride semiconductor underlayer with a coating thickness of 10 μm or less. Similarly, if the groove width G1 exceeds 30 μm, it becomes difficult to completely bury the groove 1 even if the nitride semiconductor underlayer is laminated to a coating film thickness of 20 μm or more.

The lower and upper limits of the groove width G2 were estimated from the following viewpoints. Similarly to the lower limit of the groove width G1, the lower limit of the groove width G2 of the groove 2 in which the depression is formed above the groove depends on the size of the light emitting portion in the light emitting element. For example, when a nitride semiconductor laser device is manufactured in a region above a groove 2 in which a depression is formed within the groove width G2, the light emitting portion below the ridge stripe portion of the laser device is formed as shown in FIG. It preferably belongs to region II in (b). Ridge stripe width is approximately 1 μm to 3 μm
Since the minimum depression width can be estimated at 1 μm, the lower limit of the groove width G2 is the width of the region IV including the depression = the depression width (1 μm) +2 μm × 2 (see FIG. 11B) and the stripe width ( 1 μm) × 2 and 7 μm or more.

On the other hand, the upper limit value of the groove width G2 of the groove 2 in which the depression is formed above the groove is not particularly limited from the viewpoint of the laser oscillation life. However, if G2 is too large, the dent density per unit area of the wafer decreases, and the effect of alleviating crystal distortion and the effect of suppressing cracks decrease.
Along with this, the yield of light emitting element chips per wafer also decreases. Therefore, from the above viewpoint, the upper limit of the groove width G2 is 100 μm or less, and more preferably 75 μm or less.

In the above description, the processing substrate in which only the groove width is changed has been described. However, it is needless to say that the processing substrate may be formed by changing not only the groove width but also the groove depth and / or the hill width. . This is the same for the processed substrate in other embodiments.

(Groove Depth) A groove formed in a nitride semiconductor substrate is easily buried in a nitride semiconductor base layer if the depth is relatively small, and is difficult to be buried if it is deep. This is the same as the relationship with the mask thickness in the mask substrate. The formation of the depression by adjusting the groove depth is preferable since the yield of the light emitting element chips per wafer does not decrease as compared with the case where the depression is formed by adjusting the groove width.

According to the study results of the present inventors, the groove depth H1 for completely and flatly covering the groove formed on the processed substrate with the nitride semiconductor base layer is not less than 1 μm and not more than 9 μm. And more preferably 2 μm or more and 6 μm or less. On the other hand, the groove depth H2 for forming a depression without completely covering the groove formed in the processing substrate with the nitride semiconductor base layer is preferably 1 μm or more, more preferably 2 μm or more. I liked it. There is no particular limitation on the upper limit of the groove depth H2, and the remaining thickness h as shown in FIG. 4 may be 100 μm or more. However, whether or not a dent is formed above the groove of the processing substrate depends on the thickness of the nitride semiconductor underlayer coating. Therefore, when the groove is completely and flatly covered or when a dent is formed above the groove. It is necessary to adjust the coating thickness of the nitride semiconductor underlayer together with the groove depths H1 and H2.

The lower limit and the upper limit of the groove depth H1 were estimated from the following viewpoints. The lower limit of the groove depth H1 of the groove 1 in which no depression is formed above the groove is preferably 1 μm or more, more preferably 2 μm or more. This is because if the groove depth H1 is smaller than 1 μm, the growth in the vertical direction with respect to the main surface of the substrate has priority over the horizontal growth in the crystal growth mode, and the effect of reducing the crystal distortion due to the horizontal growth is reduced. This is because there is a possibility that it will not be sufficiently exhibited. If the lower limit of the groove depth H1 is 2 μm or more, the effect of reducing crystal distortion due to lateral growth can be sufficiently exhibited.

On the other hand, the upper limit of the groove depth H1 is 9 μm.
m or less, and more preferably 6 μm or less. This is because, if the groove depth H1 exceeds 6 μm, it becomes difficult to completely bury the groove 1 having the groove depth H1 by laminating the nitride semiconductor underlayer with a coating thickness of 10 μm or less. . Similarly, the groove depth H
If 1 exceeds 9 μm, the nitride semiconductor underlayer is coated with a film thickness of 2
This is because it becomes difficult to completely bury the groove 1 even if the groove 1 is laminated to a thickness of 0 μm or more.

The lower and upper limits of the groove depth H2 were estimated from the following viewpoints. The lower limit of the groove depth H2 of the groove 2 in which the depression is formed above the groove is 1 μm as in the case of the groove depth H1.
m or more, more preferably 2 μm or more. This is because, as described with respect to the groove depth H1, if the effect of reducing the crystal distortion due to the lateral growth is not sufficiently obtained, the characteristics of the light emitting element formed in the region above the groove 2 (for example, the laser oscillation life) may be reduced. This is because there is a possibility that it will decrease. While the lower limit value of the groove depths H2 and H1 is the same, whether a dent is formed in the region above the groove by the nitride semiconductor film or is completely buried is determined by
It depends on the coating thickness of the nitride semiconductor underlayer. On the other hand,
There is no particular limitation on the upper limit of the groove depth H2, and the deeper the groove depth H2, the easier it is to form a depression. However, if the groove 2 is too deep, the processed substrate is likely to be cracked. Therefore, the remaining thickness h between the bottom of the groove and the back surface of the substrate is 100 μm.
m (see FIG. 4).

In the above description, the processed substrate in which only the groove depth is changed has been described. However, it goes without saying that the processed substrate may be formed by changing not only the groove depth but also the groove width and / or the hill width.

(Regarding the hill width) The hill formed on the processed substrate is easily buried in the nitride semiconductor base layer if the hill width is relatively narrow, and hard to be buried if it is wide. According to the study results of the present inventors, the hill width L1 for completely and flatly covering the hill formed on the processed substrate with the nitride semiconductor underlayer is:
4 μm or more and 30 μm or less, preferably 4 μm
More preferably, it is not less than m and not more than 25 μm. On the other hand, a hill width L2 for forming a depression without completely covering the hill formed on the processing substrate with the nitride semiconductor underlayer.
Is preferably 7 μm or more and 75 μm or less,
It may be 7 μm or more and 100 μm or less. However, whether or not a dent is formed above the hill of the processed substrate strongly depends on the thickness of the nitride semiconductor base layer. Therefore, when the hill is completely and flatly covered, or when a dent is formed in the region above the hill. When forming, it is necessary to adjust not only the hill widths L1 and L2 but also the coating thickness of the nitride semiconductor underlayer.

The lower limit and upper limit of the hill width L1 were estimated from the following viewpoints. Hill 1 where no depression is formed above the hill
The lower limit of the hill width L1 depends on the size of the light-emitting portion in the light-emitting element, similarly to the above-described lower limit of the groove width G1. For example, when a nitride semiconductor laser device is formed in a region of a recessed substrate that is flatly covered above a hill, the light-emitting portion below the ridge stripe portion of the laser device has a recess from the viewpoint of laser oscillation life. Region I not formed (FIG. 11)
(B)). The ridge stripe width is about 1 μm to 3 μm, and the width of the region III when no depression is formed above the hill can be estimated to be 2 μm. Therefore, the lower limit of the hill width L1 is stripe width (1 μm) × 2. 4 μm obtained by adding 2 μm width of region III
It is necessary to be above. On the other hand, the upper limit of the hill width L1 can be estimated in the same manner as the above-described upper limit of the width of the groove 1.

