JP2000294875A - Nitride laser device structure - Google Patents

Abstract

(57) [Abstract] [Object] To obtain a novel element structure in which a single transverse mode having a good FFP even at a high output and a good yield is obtained. An insulating film having a stripe-shaped opening is formed on a first p-type nitride semiconductor layer formed on an active layer, so that a second nitride semiconductor layer to be formed next is formed as described above. It grows selectively from the opening. That is, in the nitride semiconductor laser device, it is not necessary to form a ridge by etching, and a desired refractive index difference can be obtained only by stacking nitride semiconductors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nitride semiconductor (an In _b A
The present invention relates to a laser device comprising l _c Ga _1-bc N, 0 ≦ b, 0 ≦ c, b + c <1).

[0002]

2. Description of the Related Art The present inventor has proposed a practical nitride semiconductor laser.
For example, Jpn.J.Appl.Phys.Vol.37 (199
8) pp.L309-L312, Part 2, No.3B, 15 March 1998
A device structure is proposed. The technology of the above document is
A SiO formed partially on top of the substrate_TwoThrough the membrane
Nitride semiconductor composed of selectively grown GaN with few dislocations
A nitride semiconductor layer that forms the laser element structure on the substrate
Continuous oscillation at room temperature by using multiple stacked elements
It allows more than 10,000 hours. As element structure
Represents n-Al on a nitride semiconductor substrate that has been selectively grown._k
Ga_1-kAn n-type contact layer made of N (0 ≦ k <1),
In_0.1Ga_0.9Anti-crack layer made of N, n-Al
_0.14Ga _0.86N-type cladding composed of N / GaN multilayer film
Layer, n-type light guide layer made of n-GaN, In_0.02Ga
_0.98N / In_0.15Ga_0.85N multiple quantum well structure
Active layer, p-Al_0.2Ga_0.8P-type electron closure consisting of N
Embedded layer, p-type light guide layer made of p-GaN, p-Al
_0.14Ga_0.86P-type cladding made of N / GaN multilayer film
Layer, composed of a p-type contact layer of p-GaN
Have been.

Further, this laser device has a ridge structure in which a portion from a p-type contact layer to a part of a p-type cladding layer is partially etched so that an FFP (far field pattern) becomes a favorable single transverse mode. I am taking.

[0004]

However, in order to realize a high-output type nitride semiconductor laser device having the above-mentioned refractive index waveguide structure, the position to be etched is the active layer portion immediately below the ridge. It is necessary to control the effective refractive index difference from the other active layers in the order of 1/100. This is done until only a part of the p-type clad layer remains, that is, until just before the p-type light guide layer. .01 μm
The ridge must be formed by etching with the following accuracy. Although this is possible with the above structure, there is a problem in terms of yield.

Accordingly, the present invention provides a novel element structure which does not require etching for forming a ridge, so that a high output type (for example, 30 mW) has a good yield,
It is possible to obtain a nitride semiconductor laser device in which the FFP also has a favorable single transverse mode.

[0006]

That is, the present invention can achieve the object of the present invention by the following constitutions (1) to (10). (1) A first insulating film having a stripe-shaped opening is formed on a first p-type nitride semiconductor layer formed on an active layer, and a second p-type nitride is formed from the opening. A nitride semiconductor laser device comprising: a semiconductor layer; and a ridge formed by the second p-type nitride semiconductor. (2) The nitride semiconductor laser device according to (1), wherein the first p-type nitride semiconductor layer and the second p-type nitride semiconductor layer have the same composition.

(3) The stripe-shaped opening has a size of 3 μm.
m or less, wherein (1) or (2)
The nitride semiconductor laser device according to any one of the above. (4) The first p-type nitride semiconductor layer is formed of Al _x Ga _{1 -x}
An optical guide layer having an N (0 ≦ X <1) layer, and a second p-type nitride semiconductor layer is a cladding layer having Al _Y Ga _1-Y N (0 ≦ Y <1 and X <Y). The nitride semiconductor laser device according to any one of (1) and (3), wherein

(5) Each of the first and second p-type nitride semiconductor layers is an optical guide layer having an Al _x Ga ₁ -xN (0 ≦ X <1) layer. The nitride semiconductor laser device according to any one of (2) and (3). (6) The nitride semiconductor laser according to any one of (1) to (5), wherein the first insulating film has a stripe width of 2 μm or more and 200 μm or less and a film thickness of 0.5 μm or less. element.

