JPH09283838A - Semiconductor laser device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a stable single-mode oscillation by a method wherein a ridge part is formed with a second conductive type clad layer having a small diameter part formed in a current implantation region of a first clad layer, and a large diameter part forming a gap between a lower face of the periphery of the small diameter part and an upper face of the first clad layer. SOLUTION: A ridge part 60 comprises a small diameter part 60A formed coming into contact with a first clad layer 5 in a direction of wave-guiding laser beams; and a ridge type InGaAs contact layer 70 formed on a large diameter part 60B and a large diameter part 60B formed integrally thereon. The small diameter part 60A is operated as a current implantation region, and the large diameter part 60B and the p-type InGaAs contact layer 70 are operated as an electrode formation region. A gap 9 is formed between a lower face of the large diameter part 60B of the periphery of the small diameter part 60A and an upper face of the first clad layer 5. The ridge 60 comprises the small diameter part 60A and the large diameter part 60B, and the current implantation region formed by the small diameter part 60A. Therefore, it is possible to enable a stable single-mode oscillation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device and a manufacturing method thereof, and more particularly to a ridge waveguide type semiconductor laser device having a low threshold current and a low element resistance and a manufacturing method thereof.

[0002]

2. Description of the Related Art A ridge waveguide type semiconductor laser device is easier to manufacture than an embedded type semiconductor laser device.
In addition, due to the structural features, the parasitic capacitance of the element is small and it is suitable for high-speed modulation operation.

Next, a conventional ridge waveguide type semiconductor laser device of this type will be described with reference to the manufacturing process shown in FIG. On the surface of the n-type InP substrate 81, the n-type InP clad layer 82, the multiple quantum well active layer 83 of InGaAsP, the p-type InGaAsP optical guide layer 84, and the p-type In.
P clad layer 85, p-type InGaAs contact layer 87
Are epitaxially grown in this order (FIG. 6 (A)).

After that, the p-type InGaAs contact layer 8 is formed.
A first silicon dioxide film 93 is formed on the entire surface of
Other silicon dioxide film 93, leaving only the portion where
Is removed by etching.

Subsequently, by selective etching, the p-type InGaAs contact layer 87 and the p-type InP clad layer 85 are removed by etching, leaving a portion for forming the ridge 94 having a width of about 10 microns covered with the silicon dioxide film 93. At this time, the p-type InP clad layer 85 and the p-type InG
Since the aAsP light guide layer 84 has a different crystal composition, selective etching can be performed by selecting an etching solution (FIG. 6B).

After that, the first silicon dioxide film 93 used as the etching mask is removed, and a ridge-shaped p-type InG is formed.
A second silicon dioxide protective film 88 is formed on the aAs contact layer 87, the side surface of the p-type InP clad layer 85, and the entire surface of the p-type InGaAsP light guide layer 84 exposed by etching.

Subsequently, the p left in the stripe shape is left.
A part of the second silicon dioxide protective film 88 on the surface of the InGaAs contact layer 87 is removed by etching to provide a contact window 92 (FIG. 6C).

Subsequently, a p-type electrode 90 is formed on the contact window 92, the back surface of the n-type InP substrate 81 is polished to adjust its thickness, and then an n-type electrode 91 is formed.
A ridge waveguide type semiconductor laser device can be obtained (FIG. 6D).

[0009]

Generally, in a semiconductor laser device, the width of the upper surface of the ridge is sufficient so that a mask for forming a contact window can be aligned and a wide electrode formation region can be obtained in order to reduce the element resistance. Need a width,
Therefore, it is difficult to reduce the thickness to about 10 microns or less. On the other hand, in order to obtain oscillation in the fundamental guided mode, the current injection region on the lower surface of the ridge needs to be 2.5 μm or less, and both have a contradictory relationship.

In the conventional semiconductor laser device described above, the ridge 94 has a rectangular vertical cross section, the upper surface and the lower surface have the same width, and the width is about 10 μm due to the restriction due to the formation of the contact window. Therefore, it includes oscillation modes other than the fundamental guided mode.

The present invention has been made in view of the above problems, and an object thereof is to provide a ridge type semiconductor laser device capable of oscillating in a fundamental guided mode and having a low element resistance, and a manufacturing method thereof. To do.

