JP2000252589A - Gallium nitride semiconductor laser element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the yield rate of gallium nitride semiconductor laser elements of a low oscillation threshold current by making specific an angle formed by the end surface of a resonator and the direction of the current constricting stripes of an active layer, and the full width at half maximum of the intensity distribution of a laser beam in a direction parallel to the active layer respectively. SOLUTION: A crack preventing layer 3 is a ternary mixed crystal of In0.1Ga0.9N or InGaN other than this. An n-type clad layer 4 and a p-type first clad layer 11 are AlGaN ternary mixed crystals having Al composition other than Al0.1Ga0.9N. When the Al composition is larger, the energy gap difference and the refractive index difference between an active layer and a clad layer become larger, and carriers and light are effectively confined to the active layer, and an oscillation threshold current is reduced and the temperature property is improved. If stripes of ridge construction are aligned and the angle of a tilt formed by the direction of ridge stripes of each resonator and the end surface of the resonator is made to be in the extent of 90±0.1 degrees for both resonators, it is within the scope of 90±0.3 degrees in which an excellent property is shown. The yield rate can be increased by making the half value width of a laser beam intensity distribution 3 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gallium nitride based semiconductor laser device used as a light source for optical information processing of an optical disk or the like.

[0002]

2. Description of the Related Art As a semiconductor material of a semiconductor laser device (LD) having an emission wavelength in the ultraviolet to green wavelength range,
Gallium nitride based semiconductor (GaInAlN) is used. Semiconductor laser devices using this gallium nitride based semiconductor are, for example, PROCEEDINGS of The Second Inte
rnational Conference on Nitride Semiconductors
(ICNS'97) S-1, and a cross-sectional view thereof is shown in FIG. 9, 201 is a sapphire substrate, 202 is a GaN buffer layer, 203 is a GaN layer, 2
04 is a SiO ₂ film, 205 is a GaN layer, 206 is n-G
aN contact layer, 207 is an n-In _0.1 Ga _0.9 N layer,
Reference _numeral 208 denotes an n-type clad layer in which n-Al _0.14 Ga _0.86 N and GaN are alternately stacked, 209 denotes an n-GaN guide layer, 210 denotes an In _0.15 Ga _0.85 N quantum well layer and In _0.02
A multiple quantum well structure active layer comprising a Ga _0.98 N barrier layer,
211 is a p-Al _0.2 Ga _0.8 N layer, 212 is p-GaN
The guide layer 213 is a p-type clad layer in which p-Al _0.14 Ga _0.86 N and GaN are alternately stacked, and 214 is p-G
An aN contact layer, 215 is a p-side electrode, 216 is an n-side electrode, and 217 is a current constriction SiO ₂ film. Where S
The iO ₂ film 204 is 12 μm in a stripe shape having a width of 8 μm.
It is formed in a cycle. The multiple quantum well structure active layer 210 is composed of four In _0.15 Ga _0.85 N quantum well layers having a thickness of 3.5 nm, and three In _0.02 Ga _0.98 N barrier layers having a thickness of 10.5 nm, for a total of seven layers. The quantum well layers and the barrier layers are formed alternately.

In this conventional manufacturing method, a GaN buffer layer 202 and a GaN layer 203 are formed on a sapphire substrate 201, and then an SiO ₂ film 204 is formed in a stripe shape. Layer 21
4 are stacked. Further, in this conventional example, the p-type cladding layer 2 is formed to narrow the injection current.
13 and the p-GaN contact layer 214 are formed in a ridge stripe shape. Thus, the stripe-shaped region into which current is injected becomes an active region. After that, the end face of the resonator is formed by using a dry etching technique.

However, in the case of forming the cavity end face by using the dry etching technique as in this conventional example,
There have been concerns that it is difficult to accurately form the resonator end face perpendicular to the layer thickness direction, and that the end face may be uneven. Such a deviation or irregularity in the perpendicularity lowers the reflectance at the end face of the resonator, so that there is a problem that the loss of laser light increases and the oscillation threshold current value increases. So, PROCEEDINGS of The Second
International Conference on Nitride Semiconduc
In tors (ICNS'97) S-6, the influence of the tilt angle of the resonator end face formed by etching with respect to the layer thickness direction on the reflectivity and the unevenness when the end face unevenness is assumed to be formed completely at random. The effect of the magnitude of the root mean square on the reflectivity is calculated, and the requirements of the cavity facet necessary for obtaining laser oscillation are described. It shows that if the tilt angle with respect to the layer thickness direction is 4 degrees or less, the amount of decrease in reflectance can be suppressed to 40% or less. Further, regarding the unevenness of the end face, it is shown that if the magnitude of the root mean square of the unevenness assuming that the unevenness is formed completely at all is 10 nm or less, the decrease in the reflectance can be suppressed to 40% or less. I have. Therefore, in a conventional gallium nitride based semiconductor laser device, etching conditions are selected with this value as a target, and a decrease in reflectance has been suppressed.

On the other hand, attempts have been made to form the end face of the resonator by cleavage.
Japanese Journal of Applied Physics, Vol.35, Par
t2, No. 10B, pp. L1315 (1996). FIG. 10 shows a cross-sectional view thereof. In FIG. 10, 221 is a sapphire substrate having a (0001) c-plane on the surface, 222 is a non-doped GaN layer, and 223 is n-G
aN contact layer, 224 is an n-Al _0.15 Ga _0.85 N cladding layer, 225 is a non-doped GaN light guide layer, 22
Reference numeral 6 denotes a 25-nm thick In _0.15 Ga _0.85 N quantum well layer.
Layers and a 4 nm thick In _0.05 Ga _0.95 N separating them
The multiple quantum well structure active layer comprising a barrier layer and 227
-GaN optical guide layer, 228 is p-Al _0.15 Ga _0.85 N
A clad layer, 229 is a p-GaN contact layer, 230
Is a p-side electrode, 231 is an n-side electrode, and 232 is an S for current constriction.
iO ₂ film. In this conventional example, stripes are provided on the SiO ₂ film 232 to narrow the injection current, and thereafter, the end face of the resonator is formed by using a cleavage technique. However, even when the cavity facet is formed by using the cleavage technique as in this conventional example, it is described that it is difficult to form the cavity facet exactly perpendicularly to the layer thickness direction. PROCEEDINGS of The Second
International Conference on Nitride Semicond
Similarly to uctors (ISCN'97) S-6, the effect of the tilt angle of the resonator end face with respect to the layer thickness direction on the reflectance was calculated, and the requirements for the resonator end face necessary for obtaining laser oscillation were described. I have. In this conventional example, the tilt angle of the end face of the resonator with respect to the layer thickness direction is about 2 °. Thus, by reducing the tilt angle of the end face of the resonator with respect to the layer thickness direction, a decrease in reflectance is reduced. It is shown that it is suppressed.

