JP2839337B2 - Visible light semiconductor laser - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visible light semiconductor laser, and more particularly, to AlGaIn
The present invention relates to a visible light semiconductor laser that can prevent the evaporation of phosphorus from the cladding layer and the active layer during the growth of the current blocking layer in the laser structure having the active layer and the cladding layer made of a P-based material and can achieve a long life. .

[Conventional technology]

FIG. 9 is a cross-sectional view showing the structure of a conventional visible light semiconductor laser, in which 1 is an n-type (hereinafter referred to as n-) Ga.
As substrate, 2 is n- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower cladding layer, 3 is undoped Ga _0.5 In _0.5 P active layer, 4 is p-type (hereinafter referred to as p-) (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper cladding layer, 5 is a p-Ga _0.5 In _0.5 P buffer layer, 6 is an n-GaAs current blocking layer, 7 a and 7 b are p-GaAs contact layers, 8 is n
A side electrode, 9 is a p-side electrode, and 10 is a ridge. The typical thickness of each layer is 1.0 μm for the lower cladding layer 2 and 0.0 μm for the active layer 3.
The portion of the upper cladding layer 4 other than the ridge, that is, the portion sandwiched between the active layer 3 and the current blocking layer 6 is 0.8 μm.
3 μm, the ridge portion of the upper cladding layer 4 is 1.0 μm, the buffer layer 5 is 0.1 μm, the current block layer 6 is 1.1 μm, and the contact layers 7a are 0.3 μm and 7b are 3.0 μm. Also ridge
The width of 10 is 4 μm.

Next, the operation will be described. P-side electrode 9 and n-side electrode 8
When a forward voltage is applied during this period, the current flows only through the ridge 10 because of the current blocking layer 6. Since the lower clad layer 2, the active layer 3, and the upper clad layer 4 have a double hetero structure, a portion near the ridge of the active layer 3 emits light by the current injected from the ridge 10, and laser oscillation occurs.

In this laser, the following measures have been devised to stabilize the transverse mode of the laser light. The active layer 3 is 0.
Since it is as thin as 08 μm, the light emitted from the active layer exudes about 0.5 μm into the upper and lower cladding layers. However, since the upper cladding layer 4 has a thickness of only 0.3 μm outside the ridge, light emitted from the active layer 3 reaches the current blocking layer 6.
The current blocking layer is made of GaAs, and absorbs light because the band gam is smaller than that of the active layer Ga _0.5 In _0.5 P. On the other hand, in the ridge portion 10, since the upper cladding layer 4 is as thick as 1.0 μm, all the light emitted from the active layer 3 remains in the upper cladding layer and is not absorbed. That is, light absorption does not occur in the ridge portion, but light absorption occurs outside the ridge. Therefore,
An effective refractive index difference occurs between the ridge portion and the outside of the ridge, so that light is confined in the lateral direction, so that a so-called loss guide (optical waveguide mechanism using loss) is formed. Ridge width 4
By making the width narrower to about μm, laser oscillation can be performed in a stable fundamental transverse mode.

Next, the manufacturing process of this visible light semiconductor laser will be described. FIG. 10 is a sectional view showing a process flow. In the figure, the same reference numerals as those in FIG. 9 denote the same or corresponding parts,
11 is a SiN film.

First, as shown in FIG. 10 (a), an n- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower cladding layer 2, an undoped Ga _0.5 In _0.5 P active layer 3, a p- (Al _0.5 Ga _0.3 ) _0.5 In
_0.5 P upper cladding layer _{4, p-Ga 0.5 In 0.5} P buffer layer 5, and successively growing a p-GaAs contact layer 7a. The growth method is
Metal organic chemical vapor deposition (MOCVD) is used. Typical growth temperatures are 650-700 ° C. While the temperature of the GaAs substrate 1 is being raised, AsH ₃ gas is flowed into the reaction tube in order to prevent thermal decomposition of the substrate. As the growth starts, the AsH ₃ gas is cut off, and PH ₃ , tolmethylaluminum, trimethylgallium, trimethylindium, etc., which are the source gases of the AlGaInP-based semiconductor, are flown. After the growth of each of the layers 2 to 5, an 8 μm-wide SiN film 11 is formed on the contact layer 7a as shown in FIG. 10 (b). Then this S
Using the iN film 11 as an etching mask, the contact layer 7a, the buffer layer 5, and the upper cladding layer 4 are etched, and FIG.
A ridge 10 is formed as shown in FIG. Next, using the SiN film 11 as a mask, the n-GaAs current blocking layer 6 is selectively grown as shown in FIG. At this time, while raising the temperature of the substrate on which the ridge is formed, PH ₃ is supplied so that the (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper clad layer 4 is not decomposed. The n-GaAs current cut PH ₃ with the growth of a block layer, AsH ₃ becomes GaAs materials, flow SiH ₄ or H ₂ Se as the trimethyl gallium and n-type dopant gas. After growing the n-GaAs current block layer, the SiN film 11 is removed, and a P-GaAs contact layer 7b is grown as shown in FIG. Finally, p- and n-side electrodes are formed by vapor deposition as shown in FIG. 10 (f), and the semiconductor laser shown in FIG. 9 is completed.

