JPS63263787A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To reduce the thickness of an active layer near the end face of a laser resonator thinner than that of an active layer in the resonator by partly forming an SiO2 film or an Si3N4 film, and forming an AlGaAs multilayer film by a reduced pressure organic metal vapor growing method thereon. CONSTITUTION:When AlxGa1-xAs layers 2, 4 and a GaAs layer 5 are grown by a reduced pressure organic metal vapor growing method on a GaAs substrate 1 formed partly with an SiO2 film 9 and an Si3N4 film, the layers 2, 4 and 5 are grown on the substrate 1, but not grown on the film 9 and the Si3N4 film. Thus, the quantities of the Ga, Al, As which contribute to the growth are increased on the substrate 1 slightly separated from the film 9 or the Si3N4 film ss compared with the substrate 1 sufficiently separated from the film 9 or the Si3N4 film. Thus, the growing velocity is accelerated, and the thickness of the layer 3 can be reduced near the end face, and increased in a laser chip.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to semiconductor lasers, and in particular to high output and narrow emission lasers for reaction lasers formed using low pressure metal organic chemical vapor deposition (low pressure MOCVD). It is related to beam formation.

[Conventional technology]

FIG. 5 is a partially exploded perspective view showing a conventional semiconductor laser disclosed in, for example, Japanese Patent Publication No. 60-192379.
For ease of explanation, the laser resonant end face portion and the inside of the laser are shown separately. In the figure, 1 is P-GaAs
group) anti, 2 is P-A]xGal-xAs cladding layer, 3
is 1yGal-yAs active layer to P-, 4 is lxG to n-
a1-xAs cladding layer, 5 an n-GaAs contact layer, and 6 a ridge provided only near the resonator end face and extending in the direction of the resonator. Note that 3a is an active layer grown on the ridge 6, and 3b is an active layer formed inside the laser chip.

The semiconductor laser configured in this way is manufactured by applying liquid phase epitaxy (LPE) on the P-GaAs substrate 1 on which the ridge 6 is formed.
P-AlxGal-xAs cladding layer 2
, P-AlyGal-yAs active layer 3, n-Al
x Ga1-xAs cladding layer 4. An n-GaAs contact layer 5 is sequentially grown. Here, in the liquid phase growth method,
P-GaAsi plate with flat growth rate on ridge 6
The growth rate will be slower than the above. For this reason, the active layer 3a on the ridge at the laser end face is thinner than the active layer 3b inside the laser chip, which is a feature of this semiconductor laser. In a typical semiconductor laser, the thickness of the active layer is constant in the direction of the cavity, and when the active layer is uniformly thinned to enable narrow emission beams and high-power operation, the gain decreases and the thickness decreases. The value may increase or the lifespan may be shortened. For this reason, in the semiconductor laser shown in FIG. 5, only the active layer at the laser end face is thinned.
In addition to enabling a narrow radiation beam and high-output operation, the active layer inside the laser chip, which greatly affects the oscillation darkness value, is made slightly thicker to control the increase in the oscillation darkness value. Furthermore, by making the active layer inside the laser chip a little thicker, a longer life is also achieved.

FIG. 6 is an exploded perspective view showing another conventional example disclosed in Japanese Patent Application Laid-Open No. 60-192379. The same parts as in FIG. 5 are indicated using the same symbols. In the same figure, 7 is n
-GaAS current blocking layer 8 is a groove penetrating the n-GaAS current blocking layer 7; In addition, IxGal to P-
-xAs cladding layer 2. P-AlyGal-yAs active layer 3, n-8lx Ga1-xAs cluster layer 4
, the n-GaAs contact layer 5 is sequentially grown on the P-GaAs substrate 1 using a liquid phase growth method.

Similar to the semiconductor laser shown in FIG. 5, the semiconductor laser constructed in this manner has an active layer that is thinner only at the laser end facets, and has a narrow emission beam, high output operation, low oscillation darkness value, and long wavelength. This makes it possible to extend the lifespan. Also,
By providing the groove 8, a so-called loss guide transverse mode control mechanism is configured, and stable transverse mode oscillation can be performed.