In addition, Japanese Patent Application Laid-Open No. 10-173282 discloses a semiconductor laser device using a gallium nitride-based semiconductor in which one of a pair of cavity facets is formed by a dry etching technique and the other is formed by a cleavage technique. Is described.

[0007]

However, the conventional semiconductor laser device using the gallium nitride based semiconductor has the following problems. That is, even if the tilt angle of the resonator end face with respect to the layer thickness direction and the size of the root mean square of random irregularities on the end face are taken into consideration as in the conventional example,
Although the present inventors have repeatedly studied, it has been difficult to obtain a laser element having a low oscillation threshold current value with good yield.

The present invention has been made in view of such circumstances, and solves the above-mentioned problems in the gallium nitride-based semiconductor laser device, and provides a gallium nitride-based semiconductor laser device having a low oscillation threshold current value with a good yield. The purpose is to provide.

[0009]

As a result of repeated studies, the present inventor has found that the active region is formed in a stripe shape in a normal gallium nitride based semiconductor laser device. It has been found that the angle formed by the above has a great effect on obtaining a laser device having a low oscillation threshold current value with good yield.

Further, the cavity end face of the gallium nitride based semiconductor laser device is not formed with completely random irregularities as shown in the conventional example, but has periodic irregularities having a period of about 2 to 3 μm. Has been found.

In view of these points, in order to solve the above problems, a gallium nitride based semiconductor light emitting device according to the present invention comprises the following invention.

According to the first aspect of the present invention, an active layer made of a nitride semiconductor is sandwiched between a clad layer and / or a guide layer made of a nitride semiconductor on a substrate, and a current is confined in the active layer. In the semiconductor laser device provided with the striped active region, the angle between the stripe direction of the striped active region and the end face of the resonator is 90 degrees.
A gallium nitride based semiconductor laser, wherein the full width at half maximum of the intensity distribution of the laser beam in the direction parallel to the active layer in the stripe-shaped active region is within 0.3 ° and 3 μm or less. Element.

According to a second aspect of the present invention, an active layer made of a nitride semiconductor is sandwiched between a clad layer and / or a guide layer made of a nitride semiconductor on a substrate, and a current is confined in the active layer. In the semiconductor laser device provided with the striped active region, the difference between the peaks and valleys of the concavo-convex on the cavity end face within the range of the stripe-shaped active region is 25 nm.
The gallium nitride based semiconductor laser device is as follows.

According to a third aspect of the present invention, there is provided the gallium nitride-based system, wherein the full width at half maximum of the intensity distribution of the laser light in the direction parallel to the active layer in the stripe-shaped active region is 0.5 μm or more. It is a semiconductor laser device.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor laser device having a semiconductor laminated structure including an active layer made of a nitride semiconductor sandwiched between a clad layer and / or a guide layer made of a nitride semiconductor. Laminating the nitride-based semiconductor laminated structure on a substrate to form a wafer, cleaving the wafer to form a linear side, and parallel to the linear side formed by the cleavage. Or, vertically, forming a stripe-shaped active region,
Forming a cavity end face by cleaving the stripe-shaped active region in a direction perpendicular to a stripe direction of the stripe-shaped active region.

According to the present invention, in a gallium nitride based semiconductor laser device having an active region formed in a stripe shape, the tilt angle between the stripe direction of the stripe active region and the end face of the resonator is 90 degrees ± 0.3. Within this range, a semiconductor laser device having a low oscillation threshold current value with good yield can be obtained.

FIG. 4 is a diagram showing the stripe-shaped active region 100 and the cavity end face 101 as viewed from the surface of the semiconductor laser device. Here, as shown in FIG. 4, the X-axis is taken in a direction perpendicular to the stripe-shaped active region 100, and assuming that the tilt angle between the X-axis and the resonator end face 101 is θ, the amount of decrease in reflectance R / R ₀ Is represented by the following equation.

[0018]

(Equation 1)

Here, u ₀ (x) is a function representing the intensity distribution of the laser light, and β is the propagation constant of this laser light. FIG. 5 shows the result of calculating the dependence of the reflectivity reduction R / R _{0 on} the tilt angle θ with respect to the full width at half maximum of various laser light intensity distributions. It can be seen from FIG. 5 that even if the angle between the stripe direction of the stripe-shaped active region and the end face of the resonator deviates from 90 degrees to within 1 degree, the reflectance is greatly reduced. Therefore, it can be seen that the tilt angle between the stripe direction of the stripe-shaped active region and the resonator end face has a far greater effect than the tilt angle of the resonator end face with respect to the layer thickness direction. Also, from FIG. 5, for the full width at half maximum of the intensity distribution of various laser beams,
If the tilt angle is 0.3 degrees or less, the reflectivity does not become 0, and it becomes possible to function as a resonator end face.

FIG. 6 is a graph showing a change in the oscillation threshold current value due to a decrease in the reflectance. As a result, when the reflectance at the resonance end face of the gallium nitride based semiconductor laser device having the reflectance R ₀ of 0.5 decreases due to the tilt or unevenness of the resonator end face, the oscillation threshold current value increases and the reflectance becomes R _0. It can be seen that the oscillation threshold current value becomes about twice as large when the value becomes half. Accordingly, it is preferable to reduce the amount of decrease in the reflectance of the end face of the resonator. The present inventor has found that this decrease in reflectivity is greatly affected by the full width at half maximum of the intensity distribution of the laser beam. As a result, as can be seen from FIG. 5, the narrower the laser beam intensity distribution, the more the amount of decrease in reflectance is suppressed, and
The full width at half maximum of the laser light intensity distribution in the direction parallel to the active layer is preferably 3 μm or less. As a result, the amount of decrease in reflectance can be suppressed to 40% or less, and a gallium nitride based semiconductor laser device having a low oscillation threshold current value can be obtained.