(7) An electrode is formed on an uppermost layer surface of the ridge, and a second insulating film is formed on a side surface of the ridge and a surface of the first insulating film. The nitride semiconductor laser device according to any one of (1) to (6). (8) The nitride semiconductor laser device according to any one of (1) to (7), wherein the nitride semiconductor is formed by stacking a nitride semiconductor on a substrate containing at least epitaxially grown GaN. Nitride semiconductor laser device.

That is, according to the present invention, a first insulating film having a stripe-shaped opening is formed on a first p-type nitride semiconductor layer formed on an active layer. The second p-type nitride semiconductor layer is selectively grown from the opening. That is, in the nitride semiconductor laser device, it is not necessary to form a ridge by etching, and a desired refractive index difference can be obtained only by stacking nitride semiconductor layers. Further, an element having a better single-transverse mode with a higher yield than forming a ridge by etching and having a good FFP can be obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a nitride semiconductor laser device according to the present invention, a first insulating film formed on a first p-type nitride semiconductor layer is formed in a stripe shape having an opening so that the first insulating film has a first shape.
The second p-type nitride semiconductor layer after the formation of the insulating film
When growing by E (metal organic chemical vapor deposition), the nitride semiconductor is selectively grown upward (in the stacking direction) from the opening between the insulating films. By selective growth, the nitride semiconductor is already in a ridge shape without etching, and the FFP is formed without forming a new ridge.
(Far field pattern) can obtain a good single transverse mode. The width of the opening between the insulating films is 3 μm or less. If it is larger than 3 μm, the oscillation will be not a single transverse mode but a multimode. Further, it is desirable that the width of the opening be 1 μm or more and 2 μm or less.

In the present invention, the thickness of the first insulating film is preferably not less than 10 Å and not more than 0.5 μm.
Or less, preferably 10 angstrom or more,
1 μm or less. Thus, the thinner the first insulating film, the better. When the first insulating film is formed thick, when a second p-type nitride semiconductor is grown by MOVPE, a raw material gas, a carrier gas, or the like efficiently hits an opening between the insulating films. It disappears and crystallinity deteriorates.

In the present invention, it is desirable that the stripe width of the first insulating film is not less than 2 μm and not more than 200 μm. The reason why the stripe width is set to 2 μm or more is to make the end portion of the p-electrode be on the insulating film when the ridge-shaped nitride nitride semiconductor is covered with the p-electrode. If the stripe width is small, the p-electrode covers the entire first insulating film, and the end of the p-electrode may reach the first p-type nitride semiconductor under the first insulating film. If it does, it will not oscillate as a laser. More preferably, the stripe width is 10 μm or more. When the stripe width is larger than 200 μm, when the second nitride semiconductor is formed, not only the nitride semiconductor is selectively grown from the opening of the first insulating film, but also the first nitride semiconductor is formed.
The nitride semiconductor grows also on the insulating film. The nitride semiconductor grown on the insulating film has very many dislocations and is combined with the selectively grown nitride semiconductor. If the nitride semiconductor on the insulating film is not etched, the nitride semiconductor does not have a ridge shape. It is not preferable.

The first insulating film is capable of withstanding a MOVPE reaction atmosphere. As a material satisfying this condition, for example, SiON (SiN, SiO ₂
Compound), SiN, SiO _2, etc., and any substance may be used, but SiON is preferably used. SiON is a very chemically stable substance, and decomposition does not occur even if this film is extremely thin.

The second insulating film formed on the side surface of the ridge and the surface of the first insulating film may be made of a material having a refractive index smaller than that of GaN, such as ZrO ₂ or SiO _2. Examples include ZrO ₂ . This material determines the effective refractive index difference between the active layer portion immediately below the ridge and the other active layer portions.