Further, the lower limit and the upper limit of the hill width L2 were estimated as follows. The lower limit of the hill width L2 of the hill 2 in which no depression is formed on the hill depends on the size of the light emitting portion in the light emitting element, similarly to the above lower limit of the groove width G2.
For example, when a nitride semiconductor laser device is formed in a region above a hill 2 having a hill width L2 including a depression, the light emitting portion below the ridge stripe portion of the laser device is shown in FIG. It preferably belongs to the region II in the middle. The ridge stripe portion is formed with a width of about 1 to 3 μm, and the minimum depression width can be estimated at 1 μm. Therefore, the lower limit of the hill width L2 is the width of the region IV including the depression = the depression width (1 μm) +2 μm × 2. And stripe width (1 μm) ×
2 plus 7 μm.

On the other hand, the upper limit value of the hill width L2 of the hill 2 where the depression is formed above the hill is not particularly limited from the viewpoint of the laser oscillation life. However, for the same reason as the upper limit of the groove width G2 of the groove 2, the upper limit of the hill width L2 is 100 μm.
Or less, more preferably 75 μm or less.

(Longitudinal direction of groove) The longitudinal direction of the groove in the processing substrate is basically the same as the description of the longitudinal direction of the stripe-shaped growth suppressing film on the mask substrate.

(Regarding Nitride Semiconductor Underlayer Covering Processed Substrate) A GaN film, an AlGaN film, an InGaN film, or the like can be used as the nitride semiconductor underlayer that covers the processed substrate. The contents related to such an underlayer are basically the same as the contents described when a mask substrate is used.

(Regarding the formation position of the light emitting portion) As a result of a detailed study by the present inventors, the position of the light emitting portion (below the ridge stripe portion) of the nitride semiconductor laser device to be formed on the recessed substrate is determined. It has been found that the laser oscillation lifetime varies depending on the laser oscillation lifetime. Here, the light emitting portion is a portion of the light emitting layer which substantially contributes to light emission when a current is injected into the light emitting element. For example, in the case of a nitride semiconductor laser device having a ridge stripe structure, it is a light-emitting layer portion below a ridge stripe portion into which current is confined and injected.

In FIG. 12, the horizontal axis of the graph is the ridge stripe end a in the width direction from the center c of the groove of the recessed substrate.
The vertical axis indicates the laser oscillation life under the conditions of a laser output of 30 mW and an ambient temperature of 60 ° C. Here, the distance from the groove center c to the ridge stripe end a (hereinafter referred to as c-a distance) is indicated such that the right side in the width direction from the groove center c is positive and the left side is negative. FIG.
In the nitride semiconductor laser device measured in Step 2, Ga
A processing substrate using an N substrate is used, the ridge stripe width is 2 μm, the groove width is 18 μm, and the hill width is 15 μm.
m and the depression width above the hill was 3 μm.

As can be seen from FIG. 12, the laser oscillation lifetime of a nitride semiconductor laser device having a ridge stripe formed above a groove tends to be longer than that of a nitride semiconductor laser device having a ridge stripe formed above a hill. Indicated. Further investigation revealed that, even in the region above the groove, if the ridge stripe portion was formed in a region where the ca distance was larger than -3 μm and smaller than 1 μm, the laser oscillation life was dramatically improved. It was found to decrease. Here, taking into account that the width of the ridge stripe portion is 2 μm, the ca distance −3 μm is converted into the distance from the groove center c to the ridge stripe end b (hereinafter referred to as c−b distance). If c-b
The distance will be -1 μm. That is, at least a part of the ridge stripe portion of the nitride semiconductor laser device is
From this, it was found that the laser oscillation life was dramatically reduced when formed so as to be included within a range of less than 1 μm in the width direction.

Region where the laser oscillation life is dramatically reduced (range of less than 1 μm in the width direction from the groove center c to the left and right).
Will be referred to as a region III. Therefore, it is preferable that the ridge stripe portion of the nitride semiconductor laser element be formed so as to include the entire area (ab width) in a range excluding the region III. Here, within the groove width range, a range of 1 μm or more in the width direction from the groove center c in the width direction is referred to as a region I. The region I is a region where a nitride semiconductor laser device having a longer laser oscillation life can be formed than the region II described below, and is the most preferable region among the recessed substrates.

On the other hand, in the region above the hill, similar to the region above the groove, the ca distance is larger than 11 μm and 2
It can be seen that when the light emitting portion of the nitride semiconductor laser device is formed in a region smaller than 0 μm, the laser oscillation life is dramatically reduced. Here, when the state of the ca distance of 11 μm is represented by the distance from the dent end d to the ridge stripe end b, it is 2 μm. Similarly, the state of the ca distance of 20 μm is from the dent end e to the ridge stripe end a. If expressed as a distance, it will be 2 μm. That is, when at least a part of the light emitting portion below the ridge stripe portion is included within a range of 2 μm from both sides of the dent end to the outside, the laser oscillation life is dramatically reduced. The region where the laser oscillation life is dramatically reduced is referred to as IV. Therefore, in the region above the hill, the concave end d excluding the region IV
It is preferable that the entire ridge stripe portion (ab) is formed to be included in a range of 2 μm or more on the left side in the width direction or 2 μm or more on the right side of the concave end e. Here, in a region above the hill, a region that is 2 μm or more to the left in the width direction from the dent end d and 2 μm or more to the right from the dent end e is referred to as a region II. In this region II, a nitride semiconductor laser device having a lifetime of several thousand hours can be formed although the laser oscillation life is shorter than that of the above-mentioned region I.

In FIG. 11, the above-mentioned regions I to IV are shown in a schematic cross-sectional view of the substrate having a depression. That is, the light emitting portion of the nitride semiconductor laser device fabricated on the recessed substrate is preferably formed at a position avoiding at least the regions III and IV, of which the region I is the most preferable, and the region II is the most preferable. Then it was preferred (see FIG. 12).

FIG. 11 (a) shows a case where a depression is formed only in the region above the hill. For example, as in Embodiments 6 to 8 described later, the region above the hill is nitrided. As shown in FIG. 11B, the range of the region I when completely and flatly covered with the semiconductor underlayer is in the region above the hill and from the center of the hill to the right or left in the width direction. The region was 1 μm or more apart. This is because if the light emitting portion is formed so as to be included in a range of 1 μm to the left and right from the center of the hill (region III where no depression is formed above the hill), the laser oscillation life is dramatically reduced. It is.

Similarly, in FIG. 11A, no dent is formed above the groove. For example, when a dent is formed above the groove as in Embodiments 4, 7, and 8 described later. The region II was within the region above the groove and was separated from both ends of the recess by 2 μm or more in the width direction to both outsides (see FIG. 11B). because,
This is because the laser oscillation life is dramatically reduced if the light emitting portion is formed so as to be included within a range of 2 μm left and right from both ends of the recess (region IV when the recess is provided above the groove). .

The same tendency as in FIG. 12 was shown even when the groove width, the hill width, and the ridge stripe width were variously changed. Further, even when the processing substrate was changed from a GaN substrate to a substrate including a basic substrate, the same tendency as in FIG. 6 was shown, although the laser oscillation life was shorter than that of the GaN substrate. Therefore, also in these cases, it is considered that the light emitting portion forming region of the light emitting element to be formed on the recessed substrate has the relationship shown in FIG. Similarly, a light emitting diode (LE
D) With respect to the element, the effect of the present invention can be obtained as long as one of the regions I and II shown in FIG. 11 exists below the light emitting portion into which the current is injected.