In the conventional gallium nitride based semiconductor laser device, since the tilt angle between the direction of the stripe and the end face of the resonator is not considered at all, this angle is 90 degrees ±
In some cases, the semiconductor laser device is manufactured beyond the range of 0.3 degrees, which makes it difficult to obtain a semiconductor laser device having a low oscillation threshold current value with good yield. Therefore,
According to the present invention, it has become possible to obtain a semiconductor laser device having a low oscillation threshold current value with good yield.

Further, according to the present invention, in a semiconductor laser having an active region formed in a stripe shape, the difference between the peaks and valleys of the concave and convex of the cavity end face within the range of the stripe active region is set to 25 nm or less. Thus, a semiconductor laser device having a low oscillation threshold current value with a high yield can be obtained.
FIG. 7 shows a view of the semiconductor laser device from the surface, showing the stripe-shaped active region 110 and the cavity end face 111 on which the unevenness is formed.

Here, as shown in FIG.
Assuming that the X-axis is taken in a direction perpendicular to the axis 10 and the function representing the magnitude of the deviation between the X-axis and the cavity facet 111 is φ (X), the amount of decrease in reflectance R / R due to this φ (X) ₀ is represented by the following equation.

[0024]

(Equation 2)

Here, φ (X) has a period of 2 μm to 3 μm.
This is a periodic function of about m, and is represented by a trigonometric function where the amplitude is D. Twice the amplitude D represents the difference between the peaks and valleys of the periodic unevenness. FIG. 8 shows the result of calculating the dependence of the reflectance reduction R / R _{0 on} the amplitude D. This graph shows almost the same result with respect to the period of the trigonometric function when the period is within the range of 2 μm to 3 μm. As can be seen from this figure, the periodic unevenness of the cavity end face can suppress the decrease in the reflectance to 40% or less if the difference between the peak and the valley is 25 nm or less, and reduce the oscillation threshold current value to a low value. A gallium-based semiconductor laser device can be obtained. On the other hand, the graph of FIG. 8 hardly changes even with respect to the full width at half maximum of the intensity distribution of the laser light, but the full width at half maximum of the intensity distribution of the laser light becomes very narrow, and the period of the unevenness of the cavity end face becomes one quarter. When the value is about 1, the resonator end face is tilted with respect to the stripe direction of the stripe-shaped active region. Therefore, it is preferable that the full width at half maximum of the intensity distribution of the laser beam in the direction parallel to the active layer is wider than a quarter of the period of the unevenness. Specifically, since periodic irregularities on the cavity end face are observed at about 2 μm to 3 μm, the full width at half maximum of the laser light intensity distribution is 0.5 μm.
It is preferably wider than μm.

Further, according to the present invention, at least one of the sides around the substrate is a straight side formed by cleavage, so that a stripe-shaped active region can be formed based on the straight side. Therefore, the tilt angle between the stripe direction of the stripe-shaped active region and the end face of the resonator can be accurately controlled.

As a result, two points, the tilt angle between the stripe direction of the stripe active region and the cavity facet, and the size of the periodic irregularities on the cavity facet, which have not been taken into consideration at all, have been considered. By taking this into consideration, it becomes possible to provide a gallium nitride based semiconductor laser device having a low oscillation threshold current value with good yield.

The decrease in the reflectivity of the cavity surface due to the tilt angle between the stripe direction of the stripe-shaped active region and the cavity facet and the size of the periodic irregularities on the cavity facet are caused by the above-mentioned factors. From the expression representing the amount of decrease in reflectivity, the shorter the laser emission wavelength is, the larger the decrease is, so that the present invention is particularly effective for gallium nitride based semiconductor laser devices having an emission wavelength of about 400 nm to 500 nm. I can say.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to specific examples. (First Embodiment) FIG. 1 is a sectional view showing a gallium nitride based semiconductor laser device according to a first embodiment of the present invention. In this figure, 1 is n-GaN having a c-plane as a surface
Substrate, 2 n-GaN layer, 3 n-In _0.1 Ga _0.9 N anti-cracking layer, the n-Al _0.1 Ga _0.9 Nn type cladding layer 4, 5 is n-GaN guide layer, an In _0.15 of 6 2 layers Ga
_An active layer having a multiple quantum well structure including a _0.85 N quantum well layer and three In _0.03 Ga _0.97 N barrier layers, and 7 is Al _0.2 Ga _0.8
N evaporation prevention layer, 8 is a p-GaN guide layer, 9 is p-Al
_0.1 Ga _0.9 Np type first cladding layer, 10 is p-In _0.03
Ga _0.97 N etch stop layer, 11 is p-Al _0.1 Ga
_0.9 Np-type second cladding layer, 12 is a p-GaN p-type contact layer, 13 is a p-side electrode, 14 is an n-side electrode, and 15 is a SiO ₂ insulating film for current confinement.

In the present invention, the crack preventing layer 3 is made of In.
_An InGaN ternary mixed crystal having an In composition other than _0.1 Ga _0.9 N may be used.

If the In composition of the n-type cladding layer 4, the p-type first cladding layer 9 and the p-type second cladding layer 11 is small or the layer thickness is small, cracks may not occur. The crack prevention layer 3 may not be formed.

The n-type cladding layer 4, the p-type first cladding layer 9, and the p-type second cladding layer 11 may be an AlGaN ternary mixed crystal having an Al composition other than Al _0.1 Ga _0.9 N. In this case, when the Al composition is increased, the energy gap difference and the refractive index difference between the active layer and the cladding layer increase, and carriers and light are effectively confined in the active layer, further reducing the oscillation threshold current value and improving the temperature characteristics. Can be achieved. Also, if the Al composition is reduced to such an extent that the confinement of carriers and light is maintained, the mobility of carriers in the cladding layer increases, and thus there is an advantage that the device resistance of the semiconductor laser device can be reduced. Furthermore, these cladding layers may be quaternary or more mixed crystal semiconductors containing trace amounts of other elements, and may include an n-type cladding layer 4, a p-type first cladding layer 9, and a p-type second cladding layer 1.
The composition of the mixed crystal does not have to be the same as that of 1.

The energy gap of the n-GaN guide layer 5 and the p-GaN guide layer 8 is different from the energy gap of the quantum well layer forming the multiple quantum well structure active layer 6 by the n-type cladding layer 4 and the p-type If the material has a value between the energy gaps of one clad layer 9, GaN
Any other material, for example, InGaN ternary mixed crystal, A
You may use 1GaN ternary mixed crystal, InGaAlN quaternary mixed crystal, or the like. It is not necessary to dope the entire guide layer with a donor or an acceptor, and only a part of the multiple quantum well structure active layer 6 side may be non-doped, or the entire guide layer may be non-doped. In this case, there are advantages that the number of carriers existing in the guide layer is reduced, light absorption by free carriers is reduced, and the oscillation threshold current can be further reduced.