The p-type light guide layer has at least Al _x
It has a Ga _1-X N (0 ≦ X <1) layer, and the p-type cladding layer has at least Al _Y Ga _1-Y N (0 ≦ Y <1 and X <
Y), for example, both of which have a structure as in the embodiment described later. Some or all of these layers cause the wafer to be once out of the MOVPE reactor in order to form a striped first insulating film before they are formed. Sex is slightly worse. However, up to the active layer, the crystallinity is good and there are almost no dislocations.
This can sufficiently achieve the object of the present invention in which a single transverse mode in which the FFP is good even at a high output.

Further, the structure of the nitride semiconductor device according to one embodiment of the present invention will be described below with reference to FIG. 1 which is a schematic sectional view of the nitride semiconductor device. FIG. 1 shows a sapphire substrate 1, a nitride semiconductor substrate 2, an n-type contact layer 3, an n-type cladding layer 4, an n-type light guide layer 5, an active layer 6, a p-side cap layer 7, and a p-type light guide layer 8. , A p-type cladding layer 9 and a p-type contact layer 10 are sequentially laminated. Further, an n-ohmic electrode 20 and an n-pad electrode 21 are formed on the n-type
A p-ohmic electrode 22 and a p-pad electrode 23 are formed thereon.

In the present invention, the substrate is, for example, C
Sapphire having any one of a surface, an R surface and an A surface as a main surface,
Conventionally known substrate materials such as an insulating substrate such as spinel (MgA1 ₂ O ₄ ) and an oxide substrate lattice-matched with a nitride semiconductor may be used, or an off-angle substrate may be used. Further, these substrate materials can also be used as heterogeneous substrates used in selective growth described later.

In the present invention, the substrate is made of a material having the above-mentioned substrate material and a nitride semiconductor having few dislocations selectively grown thereon by utilizing lateral growth of the nitride semiconductor. be able to.

As a method of selective growth of a nitride semiconductor,
There is no particular limitation, as long as the method can reduce crystal dislocation of the nitride semiconductor. For example, in J. J. A. P. And Japanese Patent Application No. 10-77245 filed by the present applicant.
No., Japanese Patent Application No. 10-275826, Japanese Patent Application No. 10-363.
No. 520, and the like, and the like. ELOG (Epitaxial Latera
l Overgrowth GaN) is obtained.

In the present invention, it is desirable to use this ELOG substrate. By using an ELOG substrate, a nitride semiconductor having very few crystal dislocations can be obtained at least up to the first p-type GaN, and a nitride semiconductor laser having high output and excellent characteristics can be obtained.

Further, in the present invention, other active layers,
The device structure such as the cladding layer is not particularly limited, and various layer structures can be used. As a specific embodiment of the device structure, for example, there is a device structure described in an example described later. Also, the electrodes and the like are not particularly limited, and various types can be used.
In the present invention, the nitride semiconductor is grown by MOVPE, M
All known methods for growing a nitride semiconductor, such as OCVD (metal organic chemical vapor deposition), HVPE (halide vapor deposition), and MBE (molecular beam vapor deposition), can be applied.

[0023]

Example 1 (Nitride Semiconductor Substrate 2) As shown in FIG. 1, a sapphire substrate 1 having a main surface C as an orientation flat surface was prepared. Is set in a MOCVD reaction vessel, and a layer made of undoped GaN at 500 ° C. as an underlayer is 200 Å,
Subsequently, a layer of undoped GaN is formed at 1050 ° C. to form a nitride semiconductor layer having a thickness of 2.5 μm and a total thickness of about 2.5 μm.

Next, after growing a nitride semiconductor layer, a stripe-shaped photomask is formed on the surface of the nitride semiconductor layer, and a stripe width of 10 μm and a window portion of 5 μm are formed by a CVD apparatus.
A protective film made of m ₂ SiO ₂ is formed with a thickness of 0.5 μm. At this time, the stripe direction is formed perpendicular to the orientation flat surface.