[0012]

In order to solve the above problems, in a laser device according to the present invention, a first conductivity type semiconductor substrate and one or several layers directly or on the first conductivity type semiconductor substrate. A first conductivity type clad layer formed via a crystal layer, an active layer formed on the first conductivity type clad layer directly or through one or several crystal layers, and an active layer formed on the active layer. A first conductivity type first clad layer formed directly or via one or several crystal layers, and a crystal layer directly or one or several layers on the second conductivity type first clad layer. A ridge formed through the ridge, the ridge being formed in a current injection region of the first cladding layer and a wide area integrally formed with the ridge on the ridge and the periphery of the ridge. A gap is formed between its lower surface and the upper surface of the first cladding layer. Characterized by comprising the second-conductivity-type cladding layer having a majority.

The ridge has a T-shaped cross-section.
It is characterized in that it has either an inverted convex shape or a trapezoidal shape.

Further, an insulating material is filled in a gap between the lower surface of the large portion around the small portion of the ridge and the first cladding layer.

In order to solve the above problems, in the method of manufacturing a semiconductor laser device according to the present invention, the first conductivity type semiconductor substrate is directly or through one or several crystal layers on the first conductivity type semiconductor substrate. A step of forming a clad layer, a step of forming an active layer directly on the first conductivity type clad layer or via one or several crystal layers, and a crystal of one or several layers directly on the active layer Forming a second conductivity type first clad layer through a layer, forming a stripe-shaped amorphous film in a portion on the second conductivity type first clad layer where current injection is to be performed, Forming a confinement layer having a composition different from that of the first cladding layer on the first cladding layer using the amorphous film as a mask; etching the amorphous film to form a current injection region; On the implantation region, on the constriction layer, Forming a second clad layer of the second conductivity type that acts as a clad layer in cooperation with the first clad layer of the second conductivity type, etching away a portion of the second clad layer of the second conductivity type, and The method further includes, in this order, a step of forming a ridge wider than the current injection region and a step of etching away the constriction layer from the side surface of the ridge.

Further, in the method of manufacturing a semiconductor laser device according to the present invention, the step of forming the first conductivity type cladding layer directly on the first conductivity type semiconductor substrate or through one or several crystal layers, A step of forming an active layer directly on the first conductivity type clad layer or through one or several crystal layers, and a second conductivity type directly on the active layer or through one or several crystal layers; Forming a first cladding layer of
A step of forming a constriction layer having a composition different from that of the second conductivity type first clad layer on the second conductivity type first clad layer, a part of the constriction layer is etched into a groove shape, and a current injection region is formed. Forming a second conductivity type second clad layer on the current injection region and the constriction layer,
The second clad layer of the second conductivity type located on the current injection region is left wider than the current injection region width, and the other second clad layer portion is removed by etching to have a small portion and a large portion. The method is characterized by including a step of forming a ridge and a step of removing the constriction layer by etching in this order.

Further, in the method of manufacturing a semiconductor laser device according to the present invention, the step of forming the first conductivity type clad layer on the first conductivity type semiconductor substrate directly or through one or several crystal layers, A step of forming an active layer directly on the first conductivity type clad layer or through one or several crystal layers, and a second conductivity type directly on the active layer or through one or several crystal layers; Forming a first cladding layer of
A step of forming a constriction layer having a composition different from that of the second conductivity type first clad layer on the second conductivity type first clad layer, a part of the constriction layer is etched into a groove shape, and a current injection region is formed. Forming a second conductivity type second clad layer that acts as a clad layer in cooperation with the second conductivity type first clad layer on the current injection region by selective epitaxial growth to reach the constriction layer. The process of spreading and forming,
A step of etching away the narrowing layer below the second cladding layer in this order.

In the method for manufacturing a semiconductor laser device according to the present invention, the step of forming the first conductivity type cladding layer directly on the first conductivity type semiconductor substrate or through one or several crystal layers, A step of forming an active layer directly on the first conductivity type clad layer or through one or several crystal layers, and a second conductivity type directly on the active layer or through one or several crystal layers; Forming a first cladding layer of
Forming a stripe-shaped amorphous film on a portion of the second conductivity type first clad layer where a current is to be injected; and using the amorphous film as a mask to form the first clad layer on the first clad layer. A step of forming a confinement layer having a composition different from that of the clad layer, a step of etching away the amorphous film to form a current injection region, and a step of forming a current injection region on the current injection region in cooperation with a first conductivity type first cladding layer. A second clad layer of the second conductivity type that acts as a clad layer by selective epitaxial growth, extending over the constriction layer to form, a step of etching away the constriction layer under the second clad layer, Is included in this order.