[Problem that the invention seeks to solve]

As explained above, in conventional semiconductor lasers, in order to maintain an appropriate thickness of the active layer inside the laser by thinning only the active layer on the laser end face, the growth rate on the ridge in the liquid phase growth method is lower than the growth rate on the flat part. It is formed by taking advantage of the fact that it is slower than the speed. However, when growing each layer by low-pressure metal organic chemical vapor deposition (MOCVD), which allows the use of large-area wafers and has excellent film thickness control accuracy, the growth rate on the ridge is also flat. Since the growth rate is also the same, the active layer cannot be made thin only at the laser end face portion, and this poses the problem that a semiconductor laser with such a configuration cannot be obtained.

This invention was made to solve this problem, and even when manufactured using the low pressure organometallic vapor phase epitaxy method, the active layer can be made to have an appropriate thickness only in the vicinity of the laser end face. Thereby, the aim is to obtain a semiconductor laser with a narrow radiation beam, high power operation, low threshold and long lifetime.

[Means for solving problems]

The semiconductor laser according to the present invention has a 5in2 film or a 5iJa film partially formed inside a laser chip.

[Effect]

In the semiconductor laser of the present invention, when an AlxGa1-xAs layer and a GaAx layer are grown by low pressure organometallic vapor phase epitaxy on a GaAs substrate on which a SiO□ film and a 5iJ4 film are partially formed, an Al
The xGa1-xAs and GaAx layers grow, but the S
It does not grow on iO2 and 5iJ4 films. In addition, in low-pressure organometallic vapor phase epitaxy, trimethylgallium (TMG), trimethylaluminum (), which is supplied in a gaseous state,
TMA) and aluminum (ASH3) decompose near the substrate, which causes a chemical reaction and grows epitaxially on the substrate.

TMAyAsH does not undergo evitacashal growth on the SiO2 film or Si3N film, but diffuses over the Sto film or SiJa film to the exposed portion of GaAs, where it grows evitacashally.

For this reason, the SiO2 film or Si3N film is more likely to be
On the GaAs substrate slightly away from the i3N4 film, the amount of Ga + As + AsO that contributes to growth increases, and the growth rate increases accordingly. Utilizing this difference in growth rate, it becomes possible to make the active layer thinner near the end face and thicker inside the laser chip.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
This figure is an exploded perspective view showing a semiconductor laser according to the present invention, and the same parts as in FIGS. 5 and 6 are indicated using the same symbols. In the figure, reference numeral 9 denotes a 540 g film provided only on a portion of the flat P-GaAs substrate 1.

The semiconductor laser constructed in this way is manufactured by first forming a P-^1xGal-xAs cladding layer 2゜P-] on the surface of the P-GaAs substrate 1 shown in Fig. 2 using a low-pressure organometallic vapor phase epitaxy method. yGal-yAs activity JW3. n-Alx G
a1-xAs cladding layer 4. An n-GaAs contact layer 5 is sequentially grown.

Here, as shown in FIG. 2, the 530g film 9 is formed at two locations inside the laser chip, thereby providing a stripe portion 10 of a constant width between them.

Therefore, the surface of the P-GaAs substrate 1 is exposed in the stripe portion 10.

Next, on this P-GaAs substrate 1, a P-AlxGal-xAs cladding layer 2°P- is deposited onto a 1yGal-yAs active layer 3. n-Alx
When the Ga1-xAs cladding layer 4 and the n-GaAs contact layer 5 are grown in sequence, they do not grow on the 5iOz film 9, but only on the exposed portion of the P-GaAs substrate 1. Furthermore, since TMC and TMA decomposed on the SiO□ film 9 are not consumed on the SiO2 film 9, they diffuse on the Sing film 9 and reach the cut portions of the SiO□ film 9, such as the stripe portion 10. Therefore, there is more G in the stripe portion 10 than in the vicinity of the end face of the laser chip.
a. AI is supplied, and as a result, the thickness of each layer of the stripe section 10 inside the laser chip becomes thicker than the thickness of each layer near the end face of the laser chip.
A semiconductor laser having the structure shown in FIG. 1 is obtained.

In a semiconductor laser configured in this manner, the active layer is thinned only at the end face portion of the laser chip, so that a narrow radiation beam, high output operation, low threshold value, and long life can be obtained. This will be explained in detail as follows.