The multi-quantum well structure active layer 6 has two In _0.15 Ga _0.85 N quantum well layers and three In _0.03 Ga layers.
The composition of the _0.97 N barrier layer may be set according to the required laser oscillation wavelength. To increase the oscillation wavelength, increase the In composition of the quantum well layer, and to shorten the oscillation wavelength, increase the In composition of the quantum well layer. Make it smaller. Further, the quantum well layer and the barrier layer may be a quaternary or higher mixed crystal semiconductor containing a trace amount of another element in an InGaN ternary mixed crystal. Further, the barrier layer is simply GaN
May be used. Further, the number of layers of the quantum well layer and the barrier layer is not limited to the present embodiment, and other numbers may be used. A single quantum well structure active layer may be used.

In this embodiment, the Al _0.2 Ga _0.8 N evaporation preventing layer 7 is formed so as to be in contact with the multiple quantum well structure active layer 6. This is because when growing the p-GaN guide layer 8 after growing the multiple quantum well structure active layer 6, it is necessary to raise the growth temperature, but during this time the multiple quantum well structure active layer 6 evaporates. It is to prevent. Therefore, any material that protects the quantum well layer can be used as the evaporation prevention layer 7 and has a different Al composition.
N-ternary mixed crystal or GaN may be used. Further, Mg may be doped into the evaporation preventing layer 7, and in this case, p-
There is an advantage that holes are easily injected into the active layer 6 from the GaN guide layer 8 or the p-Al _0.1 Ga _0.9 Np type clad layer 9. Further, when the In composition of the quantum well layer is small, the quantum well layer does not evaporate without forming the evaporation prevention layer 7, and thus the gallium nitride based semiconductor of the present embodiment can be obtained without forming the evaporation prevention skin 7. The characteristics of the laser element are not impaired.

Next, a method for fabricating the gallium nitride based semiconductor laser device will be described with reference to FIG. In the following description, the case where the MOCVD method (metal organic chemical vapor deposition method) is used is shown, but any growth method capable of epitaxially growing a gallium nitride-based semiconductor may be used, such as MBE method (molecular beam epitaxial growth method) or HVPE. Other vapor phase growth methods such as (hydride vapor phase epitaxy) can also be used.

First, trimethylgallium (TMG), ammonia (NH 3), and the like were placed on a 100 μm-thick n-GaN substrate 1 having a c-plane as a surface and set in a predetermined growth furnace.
₃ ) By using silane gas (SiH ₄ ) as a raw material, a 3 μm-thick Si-doped n-GaN layer 2 is grown at a growth temperature of 1050 ° C. Next, the growth temperature was lowered to 750 ° C.
And NH ₃ and SiH ₄ , and trimethylindium (TM
I) is used as a raw material, and a Si-doped n-
The In _0.1 Ga _0.9 N crack preventing layer 3 is grown. next,
The growth temperature was raised again to 1050 ° C., and TMG and NH ₃
And SiH ₄ and trimethylaluminum (TMA) as raw materials and a 1.0 μm thick Si-doped n-Al
_{A 0.1} Ga _0.9 Nn-type clad layer 4 is grown. Then, T
Except for MA, the Si-doped n-GaN guide layer 5 having a thickness of 0.1 μm is grown at a growth temperature of 1050 ° C.

Thereafter, the growth temperature is lowered again to 750 ° C.
Using TMG, NH ₃ and TMI as raw materials, In _0.03 Ga
_0.97 N barrier layers (thickness 5nm), IN _0.15 Ga _0.85 N quantum well layer (thickness 3nm), In _0.03 Ga _0.97 N barrier layers (thickness _{5nm), IN 0.15 Ga 0. 85} N quantum well layer (thickness 3n
m), an In _0.03 Ga _0.97 N barrier layer (thickness: 5 nm) is sequentially grown to form a multiple quantum well structure active layer (total thickness: 21 nm) 6. Subsequently, using TMG, TMA and NH ₃ as raw materials, an Al _0.2 Ga _0.8 N evaporation preventing layer 7 having a thickness of 10 nm is grown at a growth temperature of 750 ° C.

Next, the growth temperature was raised again to 1050 ° C., and TMG, NH ₃ , and cyclopentadienyl magnesium (Cp ₂ Mg) were used as raw materials, and the thickness was 0.1 μm.
The Mg-doped p-GaN guide layer 8 is grown. Subsequently, TMA was added to the raw material, and the growth temperature was kept at 1050 ° C., and the Mg-doped p-Al _0.1 Ga _0.9 N having a thickness of 0.3 μm was formed.
A p-type first cladding layer 9 is grown. Next, the growth temperature is set to 75
0 ° C., and using TMG, NH ₃ , Cp ₂ Mg, and TMI as raw materials, Mg-doped p-In _0.03
A Ga _0.97 N etch stop layer 10 is grown.

Next, the growth temperature was increased again to 1050 ° C., and TMG, NH ₃ , Cp ₂ Mg, and TMA were used as raw materials, and a 0.8 μm-thick Mg-doped p-Al _0.1 Ga
_{A 0.9} Np type second cladding layer 11 is grown. Then, T
The MA is removed from the raw material, and the Mg-doped p-GaN p-type contact layer 12 having a thickness of 0.1 μm is grown at a growth temperature of 1050 ° C. to complete a gallium nitride-based epitaxial wafer.

Thereafter, the wafer having the nitride-based semiconductor structure laminated on the substrate is annealed in a nitrogen gas atmosphere at 800 ° C. to lower the resistance of the Mg-doped p-type layer.