Further, in the method of manufacturing a semiconductor laser device according to the present invention, the step of forming the first conductivity type cladding layer directly on the first conductivity type semiconductor substrate or through one or several crystal layers, A step of forming an active layer directly on the first conductivity type clad layer or via one or several crystal layers, and a second conductivity type on the active layer directly or via one or several crystal layers. A step of forming a light guide layer, in the region to be injected current on the second conductivity type light guide layer,
A step of forming a stripe-shaped amorphous film, a step of etching and removing the amorphous film to form a current injection region, and a second conductivity type clad layer on the current injection region by selective epitaxial growth to form the constriction layer. The method is characterized by including, in this order, a step of extending and forming to the upper side, and a step of etching and removing the narrowing layer under the second clad layer.

[0020]

DETAILED DESCRIPTION OF THE INVENTION A semiconductor laser device according to a first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a sectional view of a semiconductor laser device.

With the addition of S (sulfur), the carrier concentration becomes 3 × 1.
On the surface of the n-type InP substrate 1 of about 0 ¹⁸ (cm ^-3 ), a carrier concentration of 1 × 10 ¹⁸ (c
m ⁻³ ) n-type InP clad layer 2 with a thickness of 7 nm and P
Impurity-free InGaAsP well layer with L (photoluminescence) emission wavelength of 1.35 μm and impurity-free InGaA with PL emission wavelength of 1.1 μm and thickness of 10 nm
A multi-quantum well active layer 3 consisting of 10 pairs of sP barrier layers, a carrier concentration of 1 by adding 0.3 μm thick Zn (zinc)
× 10 ¹⁸ (cm ⁻³ ) p-type InP first cladding layer 5 is M
The layers are sequentially formed by the OCVD method.

Further, Zn is added to the central portion of the upper surface of the p-type InP first cladding layer 5 so that the carrier concentration is 1 × 10.
¹⁸ (cm ⁻³ ) p-type InP second cladding layer and p-type In
Longitudinal T-shaped ridge 60 composed of GaAs contact layer
Are formed.

The ridge 60 has a width of 1.5 μm and a thickness of 0.2 μm formed in contact with the first cladding layer 5 in the direction in which the laser light should be guided. Width 10 micron integrally formed on 60A, thickness 1.
It is composed of a 5 μm large portion 60B and a ridge-shaped p-type InGaAs contact layer 70 formed on the large portion 60B. The small portion 60A acts as a current injection region, and the large portion 60B and the p-type InGaAs contact layer 70 act as an electrode formation region. Ridge 6
In No. 0, a 0.2-micron gap 9 is formed between the lower surface of the large-diameter portion 60B and the upper surface of the first cladding layer 5 around the small-diameter portion 60A.

Around the first cladding layer 5, the ridge 60
The side surface of the large-diameter portion 60A and the periphery of the contact layer 70 are covered with the silicon dioxide protective film 8 and exposed to the exposed p-type InGa.
A p-type electrode 10 is formed on the As contact layer 7.

On the other hand, on the back surface of the n-type InP substrate 1, an n-type electrode 11 is formed after the thickness is adjusted by polishing. In the semiconductor laser device described above, the ridge 60
Is composed of a small portion 60A and a large portion 60B, and the current injection region is formed by the small portion 60A having a width of 1.5 μm, so that stable single mode oscillation is possible. Further, since the p-type electrode is formed on the large-diameter portion 60B formed to have a width of 10 microns, the element resistance can be sufficiently reduced.

Since the p-type InP first cladding layer 5 and the lower surface of the large portion 60B around the small portion 60A of the ridge 60 are separated by the gap 9, the electrical breakdown voltage therebetween is high. Further, since the difference in refractive index between the p-type InP first cladding layer 5 and the air in the gap 9 is large, it is possible to oscillate in a stable mode up to a high optical output.

Next, a method of manufacturing the semiconductor laser device according to the second embodiment of the present invention will be described with reference to FIG. First, on the n-type InP substrate 1, the n-type InP clad layer 2 having a thickness of 2 μm is formed by the first MOCVD growth.
A multiple quantum well active layer 3 made of InGaAsP and a p-type InP first cladding layer 5 having a thickness of 0.3 μm are sequentially stacked (FIG. 2A).