[Problems to be solved by the invention]

The conventional visible semiconductor laser is configured as described above, and the n-GaAs layer is used as the current blocking layer as described above.

In the current block layer growth step, as described above,
While the ridge-formed substrate is being heated to the growth temperature of the current block layer, the growth apparatus is set to a PH ₃ atmosphere to apply phosphorous pressure to the substrate, and phosphorus evaporates from the cladding layer and the active layer to crystallize these layers. Although prevents the defect from entering, at the same time device atmosphere n-GaAs layer growth starting must switch from PH ₃ to AsH _3. For this reason, during the growth of the GaAs layer, especially when the GaAs layer is thin in the initial stage of growth, there is no phosphorous pressure (Al
_0.7 Ga _0.3 ) _0.5 In _0.5 P From the upper cladding layer, P is likely to evaporate and crystal defects are likely to occur, and the Ga _0.5 In _0.5 P active layer outside the ridge is only 0.3 μm away from the surface (Al _0.7 Ga
_0.3 ) _0.5 In _0.5 P Not only the upper cladding layer but also Ga _0.5 In _0.5 P
The active layer also has crystal defects. The active layer is a layer that directly contributes to laser oscillation and is sensitive to defects. As a result, there is a problem that the life of the laser is shortened.

Here, the crystal of the composition of the flow PH ₃ to apply a phosphorus pressure even during GaAs current blocking layer 6 grown _{GaAs 1-x P x (0} <x <1) is deposited, GaAs _1-x P _x is (Al _0.7 Ga _0.3 )
Since there is no lattice matching with the _0.5 In _0.5 P cladding layer, it is difficult to obtain a single crystal layer.

Also, instead of the GaAs current block layer, (Al _x Ga _1-x )
_{When a 0.5} In _0.5 P (0 <x ≦ 1) current block layer is used,
Phosphorus pressure can be applied during growth, but because the band gap is larger than the active layer, it does not absorb light emitted by the active layer. Therefore, the transverse mode cannot be stabilized by the loss guide. (Al _x Ga _1-x ) _0.5 In _0.5 P When the Al composition of the P current block layer is larger than the Al composition of the cladding (x> 0 in this example).
In 7), optical waveguide can be provided by a real refractive index difference instead of a loss guide, but there is a problem that crystal growth is difficult when the Al composition is large.

The present invention has been made in order to solve the above-mentioned problems, and can prevent crystal defects from entering due to evaporation of phosphorus from a cladding layer and an active layer during the growth of a current blocking layer. It is an object of the present invention to provide a visible light semiconductor laser capable of realizing both transverse mode stability and long life by a loss guide by giving a light absorption effect to a block layer.

[Means for solving the problem]

The visible light semiconductor laser according to the present invention has an InGaAsP containing P which is lattice-matched with GaAs except for InGaP as a current blocking layer.
It uses a base material.

An upper cladding layer covering the active layer with a predetermined thickness; and a second upper cladding layer disposed in a ridge shape on a part of the surface of the first upper cladding layer. And an etching stopper layer is provided on the surface of the first upper cladding layer, and a current blocking layer is provided via the etching stopper layer.

[Action]

In the present invention, the current blocking layer is made of an InGaAsP-based material containing P, which is lattice-matched with GaAs except for InGaP, so that a phosphorous pressure can be applied even during the growth of the current blocking layer, and the active layer made of the AlGaInP-based material can be used. Further, it is possible to prevent crystal defects from entering the upper cladding layer.

InxGa _1-x As _1-y P _y is (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P
Since it is lattice-matched with the layer, a high-quality single crystal can be grown on the (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding, and the band gap is smaller than that of the Ga _0.5 In _0.5 P active layer. Absorption allows stabilization of the transverse mode by the loss guide.