Subsequently, a part of the wafer is cleaved to form a straight side A. In the present embodiment, the cleavage plane formed on this side is (1-100) plane. Further, p is formed using ordinary photolithography and dry etching techniques.
-P-GaN so as to form a ridge structure in the form of a stripe having a width of 2 μm on the outermost surface of the p-type contact layer 12.
p-type contact layer 12 and p-Al _0.1 Ga _0.9 Np-type second
The clad layer 11 is etched. At this time, the etching depth is p-In _0.03 Ga _0.97 N etch stop layer 10.
When reaching, In atoms appear on the etched surface,
Etching was stopped when the In atoms were detected by elemental analysis, so that the etching depth could be accurately controlled. Note that the etch stop layer 10 may be an InGaN ternary mixed crystal or an InGaAlN quaternary mixed crystal having another In composition, as long as the etching can be stopped by detecting atoms other than Al atoms and Ga atoms. If the desired etching depth can be controlled by the etching time by sufficiently controlling the etching rate, the etch stop layer 10 may be omitted.

The stripe-shaped ridge structure is an active region into which current is injected only in this region. When the ridge structure is formed by photolithography, the straight side A and the stripe of the ridge structure are formed. The photomask is aligned so as to be vertical. In this embodiment, the direction of the stripe of the ridge structure is the <1-100> direction. By forming a straight side A by cleaving a part of the wafer in this manner, the stripe of the ridge structure can be aligned with respect to the side A, so that the direction of the stripe can be accurately cleaved. Can be formed perpendicular to the direction.

Subsequently, an SiO ₂ insulating film 15 having a thickness of 200 nm is formed as a current blocking layer on the side surfaces of the ridge and on the surface of the p-type layer other than the ridge, and this SiO ₂ insulating film 15 and p-Ga
A p-side electrode 13 made of nickel and gold is formed on the surface of the Np type contact layer 12. Further, the n-
The back surface of the GaN substrate 1 is polished by a normal polishing technique to reduce the thickness of the wafer to 30 μm, and the n-side electrode 14 made of titanium and aluminum is formed on the back surface of the n-GaN substrate 1. Complete the wafer.

Thereafter, the wafer is cleaved in a direction perpendicular to the ridge stripe to form a laser cavity end face, and a laser resonator is formed in a direction parallel to the ridge stripe. Here, the cleavage plane forming the resonator surface was a (1-100) plane, and the length of the resonator was 500 μm. In the present embodiment, when the ridge stripe is formed by photolithography, the stripe of the ridge structure is aligned with reference to the side A of the wafer formed by cleavage, so that both resonator surfaces are aligned with the direction of the ridge stripe. 90 ° ± 0.1 tilt angle with the container end face
Degree, which is within a range of 90 degrees ± 0.3 degrees, which is a tilt angle showing good characteristics.

Further, by forming the cavity end face using the cleavage plane of the n-GaN substrate, the periodic unevenness of the end face is reduced, and the difference between the peak and the valley of the unevenness is set to about 1 nm. And was suppressed within the range of 25 nm or less.

Further, SiO ₂ and Ti
Oscillation wavelength (λ) / 4 in which three layers of O ₂ are alternately stacked.
A dielectric multilayer reflective film is formed, and the reflectance of the cavity end face is set to 60.
%.

Subsequently, this laser element is divided into individual laser chips. Then, the n-side electrode 14 of each chip is bonded and mounted on the stem, and the p-side electrode 13 and the lead terminal are connected by wire bonding to complete a gallium nitride based semiconductor laser device.

The gallium nitride based semiconductor laser device thus manufactured had an oscillation wavelength of 410 nm and an oscillation threshold current value of 40 mA, and excellent laser characteristics were obtained.
In addition, variations in the characteristics of each semiconductor laser element chip within one wafer were reduced, and the yield was improved. Such a good yield and a low oscillation threshold current value are obtained because the angle between the direction of the ridge stripe and the end face of the resonator, which has not been considered at all, is 90 ° ± 0.
This is because the fall of the reflectance at the cavity facet was suppressed by setting the range of 3 degrees and the difference between the peaks and valleys of the periodic unevenness on the facet to 25 nm or less.

In the structure of this embodiment, the full width at half maximum of the intensity distribution of the laser beam in the direction parallel to the active layer is 2.
The thickness is about 9 μm, but is not limited to this embodiment, and if the full width at half maximum is 0.5 μm or more and 3 μm or less, a gallium nitride-based semiconductor laser device having good laser characteristics and good yield can be obtained. In the present embodiment, the full width at half maximum of the laser light intensity distribution in the direction parallel to the active layer is determined by the stripe width of the ridge structure and the layer thickness of the p-type first cladding layer. FIG. 2 shows a case where the full width at half maximum of the laser light intensity distribution based on the correlation between the thickness of the p-type first cladding layer and the width of the ridge stripe is 3 μm. If the full width at half maximum of the laser light intensity distribution is the stripe width in the shaded area shown in FIG. 2 and the thickness of the p-type first cladding layer, the full width at half maximum of the laser light intensity distribution in the direction parallel to the active layer is 0. It can be set to 0.5 μm or more and 3 μm or less.

As a result, a gallium nitride based semiconductor laser device having good laser characteristics with good yield can be obtained. Although the graph shown in FIG. 2 changes depending on the structure of the semiconductor laser device, the amount of decrease in the reflectivity is affected by the full width at half maximum of the intensity distribution of the laser light. Full width at half maximum of 0.5 μm or more 3
The stripe width or the like may be set so as to be not more than μm.

In this embodiment, the straight side A of the wafer is the (1-100) plane and the direction of the ridge stripe is the <1-100> direction perpendicular to the side A, but the direction of the ridge stripe is The <11-20> direction parallel to the side A may be used. This is because in the case of GaN, a cleavage plane that can be used as a resonator end face can be formed even on the (11-20) plane. Further, the straight side A of the wafer is defined as (11-2).
0), and the direction of the ridge stripe may be perpendicular or parallel to the side A.