Although the nitride semiconductor laser device in FIG. 12 has a ridge stripe structure,
The same tendency as in FIG. 12 can be obtained even in a nitride semiconductor laser device having a current blocking structure. (In the case of a current blocking structure, the ridge stripe portion in FIG. 12 corresponds to a portion where current is confined. The width of the ridge stripe corresponds to the width at which the current is confined). That is, in the nitride semiconductor laser device, current is confinedly injected into the light emitting layer,
It suffices that one of the regions I and II shown in FIG. 11 exists below the light emitting portion contributing to laser oscillation.

However, in the case of the nitride semiconductor laser device having the current blocking structure, the laser oscillation life is about 2 times as compared with the device having the ridge stripe structure described above.
It was about 0-30% lower. Further, the nitride semiconductor laser device having the current blocking structure has a large decrease in the yield due to the occurrence of cracks as compared with the device having the ridge stripe structure. Regarding these causes, the same reason as in the case of using the mask substrate can be considered.

[Embodiment 2] In Embodiment 2, a method of manufacturing a substrate with a depression using a mask substrate is shown in FIGS.
Will be described with reference to FIG. Note that items not specifically mentioned in the present embodiment are the same as those in the first embodiment. 3A and 3B show names of respective portions of the substrate with depressions, FIG. 9A shows a substrate with depressions when the cross-sectional shape of the depressions is rectangular, and FIG. The figure shows a substrate with a depression in the case of an inverted trapezoidal shape (a V-shaped shape as crystal growth proceeds further).

The mask substrate in FIG. 9 can be manufactured as follows. First, on a surface of an n-type GaN substrate having a (0001) principal plane orientation, a growth suppression film made of SiO ₂ was formed in a stripe-shaped mask pattern by using a normal lithography technique. The stripe-shaped growth suppressing films thus formed are periodically arranged along the <1-100> direction of the n-type GaN substrate, and have a mask width of 18 μm, a mask thickness of 0.2 μm, and a space width of 7 μm. Was.

After the produced mask substrate is sufficiently organically cleaned, it is carried into an MOCVD (metal organic chemical vapor deposition) apparatus, and a nitride semiconductor base layer made of an n-type GaN film having a coating thickness of 6 μm is laminated. Was done. In the formation of this n-type GaN underlayer, NH ₃ (ammonia), which is a raw material for a group V element, and II are used on a mask substrate set in a MOCVD apparatus.
TMGa (trimethylgallium) or TEGa (triethylgallium) as a raw material for a group I element is supplied, and 105
At a crystal growth temperature of 0 ° C., SiH ₄
(Si impurity concentration 1 × 10 ¹⁸ / cm ³⁾ was added.

FIG. 9A is a schematic cross-sectional view of a substrate with a depression manufactured by the above-described method. As can be seen from this figure, a depression was formed in the region above the growth suppression film under the above-described growth conditions. The depression was formed such that the center position of the mask of the growth suppressing film and the center position of the depression width almost coincided with each other. Furthermore, <1-100 of GaN crystal
The cross-sectional shape of the depression when the growth suppressing film was formed along the direction> was almost rectangular.

The nitride semiconductor light emitting device according to the present invention is formed on the recessed substrate thus manufactured.
This is the same in other embodiments.

In the present embodiment, a depression is present on the surface of the underlying layer of the nitride semiconductor film. However, the underlying layer is grown so that a void is formed between the growth suppressing film and the depression. This is more preferable because the effect of alleviating the crystal lattice strain can be obtained even in the voids.

The n-type GaN layer (nitride semiconductor underlayer) grown on the mask substrate is not limited to this.
_{Al x Ga y In z N (} 0 ≦ x ≦ 1; 0 ≦ y ≦ 1; 0 ≦ z
≦ 1; x + y + z = 1) layer, Si, O,
Cl, S, C, Ge, Zn, Cd, Mg, or Be may be doped.

In this embodiment, the GaN crystal <1-10
Although the stripe-shaped growth suppressing film is formed along the <0> direction, it may be formed along the <11-20> direction. G
When a stripe-shaped mask was formed along the <11-20> direction of the aN crystal, as shown in FIG. 9B, the cross-sectional shape of the depression was close to an inverted trapezoidal shape. However,
When the bottom of the depression is buried, its cross-sectional shape becomes closer to a V-shape.

In this embodiment, the main surface is (0001)
Although a GaN substrate having a plane is used, other plane orientations and other nitride semiconductor substrates may be used. The numerical values of the mask width, the space width, and the mask thickness formed on the mask substrate described in the present embodiment, and the numerical values of the coating thickness of the nitride semiconductor underlayer are the same as those of the first embodiment. If the stated numerical range condition is satisfied,
Other numerical values may be adopted. This is the same in other embodiments.

[Embodiment 3] In Embodiment 3, a method of manufacturing a substrate with a depression using a processed substrate is shown in FIGS.
Will be described with reference to FIG. Note that items not specifically mentioned in the present embodiment are the same as those in the first embodiment. FIG. 5 shows the name of each part of the recessed substrate, FIG. 13 (a) shows the recessed substrate when the transverse cross-sectional shape of the recess is rectangular, and FIG. 13 (b) shows the recessed cross-sectional shape of the recess. The figure shows a substrate with a depression in the case of an inverted trapezoidal shape (a V-shaped shape as crystal growth proceeds further).

The processed substrate in FIG. 13 can be manufactured as follows. First, a dielectric film such as SiO ₂ or SiN _x was deposited on the surface of an n-type GaN substrate having a (0001) principal plane orientation. Then, a resist material was applied to the dielectric film using a normal lithography technique, and the resist material was formed into a stripe-shaped mask pattern. Along the mask pattern, a groove was formed by etching a part of the surface of the dielectric film and the GaN substrate using a dry etching method. After that, the resist material and the dielectric film were removed. The grooves and hills formed in this way are n-type GaN
Along the <1-100> direction of the substrate, the groove width is 18 μm.
m, groove depth 3 μm, and hill width 7 μm.

The processed substrate thus produced is sufficiently organically cleaned and then carried into an MOCVD (metal organic chemical vapor deposition) apparatus in the same manner as in the second embodiment.
A nitride semiconductor underlayer composed of a p-type GaN film was laminated.
In forming the n-type GaN underlayer, NH as a raw material for group V elements is placed on a processing substrate set in a MOCVD apparatus.
TMGa or TEGa as a material for Group ₃ and III elements was supplied, and SiH ₄ (Si impurity concentration 1 × 10 ¹⁸ / cm ³ ) was added to the material at a crystal growth temperature of 1050 ° C.

FIG. 13A is a schematic cross-sectional view of a substrate having a depression manufactured by the above-described method. As can be seen from the figure, a depression was formed only in the region above the hill under the above growth conditions, and the groove was buried flat by the n-type GaN underlayer. The depression was formed such that the center position of the hill width and the center position of the depression width almost coincided with each other. Furthermore, the cross-sectional shape of the depression when the groove was formed along the <1-100> direction of the GaN crystal was almost close to a rectangular shape.

In addition to the groove forming method in the present embodiment, a processed substrate may be manufactured by directly applying a normal resist material on the surface of the nitride semiconductor substrate. However, as described above, it was preferable to form the groove via the dielectric film because the shape of the groove was steep.

In this embodiment, the low-temperature GaN
N-type GaN layer is grown on the buffer layer (nitride semiconductor underlayer) is not limited to this, Al _x Ga _y In _z N
(0 ≦ x ≦ 1; 0 ≦ y ≦ 1; 0 ≦ z ≦ 1; x + y + z =
1) It may be a layer, Si, O, Cl, S, C, G
e, Zn, Cd, Mg, or Be may be doped.