Next, a first silicon dioxide film 21 which is an amorphous layer is formed on the entire surface of the p-type InP first cladding layer 5, and then the first dioxide is formed in a stripe shape having a width of about 1.5 μm. The silicon film 21 is left and the others are removed, and the striped first silicon dioxide film 21 is used as a mask to selectively grow the n-type InGaAs layer 22 to be a confinement layer on the first cladding layer 5 (FIG. 2). (B)).

Subsequently, the first silicon dioxide film 21 is removed by etching, and the n-type InGaAs 22 and the p that serve as the confinement layer are formed.
The p-type InP second clad layer 6 and the p-type InGaAs contact layer 7 are grown in this order on the type InP first clad layer 5 by the second MOCVD method (FIG. 2).
(C)).

Subsequently, the p-type InGaAs contact layer 7
A second silicon dioxide film 23 is formed on the second silicon dioxide film 23 and is removed by etching, leaving only the portion where the ridge is to be formed (FIG. 2).
(D)). Next, the p-type InGaAs contact layer 7 and the p-type InP second cladding layer 6 are selectively etched by using the second silicon dioxide film 23 as a mask, and the first cladding layer 5 is formed.
A ridge 60 having a small portion 60A formed in contact with the small portion 60A, a large portion 60B integrally formed on the small portion 60A, and a p-type InGaAs contact portion 70 is formed (FIG. 2).
(E)).

After that, the n-type I on the first cladding layer 5 is formed.
The nGaAs layer 22 is removed by etching, and the lower surface of the large portion 60B around the small portion 60A of the ridge 60 and the first cladding layer 5 are removed.
A gap 9 is formed between the upper surface and the upper surface (FIG. 2 (F)).

Next, the silicon dioxide protective film 8 is formed on the periphery of the upper surface of the first cladding layer 5, the side surface of the large portion 60B of the ridge 60, the side surface of the contact layer 70 and the entire upper surface. The protective film 8 is not formed in the gap on the lower surface of the large portion 60B of the ridge 60.

The silicon dioxide protective film 8 may be formed by, for example, a vacuum evaporation method having a strong anisotropy. Next, only the silicon dioxide protective film 8 in the portion where the p-type electrode is to be formed on the contact layer 70 is removed by etching to provide the contact window 7A (FIG. 2 (G)).

Subsequently, a p-type electrode 10 made of AuZn is formed on the contact layer 70 in the contact window 7A portion, and the back surface of the n-type InP substrate is polished to an appropriate thickness if necessary, and then n-type made of AuGe is formed. The electrode 11 is formed to obtain the semiconductor laser device shown in FIG. 1 (FIG. 2 (H)).

According to the above manufacturing method, the first silicon dioxide film 21 is used to form the small portion 60A of the ridge 60 which becomes the current injection region, and the second silicon dioxide film 23 different from this is formed. Is used to form the large-diameter portion 60B of the ridge 60 as an electrode formation region, and a ridge having a current injection region of 1.5 μm width and a wide electrode formation area of 10 μm or more can be easily obtained. .

Next, a method of manufacturing the semiconductor laser device according to the third embodiment of the present invention will be described with reference to FIG. Here, the same parts as those in FIG.

FIG. 3A shows an n-type InP clad layer 2,
An n-type InGaAs layer 22 is formed on the double hetero structure including the multiple quantum well active layer 3 and the p-type InP first cladding layer 5.
Are continuously formed.

Here, a resist film 41 having an opening is formed in a portion where a current injection portion is to be provided in a later step, and the n-type InGaAs layer 22 is formed using the resist film 41 as a mask.
Is selectively etched (FIG. 3B).

Subsequently, after removing the resist film 41,
The p-type InP second cladding layer 6 and the p-type InGaAs contact layer 7 are formed in this order by the same method as in the above-described FIG. 2C (FIG. 3C).

After that, a semiconductor laser device can be obtained by the method described in the description of FIGS. 2D to 2H. The semiconductor laser device manufacturing method according to the third embodiment of the present invention shown here has the following unique effect in addition to the effects of the semiconductor laser device manufacturing method described above. . That is, the second MOCV
Since the contact layer is also grown by D growth, the crystal growth process until the semiconductor laser device is manufactured can be completed in two times, and the process can be simplified.