The laser cavity length is 250 μm, and the SiO2 film 9 is formed within the chip at a distance of 15 μm from both end faces. Further, the width of the stripe portion 100 is 10μ. Also,
The oscillation dark value current of the laser is approximately determined by the film thickness of the active N3b formed on the stripe portion IO, and the oscillation dark value current is the lowest when the film thickness of this active layer is about 0.1 μm.

On the other hand, when the thickness of the active layer near the laser resonator end face becomes thinner, the amount of light seeping out from the active layer 3a to the cruts N2, 4 increases, and the light emitting spot at the end face becomes larger. As a result,
The amount of light seeping out from the active layer 3a to the cladding layer 2.4 increases, the light density at the laser end face is reduced, end face breakage becomes less likely to occur, and high output operation becomes possible. Also, the larger the emission spot at the end face, the narrower the radiation beam. For example, if the thickness of the active layer at the end face is 0.1μ
When m, the full angle at half maximum in the direction perpendicular to the junction of the radiation beams is about 40°, but when it is 0.03 μm, it narrows to about 16°. Therefore, the activity J'i inside the resonator
By setting the film thickness of 3b to 0.1 μm and setting the film thickness of active N3a near the resonator to 0.03 μm, a semiconductor laser with a low threshold, narrow emission beam, and high output can be obtained.

FIG. 3 is a perspective view showing another embodiment of the semiconductor laser according to the present invention, particularly when applied to a semiconductor laser having a transverse mode control mechanism. Hereinafter, the manufacturing method will be explained using the process diagrams shown in FIGS. 4(a,) to (d).

First, as shown in FIG. 4(a), a P-GaAs substrate 1 is
An n-GaAS current blocking layer 7 is formed thereon, and a SiO□ film 9 is further formed on the P-GaAs substrate 1 in a portion that will become the inside of the laser resonator.

Next, as shown in FIG. 4(b), after applying a resist 11, only the portion of the resist 11 where the striped portion 10 shown in FIG. 2 is to be formed is removed through a photolithography process.

Next, by dry etching using CF, the SiO□ film 9 in the stripe forming portion is removed, as shown in FIG. 4(C).

Next, using the resist 11 as a mask, a wet etching process is performed to form the groove 8 shown in FIG. 4(d).

Next, after removing the resist 11, P-AlxGal-x
As cladding layer 2, P-AlyGal-yAs active layer 3. n-Alx Ga1-xAs cladding layer 4,
By sequentially forming n-GaAs contact layers 5, a semiconductor laser having the structure shown in FIG. 3 can be obtained.

In other words, in the semiconductor laser thus formed, the active layer is bent to reflect the shape of the groove 8. Here, since the left and right sides of the active layers 3a and 3b are surrounded by the cladding layer 2 having a smaller refractive index than the active layer, an optical waveguide mechanism is formed and it becomes possible to control the transverse mode. Also, in this semiconductor laser, the active layer 3b at the end face of the cavity becomes thinner than the active layer 3b inside the cavity due to the effect of the 5iOz film 9, resulting in a narrow radiation beam, high output operation, and low The threshold value and lifespan can be increased. The semiconductor laser in this invention is partially S
On the GaAs substrate on which the iO□ film and 5i3Nn film were formed, AlxGa1-
When the xAs layer and the GaAx layer are grown, the AlxGa1-xAs layer and the GaAx layer grow on the GaAs substrate, but not on the 5iOi film and the Si3N4 film. In addition, in the low-pressure organometallic vapor phase epitaxy method, trimethylgallium (TMG), I-limethylaluminum (TMA), and aluminium (A s H,) are supplied in a gaseous state.
is decomposed near the substrate, and this causes a chemical reaction to cause Evitacashal growth on the substrate.
, TMAyAs Hs is a SiO2 film or 5iJ4
Evitacashal growth does not occur on the film, but rather it diffuses over the SiO□ film or Si:+Nn film to the exposed portion of GaAs, where it undergoes evitacashal growth.

For this reason, the 5iO1 film or 5iJn film is
On the GaAs substrate slightly away from the Jn film, the amount of Ga+At+As that contributes to growth increases, and the growth rate increases accordingly. Utilizing this difference in growth rate, it becomes possible to make the active layer thinner near the end face and thicker inside the laser chip.