In this embodiment, the groove forming method by the dry etching method has been exemplified, but it goes without saying that other groove forming methods may be used. For example, a wet etching method, a scribing method, a wire saw process, an electric discharge process, a sputtering process, a laser process, a sand blast process, a focus ion beam process, or the like can be used.

In this embodiment, the GaN crystal <1-10
Although the groove is formed along the <0> direction, the groove may be formed along the <11-20> direction. <11 of GaN crystal
FIG. 13B shows a case where a groove is formed along the −20> direction.
As shown by, the cross-sectional shape of the depression was close to an inverted trapezoidal shape. However, if the bottom of the dent is buried, the cross-sectional shape becomes close to a V-shape.

In this embodiment, the main surface is (0001)
Although a GaN substrate having a plane is used, other plane orientations and other nitride semiconductors may be used. The numerical values of the groove width, the hill width, and the groove depth formed on the processing substrate described in the present embodiment and the numerical value of the coating thickness of the nitride semiconductor underlayer are the same as those in the first embodiment. Other numerical values may be adopted as long as the numerical range conditions described above are satisfied. This is the same in other embodiments.

[Embodiment 4] In Embodiment 4, a method of manufacturing a substrate having a depression not only above a hill but also above a groove will be described with reference to FIG. Note that, for items not specifically mentioned in the present embodiment,
This is similar to the first and third embodiments.

That is, the processed substrate and the nitride semiconductor underlayer (GaN underlayer in this embodiment) in FIG. 14 are manufactured in the same manner as in the third embodiment. However, the coating thickness of the GaN underlayer was relatively thin, and was 3 μm.

Since the recessed substrate has a depression not only above the hill but also above the groove, there is no concentrated portion of the crystal distortion due to the collision of the crystals generated by the lateral growth, and the crystal distortion is almost alleviated. GaN underlayer.

The substrate with depressions in Embodiment 4 can be easily obtained mainly by adjusting the thickness of the GaN underlayer covering the processed substrate to a small value.

[Embodiment 5] In Embodiment 5, except that the hill width formed on the processed substrate is not a fixed value but various different values, the above-described Embodiments 1 and 3 are described.
Is the same as

FIG. 15 is a schematic cross-sectional view showing a substrate having a depression in this embodiment, and the groove width G1 is 12 μm.
m, groove depth H1 is 3 μm, and only hill width is L1 = 8 μm
m and L2 = 14 μm. A nitride semiconductor base layer made of an InGaN film having a coating thickness of 5 μm was laminated on such a processed substrate to produce a recessed substrate of the fifth embodiment.

As can be seen from FIG. 15, by changing the width of the hill formed on the processing substrate in various ways, the depression 2 formed above the relatively wide hill 2 is formed above the narrow hill 1. It tends to be larger than the recess 1 that is formed. A relatively large dent has a greater effect of alleviating crystal distortion and suppressing cracks than a small dent. A recessed substrate including recesses having different sizes as in the present embodiment is preferable in the following points.

In other words, a relatively small dent among the pitted substrates can form a light-emitting element having a long laser oscillation life, although the effect of alleviating crystal distortion and the effect of suppressing cracks are smaller than the large dent. This is preferable because it is possible to widen the appropriate regions (regions I and II in FIG. 11) (the yield of the light-emitting element chip is increased). On the other hand, a relatively large dent in a substrate with a dent reduces the generation of residual crystal distortion and cracks, which cannot be suppressed by a small dent, although the area where a light emitting element with a long laser oscillation life can be formed becomes narrow. This is preferable because the yield of the light emitting element chips can be increased. That is, it can be seen that the substrate with depressions of the present embodiment is preferable from the viewpoint of productivity and yield.

In the present embodiment, two types of processed substrates having different hill widths are illustrated, but it is needless to say that two or more types of processed substrates having different hill widths may be used.

[Sixth Embodiment] In the sixth embodiment, the hill width formed in the processing substrate is not a fixed value but is set to various different values. Embodiment 5 is the same as Embodiment 5 except that (see FIG. 16) is completely and flatly covered with the nitride semiconductor film. In addition, matters that are not particularly mentioned in the present embodiment are the same as those in the above-described first and third embodiments.

FIG. 16 is a schematic cross-sectional view showing a substrate with a depression in this embodiment. The groove width G1 is 16 μm.
The groove depth H1 was 2 μm, and only the hill width had two values, L1 = 4 μm and L2 = 24 μm. An AlGaN film having a coating thickness of 4 μm was laminated on such a processed substrate, and a substrate with depressions according to the sixth embodiment was manufactured.

As can be seen from FIG. 16, by changing the width of the hill formed on the processing substrate in various ways, the depression 2 is formed above the relatively wide hill 2 and the relatively narrow hill 2 is formed. The upper part of 1 is completely and flatly buried with a nitride semiconductor base layer made of an AlGaN film. Such a recessed substrate in the present embodiment is preferable in the following points.

That is, since no depression is formed above the hill 1 in the substrate with depressions, it is possible to form a light emitting element having a long laser oscillation life, although the effect of alleviating crystal distortion and the effect of suppressing cracks are small. Area is Embodiment 4
(The yield rate of the light-emitting element chip is increased). On the other hand, among the substrates with depressions, the depressions 2 formed above the hills 2 have an effect of alleviating crystal distortion and an effect of suppressing cracks (increase in the yield of light emitting element chips). Therefore, among the hills formed on the processed substrate, a dent-formed substrate in which a dent is not formed above some hills and a dent is formed above other hills is an embodiment from the viewpoint of productivity. 5 is preferable.

In this embodiment, two types of processed substrates having different hill widths are exemplified, but it is needless to say that processed substrates having two or more types of different hill widths may be used.

Embodiment 7 Embodiment 7 is the same as Embodiments 1 and 3 except that the depth of the groove formed in the processed substrate is not a fixed value but various different values. It is.

FIG. 17 is a schematic cross-sectional view showing a substrate with a depression according to this embodiment. The groove width G1 is 18 μm.
The hill width L1 is 5 μm, and only the groove depth is H1 = 2.5 μm.
m and H2 = 10 μm. A nitride semiconductor base layer made of a GaN film having a coating thickness of 6 μm was laminated on such a processed substrate to produce a recessed substrate of the sixth embodiment.

As can be seen from FIG. 17, the recess 2 is formed only above the relatively deep groove 2 by variously changing the depth of the groove formed in the processing substrate. The recessed substrate in the present embodiment is preferable in the following points.

That is, since no recess is formed above the recessed substrate except for the groove 2, a light emitting element having a long laser oscillation life can be formed although the effect of alleviating crystal distortion and the effect of suppressing cracks are small. The possible area can be widened (the yield of the light emitting element chip is increased). On the other hand, the depression 2 formed above the groove 2 in the substrate with depression has an effect of alleviating crystal distortion and an effect of suppressing cracks. Therefore, a recessed substrate in which a depression is formed above some of the grooves formed on the processing substrate and no depression is formed on the other grooves, from the viewpoint of the productivity of light emitting element chips. preferable.

In this embodiment, two types of processed substrates having different groove depths are exemplified, but it is needless to say that two or more types of processed substrates having different groove depths may be used. In addition, the present embodiment corresponds to the above-described fourth to sixth embodiments.
Needless to say, it may be combined with at least one of the above.