Further, an upper cladding layer includes a first upper cladding layer and a second ridge disposed on the surface of the first upper cladding layer.
GaAs except for InGaP
Since the current blocking layer made of an InGaAsP-based material that is lattice-matched with that of P and is disposed on the surface of the first upper cladding layer via the etching stopper layer, the current blocking layer has high crystallinity.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

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

The structure of the present embodiment is the same as the conventional example except that the material of the current blocking layer is different. In the figure, 1
Is an n-GaAs substrate, 2 is an n- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower cladding layer, 3 is an undoped Ga _0.5 In _0.5 P active layer, and 4 is a p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper layer. Cladding layer, 5 is p-
Ga _0.5 In _0.5 P buffer layer, 7a and 7b are p-GaAs contact layers, 8 is an n-side electrode, 9 is a p-side electrode, 10 is a ridge, and 12 is n
-In _1-x Ga _x As _1-y P _y current blocking layer. In addition, In _1-x Ga
_x As _1-y P _y has a band gap more than the Ga _0.5 In _0.5 P active layer in the range of lattice matching with (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P, that is, the x, y composition in the range of lattice matching with GaAs. Becomes smaller.

FIG. 2 shows the relationship between the composition of x, y of In _1-x Ga _x As _1-y P _y , the band gap, and the lattice constant. In the drawing, the combination of x and y that lattice-match with GaAs is indicated by a broken line. This x, y
, The band gap is always smaller than Ga _0.5 In _0.5 P.

Next, the manufacturing process of this embodiment will be described. FIG. 3 is a sectional view showing a manufacturing process of the semiconductor laser of FIG.
In the figure, the same reference numerals as in FIG. 1 denote the same or corresponding parts, and 11 denotes a SiN film.

First, as shown in FIG. 3A, an n- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower cladding layer 2, an undoped Ga _0.5 In _0.5 P active layer 3, p- ( Al _0.7 Ga _0.3 ) _0.5 In _0.5
P upper cladding layer 4, p-Ga _0.5 In _0.5 P buffer layer 5, p-GaAs
The contact layer 7a is sequentially grown. A typical growth temperature of these layers is 650 to 700 ° C., and while raising the temperature of the GaAs substrate 1, an AsH ₃ gas is flowed into the reaction tube to prevent thermal decomposition of the substrate. As the growth starts, the AsH ₃ gas is turned off, and PH ₃ , trimethylaluminum, trimethylgallium, trimethylindium, etc., which are the source gases of the AlGaInP-based semiconductor, are flown. After the above layers are grown, an 8 μm wide SiN film 11 is formed on the contact layer 7a as shown in FIG. 3 (b). The formation temperature of the SiN film is
200 ° C. Next, using the SiN film 11 as a mask, the contact layer 7a, the buffer layer 5, and the upper cladding layer 4 are etched as shown in FIG. Up to this point, it is the same as the conventional example.

Then the SiN film 11 as a mask, as shown in FIG. 3 (d), is selectively grown _{n-In 1-x Ga x} As 1-y P y current blocking layer 12. This In _1-x Ga _x As _1-y P _y is grown by the metal organic chemical vapor deposition (MOCVD) like the other layers. A typical growth temperature is 600 ° C. When raising the temperature of the substrate on which the ridge is formed to 600 ° C, apply PH ₃ (diluted in 10% hydrogen base) at 300 cc / min to apply phosphorus pressure to prevent crystal defects from entering the upper cladding layer and the active layer. I have. flow _{n-In 1-x Ga x} As 1-y P y growth starting with trimethylindium simultaneously as a material, trimethyl gallium, H ₂ Se or SiH ₄ as the AsH _3, PH ₃ and n-type dopants. As described above, PH ₃ flows during the growth of the current blocking layer 12 and a phosphorus pressure is applied, so that p- (Al _0.7 Ga
_0.3 ) _0.5 In _0.5 P Phosphorus hardly evaporates from the upper cladding layer 4 and crystal defects hardly enter. Although the active layer 3 is only 0.3 μm away from the regrown surface outside the ridge, crystal defects are unlikely to occur because of the phosphorus pressure. Therefore, in the present embodiment, since the upper clad layer and the active layer are less likely to have crystal defects in the manufacturing process, the present embodiment can realize a longer laser life.