Next, a method of manufacturing the semiconductor laser device according to the fourth embodiment of the present invention will be described with reference to FIG.
Here, of the numbers given to the drawings, the same parts as those in FIG. 2 are given the same numbers and their explanations are omitted.

First, a first MO film is formed on the n-type InP substrate 1.
By CVD growth, an n-type InP clad layer 2 having a thickness of 2 μm, a multiple quantum well layer 3 made of InGaAsP, and a p-type InP first clad layer 5 having a thickness of 0.3 μm are sequentially formed (FIG. 4A). )). Next, after forming a first silicon dioxide film on the entire surface of the p-type InP first cladding layer 5, only the stripe-shaped first silicon dioxide film 21 having a width of about 1.5 μm is left and the others are removed. Furthermore, the second M
The first silicon dioxide film 21 other than the first silicon dioxide film 21 formed by the OCVD growth.
The n-type InGaAs layer 22 is selectively grown on the clad layer 5 of FIG. 4 (FIG. 4 (B)).

Then, the first silicon dioxide film 21 is removed, and the second silicon dioxide film 63 is formed on the entire surfaces of the n-type InGaAs layer 22 and the first cladding layer 5 again. Furthermore,
The portion of the second silicon dioxide film 63 including the portion of the first cladding layer 5 exposed from the confinement layer 22 where a ridge having a width of about 10 μm is to be formed is removed in stripes (FIG. 4).
(C)).

Next, using the second silicon dioxide film 63 as a mask, the p-type InP second clad layer and p-type InGaAs are formed.
The p-type I contact layer formed by selectively forming the contact layer continuously by the third MOCVD growth and contacting the first cladding layer 5 is formed.
A ridge 64 including a small portion 64A made of the nP second clad layer, a large portion 64B integrally formed on the small portion 64A, and a p-type InGaAs contact layer 65 integrally formed on the large portion 64B. To form. At this time, the side surface 66 of the ridge forms a (111) plane and grows in a trapezoidal shape (FIG. 4D).

Subsequently, the p-type InGaAs contact layer 6
The side surface 66 of the large-sized portion 64B of the ridge layer 64 is etched with a hydrochloric acid-based etching solution using the fifth and second silicon dioxide films 63 as a mask. As a result, the ridge side surface 66
The crystal plane orientation of the surface of

[0046]

[Outside 1] To form a ridge side surface 73 perpendicular to the substrate surface, and an opening 67 is formed between the ridge side surface 66 and the second silicon dioxide film 63.

When such etching is performed,
Undercut does not occur in the InP clad layer below the InGaAs contact layer 65. Then, the n-type InGaAs layer 22 exposed from the opening is etched through the opening with a sulfuric acid-based etching solution to remove the ridge layer 64.
The n-type InGaAs layer 22 under the large portion 64B is completely removed. As a result, a gap 9 is formed between the lower surface of the large diameter portion 64B of the ridge 64 and the upper surface of the first cladding layer 5 (FIG. 4 (E)). Subsequently, after the silicon dioxide protective film 8 is formed on the entire surface of the substrate, the silicon dioxide protective film 8 is removed only on the portion of the contact layer 65 above the ridge 64 where the p-type electrode is to be formed, the contact window 7 is opened, and lift-off is performed. By the method, the p-type electrode 10 made of AuZn is formed.

Subsequently, the back surface of the substrate is polished to have an appropriate thickness, and then the n-type electrode 11 is formed on the back surface of the substrate by AuGe.
To form a semiconductor laser device (FIG. 4 (F)). According to the method for manufacturing a semiconductor laser device according to the fourth embodiment of the present invention described above, in addition to the advantages described in the method for manufacturing a semiconductor laser device according to the second embodiment of the present invention, the following advantages There is. That is, since the ridge 64 is formed by selective growth, growth can be performed in a self-aligned manner, mask alignment is not required, and manufacturing is simple.

Next, a semiconductor laser device according to the fifth embodiment of the present invention will be described in detail with reference to FIG.
5A is a cross-sectional view of the semiconductor laser device, FIG.
FIG. 6 is a cross-sectional view in the XY direction of FIG.

5 (A) and 5 (B), the same parts as those in FIG. 1 are designated by the same reference numerals, and the description of the same parts will be omitted. As shown in FIG. 5A, here, 0.2 μm of p-type InGaAs is formed on the multiple quantum well active layer 3.
A P light guide layer 4 is placed. Further, as shown in FIG. 5B, a grating is formed on the p-type InGaAsP light guide layer 4 according to the oscillation wavelength of the semiconductor laser device.