[Eighth Embodiment] In the eighth embodiment, except that the width of the groove formed in the processing substrate is not a fixed value but various different values, the first and third embodiments are described above.
Is the same as

FIG. 18 is a schematic cross-sectional view showing a substrate with a depression in this embodiment, in which the hill width L1 is 5 μm,
The groove depth H1 is 4 μm, and only the groove width is G1 = 12 μm
And G2 = 24 μm. A nitride semiconductor base layer made of a GaN film having a coating thickness of 6 μm was laminated on such a processed substrate to produce a recessed substrate of the eighth embodiment.

As can be seen from FIG. 18, the recess 2 is formed only above the relatively wide groove 2 by changing the width of the groove formed on the processing substrate in various ways. The substrate with a depression according to the present embodiment has the same effects as those of the above-described seventh embodiment.

In this embodiment, the processed substrates having two types of different groove widths are exemplified, but it is needless to say that processed substrates having two or more types of different groove widths may be used. In addition, it is needless to say that this embodiment may be combined with at least one of the above-described fourth to seventh embodiments.

[Ninth Embodiment] In the ninth embodiment, a nitride semiconductor laser device was manufactured on the substrate having a depression in the first or second embodiment.

(Crystal Growth) FIG. 19 shows a nitride semiconductor laser device after a wafer of a nitride semiconductor laser grown on a recessed substrate is divided into chips. FIG.
Is an n-type GaN substrate 100, a SiO ₂ growth suppressing film 101, an n-type Al _0.05 Ga
_0.95 N underlayer 102, substrate 200 with depression, n-type In
_0.07 Ga _0.93 N crack prevention layer 103, n-type Al _0.1 G
a _0.9 N clad layer 104, n-type GaN optical guide layer 10
5, light-emitting layer 106, p-type Al _0.2 Ga _0.8 N carrier block layer 107, p-type GaN light guide layer 108, p-type Al
_0.1 Ga _0.9 N cladding layer 109, p-type GaN contact layer 110, n-electrode 111, p-electrode 112 and SiO ₂
The dielectric film 113 is included.

In manufacturing such a nitride semiconductor laser device, first, the substrate 200 with a depression according to the first or second embodiment was formed. However, in the ninth embodiment, the longitudinal direction of the stripe-shaped growth suppressing film 101 is formed along the <1-100> direction of the GaN substrate.

Next, using a MOCVD apparatus, NH _{3 serving as a} group V element source and TMGa or TEGa serving as a group III element source were converted into II
TMIn (trimethyl indium) as a raw material for Group I elements and SiH ₄ (silane) as impurities were added, and 800
An n-type In _0.07 Ga _0.93 N crack preventing layer 103 was grown to a thickness of 40 nm at a crystal growth temperature of ° C. Next, the substrate temperature is raised to 1050 ° C., and TMAl (trimethylaluminum) or TEAl
(Triethylaluminum) with a thickness of 0.9
[mu] m n-type Al _{0. 1} Ga _0.9 N cladding layer 104 (Si impurity concentration 1 × 10 ¹⁸ / cm ³⁾ of is grown, followed by n-type GaN light guide layer 105 (Si impurity concentration 1 × 10
¹⁸ / cm ³ ) was grown to a thickness of 0.1 μm.

After that, the substrate temperature is lowered to 800 ° C.
A light emitting layer (multiple quantum well structure) 106 in which an In _0.01 Ga _0.99 N barrier layer having a thickness of 8 nm and an In _0.15 Ga _0.85 N well layer having a thickness of 4 nm were alternately laminated was formed. In this embodiment, the light emitting layer 106 has a multiple quantum well structure starting at the barrier layer and ending at the barrier layer, and includes three (three periods) quantum well layers. In addition, S is added to both the barrier layer and the well layer.
i impurity was added at a concentration of 1 × 10 ¹⁸ / cm ³ . Note that a crystal growth interruption period of 1 second or more and 180 seconds or less may be inserted between the barrier layer and the well layer or between the well layer and the barrier layer. This is preferable because the flatness of each layer is improved and the half width of the emission spectrum is reduced.

When As is added to the light emitting layer 106, AsH ₃ or TBAs (tert-butylarsine) is used.
And when P is added, PH ₃ or TBP
(Tertiary butyl phosphine) and, if Sb is added, TMSb (trimethylantimony)
Alternatively, TESb (triethylantimony) may be used. Further, when the light emitting layer is formed, N material is
N ₂ H ₄ (dimethylhydrazine) may be used in addition to H ₃ .

Next, the temperature of the substrate is raised again to 1050 ° C., and a p-type Al _0.2 Ga _0.8 N carrier block layer 107 having a thickness of 20 nm, a p-type GaN optical guide layer having a thickness of 0.1 μm, and a A 0.5 μm p-type Al _0.1 Ga _0.9 N cladding layer 109 and a 0.1 μm thick p-type GaN contact layer 110 were sequentially grown. As the p-type impurity, Mg (EtCP ₂ Mg: bisethylcyclopentadienyl magnesium) is 5 × 10 ¹⁹ / cm ³ to 2 × 1.
It was added at a concentration of 0 ²⁰ / cm ³ . It is preferable that the p-type impurity concentration of p-type GaN contact layer 110 be increased as approaching the interface with p-electrode 112. By doing so, the contact resistance at the interface with the p-electrode is reduced. Further, a small amount of oxygen may be mixed during the growth of the p-type layer in order to remove residual hydrogen in the p-type layer which is preventing activation of Mg which is a p-type impurity.

After the growth of the p-type GaN contact layer 110 in this manner, all gases in the reactor of the MOCVD apparatus are changed to nitrogen carrier gas and NH ₃ ,
The substrate temperature was cooled at a cooling rate of 0 ° C./min. When the substrate temperature was cooled to 800 ° C., the supply of NH ₃ was stopped, and the substrate temperature was maintained for 5 minutes and then cooled to room temperature. The holding temperature of this substrate is from 650 ° C. to 900
° C, and the holding time is 3 minutes or more and 1 hour.
Preferably, it was less than 0 minutes. Further, the cooling rate to room temperature is preferably 30 ° C./min or more. The crystal growth film thus formed was evaluated by Raman measurement. As a result, even if the conventional p-type annealing was not performed, the growth film had already exhibited p-type characteristics (that is, Mg was activated). Had been turned). Also, the p electrode 112
The contact resistance at the time of forming was also reduced. In addition to this, if conventional p-type annealing is combined, Mg
The activation rate was further improved, which was favorable.

In the crystal growth step according to the present embodiment, the crystal may be continuously grown from the mask substrate to the nitride semiconductor laser device, or the growth step from the mask substrate to the recessed substrate may be performed in advance. Regrowth for growing the nitride semiconductor laser device may be performed later.

In the present embodiment, the In _0.07 Ga _0.93 N crack preventing layer 103 may have an In composition ratio other than 0.07, or the InGaN crack preventing layer may be omitted. However, when lattice mismatch between the cladding layer and the GaN substrate becomes large, it is preferable to insert an InGaN crack prevention layer.

Although the light emitting layer 106 of this embodiment starts with a barrier layer and ends with a barrier layer, the light emitting layer 106 may start with a well layer and end with a well layer. Further, the number of well layers in the light emitting layer is not limited to the three layers described above. If the number of layers is 10 or less, the threshold current value becomes low and continuous oscillation at room temperature was possible. In particular, when the number of well layers is 2 or more and 6 or less, the threshold current value is preferably reduced.

In the light emitting layer 106 of this embodiment, Si is added to both the well layer and the barrier layer at a concentration of 1 × 10 ¹⁸ / cm ³ , but Si may not be added. However, the emission intensity was higher when Si was added to the light emitting layer. The impurity added to the light emitting layer is not limited to Si, and at least one of O, C, Ge, Zn, and Mg may be added. The total amount of impurities added was preferably about 1 × 10 ¹⁷ to 1 × 10 ¹⁹ / cm ³ . Further, the layer to which the impurity is added is not limited to both the well layer and the barrier layer, and the impurity may be added to only one of these layers.