〔Effect of the invention〕

As explained above, according to the present invention, a 5iOt film or a 5iJ4 film is partially formed inside a laser resonator, and AlGa
Since the As multilayer film is formed, the active layer near the end face of the laser resonator can be easily made thinner than the active layer inside the laser resonator.
The effect is that a semiconductor laser with high output operation, low threshold value and long life can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially exploded perspective view of a semiconductor laser according to an embodiment of the present invention, FIG. 2 is a perspective view showing a substrate portion of the semiconductor laser shown in FIG. 1, and FIG. 3 is a perspective view of another semiconductor laser according to the present invention. Partially exploded perspective view showing the embodiment, FIG. 4(a) -
(d) is a process diagram showing the manufacturing process of the semiconductor laser shown in FIG. 3, and FIGS. 5 and 6 are perspective views showing the conventional semiconductor laser. 1 is P-GaAs substrate, 2 is P-AlxGal-xAs
cladding layer, 3 is P-AlyGal-yAs active layer, 3
a, 3b are active layers, 4 is n-Alx Ga1-xAs cladding layer, 5 is yl-GaAs contact layer, 6 is ridge, 7 is n-GaAS current blocking layer, 8 is groove, 9 is SiO□ film, 10 1 is a stripe portion, and 11 is a resist. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. \l'jlr%") 71] S1 2nd figure 4th figure Procedural amendment (voluntary) 3. Person who makes corrections 5.? Ifi is correct (1) Full text of the specification 6. Contents of amendment (1) The full text of the specification is amended as shown in the attached sheet. 7. Attached documents (1) Document containing the entire text of the amended specification: 1 copy
Specification 1, Name of the Invention Semiconductor Laser 2, Claims (]) A semiconductor laser in which a cladding layer, an active layer, a cladding layer, and a contact layer are sequentially formed on a GaAs substrate and emits laser light, wherein the GaAs substrate Top■1/
--SiO□ film or SiS inside the resonator
A semiconductor laser characterized in that the Na film is formed leaving a stripe portion along the waveguide direction of light. (2) SiO□ formed on GaAs substrate
2. The semiconductor laser according to claim 1, wherein no AlGaAs multilayer film is formed on the film or the 5iJ4 film by low pressure organometallic vapor phase epitaxy. (3) A1yG formed near the laser cavity surface
a1-yAs active layer is SiO□ film or 5iJ
AI and G formed on the stripe section sandwiched between the four films.
2. The semiconductor laser according to claim 1, wherein the semiconductor laser is thinner than the a+-yAs active layer. (4) By forming the growth layer using low pressure organometallic vapor phase epitaxy, the growth layer formed on the GaAs substrate near the SiO□ film partially formed on the GaAs substrate or the 5iJa film can be grown. The SiO□ film or St:I
2. The semiconductor laser according to claim 1, wherein the layer is thicker than a growth layer formed on a GaAs substrate sufficiently distant from the N4 film. 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a semiconductor laser, and in particular to a semiconductor laser formed using a low-pressure metal organic chemical vapor deposition method ($i-pressure MOCVD method) to increase the output power and This is related to narrowing the radiation beam. [Prior Art] FIG. 5 is a partially exploded perspective view showing a conventional semiconductor laser disclosed in, for example, Japanese Unexamined Patent Publication No. 192379/1982.
For ease of explanation, the laser resonant end face portion and the inside of the laser are shown separately. In the figure, 1 is P-GaAs
Substrate, 2 is P, -A1xGa, -, tAs cladding layer, 3 is P-Al, Ga1-yAs active layer, 4 is n
-Al. A Gal-11A5 cladding layer, 5 is an n-GaAs contact layer, and 6 is a ridge provided only near the end face of the resonator and extending in the direction of the resonator. Note that 3a is ridge 6
The active layer 3b grown on top is an active layer formed inside the laser chip. The semiconductor laser configured in this way is manufactured by applying liquid phase epitaxy (LPE) on the P-GaAs substrate 1 on which the ridge 6 is formed.
P-A1. Ga, yAs cladding layer 2,
P-AI, Ga, -yAs active layer 3. n-A1. G