Subsequently, the GaN in the portion where the SiO ₂ film is not formed is etched by the RIE apparatus until the sapphire substrate is exposed, thereby forming irregularities.
Is striped, and finally SiO ₂ on the upper part of the protrusion is removed.

After the formation of the striped GaN, the wafer is transferred to a reaction vessel and, at 1050 ° C., TMG is added to the source gas.
Using (trimethylgallium) and ammonia, a second nitride semiconductor layer made of undoped GaN is grown to a thickness of 15 μm. Thus, a nitride semiconductor substrate (ELOG substrate) 2 is obtained.

(N-type contact layer 3) Next, on the obtained nitride semiconductor substrate 2, TMG, ammonia, and silane gas as an impurity gas were used, and 1 × 10 ¹⁸ Si at 1050 ° C.
/ Cm ³ doped GaN n-type contact layer 3
Is grown to a thickness of 4.5 μm.

(N-type cladding layer 4)
0 ° C, undoped Al using TMA (trimethylaluminum), TMG and ammonia as source gas
An A layer of GaN is grown to a thickness of 25 Å, and then TMA is stopped, G is doped with Si at 5 × 10 ¹⁸ / cm ³ using silane gas as an impurity gas.
A B layer of aN is grown to a thickness of 25 Å. This operation is repeated 160 times to laminate the A layer and the B layer to grow the n-type cladding layer 4 composed of a multilayer film (superlattice structure) having a total film thickness of 8000 Å.

(N-type light guide layer 5) Next, at the same temperature, an N-type light guide layer 5 made of undoped GaN is grown to a thickness of 750 angstroms using TMG and ammonia as source gases.

(Active Layer 6) Next, the temperature was raised to 800 ° C., and TMI (trimethylindium), TM
G and ammonia, silane gas as an impurity gas, and InGa doped with 5 × 10 ¹⁸ / cm ^{3 of} Si.
A N barrier layer is grown to a thickness of 100 Å. Subsequently, the silane gas is stopped and the undoped I
A well layer of nGaN is grown to a thickness of 50 Å. This operation is repeated three times, and finally, the active layer 6 having a multiple quantum well structure (MQW) having a total film thickness of 550 Å, on which the barrier layers are stacked, is grown.

(P-side cap layer 7) Next, at the same temperature, using TMA, TMG and ammonia
Using Cp ₂ Mg (cyclopentadienyl magnesium) as an impurity gas, a p-side cap layer 7 made of AlGaN doped with 1 × 10 ¹⁹ / cm ^{3 of} Mg is grown to a thickness of 100 Å.

(P-type light guide layer 8)
0 ° C, using TMG and ammonia as raw material gas,
The p-type light guide layer 9 made of undoped GaN is 750
It is grown to a thickness of Å. The p-type light guide layer 8 is grown as undoped, but the Mg concentration is 5 × 10 ¹⁶ due to the diffusion of Mg from the p-side cap layer 7.
/ Cm ³ , indicating p-type. This layer is intentionally made of Mg
May be doped. After stacking the above layers, the wafer is taken out of the MOVPE reaction vessel.

(First Insulating Film 30) Next, the wafer is transferred to a CVD apparatus, and a first insulating film 30 made of SiON is formed in a stripe shape perpendicular to the orientation flat surface of sapphire. This insulating film 30 has a stripe width of 10 using a mask technique.
μm, the opening is 1.5 μm, and the film thickness is 500 Å.

(P-type cladding layer 9) Next, the substrate is taken out of the CVD apparatus, set again in the MOVPE reaction vessel, the temperature is raised to 1050 ° C., and TMA, TMG and ammonia are used as raw material gases, and A is made of undoped AlGaN. A layer is grown to a thickness of 25 Å, followed by T
Stopping MA, using Cp ₂ Mg as an impurity gas,
Is grown at a thickness of 25 angstroms from a B layer made of GaN doped with 5 × 10 ¹⁸ / cm ³ . This operation is repeated 100 times to laminate the A layer and the B layer, thereby growing the p-type cladding layer 9 composed of a multilayer film (superlattice structure) having a total thickness of 5000 Å.

