JP3532433B2 - Surface emitting semiconductor laser and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface emitting semiconductor laser having a structure in which an active layer is sandwiched by a semiconductor multilayer film reflecting mirror.

[0002]

2. Description of the Related Art In long-distance optical communication, a laser having a wavelength of 1.3 to 1.55 .mu.m band, which has the smallest optical loss, is required as a signal light due to the characteristics of currently used optical fibers. Therefore, when a surface emitting semiconductor laser is used as a laser light source for optical communication, the oscillation wavelength is 1.3.
It is necessary to be in the range of ˜1.55 μm. This surface emitting semiconductor laser has an advantage that a conventional single mode optical fiber can be used. On the other hand, in the surface emitting semiconductor laser, in order to oscillate at a low threshold value, a light reflection layer having an extremely high reflectance, a current confinement structure for efficiently confining current in the active layer, and efficient light confinement A waveguiding structure is required. Further, it is important that the light reflecting layer is made of an electrically conductive material in order to easily manufacture the device.

As such a surface emitting semiconductor laser, there is one having a structure shown in FIG. This is an n-type distributed feedback reflector (DBR) 602 formed on a substrate 601 and p
The active layer 602 is sandwiched between the DBR 603 and the DBR 603. Here, in order to obtain a long-wavelength laser beam, gallium (Ga), indium (In), and arsenic (A
GaInAsP which is a mixed crystal (compound) of s) and phosphorus (P)
In addition, GaInAs, which is a mixed crystal of Ga, In, and As, or InAs, which is a mixed crystal of In and As, is used.
For example, if InAs is used, oscillation with a wavelength longer than 1.55 μm can be obtained, and by adding Ga to this, a long-wavelength laser with a shorter wavelength of about 1.55 to 1.3 μm can be obtained. . In such a surface emitting semiconductor laser, for example, the DBR 60 whose reflectance is lowered by passing a current between the DBR 602 and the DBR 604.
Laser light having a wavelength determined by the material forming the active layer 602 can be obtained from the second side.

In such a surface emitting semiconductor laser, the lower DBR, the active layer and the upper DBR are formed by continuous crystal growth on, for example, an InP substrate by using a crystal growth technique in a vapor phase. There is a technology to do. In this case, the layers to be laminated need to be lattice-matched to the substrate, but there is an advantage that elements can be formed with good crystallinity and high yield. For example, InP is used on the substrate and D
The BR and the active layer may be made of GaInAsP. Here, the DBR is configured by alternately stacking layers having different refractive indexes by changing the composition ratio of GaInAsP, but in order to achieve lattice matching with the substrate,
Since the composition ratio of GaInAsP cannot be changed significantly,
Since the difference in refractive index cannot be made large, the reflectance of DBR cannot be made large. As a result, as described above, I
A surface emitting semiconductor laser using GaInAsP lattice-matched with an nP substrate has not reached room temperature continuous oscillation.

On the other hand, there is a technique for forming a surface emitting semiconductor laser by bonding a DBR made of AlGaAs grown in lattice matching on a GaAs substrate and an active layer formed in lattice matching on an InP substrate. . AlGaAs
If this is used to grow a crystal on a GaAs substrate, a DBR having a large reflectance can be formed by alternately laminating layers having a large refractive index difference in a lattice-matched state. However, these lattice-matched AlGa
If As is used in the active layer, a long wavelength laser of 1.3 to 1.55 μm cannot be obtained. Also, GaAs
On the substrate, GaInAs with a small In composition ratio is formed.
Then, it is possible to grow by lattice matching, but long-wavelength laser oscillation cannot be obtained even if the active layer is used with a small In composition ratio. On the other hand, when the composition ratio of In is increased so that long-wavelength laser oscillation can be obtained, GaA
It is not possible to grow crystals of GaInAs in a lattice-matched state on the s substrate.