a, -yAs cladding layer 4.1-GaAs contact layer 5 are sequentially grown. Here, in the liquid phase growth method, the growth rate on the ridge 6 is slower than the growth rate on the flat P-GaAs substrate 1. For this reason, the active layer 3a on the ridge at the laser end face is thinner than the active layer 3b inside the laser chip, which is a feature of this semiconductor laser. In a typical semiconductor laser, the thickness of the active layer is constant in the direction of the cavity, and when the active layer is uniformly thinned to enable narrow emission beam and high-power operation, the gain decreases and the thickness decreases. The value may increase or the lifespan may be shortened. For this purpose, in the semiconductor laser shown in FIG. 5, only the active layer at the laser end face is thinned to enable a narrow emission beam and high-output operation. The active layer is made slightly thicker to control the increase in the oscillation darkness value. Furthermore, by making the active layer inside the laser chip a little thicker, a longer life is also achieved. FIG. 6 is an exploded perspective view showing another conventional example disclosed in Japanese Patent Application Laid-Open No. 60-192379, in which the same parts as in FIG. 5 are indicated using the same symbols. In the same figure, 7 is n-
The GaAs current blocking layer 8 is a groove penetrating the n-GaAs current blocking layer 7. In addition, P-A1. Ga1-
yAs cladding layer 2, P-AI, Ga, -,^S active layer 3, n-^1xGa, -yAs cladding@4,
The n-GaAs contact layer 5 is sequentially grown on the P-GaAs substrate 1 using a liquid phase growth method. Similar to the semiconductor laser shown in FIG. 5, the semiconductor laser constructed in this manner has an active layer that is thinner only at the laser end facets, and has a narrow emission beam, high output operation, low oscillation darkness value, and long wavelength. This makes it possible to extend the lifespan. Also,
By providing the groove 8, a so-called loss guide transverse mode control mechanism is configured, and stable transverse mode oscillation can be performed. [Problems to be Solved by the Invention] As explained above, conventional semiconductor lasers use liquid phase growth in order to thin only the active layer at the laser end face and maintain an appropriate thickness of the active layer inside the laser. It is formed by taking advantage of the fact that the growth rate on the ridge in the method is slower than the growth rate on the flat part. However, when growing each layer by low-pressure metal organic chemical vapor deposition (MOCVD), which allows the use of large-area wafers and has excellent film thickness control accuracy, the growth rate on the ridge is also flat. Since the growth rate is also the same, the active layer cannot be made thinner only at the end face portion of the laser, resulting in the problem that a semiconductor laser with such a configuration cannot be obtained. This invention was made to solve this problem, and even when manufactured using the low pressure organometallic vapor phase epitaxy method, the active layer can be made to have an appropriate thickness only in the vicinity of the laser end face. Thereby, the aim is to obtain a semiconductor laser with a narrow radiation beam, high power operation, low threshold and long lifetime. [Means for Solving the Problems] A semiconductor laser according to the present invention has a 5iOz film or a 5iJ4 film partially formed inside a laser chip. [Function] In the semiconductor laser of the present invention, an AlxGa+-Js layer and a GaAs layer are grown on a GaAs substrate on which a SiO2 film and a 5iJa film are partially formed by low-pressure organometallic vapor phase epitaxy. is Alx
Ga+-XA3 layer and GaAs layer grow, but Si
It does not grow on O2 and 5iJa films. In addition, in the low pressure organometallic vapor phase epitaxy method, trimethylgallium (TMG) and trimethylaluminum (TMG), which are supplied in a gaseous state, are used.
MA), arsine (^5H3) decomposes near the substrate, which causes a chemical reaction and grows epitaxially on the substrate.
TMG and TMAyAsHs decomposed on the i3N4 membrane are
It does not grow epitaxially on the SiO□ film or 5i3NJll, but diffuses over the SiO□ film or Si3N4 film to the exposed portion of GaAs, where it grows epitaxially. For this reason, it is better to place a GaAs substrate slightly away from the SiO□ film or 5iJ4 film than to place it on a GaAs substrate that is sufficiently far away from the Si, N, or Si film.
On the aAs substrate, Ga, AIyAsO, which contributes to growth
The amount increases, and the growth rate increases accordingly. Utilizing this difference in growth rate, it becomes possible to make the active layer thinner near the end face and thicker inside the laser chip. [Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. 1st