(P-type contact layer 10) Next, at the same temperature, TMG and ammonia are used as source gases, Cp ₂ Mg is used as an impurity gas, and Mg is 1 × 10 ²⁰ / cm ^3.
The p-type contact layer 10 made of doped GaN is
It is grown to a thickness of 0 Å.

After the reaction is completed, the wafer is annealed in a nitrogen atmosphere at 700 ° C.
The resistance of the mold layer is further reduced. After annealing, the wafer is taken out of the reaction vessel, and the surface of the n-type contact layer 3 on which the n-electrode is to be formed is exposed using RIE (reactive ion etching).

Further, a p-ohmic electrode 22 and a p-pad electrode 23, an n-ohmic electrode 20 and an n-pad electrode 21 are provided on each contact layer, and a ZrO ₂ is formed as the second insulating film 31. When a Zr oxide is formed as the second insulating film, not only can the pn surface be insulated, but also the
This is preferable because the transverse mode can be stabilized.

As described above, the sapphire substrate of the wafer on which the n-electrode and the p-electrode are formed is polished to 70 μm, and then cleaved in a bar shape from the substrate side in a direction perpendicular to the stripe-shaped electrodes. A resonator is formed on a cleavage plane (11-00 plane, a plane corresponding to the side surface of a hexagonal columnar crystal = M plane).
A dielectric multilayer film made of SiO ₂ and TiO ₂ is formed on the cavity surface, and finally, the bar is cut in a direction parallel to the p-electrode to obtain a laser device as shown in FIG. The obtained laser element was set on a heat sink, and the respective electrodes were wire-bonded, and laser oscillation was attempted at room temperature.

As a result, the threshold voltage of 2.0 k
A / cm ² , 405n oscillation wavelength at 30mW output
m continuous oscillation was confirmed, a life of 1000 hours or more was exhibited, and the yield was further improved.

[Embodiment 2] In the embodiment 1, the active layer 6
And, the layers up to the p-side cap layer 7 are formed in the same manner. (P-type light guide layer 8 and first insulating film 30) Next, the temperature is set to 1050 ° C., TMG and ammonia are used as source gases, and 50 parts of undoped GaN are used as a part of the p-type light guide layer 8. It is grown to a thickness of Å.

After laminating a part of the p-type light guide layer, the wafer is taken out of the MOVPE reaction vessel. Subsequently, the wafer is transferred to a CVD apparatus, and the first wafer made of SiON is formed.
The insulating film 30 is formed in a stripe shape perpendicular to the orientation flat surface of sapphire. This insulating film 30 has a stripe width of 10 μm, an opening of 1.5 μm,
The thickness is set to 500 angstroms.

Further, after being taken out of the CVD apparatus, M
Set in an OVPE reactor and add undoped GaN to 7
It is grown to a thickness of 00 Å. As a result, undoped GaN is selectively grown from the openings of the insulating film formed in a stripe shape, so that the p-type light guide layer is a layer having a total film thickness of 750 angstroms partially sandwiching the insulating film.

Hereinafter, a laser device is obtained in the same manner as in Example 1 after the p-type cladding layer. Example 1
Similarly, at room temperature, the threshold value is 2.0 kA / cm ² ,
At an output of 0 mW, continuous oscillation of an oscillation wavelength of 405 nm was confirmed, and a life of 1000 hours or more was shown.

Example 3 A laser device was fabricated in the same manner as in Example 1, except that the thickness of the first insulating film 30 was changed to 1000 Å. At room temperature, with a threshold value of 2.3 kA / cm ² and an output of 30 mW, continuous oscillation of an oscillation wavelength of 405 nm was confirmed, and a life of 800 hours or more was shown.

Example 4 A laser device was manufactured in the same manner as in Example 1, except that the opening of the first insulating film 30 formed in a stripe shape was 2 μm. As a result, continuous oscillation with an oscillation wavelength of 405 nm was confirmed at a threshold of 2.5 kA / cm ² and an output of 30 mW, indicating a life of 800 hours or more.