Therefore, an active layer made of GaInAsP is formed in a lattice-matched state on the InP substrate, and this active layer and the DBR made of AlGaAs described above are bonded to each other, so that a laser having a desired long wavelength can be produced at room temperature. It is possible to oscillate continuously. In this case, first, Ga
A p-type DBR made of AlGaAs is formed on an As substrate, while an active layer made of GaInAsP is formed on an InP substrate, and they are bonded so that the DBR and the active layer are in contact with each other. Then, only the InP substrate on which the active layer is formed is removed. On the other hand, AlGa on GaAs substrate
An n-type DBR made of As is formed in advance and I of the active layer is formed.
If the n-type DBR is attached to the surface from which the nP substrate has been removed so that they are in contact with each other, and the GaAs substrate is removed from the n-type DBR, a high reflectance is obtained. In addition, GaI that can obtain long-wavelength laser oscillation
It is possible to obtain a surface emitting semiconductor laser in which an active layer made of nAsP is sandwiched.

[0007]

However, when the surface emitting semiconductor laser is formed by laminating in such a manner,
First, there was a problem that the yield was poor. When the element is formed by bonding, the surface to be bonded will be defective unless the degree of cleanliness is high. It is not easy to obtain the cleanliness of the surfaces to be bonded, but in the case of the element by the above-mentioned bonding, it is necessary to bond twice.
Further, since the substrate is removed once and then the bonding is performed, it is very difficult to obtain high cleanliness. Further, although a high pressure is applied to the bonding, there is a problem that the active layer is likely to be distorted because the high pressure is applied by the bonding performed twice. Further, since the surfaces to be bonded are not lattice-matched, defects are likely to occur at the interface.

As described above, in the related art, it is impossible to form a DBR having a high reflectance with an element which has a good crystallinity and can be manufactured with a high yield, so that continuous oscillation at room temperature cannot be obtained. On the other hand, in an element by bonding that can obtain continuous oscillation at room temperature, the bonding process is complicated and the yield is poor, and the output required for optical communication cannot be obtained due to defects at the bonding interface. There was a problem. The present invention has been made to solve the above problems, and it is an object of the present invention to obtain a long wavelength laser required for long-distance optical communication stably and with high output for a long period of time. To aim.

[0009]

In the method of manufacturing a surface emitting semiconductor laser according to the present invention, first, a first distributed feedback type reflection mirror of the first conductivity type is formed on a first substrate having the first conductivity type. ,
A metal film made of indium is formed on the first distributed feedback mirror. On the other hand, the second distributed feedback mirror of the second conductivity type is formed on the second substrate. Then, the metal film and the second distributed feedback mirror are bonded by heating and melting the metal film in a state where the surface of the metal film and the surface of the second distributed feedback mirror are in contact with each other. After that, arsenic is diffused from the side surface to the bonded metal film to form an active layer composed of a semiconductor layer of a compound of indium and arsenic, and the active layer is formed by the first distributed feedback mirror and the second distributed feedback. It is in a state of being sandwiched between the type reflector. Then, the second substrate was removed, and the first and second electrodes were formed on the back surface of the first substrate and the second distributed Bragg reflector. Since it is manufactured in this way, the active layer is formed in the first distributed feedback mirror and the second distributed feedback mirror.
The active layer is completed after a sandwich of two materials is formed.

Here, the metal film may contain gallium in addition to indium. The wavelength of the oscillating laser can be adjusted by adjusting the amount of gallium. Also, the first
By forming a barrier layer on the distributed feedback reflection mirror and then forming a metal film on the barrier layer, the active layer can have a quantum well structure including a barrier layer and a semiconductor layer. Here, if a metal film is formed on the barrier layer after forming a plurality of recesses in the barrier layer, the active layer can be a quantum well structure including a quantum box made of a semiconductor layer formed in the recess of the barrier layer. . In the first and second distributed feedback mirrors, the first semiconductor layer made of a compound of aluminum, gallium, and arsenic and the first semiconductor layer are formed by changing the composition ratio of aluminum and gallium. One semiconductor layer and a second semiconductor layer having a different refractive index may be alternately stacked.