This figure is an exploded perspective view showing a semiconductor laser according to the present invention, and the same parts as in FIGS. 5 and 6 are indicated using the same symbols. In the figure, reference numeral 9 denotes a SiO□ film provided only on a portion of the flat P-GaAs substrate 1. The semiconductor laser constructed in this way is manufactured by first forming a P-AlxGa+-xAs cladding layer 2-A1yGa+-yAs active layer on the surface of a P-GaAs substrate 1 shown in FIG. 3, n-AlxG
An a+-yAs cladding layer 4 and an n-GaAs contact layer 5 are grown in sequence. Here, as shown in FIG. 2, the Sin film 9 is formed at two locations inside the laser chip, thereby providing a striped portion 10 of a constant width between them. Therefore, the surface of the P-GaAs substrate 1 is exposed in the stripe portion 10. Next, on this P-GaAs substrate 1, P-A1. Ga,...,yAs cladding layer 2°P-A1yGa+-yAs active layer 3. n-81
xGal-yAs cladding layer 4, n-GaAs
If the contact N5 is grown in sequence, it will not grow on the SiO□ film 9, but will grow only on the exposed portion of the P-GaAs substrate 1. In addition, since TMG and TMA decomposed on the SiO□ film 9 are not consumed on the SiO□ film 9, they are diffused on the SiO□ film 9 to form the stripe portion 10.
etc. reaches the cut portion of the SiO□ film 9. Therefore, more Ga and AI are supplied to the stripe section 10 than near the end surface of the laser chip, and as a result, the thickness of each layer of the stripe section 10 inside the laser chip becomes smaller than that of each layer near the end surface of the laser chip. This results in a semiconductor laser having the structure shown in FIG. 1. A semiconductor laser configured in this manner has a thin active layer only at the end face of the laser chip, which results in a narrow radiation beam, high output operation, low threshold value, and long life. The details are as follows: The laser resonator length is 250 μm, and the SiO□ film 9 is formed in the chip at a distance of 15 μm from both end faces.Furthermore, the width of the stripe portion 10 is 10 μm. Further, the oscillation dark value current of the laser is approximately determined by the film thickness of the active N3b formed on the stripe portion 10, and the oscillation dark value current is the lowest when the ll*thickness of this active layer is about 0.1 μm. On the other hand, when the thickness of the active layer near the end face of the laser cavity becomes thinner, the light seeping out from the active N3 a to the crat layer 2.4 increases, and the light emitting spot at the end face becomes larger.As a result, the active N3 The light seeping into the cladding layer 2.4 from a increases, the light density at the laser end face decreases, end face breakage becomes less likely to occur, and high output operation becomes possible.Furthermore, as the light emitting spot at the end face becomes larger, The radiation beam becomes narrower, for example if the active layer thickness at the end face is 0.1
When the diameter is 0.03 μm, the full width at half maximum in the direction perpendicular to the junction of the radiation beam is approximately A06, but when the diameter is 0.03 μm, it is 16
It becomes narrower by about °. Therefore, if the thickness of the active layer 3b inside the resonator is set to 0.1 μm and the thickness of the active layer 3a near the resonator is set to 0.03 μm, it is possible to achieve a low threshold, a narrow radiation beam, and a high output semiconductor. You will get a laser. FIG. 3 is a perspective view showing another embodiment of the semiconductor laser according to the present invention, particularly when applied to a semiconductor laser having a transverse mode control mechanism. Hereinafter, the manufacturing method will be explained using the process diagrams shown in FIGS. 4(a) to 4(d). First, as shown in FIG. 4(a), a P-GaAs substrate 1 is
An n-GaAs current blocking layer 7 is formed on the P-GaAs substrate 1, and a 5i (h film 9) is formed on the P-GaAs substrate 1 in a portion that will become the inside of the laser resonator. After applying the resist 11 as shown in FIG. 2, only the portion of the resist 11 where the stripe portion 10 shown in FIG. As shown in FIG. 4(c), the 5402 film 9 in the stripe forming portion is removed. Next, using the resist 11 as a mask, a wet etching process is performed to form the groove 8 shown in FIG. 4(d). Next, after removing the resist 11, a P-Al.