Thereafter, the SiN film 11 is removed, a p-GaAs contact layer 7b is grown as shown in FIG. 3 (e), and the n-side electrode 8 is contacted on the back surface of the substrate 1 as shown in FIG. 3 (f). The laser element is completed by forming the p-side electrode 9 on the layer 7b.

As described above, in the present embodiment, the phosphorus pressure can be applied even during the growth of the current blocking layer. Since the current blocking layer can be grown at a lower temperature than the GaAs current blocking layer, there is an effect that crystal defects are less likely to enter the upper cladding layer and the active layer. In other words, GaAs has a minimum growth temperature of about 650 ° C for good crystal growth,
In _1-x Ga _x As _1-y P _y used in the current block layer of this embodiment is 6
Good crystal growth is possible at about 00 ° C., and the temperature of the current block layer growth step can be lowered by about 50 ° C., whereby phosphorus is less likely to evaporate from the upper cladding layer and the active layer, and crystal defects are reduced. Is difficult to enter.

Next, the operation of the laser of the present embodiment manufactured in the above-described manufacturing process will be described.

When a forward voltage is applied between the p-side electrode 9 and the n-side electrode 8, the current flows only the ridge portion 10 because of the _{n-In 1-x Ga x} As 1-y P y current blocking layer 12. Since the lower clad layer 2, the active layer 3, and the upper clad layer 4 have a double hetero structure, a portion near the ridge of the active layer 3 emits light by the current injected from the ridge 10, and laser oscillation occurs.

In this laser, the following measures have been devised to stabilize the transverse mode of the laser light. The active layer 3 is 0.
Since it is as thin as 08 μm, the light emitted from the active layer exudes about 0.5 μm into the upper and lower cladding layers. However, since the upper cladding layer 4 has a thickness of only 0.3 μm outside the ridge, the light emitted from the active layer 3 is not reflected on the In _{1 -x} Ga _x As _{1 -y} P _y current blocking layer 1.
Reach up to 2. As can be seen from FIG. 2, the band gap of the In _1-x Ga _x As _1-y P _y current blocking layer 12 is Ga _0.5 In _0.5 P
The light generated in the active layer 3 is absorbed by the current blocking layer 12 because it is smaller than the band gap of the active layer. On the other hand, in the ridge portion 10, since the upper cladding layer 4 is as thick as 1.0 μm, all the light emitted from the active layer 3 remains in the upper cladding layer and is not absorbed. That is, light absorption does not occur in the ridge portion, but light absorption occurs outside the ridge. Therefore, an effective refractive index difference occurs between the ridge portion and the outside of the ridge, so that light is confined in the lateral direction, so that a so-called loss guide (optical waveguide mechanism using loss) is formed. In such a structure, laser oscillation can be performed in a stable fundamental transverse mode by reducing the ridge width to about 4 μm.

FIG. 4 is a sectional view showing the structure of a visible light semiconductor laser according to a second embodiment of the present invention. In the drawing, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and reference numeral 15 denotes an etching stopper layer made of p-GaInP or p-AlGaInP.

In this embodiment, in order to control the distance between the active layer 3 and the current blocking layer 12 with good reproducibility, these cladding layers are selectively etched between the first upper cladding layer 4a and the second upper cladding layer 4b. Stopper layer made of material that can be used
15 is inserted.

FIG. 5 is a sectional view showing the structure of a visible light semiconductor laser according to a third embodiment of the present invention. In the figure, the same reference numerals as in FIG. 1 denote the same or corresponding parts, and 15 denotes an etching stopper layer made of p-GaInP or p-AlGaInP, 10 '.
Is a forward mesa ridge.

This embodiment also has a configuration in which an etching stopper layer 15 is inserted in order to control the thickness of the first upper cladding layer 4a, that is, the distance between the active layer 3 and the current blocking layer 12 with good reproducibility. Also, the ridge shape of the laser shown in FIGS. 1 and 4 is an inverted mesa, whereas this embodiment is a forward mesa.

Next, the manufacturing process of this embodiment will be described. FIG. 6 is a sectional view showing a manufacturing process of the semiconductor laser of FIG. 5,
In the figure, the same reference numerals as those in FIG. 3 denote the same or corresponding parts.