In the p-type Al _0.2 Ga _0.8 N carrier block layer 107 of the present embodiment, the Al composition ratio may be other than 0.2, or this carrier block layer may be omitted. However, the threshold current value was lower when the carrier block layer was provided. This is because the carrier block layer 107 has a function of confining carriers in the light emitting layer 106. It is preferable to increase the Al composition ratio of the carrier block layer because this increases the confinement of carriers. Conversely, it is preferable to reduce the Al composition ratio within a range in which the confinement of carriers is maintained, because the carrier mobility in the carrier block layer increases and the electric resistance decreases.

In this embodiment, the p-type cladding layer 109 and
Al as the n-type cladding layer 104 _0.1Ga_0.9N crystal
Although it was used, even if its Al composition ratio was other than 0.1
Good. If the mixed crystal ratio of Al increases,
The energy gap difference and the refractive index difference increase,
And light are efficiently confined in the light emitting layer, causing laser oscillation.
The threshold current value can be reduced. Conversely, carriers and light
The Al composition ratio within the range where the confinement of
Then, the carrier mobility in the cladding layer increases,
The operating voltage of the device can be reduced.

The thickness of the AlGaN cladding layer is 0.7 μm
It is preferably within a range of about 1.5 μm, which makes the vertical and lateral modes unimodal and increases the light confinement efficiency, thereby improving the optical characteristics of the laser and reducing the laser threshold current value. .

The cladding layer is not limited to the AlGaN ternary mixed crystal, but may be made of AlInGaN, AlGaNP, or AlGaN.
It may be a quaternary mixed crystal such as As. Further, the p-type cladding layer has a superlattice structure including a p-type AlGaN layer and a p-type GaN layer, or a p-type AlGa
It may have a superlattice structure including an N layer and a p-type InGaN layer.

In the present embodiment, the crystal growth method using the MOCVD apparatus has been described as an example, but the molecular beam epitaxy method (MB
E) or hydride vapor phase epitaxy (HVPE) or the like may be used.

(Chip Formation Step) The epi-wafer formed by the above-described crystal growth (wafer having a nitride semiconductor multilayer structure epitaxially grown on a mask substrate) is subjected to MOCV.
It is taken out from the D device and processed into a laser element. Here, the surface of the epitaxial wafer on which the nitride semiconductor multilayer film structure was formed had a depression, and was not completely and flatly buried.

Since the mask substrate 100 is an n-type conductive nitride semiconductor, an n-electrode 111 is formed on the back surface thereof in a stack of Hf / Al in this order (see FIG. 19). As the n-electrode, a stack of Ti / Al, Ti / Mo, or Hf / Au may be used. It is preferable to use Hf for the n-electrode because the contact resistance is reduced.

The p-electrode portion is etched in a stripe shape along the longitudinal direction of the growth suppressing film of the mask substrate 100,
As a result, a ridge stripe portion (see FIG. 19) was formed. In the case where the growth suppressing films of the mask substrate are in a grid pattern, the lengthwise direction of the masks may be set to <1-1 of the nitride semiconductor.
One of the 00> direction and the <11-20> direction may be selected. The ridge stripe portion has a stripe width W = 2.0
.mu.m, and formed so as to be included in the above-described region I (see FIG. 8). Thereafter, a SiO ₂ dielectric film 113 is deposited, the upper surface of the p-type GaN contact layer 110 is exposed from the dielectric film, and a p-electrode 112 is formed on the Pd / M
It was formed by vapor deposition as an o / Au stack. Pd / Pt / Au, Pd / Au, or Ni /
A stack of Au or the like may be used. Also, the p electrode 11
A pad electrode made of Au may be interposed between 2 and the wire bond.

Finally, the epi-wafer is cleaved at a plane perpendicular to the longitudinal direction of the ridge stripe, and a resonator length of 50
A 0 μm Fabry-Perot resonator was fabricated. The resonator length is generally preferably in the range of 300 μm to 1000 μm. The M-plane {1-100} of the nitride semiconductor crystal is an end face of a mirror end face having a cavity length in which a groove is formed along the <1-100> direction. The cleavage for forming the mirror end face and the division of the laser element are performed by the mask substrate 10.
0 from the back side using a scriber. However, the cleavage was not performed by scribing scratches by the scriber across the entire back surface of the wafer, but was cleaved by scribing scratches on only a part of the wafer, for example, both ends of the wafer. . As a result, the sharpness of the end face of the element and shavings due to scribe do not adhere to the epi surface, so that the element yield is improved. On the surface of the chip-divided nitride semiconductor light-emitting device (laser device), two or more depressions were present with the ridge stripe portion of the nitride semiconductor light-emitting device interposed therebetween. The p-electrode 112 was formed on a region including two or more dents, and the wire bond was formed on a region including one or more dents.

As a feedback method of the laser resonator,
Commonly known DFB (distributed feedback), DBR (distributed Bragg reflection) and the like can also be used.

After the mirror facets of the Fabry-Perot resonator were formed, SiO ₂ and TiO ₂ dielectric films were alternately deposited on the mirror facets to form a dielectric multilayer reflective film having a reflectance of 70%. Been formed. As the dielectric multilayer reflective film, a multilayer film such as SiO ₂ / Al ₂ O ₃ can be used.

Although the n-electrode 111 was formed on the back surface of the mask substrate 100, a part of the n-type Al _0.05 Ga _0.95 N film 102 was exposed from the front side of the epiwafer by using a dry etching method. An n-electrode may be formed on the region.

(Package mounting) The obtained semiconductor laser device is mounted on a package. When using a high output (30 mW or more) nitride semiconductor laser device, attention must be paid to heat dissipation measures. The high-power nitride semiconductor laser element can be connected to the package body by using a solder material such as In solder, PbSn-based solder, or AuSn-based solder with the semiconductor bonding being either up or down, It is preferable to make connection on the side from the viewpoint of heat radiation. Incidentally, the high power nitride semiconductor laser device can be usually directly attached to the package body or the heat sink portion. However, Si, AlN, diamond, Mo, C
The connection may be made via a submount such as uW, BN, Fe, SiC, Cu, or Au.

As described above, the nitride semiconductor laser device according to the present embodiment is manufactured. Although the GaN mask substrate 100 is used in the present embodiment, a processed substrate of another nitride semiconductor may be used. For example, in the case of a nitride semiconductor laser, a layer having a lower refractive index than the cladding layer needs to be in contact with the outside of the cladding layer in order to make the vertical and transverse modes unimodal, and an AlGaN substrate can be preferably used. .

In the present embodiment, the formation of the nitride semiconductor laser device on the substrate having the depressions alleviates the crystal distortion and suppresses the occurrence of cracks.
A laser oscillation life of about 18000 hours was obtained with a laser output of 30 mW under the condition of an ambient temperature of 60 ° C., and an improvement in element yield by crack suppression effect was achieved.

[Tenth Embodiment] In the tenth embodiment, a nitride semiconductor light emitting diode (LED) element is formed on any of the recessed substrates in the first to eighth embodiments. At this time, the nitride semiconductor LED element layer was formed by a method similar to the conventional method.