According to the semiconductor laser device of the fifth embodiment, in addition to the features of the semiconductor laser device of the first embodiment, the oscillation wavelength can be controlled by the grating.

In the above description of each embodiment, n-type In
Although the semiconductor laser device using the P substrate and having the active layer of the multiple quantum well structure has been described, the application of the present invention is not limited to this, and the semiconductor laser device of the double hetero structure and the GaAs substrate are used. Formed GaAl
It goes without saying that it can be applied to a semiconductor laser device using As, GaAsP, GaAlAsP or the like for the active layer and the cladding layer. An optical guide layer may be used instead of the first cladding layer.

Further, in each of the above-mentioned embodiments, an insulating material having a small refractive index such as silicon dioxide, silicon nitride, or strontium oxide may be filled in the gap between the lower surface of the large portion of the ridge and the upper surface of the first cladding layer. Good.

In this case, for example, the refractive index of the silicon dioxide film is about 1.5, which is larger than that of gas,
It is sufficiently smaller than that of InP, and the silicon dioxide film is a dielectric, and the p-type InP first cladding layer 5 and the p-type I
The electrical breakdown voltage between the nP second cladding layer 6 and the nP second cladding layer 6 can be made sufficiently large, and the effects of the present invention can be enjoyed. Further, the ridge may be formed in an inverted convex shape or an inverted trapezoidal shape in vertical section.

[0055]

As described above, according to the present invention, a ridge type semiconductor laser device capable of oscillating in a fundamental guided mode and having a low element resistance can be obtained.

[Brief description of drawings]

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

FIG. 2 is a manufacturing step sectional view of a semiconductor laser device according to a second embodiment of the present invention.

FIG. 3 is a part of a manufacturing process sectional view of a semiconductor laser device according to a third embodiment of the present invention.

FIG. 4 is a part of a manufacturing process sectional view of a semiconductor laser device according to a fourth embodiment of the present invention;

FIG. 5 is a sectional view of a semiconductor laser device according to a fifth embodiment of the present invention.

FIG. 6 is a part of a cross-sectional view of a manufacturing process of a conventional semiconductor laser device.

[Explanation of symbols]

1, 81 ... n-type InP substrate 2, 82 ... n-type InP clad layer 3, 83 ... multiple quantum well active layer 4, 84 ... p-type InGaAsP optical guide layer 5 ... p-type InP first clad layer 85 ... p-type InP clad layer 6 ... p-type InP second clad layer 60, 64, 94 ... Ridge 60A, 64A ... Ridge portion 60B, 64B ... Large part of ridge 65, 70 ... Ridge-shaped p-type InGaAs contact layer 7, 87 ... P-type InGaAs contact layer 8 ... Silicon dioxide protective film 88 ... Second silicon dioxide protective film 9 ... Gap 10, 90 ... p-type electrode 11, 91 ... n-type electrode 7A, 92 ... contact window 21 ... first silicon dioxide film (amorphous film) 22 ... n-type InGaAs layer (narrowing layer) 23, 63 ... second silicon dioxide film 66 ... ridge sides 67 ... opening 73 ... vertical ridge sides 93 ... the first silicon dioxide film (amorphous film)

Claims (8)