Further, the surface emitting semiconductor laser of the present invention is
A first distributed feedback reflector of the first conductivity type formed on a first substrate having the first conductivity type, and a compound of indium and arsenic formed on the first distributed feedback reflector On an active layer made of a semiconductor, a second distributed feedback mirror of the second conductivity type formed on the active layer, a first electrode formed on the back surface of the substrate, and a second distributed feedback mirror And a second electrode formed on the first and second distributed feedback mirrors, each of which is made of a material that is not lattice-matched with the active layer. As a result, the semiconductor forming the active layer is formed in a state not having a single crystal structure.

Here, the active layer may be composed of a semiconductor made of a compound containing gallium in addition to indium and arsenic. Further, the active layer may have a quantum well structure including a barrier layer and a well layer made of a semiconductor, in which case the barrier layer has a plurality of recesses, the semiconductor layer is formed so as to fill the recesses, and the active layer is Alternatively, a quantum well structure including a quantum box with a semiconductor layer filling the recess may be used. In the first and second distributed feedback mirrors, the first semiconductor layer made of a compound of aluminum, gallium and arsenic and the first semiconductor layer have different composition ratios of aluminum and gallium. A multilayer film in which the first semiconductor layer and the second semiconductor layer having a different refractive index are alternately stacked may be used.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG.
Substrate made of GaAs in the shape of, for example, 2 inches in diameter
1 was prepared, and a layer made of n-type GaAs having an optical length of λ / 4 for a wavelength λ = 1.55 μm and an n-type Al _0.9 Ga layer having an optical length of λ / 4 were also provided on the surface 32 sets of _0.1 As layers are alternately laminated to form a multi-layered n-type distributed feedback mirror (DBR) 102. Next, as shown in FIG. 1B, a spacer layer 103 made of GaAs is formed.

Next, as shown in FIG. 1C, a GaInAs layer is formed on the spacer layer 103, and the enlarged view of FIG.
The barrier layer 104 was formed by arranging and forming the concave portions as shown in (c ′) in a matrix. Here, the recess is formed to a size such that a quantum confinement effect can be obtained. The recess may be formed by, for example, a lithography technique using an X-ray or an electron beam as a light source and a selective etching technique. Next, as shown in FIG. 1D, a metal layer 105 made of In was formed on the barrier layer 104 by, for example, a vacuum vapor deposition method.

On the other hand, as shown in FIG. 1 (e), p-type G
For example, a substrate 106 made of aAs and having a diameter of 2 inches is prepared, and a layer made of p-type GaAs having an optical length of λ / 4 for a wavelength λ = 1.55 μm and an optical length of λ are similarly provided on the substrate 106. 20 sets of p-type Al _0.9 Ga _0.1 As layers each having a thickness of / 4 are alternately laminated to form a p-type distributed feedback mirror (DBR) 107 having a multilayer structure. However, from the top layer 1,
Below the two layers is a layer 10 composed of Al _0.98 Ga _0.02 As.
7a is arranged. In addition, a spacer layer 108 made of GaAs is formed.

Next, as shown in FIG. 2 (f), the substrate 10
1 and the substrate 106 are opposed to each other, and the surface of the metal layer 105 and the surface of the spacer layer 108 are brought into contact with each other. Then, in a state of being heated to, for example, 200 ° C. which is higher than the melting point of In, the substrate 1
01 and the substrate 106 are bonded together. And FIG.
As shown in (g), the spacer layer 103 and the spacer layer 1
08, the barrier layer 104 and the metal layer 105
Get a close contact with and. At this time, the metal layer 105 is
The barrier layer 104 is formed so as to fill in the recesses of the barrier layer 104 so as to be planarized, and when viewed from the metal layer 105, a plurality of protrusions are formed in a matrix on the surface of the metal layer 105. Here, the total thickness of the spacer layers 103 and 108, the metal layer 105, and the barrier layer 104 is set to be an integral multiple of half the length of the desired optical wavelength of the laser light.