First, as shown in FIG. 6 (a), on the n-GaAs substrate _{1 n- (Al 0.7 Ga 0.3)} 0.5 In 0.5 P lower cladding layer 2, an undoped Ga _0.5 In _0.5 P active layer 3, p-( Al _0.7 Ga _0.3 ) _0.5 In _0.5
P first upper cladding layer 4a, p-AlGaInP etching stopper layer 15, p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P second upper cladding layer 4
b, p-Ga _0.5 In _0.5 P buffer layer 5, p-GaAs contact layer 7a
Grow sequentially. Here, the Al composition ratio of the etching stopper layer 15 is considerably smaller than the Al composition ratio of the cladding layer in order to enable selective etching with the cladding layer, and its thickness is as very thin as 40 ° to 200 °. It is. Next, an SiN film 11 is formed on the contact layer 7a as shown in FIG. 6 (b). Next, using the SiN film 11 as a mask,
The ridge 10 is formed by etching the contact layer 7a, the buffer layer 5, and the second upper cladding layer 4b by selective etching using the etching stopper layer 15, as shown in FIG. 6C. Thereafter, using the SiN film 11 as a mask, FIG.
As shown in the figure, the n-In _1-x Ga _x As _1-y P _y current block layer 12
Is selectively grown by MOCVD. Here, the etching stopper layer has a composition in which Al is considerably smaller than that of the cladding layer as described above, but in AlGaInP, the smaller the amount of Al, the easier it is to be thermally decomposed, and by increasing the substrate temperature for subsequent crystal growth. Although surface roughness occurs, it is difficult to form a current block layer with good crystallinity,
The growth temperature of the n-In _1-x Ga _x As _1-y P _y current block layer 12 is about 6
Since the temperature is relatively low at 00 ° C., the etching stopper layer is not roughened, and a current blocking layer having high crystallinity can be formed. Thereafter, the SiN film 11 is removed, and FIG.
As shown in FIG. 6, a p-GaAs contact layer 7b is grown, and finally, as shown in FIG.
The laser element is completed by forming the p-side electrode 9 on the contact layer 7b.

The manufacturing process of the semiconductor laser according to the second embodiment of the present invention shown in FIG. 4 is exactly the same as the manufacturing process of the semiconductor laser according to the third embodiment, except for the shape of the ridge.

FIG. 7 is a sectional view showing the structure of a visible light semiconductor laser according to a fourth embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and 13 denotes a stripe-shaped groove forming a current path provided in the current block layer 12,
14a is _{p- (Al 0.7 Ga 0.3) 0.5} In 0.5 P first upper cladding layer, 14b is _{p- (Al 0.7 Ga 0.3) 0.5} In 0.5 P second upper cladding layer. The thickness of the p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P first upper cladding layer 14a is about 0.3 μm, and the width of the groove 13 is about 4 μm. Next, the operation of the laser diode will be described. When a voltage is applied between the electrodes 8 and 9, the current is
It flows through the inside, and the portion below the groove of the active layer 3 emits light, and laser oscillation occurs. _{n-In x Ga 1-x} As 1-y P y current blocking layer also serves as an absorption layer of light, the transverse mode is stabilized on the same principle as the above embodiment.

 Next, the manufacturing process of this embodiment will be described with reference to FIG.

First, as shown in FIG. 8 (a), on the n-GaAs substrate _{1 n- (Al 0.7 Ga 0.3)} 0.5 In 0.5 P lower cladding layer 2, an undoped Ga _0.5 In _0.5 P active layer 3, p-( Al _0.7 Ga _0.3 ) _0.5 In _0.5
P first upper cladding layer 4a, sequentially grown _{n-In 1-x Ga x} As 1-y P y current blocking layer 12. Here, considering that n-GaAs is grown as a current blocking layer, p- (Al _0.7 GA
_0.3 ) _0.5 In _0.5 P Phosphorus pressure is applied by flowing PH ₃ in the growth apparatus until the first upper cladding layer 4a is grown, but n-GaAs
Cut the PH ₃ with the onset of growth, for the flow of AsH ₃ in place, the cladding layer in the GaAs when the current blocking layer is several tens of Å and thin in the initial growth stages of the blocking layer, and not sufficiently protect the active layer, Phosphorus evaporates from the cladding layer and the active layer, causing crystal defects. However, in the present embodiment, since n-In _1-x Ga _x As _1-y P _y is used as the current blocking layer, a phosphorus pressure is applied even in the initial stage of the growth of the current blocking layer 12, whereby Crystal defects can be prevented by evaporation of phosphorus from the cladding layer and the active layer. Next, a mask pattern 11 is formed as shown in FIG. 8B, and a stripe groove 13 for a current path is formed in the current block layer 12 by etching as shown in FIG. 8C. Thereafter, p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P second upper cladding layer 4
b, p-Ga _0.5 In _0.5 P buffer layer 5 and p-GaAs contact layer 7 are sequentially crystal-grown, and finally, as shown in FIG. P on 7
The side electrode 9 is formed to complete the laser device.