yAs active layer 3°n-A1. Ga1-yAs cladding layer 4. By sequentially forming n-GaAs contact layers 5, a semiconductor laser having the structure shown in FIG. 3 can be obtained. In other words, in the semiconductor laser thus formed, the active layer is bent to reflect the shape of the groove 8. Here, since the left and right sides of the active layers 3a and 3b are surrounded by the cladding N2 having a smaller refractive index than the active layer, an optical waveguide mechanism is formed and it becomes possible to control the transverse mode. In addition, in this semiconductor laser as well, the active layer 3b at the end face of the cavity becomes thinner than the active layer 3b inside the cavity due to the influence of the SiO2 film 9, resulting in a narrow radiation beam, high output operation, and low The threshold value and lifespan can be increased. The semiconductor laser in this invention is partially S
A1. Ga1-. When AsJi and GaAs layers are grown, AlxGa+-xAs and GaAx layers are grown on the GaAs substrate, but not on the SiO2 and 5iJ4 films. In addition, in the low-pressure organometallic vapor phase epitaxy method, trimethylgallium (TMG), trimethylaluminum (TMA), and arsine (AsHi), which are supplied in a gaseous state, decompose near the substrate, causing a chemical reaction that causes a chemical reaction to occur on the substrate. However, the S on the substrate grows epitaxially.
TMG decomposed on iO□ film or Si3N4 film. TMA, AsH3 is a 5iOz film or Si
3N does not grow epitaxially on the film, but diffuses over the SiO□ film or Si3N4 film to the exposed portion of GaAs, where it grows epitaxially. For this reason, the SiO□ film or the 5
On the GaAs substrate slightly away from the iJ4 film, the amount of Ga and AIyAsO contributing to growth increases, and the growth rate increases accordingly. Taking advantage of this difference in growth rate,
This makes it possible to make the active layer thinner near the end face and thicker inside the laser chip. [Effects of the Invention] As explained above, according to the present invention, a 5iOz film or a Si:lN4 film is partially formed inside a laser resonator, and AlG
Since the aAs multilayer film is formed, the active layer near the end face of the laser resonator can be easily made thinner than the active layer inside the laser resonator, resulting in a narrow radiation beam, high output operation, This has the effect of providing a semiconductor laser with a low threshold value and long life. 4. Brief Description of the Drawings FIG. 1 is a partially exploded perspective view of a semiconductor laser according to an embodiment of the present invention, FIG. 2 is a perspective view showing the substrate portion of the semiconductor laser shown in FIG. 1, and FIG. Partially exploded perspective views showing other embodiments of the semiconductor laser according to the invention, FIG. 4(a)-
(d) is a process diagram showing the manufacturing process of the semiconductor laser shown in FIG. 3, and FIGS. 5 and 6 are perspective views showing the conventional semiconductor laser. 1 is P-GaAs substrate, 2 is P-^1xGa, -XAs
Cladding layer, 3 is P-AI, Ga+-yAs active layer, 3
a, 3b are active layers, 4 is an n-AlxGa1-XAs cladding layer, 5 is an n-GaAs contact layer, 6 is a ridge,
7 is n-GaAs current blocking layer, 8 is groove, 9 is SiO
□ film, 10 is a stripe portion, 11 is a resist. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (4)

[Claims] (1) In a semiconductor laser that emits laser light by sequentially forming a cladding layer, an active layer, a cladding layer, and a contact layer on a GaAs substrate, SiO_2 A semiconductor laser characterized in that a film or a Si_3N_4 film is formed leaving a stripe portion along the waveguide direction of light. (2) An AiGaAs multilayer film is formed on the SiO_2 film or the Si_3N_4 film formed on the GaAs substrate by low pressure organometallic vapor phase epitaxy. semiconductor laser. (3) Al_yGa formed near the laser resonant end facet
_1_-_yAs active layer is a SiO_2 film or Si
2. The semiconductor laser according to claim 1, wherein the semiconductor laser is thinner than the Al_yGa_1_-_yAs active layer formed on the stripe portion sandwiched between the _3N_4 films. (4) GaAs near the SiO_2 film or Si_3N_4 film partially formed on the GaAs substrate by forming a growth layer using low pressure organometallic vapor phase epitaxy.
2. The semiconductor laser according to claim 1, wherein the growth layer formed on the substrate is made thicker than the growth layer formed on the GaAs substrate sufficiently distant from the SiO_2 film or the Si_3N_4 film.