In this embodiment, an n-type gallium nitride
, But the p-type and n-type configurations are reversed.
It does not matter. Further, the current blocking layer is made of SiO_Two
Not only the insulating film 15 but also other dielectric insulating films such as SiN,
Use an n-type conductive or semi-insulating semiconductor material.
Can also be. Also stripes to form active regions
The structure is not limited to the ridge structure as in the present embodiment.
Etching is performed up to the n-type layer when forming, so-called buried
After forming the embedded structure and the current confinement layer, current injection is performed.
The current constriction layer is etched only in the region
Other stripe structures such as an internal current confinement structure may be used.
No. (Second Embodiment) FIG. 3 relates to a second embodiment of the present invention.
FIG. 1 is a cross-sectional view showing a gallium nitride-based semiconductor laser device.
You. In this figure, reference numeral 21 denotes a substrate having a c-plane as a surface.
Fire substrate, 22: GaN buffer layer, 23: n-G
aNn type contact layer, 24 is n-In _0.1Ga_0.9N
Rack prevention layer, 25 is n-Al_0.1Ga_0.9Nn type crack
Layer, 26 is an n-GaN guide layer, and 27 is a two-layer In layer.
_0.15Ga_0.85N quantum well layer and three layers of In_0.03Ga_0.97N
A multiple quantum well structure active layer comprising a barrier layer;
_0.2Ga_0.8N evaporation preventing layer, 29 is a p-GaN guide layer,
30 is p-Al_0.1Ga_0.9The p-type first cladding layer 31
p-In_0.03Ga_0.97N etch stop layer, 32 is p-
Al_0.1Ga_0.9Np type second cladding layer, 33 is p-Ga
Np type contact layer, 34 is p-side electrode, 35 is n-side electrode
The pole 36 is SiO for current confinement._TwoIt is an insulating film.

In the present invention, the GaN buffer layer 22 is not limited to GaN as long as a gallium nitride-based semiconductor can be epitaxially grown thereon, and other materials such as GaN or AlGaN ternary mixed crystal may be used. In addition, the n-GaN n-type contact layer 23 may have a doping amount distributed in the thickness direction by making only the vicinity of the buffer layer 22 non-doped. Such non-doping has the advantage that the crystallinity is improved as compared with the case of doping, and the reliability of the device is improved. However, when the element is non-doped, the device resistance is slightly increased. However, by making only the vicinity of the buffer layer 22 non-doped,
It is possible to improve the reliability without increasing the element resistance.

Next, a method for fabricating the gallium nitride based semiconductor laser device will be described with reference to FIG. In the following description, the case of using the MOCVD method (metal organic chemical vapor deposition method) is shown, but any growth method capable of epitaxially growing a gallium nitride-based semiconductor may be used, such as MBE method (molecular beam epitaxial growth method) or HVPE (hydride). Other vapor phase growth methods such as vapor phase growth method) can also be used.

First, a sapphire substrate 21 having a thickness of 350 μm and having a c-plane as a surface is set in a predetermined growth furnace.
Above, using TMG and NH ₃ as raw materials, the growth temperature is 550.
A GaN buffer layer 22 is grown at 35 ° C. to a thickness of 35 nm. Next, the growth temperature is increased to 1050 ° C., and TMG and N
Using H ₃ and SiH ₄ as raw materials, a Si-doped n-GaN n-type contact layer 23 having a thickness of 3 μm is grown. Next, the growth temperature was lowered to 750 ° C., and TMG, NH ₃ , SiH ₄ ,
Then, a Si-doped n-In _0.1 Ga _0.9 N crack preventing layer 24 having a thickness of 0.1 μm is grown using TMI as a raw material. Next, the growth temperature was raised again to 1050 ° C.
Using G, NH ₃ , SiH ₄ and TMA as raw materials, a Si-doped n-Al _0.1 Ga _0.9 Nn-type clad layer 25 having a thickness of 1.0 μm is grown. Subsequently, the TMA was removed from the raw material, and the growth temperature was kept at 1050 ° C. and the thickness of the S
An i-doped n-GaN guide layer 26 is grown.

Thereafter, the growth temperature is again lowered to 750 ° C.
Using TMG, NH ₃ and TMI as raw materials, In _0.03 Ga
_0.97 N barrier layers (thickness 5nm), In _0.15 Ga _0.85 N quantum well layer (thickness 3nm), In _0.03 Ga _0.97 N barrier layers (thickness _{5nm), In 0.15 Ga 0. 85} N quantum well layer (thickness 3n
m), an In _0.03 Ga _0.97 N barrier layer (thickness: 5 nm) is sequentially grown to form a multiple quantum well structure active layer (total thickness: 21 nm) 27. Continue to TMG
And TMA and NH ₃ as raw materials, the growth temperature is 750 ° C.
10 nm thick Al _0.2 Ga _0.8 N evaporation prevention layer 2
Grow 8.

Next, the growth temperature is raised again to 1050 ° C., and a T-type Mg-doped p-GaN guide layer 29 having a thickness of 0.1 μm is grown using TMG, NH ₃ and Cp ₂ Mg as raw materials. Subsequently, TMA was added to the raw material, and the growth temperature was kept at 1050 ° C. and the Mg-doped p-A having a thickness of 0.2 μm was formed.
A l _0.1 Ga _0.9 Np type first cladding layer 30 is grown.

Next, the growth temperature was lowered to 750 ° C.
Then, a Mg-doped p-In _0.03 Ga _0.97 N etch stop layer 31 having a thickness of 20 nm is grown using NH ₃ , Cp ₂ Mg, and TMI as raw materials. Next, the growth temperature is set to 105 again.
0 ° C., TMG, NH ₃ , Cp ₂ Mg, and T
0.8 μm thick Mg-doped p-
An Al _0.1 Ga _0.9 Np type second cladding layer 32 is grown.
Subsequently, TMA was removed from the raw material, and the growth temperature was 1050.
A Mg-doped p-GaN p-type contact layer 33 having a thickness of 0.1 μm is grown at a temperature of 0 ° C. to complete a gallium nitride-based epitaxial wafer.

Thereafter, the wafer having the nitride semiconductor structure laminated on the substrate is annealed at 800 ° C. in a nitrogen gas atmosphere to lower the resistance of the Mg-doped p-type layer.

Subsequently, a part of the wafer is cleaved to form a straight side A. In the present embodiment, the cleavage plane formed on this side is the (1-100) plane in the sapphire substrate. At this time, in the GaN layer, the (11-20) plane is shifted from the sapphire substrate by 30 degrees in the in-plane direction.
Side A. However, since the sapphire substrate may be hard and difficult to cleave, the back surface of the sapphire substrate 21 is polished by a normal polishing technique to reduce the thickness of the wafer to 100 μm.
After the thickness is reduced below, a part of the peripheral side of the wafer may be cleaved to form a linear side A.

Alternatively, a gallium nitride-based semiconductor layer grown on a sapphire substrate may have cracks in the peripheral portion of the wafer due to thermal strain with the sapphire substrate. 2
0> direction or ± 60 degrees from this direction,
If there is such a crack, it may be used instead of the side A.