Example 5 A laser device was fabricated in the same manner as in Example 1, except that the first insulating film 30 was made of SiN. As a result, a threshold value of 2.5 k
A / cm ² , 405n oscillation wavelength at 30mW output
m continuous oscillation was confirmed, indicating a life of 1000 hours or more.

[Embodiment 6] In Embodiment 1, the sapphire substrate used in fabricating the nitride semiconductor is formed such that the C surface is a main surface and the A surface is an orientation flat surface. And the off angle is 0.1
A substrate is used in which the direction along the step (step direction) is perpendicular to the A-plane at 3 °. Otherwise, a laser device is obtained in the same manner as in the first embodiment. As a result, continuous oscillation with an oscillation wavelength of 405 nm was confirmed at room temperature with a threshold value of 1.8 kA / cm ² and an output of 30 mW, indicating a life of 1000 hours or more.

Example 7 A laser device was manufactured in the same manner as in Example 1, except that the nitride semiconductor substrate was changed as follows. (Nitride Semiconductor Substrate 2) As shown in FIG. 1, a sapphire substrate 1 having a main surface C as an orientation flat surface is prepared. First, the sapphire substrate 1 is set in a MOCVD reactor. A layer made of undoped GaN at 500 ° C. as an underlayer and 200 angstrom;
Subsequently, a layer of undoped GaN is formed at 1050 ° C. to form a nitride semiconductor layer having a thickness of 2.5 μm and a total thickness of about 2.5 μm.

Next, a striped photomask is formed, and a stripe width of 10 μm and a window of 2 μm are formed by a CVD apparatus.
A protective film made of m ₂ SiO ₂ is formed with a thickness of 0.5 μm. The stripe direction is formed in a direction perpendicular to the orientation flat surface. After the formation of the protective film, the wafer was transferred to a MOVPE reaction vessel, and a nitride semiconductor layer made of undoped GaN was grown to a thickness of 15 μm at 1050 ° C. using TMG and ammonia as source gases. Substrate.

Otherwise, a laser device is obtained in the same manner as in the first embodiment. As a result, at room temperature, the threshold value was 2.0 kA /
cm ^2, continuous oscillation of an oscillation wavelength 405nm at the output of 30mW is confirmed, it showed 1000 hours or more life.

Example 8 A laser device was fabricated in the same manner as in Example 1, except that the nitride semiconductor substrate and the electrodes were changed as follows. (Nitride semiconductor substrate 2 ') MOV is formed on a sapphire substrate whose main surface is C surface where A surface is formed as an orientation flat surface.
A layer of undoped GaN at 200 ° C. in a PE reactor at 200 Å followed by 1050 ° C.
Then, a layer of undoped GaN is formed to a thickness of 2.5 μm to form a nitride semiconductor layer having a total thickness of about 2.5 μm.

Next, after growing a nitride semiconductor layer, a stripe-shaped photomask is formed on the surface of the nitride semiconductor layer, and a stripe width of 10 μm and a window portion of 5 μm are formed by a CVD apparatus.
A protective film made of m ₂ SiO ₂ is formed with a thickness of 0.5 μm. At this time, the stripe direction is formed perpendicular to the orientation flat surface.

Subsequently, the GaN in the portion where the SiO ₂ film is not formed is etched by the RIE apparatus until the sapphire substrate is exposed, thereby forming irregularities.
Is striped, and finally SiO ₂ on the upper part of the protrusion is removed.

After the stripe-shaped GaN is formed, the wafer is transferred to a MOVPE reactor, and at 1050 ° C., a second nitride semiconductor layer made of undoped GaN is formed using TMG (trimethylgallium) and ammonia as a source gas. It is grown to a thickness of 15 μm. Then, HVPE 1
A 50 μm-thick Si-doped GaN is produced. Next, the sapphire substrate of the obtained wafer and the undoped GaN layer produced by MOVPE were polished and removed to obtain a GaN substrate 2 ′ having a thickness of about 100 μm.

On the obtained GaN substrate 2 ′, from the n-type contact layer 3 to the p-type contact layer 10 are formed in the same manner as in the first embodiment. After the completion of the reaction, the wafer is annealed at 700 ° C. in a nitrogen atmosphere in a reaction vessel to further reduce the resistance of the p-type layer.