Although the active layer is made of Ga _0.5 In _0.5 P in the above embodiment, the same effect can be obtained with (Al _z Ga _{1 -z} ) _0.5 In _0.5 P.

Further, the clad layer is described as (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P, but (Al _w Ga _1-w ) _0.5 In _0.5 P (where Z <W)
However, the same effect is achieved.

In all of the above embodiments, the current blocking layer
_{Although a} single layer of _1-x Ga _x As _1-y P _y is used, the current block layer may be a multilayer. For example, n-In _1-x2 Ga _x2 As _1-y2 P _y2 and n
Or a two-layer structure of _{-In 1-x1 Ga x1 As 1} -y1 P y1.

〔The invention's effect〕

As described above, according to the present invention, as a current blocking layer
Since an InGaAsP-based material lattice-matched with GaAs and containing P was used except for InGaP, phosphorous pressure can be applied even during the growth of the current blocking layer, and there are few lattice defects in the active layer and the upper cladding layer made of the AlGaInP-based material. This has the effect of extending the life of the laser.

Further, an upper cladding layer includes a first upper cladding layer and a second ridge disposed on the surface of the first upper cladding layer.
GaAs except for InGaP
Since the current blocking layer of an InGaAsP-based material lattice-matched with P is disposed on the surface of the first upper cladding layer via the etching stopper layer, the current blocking layer has high crystallinity, and current leakage occurs. Since there is less, there is an effect that higher efficiency can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a visible light semiconductor laser according to a first embodiment of the present invention, and FIG. 2 is an In _1-x Ga _x lattice-matched GaAs.
FIG. 3 shows a range of (x, y) of As _1-y P _y and a band gap corresponding thereto, FIG. 3 is a sectional view showing a manufacturing process of the visible light semiconductor laser shown in FIG. 1, and FIG. FIG. 5 is a sectional view showing a visible light semiconductor laser according to a second embodiment of the present invention, FIG. 5 is a sectional view showing a visible light semiconductor laser according to a third embodiment of the present invention, and FIG. 7 is a cross-sectional view showing a visible light semiconductor laser according to a fourth embodiment of the present invention, FIG. 8 is a cross-sectional view showing a manufacturing process of the visible light semiconductor laser of FIG. 7, FIG. 9 is a cross-sectional view showing a conventional visible light semiconductor laser, and FIG. 10 is a cross-sectional view showing a manufacturing process of the conventional visible light semiconductor laser. In the figure, 1 is an n-GaAs substrate, 2 is n- (Al _0.7 Ga _0.3 )
_0.5 In _0.5 P Lower cladding layer, 3 is undoped Ga _0.5 In _0.5 P
Active layer, 4 is _{P- (Al 0.7 Ga 0.3) 0.5} In 0.5 P upper cladding layer, 4a, 14a is _{P- (Al 0.7 Ga 0.3) 0.5} In 0.5 P first upper cladding layer, 4b, 14b are P- ( Al _0.7 Ga _0.3 ) _0.5 In _0.5 P second upper cladding layer, 5 is a P-Ga _0.5 In _0.5 P buffer layer, 7 and
7a and 7b are P-GaAs contact layers, 8 is an n-side electrode, and 9 is a P-GaAs contact layer.
Side electrode, 10 ridge, 12 _{n-In x Ga 1-x} As y P 1-y current blocking layer, 13 groove, 15 is an etching stopper layer. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. A loss guide type visible light semiconductor laser having an active layer made of an AlGaInP-based material, upper and lower cladding layers, and a current blocking layer, wherein the current blocking layer lattice-matches with GaAs except for InGaP. A visible light semiconductor laser comprising an InGaAsP-based material containing P. 2. An upper cladding layer comprising a first upper cladding layer for covering an active layer with a predetermined thickness and a second ridge disposed on a surface of a part of the first upper cladding layer. And an upper cladding layer, an etching stopper layer is provided on the surface of the first upper cladding layer, and a current blocking layer is provided via the etching stopper layer. The visible light semiconductor laser according to claim 1.