Further, using the usual photolithography and dry etching techniques, a strip of 200 μm width is formed from the outermost surface of the p-GaN p-type contact layer 33 by n.
Etching is performed until the GaN n-type contact layer 23 is exposed to form a mesa structure. Here, when this mesa structure is formed by photolithography, the photomask is aligned so that the linear side A is perpendicular to the mesa structure stripe. In the present embodiment, the direction of the stripe of the ridge structure is <11− in the GaN layer.
20> direction.

Thereafter, the p-GaN p-type contact layer 33 is formed on the outermost surface of the p-GaN p-type contact layer 33 by using ordinary photolithography and dry etching techniques so as to form a ridge structure in a stripe shape having a width of 2 μm. The p-Al _0.1 Ga _0.9 Np type second cladding layer 32 is etched. At this time, the etching depth is p-In _0.03 G
When the a _0.97 N etch stop layer 31 is reached, In atoms appear on the etched surface. Therefore, the etching is stopped when the In atoms are detected by elemental analysis, so that the etching depth can be accurately controlled. The stripe-shaped ridge structure is an active region into which current is injected only in this region. However, when this ridge structure is formed by photolithography, the straight side A and the stripe of the ridge structure are perpendicular to each other. The photomask is aligned as described above.

In this embodiment, the direction of the stripe of the ridge structure is the <11-20> direction in the GaN layer.
By forming a straight side A by cleaving a part of the wafer in this manner, the stripe of the ridge structure can be aligned with respect to the side A, so that the direction of the stripe can be accurately cleaved. Can be formed perpendicular to the direction. In this embodiment,
A stripe having a ridge structure and a stripe having a mesa structure are formed in parallel.

Subsequently, a 200 nm thick SiO ₂ insulating film 36 is formed as a current blocking layer on the side surfaces of the ridge and on the surface of the p-type layer other than the ridge. Further, the SiO ₂ insulating film 36
A p-side electrode 34 made of nickel and gold is formed on the surface of the p-GaN p-type contact layer 33, and an n-side electrode 35 made of titanium and aluminum is formed on the surface of the n-GaN n-type contact layer 23 exposed by etching. Thus, a gallium nitride based semiconductor laser device wafer is completed.

Thereafter, the wafer is cleaved in a direction perpendicular to the ridge stripe to form a laser cavity end face, and a laser cavity is formed in a direction parallel to the ridge stripe. Here, the cleavage plane forming the resonator plane is the (11-20) plane in the GaN layer, and the length of the resonator is 500 μm. In this embodiment, when the ridge stripe is formed by photolithography, the stripe of the ridge structure is aligned with reference to the side A of the wafer formed by cleavage, so that both resonator surfaces are aligned with the direction of the ridge stripe. The angle between the cavity and the cavity end face is 90
The degree can be about ± 0.1 degrees, which is within the range of 90 degrees ± 0.3 degrees. In addition, the sapphire substrate was polished to a thickness of about 50 μm and cleaved to form a cavity facet, so that periodic irregularities on the cavity facet were reduced. And it was suppressed within the range of 25 nm or less. Here, if the cavity facets are formed by cleaving the sapphire substrate while keeping the thickness of the sapphire substrate at about 100 μm, the cavity-like irregularities may increase to 25 nm or more. By doing so, the difference between the peaks and valleys of the irregularities was reduced. Even if the difference between the peaks and valleys of the periodic unevenness of the cavity end face formed by cleavage is 25 nm or less, even if the cavity end face is polished to further reduce this size, it will not be flat.

Further, SiO ₂ and Ti
A quarter-dielectric multilayer reflective film in which three layers of O ₂ are alternately laminated is formed, and the reflectance of the cavity end face is set to 60%.

Subsequently, this laser element is divided into individual laser chips. Then, each chip is connected to the sapphire substrate 21.
The gallium nitride based semiconductor laser device is completed by mounting each of the electrodes and the lead terminal by wire bonding with the substrate facing downward.

The gallium nitride based semiconductor laser device thus manufactured had an oscillation wavelength of 410 nm and an oscillation threshold current value of 30 mA, and excellent laser characteristics were obtained.
In the second embodiment, compared to the first embodiment, the full width at half maximum of the intensity distribution of the laser beam in the direction parallel to the active layer is narrowed,
It is about 1.8 μm.

As a result, the confinement coefficient of light in the active region was increased, and the oscillation threshold current value was reduced. Further, as compared with the conventional gallium nitride based semiconductor laser device, the variation in the characteristics of each semiconductor laser device chip within one wafer was reduced, and the yield was improved. The reason why such a low oscillation threshold current value can be obtained with good yield is that the angle formed between the direction of the ridge stripe and the end face of the resonator, which has not been considered at all, is within the range of 90 ° ± 0.3 °. The reason is that the difference between the peaks and valleys of the periodic irregularities on the end face is set to 25 nm or less, thereby suppressing a decrease in the reflectivity of the end face of the resonator. Further, in this embodiment, since the stripe having the ridge structure and the stripe having the mesa structure are formed in parallel, the distance between the n-side electrode 35 and the stripe-shaped active region is constant in the resonator direction. As a result, the current can be uniformly injected at a constant voltage in the resonator, so that the light emission in the resonator becomes uniform and the oscillation threshold current value is further reduced as compared with the conventional gallium nitride based semiconductor laser device. It is possible to do.

In the configuration of this embodiment, the full width at half maximum of the intensity distribution of the laser beam in the direction parallel to the active layer is 1.
Although it is about 8 μm, the present invention is not limited to this example, and if the full width at half maximum is 0.5 μm or more and 3 μm or less, a gallium nitride based semiconductor laser device having good laser characteristics and good yield can be obtained. As in the first embodiment, the full width at half maximum of the laser beam intensity distribution in the direction parallel to the active layer is the stripe width in the hatched portion shown in FIG. 2 and the layer thickness of the p-type first cladding layer. The full width at half maximum of the intensity distribution of the laser beam in the direction parallel to the active layer can be 0.5 μm or more and 3 μm or less. As a result, a gallium nitride based semiconductor laser device having good laser characteristics with good yield can be obtained.

In this embodiment, the straight side A of the wafer is defined as the (1-100) plane of the sapphire substrate, and the direction of the ridge stripe is defined as the direction perpendicular to the side A.
Although the <11-20> direction of the GaN layer was used, the <1-10>
0> direction. This is because a cleavage plane of the GaN layer that can be used as a cavity end face can be formed in either direction. Alternatively, the straight side A of the wafer may be the (11-20) plane of the sapphire substrate, and the direction of the ridge stripe may be perpendicular or parallel to the side A.