[Claims] 1. A first-conductivity-type semiconductor substrate, a first-conductivity-type clad layer formed on the first-conductivity-type semiconductor substrate directly or through one or several crystal layers, and the first-conductivity-type semiconductor substrate. An active layer formed directly on the mold cladding layer or via one or several crystal layers, and a second conductivity type formed on the active layer directly or via one or several crystal layers A first clad layer and a ridge formed on the second conductivity type first clad layer directly or through one or several crystal layers, and the ridge is a current injection device of the first clad layer. A small portion formed in the region and a large portion which is integrally formed on the small portion and has a large area and which forms a gap between the lower surface around the small portion and the upper surface of the first cladding layer. A semiconductor laser comprising a second-conductivity-type cladding layer having Location. 2. The cross-sectional structure of the ridge is any of a T-shape, an inverted convex shape, and a trapezoidal shape.
3. The semiconductor laser device according to claim 1. 3. The insulating material is filled in a gap between the lower surface of the large portion around the small portion of the ridge and the first clad layer. Semiconductor laser device. 4. A step of forming a first-conductivity-type clad layer directly on the first-conductivity-type semiconductor substrate or via one or several crystal layers, and directly or one-layer on the first-conductivity-type clad layer. To a step of forming an active layer via several crystal layers, a step of forming a second conductivity type first clad layer directly on the active layer or via one to several crystal layers,
Forming a stripe-shaped amorphous film on a portion of the second conductivity type first clad layer where a current should be injected; and using the amorphous film as a mask, the first clad layer on the first clad layer A step of forming a confinement layer having a different composition from that of the layer, a step of etching and removing the amorphous film to form a current injection region, and a second conductivity type first cladding on the current injection region and the confinement layer Forming a second conductivity type second clad layer that acts as a clad layer in cooperation with the layer, etching away a portion of the second conductivity type second clad layer,
A method of manufacturing a semiconductor laser device, comprising: a step of forming a ridge having a width wider than that of the current injection region; and a step of etching away the constriction layer from the side surface of the ridge. 5. A step of forming a first-conductivity-type clad layer directly on the first-conductivity-type semiconductor substrate or through one or several crystal layers, directly or one-layer on the first-conductivity-type clad layer. To a step of forming an active layer via several crystal layers, a step of forming a second conductivity type first clad layer directly on the active layer or via one to several crystal layers,
A step of forming a constriction layer having a composition different from that of the second conductivity type first clad layer on the second conductivity type first clad layer, a part of the constriction layer is etched into a groove shape, and a current injection region is formed. Forming a second conductivity type second clad layer on the current injection region and the constriction layer,
The second clad layer of the second conductivity type located on the current injection region is left wider than the current injection region width, and the other second clad layer portion is removed by etching to have a small portion and a large portion. A method of manufacturing a semiconductor laser device, comprising a step of forming a ridge and a step of etching and removing the constriction layer in this order. 6. A step of forming a first-conductivity-type clad layer directly on the first-conductivity-type semiconductor substrate or through one or several crystal layers, and directly or one-layer on the first-conductivity-type clad layer. To a step of forming an active layer via several crystal layers, a step of forming a second conductivity type first clad layer directly on the active layer or via one to several crystal layers,
A step of forming a constriction layer having a composition different from that of the second conductivity type first clad layer on the second conductivity type first clad layer, a part of the constriction layer is etched into a groove shape, and a current injection region is formed. Forming a second conductivity type second clad layer that acts as a clad layer in cooperation with the second conductivity type first clad layer on the current injection region by selective epitaxial growth to reach the constriction layer. The process of spreading and forming,
A method of manufacturing a semiconductor laser device, comprising: a step of etching away the constriction layer below the second cladding layer in this order. 7. A step of forming a first-conductivity-type clad layer directly on the first-conductivity-type semiconductor substrate or through one or several crystal layers, and directly or one-layer on the first-conductivity-type clad layer. To a step of forming an active layer via several crystal layers, a step of forming a second conductivity type first clad layer directly on the active layer or via one to several crystal layers,
Forming a stripe-shaped amorphous film on a portion of the second conductivity type first clad layer where a current is to be injected; and using the amorphous film as a mask to form the first clad layer on the first clad layer. A step of forming a confinement layer having a composition different from that of the clad layer, a step of etching away the amorphous film to form a current injection region, and a step of forming a current injection region on the current injection region in cooperation with a first conductivity type first cladding layer. A second clad layer of the second conductivity type that acts as a clad layer by selective epitaxial growth, extending over the constriction layer to form, a step of etching away the constriction layer under the second clad layer, A method of manufacturing a semiconductor laser device, comprising: 8. A step of forming a first-conductivity-type clad layer directly on the first-conductivity-type semiconductor substrate or through one or several crystal layers, and directly or one-layer on the first-conductivity-type clad layer. To a step of forming an active layer via several crystal layers, a step of forming a second conductivity type optical guide layer directly on the active layer or via one to several crystal layers, the second conductivity In the area where the current should be injected on the light guide layer of the mold,
A step of forming a stripe-shaped amorphous film, a step of etching and removing the amorphous film to form a current injection region, and a second conductivity type clad layer on the current injection region by selective epitaxial growth to form the constriction layer. A method of manufacturing a semiconductor laser device, comprising: a step of forming the layer extending upward and a step of removing the constriction layer below the second cladding layer by etching in this order.