In the nitride semiconductor LED device according to the present embodiment, the color unevenness is reduced and the light emission intensity is improved as compared with the conventional case. Particularly, an LED element having a short wavelength (450 nm or less) or a long wavelength (600 nm or more), such as a white nitride semiconductor LED element or an amber nitride semiconductor LED element using a nitride semiconductor as a raw material,
By being formed on the substrate with depressions in Embodiments 1 to 8, it was possible to have an emission intensity about twice or more as compared with the conventional case.

[Embodiment 11] The embodiment 11 is similar to the embodiment 9 except that the light emitting layer contains at least any one of As, P and Sb to be substituted for a part of N. Same as 10. More specifically, at least one of the substitution elements of As, P, and Sb was included in the light emitting layer of the nitride semiconductor light emitting element by substituting at least a part of N of the well layer. At this time,
When the total composition ratio of As, P, and / or Sb contained in the well layer is x and the composition ratio of N is y, x is smaller than y and x / (x + y) is 0.3 ( 30%)
Or less, and preferably 0.2 (20%) or less. Further, the lower limit of the preferable concentration of the total of As, P, and / or Sb was 1 × 10 ¹⁸ / cm ³ or more.

The reason is that the substitution element composition ratio x is 20%
If the composition ratio x is higher than 30%, the separation of the hexagonal system and the cubic system are mixed. This is because there is a high possibility that the crystallinity of the well layer will decrease when the process starts to shift to. On the other hand, if the total concentration of the substituting elements is less than 1 × 10 ¹⁸ / cm ³ , the effect of including the substituting element in the well layer becomes difficult to obtain.

The effect of the present embodiment is that the effective mass of electrons and holes in the well layer is reduced and the mobility is reduced by including at least one of the substitution elements of As, P and Sb in the well layer. growing. In the case of a semiconductor laser device, a small effective mass means that a carrier inversion distribution for laser oscillation can be obtained with a small current injection amount, and a large mobility means that electrons and holes disappear in the light emitting layer due to radiative recombination. This also means that new electrons and holes can be injected at high speed by diffusion. That is,
Compared to an InGaN-based nitride semiconductor laser device in which the light-emitting layer does not contain any of As, P, and Sb, in the present embodiment, the threshold current density is low and the self-sustained pulsation characteristics are excellent (the Excellent) semiconductor lasers can be obtained.

On the other hand, when the present embodiment is applied to a nitride semiconductor LED, As, P, and / or S
b, the conventional InGa
The In composition ratio in the well layer can be reduced as compared with the nitride semiconductor LED element including the N well layer. This means that a decrease in crystallinity due to the separation of the concentration of In can be suppressed. Therefore, the effect of the addition of the substitution element is synergistic with the effect of the nitride semiconductor LED according to the eighth embodiment, thereby further improving the emission intensity and reducing the color unevenness. In particular, a white nitride semiconductor LE using a nitride semiconductor as a raw material
As in the case of the D element and the amber nitride semiconductor LED element, the emission wavelength is short (450 nm or less) or long (600 nm).
nm or more), the well layer can be formed without a low or no In composition ratio, so that the color unevenness is small as compared with the conventional InGaN-based nitride semiconductor LED element, Strong emission intensity can be obtained.

[Twelfth Embodiment] In the twelfth embodiment, the nitride semiconductor laser device of the ninth or eleventh embodiment is applied to an optical device. The blue-violet (380 to 420 nm wavelength) nitride semiconductor laser device according to the ninth or eleventh embodiment can be preferably used in various optical devices. For example, when used in an optical pickup device, it is preferable in the following points. That is, such a nitride semiconductor laser device operates stably at a high output (30 mW) in a high-temperature atmosphere (60 ° C.), has few device defects, and has a long laser oscillation life. It is most suitable for an optical disk device for density recording / reproducing (the shorter the light wavelength, the higher density recording / reproducing is possible).

FIG. 20 is a schematic block diagram showing an optical disk device including an optical pickup such as a DVD device as an example in which the nitride semiconductor laser device according to the ninth or eleventh embodiment is used in an optical device. I have. In this optical information recording / reproducing apparatus, a laser beam 3 emitted from a light source 1 including a nitride semiconductor laser element is modulated by an optical modulator 4 according to input information, and a scanning mirror 5 is provided.
And recorded on the disk 7 via the lens 6. The disk 7 is rotated by a motor 8. At the time of reproduction, the reflected laser light optically modulated by the bit arrangement on the disk 7 is detected by the detector 10 via the beam splitter 9, and thereby a reproduction signal is obtained. The operation of each of these elements is controlled by the control circuit 11. The output of the laser element 1 is usually 3 at the time of recording.
0 mW, and about 5 mW during reproduction.

The laser device according to the present invention can be used not only in the above-described optical disk recording / reproducing apparatus but also in a laser printer, a bar code reader, a projector using three primary colors of light (blue, green, and red) lasers. I can do it.

[Thirteenth Embodiment] In the thirteenth embodiment, the nitride semiconductor light emitting diode element according to the tenth or eleventh embodiment is used in a semiconductor light emitting device. That is, the nitride semiconductor light-emitting diode element according to Embodiment 10 or 11 can be used in at least one of the three primary colors of light (red, green, and blue) in, for example, a display device (semiconductor light-emitting device). By using such a nitride semiconductor light emitting diode element, a display device with less color unevenness and high light emission intensity can be manufactured.

Further, such a nitride semiconductor light emitting diode element capable of producing three primary colors of light can be used also in a white light source device. On the other hand, the nitride semiconductor light emitting diode device according to the present invention having an emission wavelength in the ultraviolet region to the violet region (about 380 to 420 nm) can be used as a white light source device by applying a fluorescent paint.

By using such a white light source, a backlight with low power consumption and high luminance can be realized instead of the halogen light source used in the conventional liquid crystal display. It can also be used as a backlight for a liquid crystal display of a man-machine interface in a mobile notebook computer or mobile phone,
A small and clear liquid crystal display can be provided.

[0193]

As described above, according to the present invention, in the nitride semiconductor light emitting device, the light emission lifetime and light emission intensity can be improved. Further, according to the present invention, in the nitride semiconductor light emitting device, it is possible to prevent cracks, electrode peeling, and wire bond peeling.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view illustrating an example of a mask substrate including a nitride semiconductor substrate that can be used in the present invention, and FIG. 1B illustrates a mask substrate including a base substrate.

FIGS. 2A and 2B show forms of growth suppression included in a mask substrate that can be used in the present invention, wherein FIG. 2A shows a case where stripe-like growth suppression films having two types of directions are orthogonal to each other, and FIG. Shows the case where the stripe-shaped growth suppressing films having two kinds of directions cross each other at an angle of 60 °, and (c) shows the case where the stripe-shaped growth suppressing films having three kinds of directions cross each other at an angle of 60 °. Shows the case.

FIG. 3 is a schematic cross-sectional view showing an example of a substrate having a depression that can be used in the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of a processed substrate that can be used in the present invention.

FIG. 5 is a schematic cross-sectional view showing a substrate with a depression when a processed substrate is used in the present invention.

FIG. 6 is a schematic cross-sectional view showing a crystal growth mode of a nitride semiconductor film on a mask substrate.

FIG. 7 is a schematic cross-sectional view illustrating a crystal growth mode of a nitride semiconductor film on a processing substrate.

FIG. 8 is a schematic cross-sectional view showing a preferable region for forming a light emitting element structure on a substrate having a depression including a mask substrate in the present invention.

FIG. 9 is a schematic cross-sectional view showing an example of a recessed substrate including a mask substrate that can be used in the present invention.