In this embodiment, first, n
After the p-type gallium nitride semiconductor is formed, the p-type gallium nitride semiconductor is formed. However, the p-type and n-type configurations may be reversed. Further, the current blocking layer is made of SiO
Not only the _two insulating films 36 but also other dielectric insulating films such as SiN, or an n-type conductive or semi-insulating semiconductor material can be used. Further, the stripe structure for forming the active region is not limited to the ridge structure as in the present embodiment, and a so-called buried structure in which etching is performed up to the n-type layer when forming the ridge, or a current after forming the current confinement layer. Another stripe structure such as a so-called internal current confinement structure in which the current confinement layer is etched only in the region where the implantation is performed may be used.

Further, in this embodiment, the cavity facet of the laser is formed by cleavage. However, since the sapphire substrate may be hard and difficult to cleave, the cavity facet may be formed by dry etching. At this time, the cavity end face is formed using normal photolithography and dry etching techniques.If a ridge stripe is already formed at the time of this photolithography, the ridge structure is used as a reference. By vertically aligning the dry etching regions, it is possible to make the angle between the direction of the ridge stripe and the end face of the resonator within the range of 90 ° ± 0.3 ° on both resonator surfaces. In the case where the ridge stripe is formed after the cavity end face is formed by dry etching, by aligning the ridge stripe direction vertically with respect to the cavity end face, both cavity faces are aligned with the ridge stripe direction. 90 ° ± 0.3
It is possible to stay within the range of degrees. Further, one end of the resonator may be formed by cleavage and the other end may be formed by dry etching.

[0076]

As described above, in the gallium nitride based semiconductor laser device according to the present invention, the angle between the stripe direction of the stripe-shaped active region and the end face of the resonator is 90 degrees ± 0.
The difference between the peaks and valleys of the concave and convex portions of the cavity end face within the range of the stripe-shaped active region was set to 25 nm or less. As a result, two points, which were not considered at all in the conventional gallium nitride based semiconductor laser device, the angle between the direction of the stripe and the cavity facet, and the periodic irregularities on the cavity facet were within the above range. By doing so, it is possible to suppress a decrease in the reflectance of the end face of the resonator, and it is possible to obtain a semiconductor laser device having a low oscillation threshold current value with good yield.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a semiconductor laser device according to a first embodiment of the present invention, in which the full width at half maximum of the intensity distribution of laser light in a direction parallel to the active layer is set to 0.5 μm or more and 3 μm or less; FIG. 4 is a graph showing a range of a layer thickness of a mold first cladding layer.

FIG. 3 is a sectional view showing a semiconductor laser device according to a second embodiment of the present invention.

FIG. 4 is a schematic view of a striped active region of a gallium nitride based semiconductor laser device and a resonator end face having a tilt angle θ as viewed from above the semiconductor laser device.

FIG. 5 is a graph showing the result of calculating the dependence of the reflectance reduction R / R _{0 on} the tilt angle θ with respect to the full width at half maximum of the intensity distribution of various laser beams.

FIG. 6 is a graph showing a change in an oscillation threshold current value due to a decrease in reflectance.

FIG. 7 is a schematic diagram showing a stripe-shaped active region and a cavity end face having periodic irregularities of a gallium nitride based semiconductor laser device as viewed from above the semiconductor laser device.

FIG. 8 is a graph showing the result of calculating the dependence of the reflectance reduction R / R ₀ on the difference between peaks and valleys.

FIG. 9 is a cross-sectional view of a conventional semiconductor laser device using a gallium nitride-based semiconductor.

FIG. 10 is a cross-sectional view of a conventional semiconductor laser device using a gallium nitride-based semiconductor.

[Explanation of symbols]

Reference Signs List 1 n-GaN substrate 2, 23 n-GaN contact layer 3, 24 n-In _0.1 Ga _0.9 N crack prevention layer 4, 25 n-Al _0.1 Ga _0.9 Nn-type clad layer 5, 26 n-GaN guide layer 6, 27 Multiple quantum well structure active layer 7, 28 Al _0.2 Ga _0.8 N evaporation preventing layer 8, 29 p-GaN guide layer 9, 30 p-Al _0.1 Ga _0.9 Np type first cladding layer 10, 31 p-In _0.03 Ga _0.97 N Etch stop layer 11, 32 p-Al _0.1 Ga _0.9 Np-type second cladding layer 12, 33 p-GaN p-type contact layer 13, 34 p-side electrode 14, 35 n-side electrode 15, 36 SiO ₂ insulating film 21 sapphire substrate 22 GaN buffer layer

Claims (4)

[Claims] 1. A substrate having an active layer made of a nitride semiconductor sandwiched between a clad layer and / or a guide layer made of a nitride semiconductor on a substrate, wherein the active layer has a stripe-shaped active region in which a current is narrowed. In the provided semiconductor laser device, an angle between a stripe direction of the stripe-shaped active region and an end face of the resonator is within a range of 90 ° ± 0.3 °,
Further, the full width at half maximum of the intensity distribution of the laser beam in a direction parallel to the active layer in the stripe-shaped active region is 3 μm.
m or less, wherein the gallium nitride based semiconductor laser device is not more than m. 2. An active layer comprising a nitride semiconductor sandwiched between a cladding layer and / or a guide layer comprising a nitride semiconductor on a substrate, wherein the active layer comprises a stripe-shaped active region in which a current is confined. In the provided semiconductor laser device, the difference between the peak and the valley of the unevenness on the cavity end surface within the range of the stripe-shaped active region is 25 nm or less. 3. The full width at half maximum of the intensity distribution of laser light in a direction parallel to the active layer in the stripe-shaped active region is 0.5 μm or more.
3. The gallium nitride based semiconductor laser device according to any one of items 1 to 2. 4. A cladding layer comprising a nitride semiconductor and / or
Alternatively, in a method for manufacturing a semiconductor laser device having a nitride-based semiconductor laminated structure including an active layer made of a nitride semiconductor sandwiched between guide layers, a wafer is formed by laminating the nitride-based semiconductor laminated structure on a substrate Performing a step of cleaving the wafer to form a linear side; forming a stripe-shaped active region in parallel or perpendicular to the linear side formed by the cleaving; Forming a cavity end face by cleaving in a direction perpendicular to the stripe direction of the stripe-shaped active region.