After annealing, the wafer is taken out of the reaction vessel, and the p-type ohmic electrode 22 is placed on the p-type contact layer.
And the p-pad electrode 23 with the other ridge side surfaces and the first
ZrO ₂ is formed as a _second insulating film 31 on the surface of the insulating film, and the surface on which the element structure of the nitride semiconductor is not formed is polished to a total film thickness of 100 μm to 200 μm.
An n-ohmic electrode 20 and an n-pad electrode 21 are formed on the entire polished surface.

As described above, the wafer on which the n-electrode and the p-electrode are formed is cleaved in a bar shape in a direction perpendicular to the stripe-shaped electrodes, and a resonator is formed on the cleavage plane (M plane). A dielectric multilayer film made of SiO ₂ and TiO ₂ is formed on the resonator surface, and finally, the bar is cut in a direction parallel to the p-electrode to obtain a structure shown in FIG.
The laser element shown in FIG. The obtained laser element was set on a heat sink, and the respective electrodes were wire-bonded, and laser oscillation was attempted at room temperature.

As a result, as in Example 1, continuous oscillation with an oscillation wavelength of 405 nm was confirmed at room temperature with a threshold value of 2.0 kA / cm ² and an output of 30 mW.
It showed a lifetime of more than hours.

[0059]

According to the device structure of the present invention, it is possible to obtain a nitride semiconductor laser device having a single transverse mode with a good yield and a good FFP even in a high output type.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a nitride semiconductor laser device according to one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a nitride semiconductor laser device according to another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing a nitride semiconductor laser device according to another embodiment of the present invention.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 ... Sapphire substrate 2 ... Nitride semiconductor substrate 3 ... N-type contact layer 4 ... N-type cladding layer 5 ... N-type light guide layer 6 ... Active layer 7 ... p Side cap layer 8 ... p-type light guide layer 9 ... p-type cladding layer 10 ... p-type contact layer 20 ... n ohmic electrode 21 ... n pad electrode 22 ... p ohmic electrode 23 ... p pad electrode 30 ... first insulating film 31 ... second insulating film

Claims (8)

[Claims] 1. A first insulating film having a stripe-shaped opening is formed on a first p-type nitride semiconductor layer formed on an active layer, and a second p-type insulating film is formed from the opening. A nitride semiconductor laser device comprising: a nitride semiconductor layer; and a ridge formed by the second p-type nitride semiconductor. 2. A semiconductor device comprising: a first p-type nitride semiconductor layer;
2. The nitride semiconductor laser device according to claim 1, wherein the type nitride semiconductor layers have the same composition. 3. The nitride semiconductor laser device according to claim 1, wherein said stripe-shaped opening is 3 μm or less. Wherein said first p-type nitride semiconductor layer is Al _X G
a _1-X An optical guide layer having an N (0 ≦ X <1) layer,
The second p-type nitride semiconductor layer is composed of Al _Y Ga _1-Y N (0 ≦ Y <
4. The nitride semiconductor laser device according to claim 1, wherein the nitride semiconductor laser device is a cladding layer having the following formula: 1 and X <Y). 5. 5. A method according to claim wherein said first and second p-type nitride semiconductor layer is the optical guide layer having both _{Al X Ga 1-X N (} 0 ≦ X <1) layer The nitride semiconductor laser device according to claim 2 or claim 3. 6. The first insulating film has a stripe width of 2 μm.
6. The nitride semiconductor laser device according to claim 1, wherein the nitride semiconductor laser device has a thickness of at least 200 μm and a thickness of 0.5 μm or less. 7. 7. An electrode is formed on a top surface of the ridge, and a second electrode is formed on a side surface of the ridge and a surface of the first insulating film.
7. The nitride semiconductor laser device according to claim 1, wherein said insulating film is formed. 8. The nitride semiconductor laser device according to claim 1, wherein a nitride semiconductor is laminated on a substrate containing at least epitaxially grown GaN. Item 6. The nitride semiconductor laser device according to item 1.