FIG. 10 is a diagram showing a relationship between a formation position of a ridge stripe portion of a nitride semiconductor laser device formed on a substrate having a depression including a mask substrate which can be used in the present invention and a laser oscillation life.

FIG. 11 is a schematic cross-sectional view showing a preferred region of a light emitting portion in a light emitting element structure formed on a substrate having a depression including a processed substrate that can be used in the present invention.

FIG. 12 is a diagram showing a relationship between a formation position of a ridge stripe portion of a nitride semiconductor laser element formed on a substrate having a depression including a processed substrate which can be used in the present invention and a laser oscillation life;

FIG. 13 is a schematic cross-sectional view showing another example of a substrate with a depression that can be used in the present invention.

FIG. 14 is a schematic cross-sectional view showing another example of a recessed substrate that can be used in the present invention.

FIG. 15 is a schematic cross-sectional view showing another example of a recessed substrate that can be used in the present invention.

FIG. 16 is a schematic cross-sectional view showing another example of a substrate with a depression that can be used in the present invention.

FIG. 17 is a schematic cross-sectional view showing another example of a recessed substrate that can be used in the present invention.

FIG. 18 is a schematic cross-sectional view showing another example of a substrate with a depression that can be used in the present invention.

FIG. 19 is a schematic cross-sectional view showing one example of a nitride semiconductor laser device formed on a substrate with a depression according to the present invention.

FIG. 20 is a schematic block diagram showing an example of an optical device including an optical pickup device using a nitride semiconductor laser device according to the present invention.

[Explanation of symbols]

 200 substrate with depression, 100 n-type GaN substrate, 10
1 growth suppression film, 102 n-type Al_0.05Ga_0.95N base
Layer, 103 n-type In_0.07Ga_0.93N crack prevention layer,
104 n-type Al_0.1Ga_0.9N cladding layer, 105 n
-Type GaN light guide layer, 106 light-emitting layer, 107 p-type A
l_0.2Ga_0.8N carrier block layer, 108 p-type Ga
N guide layer, 109 p-type Al_0.1Ga_0.9N clad
Layer, 110 p-type GaN contact layer, 111 n electrode,
112 p electrode, 113 SiO _TwoDielectric film.

Continued on front page F term (reference) 5F041 AA03 AA40 CA04 CA05 CA34 CA40 CA46 CA53 CA54 CA56 CA57 CA58 CA65 DA07 EE25 5F073 AA13 AA45 AA51 AA72 AA77 AA89 CA17 CB02 CB05 CB13 CB19 DA05 DA34 EA23 EA28

Claims (19)

[Claims] 1. A nitride semiconductor underlayer grown on a nitride semiconductor substrate surface or a nitride semiconductor substrate layer surface grown on a basic substrate other than a nitride semiconductor, and on the nitride semiconductor underlayer. a light-emitting element structure including a light-emitting layer including a quantum well layer or a quantum well layer and a barrier layer in contact with the quantum well layer between the n-type layer and the p-type layer; A nitride semiconductor light emitting device, characterized by including a depression that is not planarized. 2. A growth suppression film for suppressing the growth of a nitride semiconductor is partially formed on the surface of the nitride semiconductor substrate or on the surface of a nitride semiconductor substrate layer grown on a basic substrate other than the nitride semiconductor. 2. The nitride semiconductor light emitting device according to claim 1, wherein the nitride semiconductor underlayer is grown on the mask substrate. 3. 3. The nitride semiconductor light emitting device according to claim 2, wherein the growth suppressing film is formed in a stripe pattern. 4. The method according to claim 1, wherein a longitudinal direction of said stripe-shaped growth suppressing film is <1--
The nitride semiconductor light emitting device according to claim 3, wherein the nitride semiconductor light emitting device is substantially parallel to a 100> direction or a <11-20> direction. 5. A region in which the depression is formed above the stripe-shaped growth suppression film, and is located at least 2 μm in a width direction of the growth suppression film from a side end of the depression and within the width of the growth suppression film. 5. The nitride semiconductor light emitting device according to claim 3, wherein a light emitting portion of the light emitting device structure is included above the light emitting device. 6. The nitride semiconductor light emitting device according to claim 5, wherein a void exists between the growth suppressing film and the depression above the growth suppressing film. 7. The nitride semiconductor light emitting device according to claim 3, wherein a width of said growth suppressing film is in a range of 7 to 100 μm. 8. The growth suppressing film having a thickness of 0.05 to 10
The nitride semiconductor light emitting device according to any one of claims 2 to 7, wherein the thickness is within a range of μm. 9. The growth suppressing film is made of SiO ₂ , SiO, S
9. The nitride semiconductor light emitting device according to claim 2, wherein the nitride semiconductor light emitting device includes at least one of iN _x and SiON _x or at least one of W and Mo. 9. 10. The nitride semiconductor underlayer is composed of Al and In.
10. The nitride semiconductor light-emitting device according to claim 1, comprising at least one of the following. 11. The nitride semiconductor underlayer is GaN, and Si, O, Cl, S, C, Ge, Zn, Cd, M
g and Be containing at least one or more of the impurity groups, and the amount of addition is 1 × 10 ¹⁷ / cm ³ or more and 5
2. The composition according to claim 1, wherein the density is not more than × 10 ¹⁸ / cm ^3.
10. The nitride semiconductor light emitting device according to any one of items 9 to 9. 12. The nitride semiconductor underlayer is made of Al _x Ga.
_1-xN (0.01 ≦ x ≦ 0.15) and Si,
O, Cl, S, C, Ge, Zn, Cd, Mg and Be
Of at least one of the impurity groups described above, and the added amount is 3 × 10 ¹⁷ / cm ³ or more and 5 × 10 ¹⁸ / c
The nitride semiconductor light emitting device according to any one of claims 1 9, characterized in that m ³ or less. 13. The nitride semiconductor underlayer is made of In _x Ga.
_1-xN (0.01 ≦ x ≦ 0.15) and Si,
O, Cl, S, C, Ge, Zn, Cd, Mg and Be
And at least one of the impurity groups described above, and the added amount is 1 × 10 ¹⁷ / cm ³ or more and 4 × 10 ¹⁸ / c
The nitride semiconductor light-emitting device according to claim 1, wherein the value is not more than m ³ . 14. The nitride semiconductor light emitting device according to claim 1, wherein an electrode is formed on a region including at least two of the depressions. 15. The method according to claim 1, wherein a dielectric film is formed on a region including at least two of the depressions.
5. The nitride semiconductor light emitting device according to any one of items 4. 16. The nitride according to claim 1, wherein one or more dents are included in a bonding region between a wire bond and the nitride semiconductor element. Semiconductor light emitting device. 17. The quantum well layer comprises As, P, and S
17. The nitride semiconductor light emitting device according to claim 1, comprising at least one element of b. 18. An optical device or a semiconductor light emitting device comprising the nitride semiconductor light emitting device according to claim 1. Description: 19. A mask formed by partially forming a growth suppressing film for suppressing the growth of a nitride semiconductor on a surface of a nitride semiconductor substrate or on a surface of a nitride semiconductor substrate layer grown on a basic substrate other than the nitride semiconductor. A nitride semiconductor underlayer is grown on the mask substrate; and a quantum well layer or a quantum well layer and a barrier layer in contact with the quantum well layer between the n-type layer and the p-type layer on the nitride semiconductor underlayer. A step of growing a light-emitting element structure including a light-emitting layer including the step of growing the light-emitting element structure, wherein a non-planarized depression is formed above the growth suppression film also on the surface of the light-emitting element structure after the growth. A method for manufacturing a nitride semiconductor light emitting device.