Next, in the atmosphere in which hydrogen and AsH ₃ gas are flowing, the above-mentioned bonded substrate is heated to about 750 ° C. to diffuse As in the lateral direction in the metal layer 105, and FIG. As shown in, a well layer 105a made of InAs having a polycrystalline or amorphous structure is formed. As a result, as shown in FIG. 2 (h '), the well layer (semiconductor layer) 1 in which a plurality of quantum boxes formed by protrusions are arranged in a matrix
The active layer 115 composed of 05a and the barrier layer 104 can be formed. Here, to facilitate diffusion of As into the metal layer 105, a width of 200 μm from the back surface of the substrate 106 and a depth of 100 μm
The grooves are formed in a grid pattern. The substrate 105 shown in FIG. 1 (e) may be cut out in advance to have a size of about 10 mm square, and the substrates may be bonded together.

In the above description, the quantum box structure is used so as to oscillate more efficiently. However, the quantum box structure is not limited to this, and the metal layer 105 is formed without using the barrier layer 104.
s may be diffused to form an active layer composed of a layer of InAs only. Further, here, a metal film made of In was formed, and As was diffused from the outside here.
An alloy film made of nGa may be formed and As may be diffused from the outside to form an active layer made of GaInAs. By adjusting the composition ratio of Ga in the active layer, the wavelength of laser light that can be oscillated can be changed. The larger the composition ratio of Ga, the shorter the wavelength of laser light that can be oscillated. Even when GaInAs is used, a quantum box structure may be formed by appropriately changing the composition of GaInAs of the barrier layer 104 so that the bandgap energy is larger than that of GaInAs of the well layer 105a. You can

Next, as shown in FIG. 3 (i), DBR1
Only substrate 106 is removed to leave 07 and D
The BR 107 and the spacer layer 108 are processed into a substantially circular tubular shape. This can be performed by selectively removing the DBR 107 by etching using the resist pattern formed by the photolithography technique as a mask. Then, FIG.
As shown in (j), by oxidizing the layer 107a formed by increasing the Al composition ratio in advance from the surrounding (selective oxidation), the conductive region is left only in the central portion of the layer 107a, and the oxidized region is formed. The high resistance region 107b is formed in a ring shape.

Next, as shown in FIG. 3 (k), an insulating layer 110 made of polyimide is formed so as to fill the periphery of the DBR 107 and the spacer layer 108 processed into a cylindrical shape, and the surface of the insulating layer 110 is covered. An insulating film 111 made of silicon oxide is formed so as to cover, for example, by a sputtering method. Then, a ring-shaped p-side electrode 112 made of AuZnNi that makes ohmic contact with the surface of the DBR 107 is formed so as to cover the peripheral portion above the DBR 107. Further, by forming the n-side electrode 113 made of AuGeNi on the back surface of the substrate 101, a surface emitting semiconductor laser that oscillates a laser in the wavelength band of 1.55 μm is formed.

As described above, first, a metal film made of In or an alloy film of Ga and In is formed, and As is diffused from the outside, InAs or Ga is formed.
If a layer of InAs (which is not in the metallic state) was formed, it was verified whether it would function as an active layer by forming a Pin-type diode, as shown below. First, as shown in FIG. 4A, a metal film 402 made of In is formed on a substrate 401 made of n-type GaAs. Next, on the substrate 411 made of GaAs, GaI
An n-P crystal is grown to form an etching stop layer 412, and a p-type GaAs layer 413 is crystal-grown on the etching stop layer 412 to prepare a substrate, and as shown in FIG.
And the substrate 411 face each other, and the metal film 402 and the GaAs layer 4
13 and abut, and it is pasted together.

Next, they are heated to about 800 ° C. in an atmosphere in which hydrogen and AsH ₃ gas are flowing. As a result, AsH ₃ enters from the outside between the substrate 401 and the GaAs layer 413, while the metal film 402 made of In is dissolved and diffuses outward. Then, As of AsH ₃ which has entered is dissolved and diffused into In which is diffused, and InAs is reacted and produced. As a result, as shown in FIG. 4C, the n-type substrate 401 and p
-Shaped GaAs layer 413 and I layer 42 made of InAs
A Pin diode with 1 sandwiched is formed. After that, only the substrate 411 is removed by selective etching of the etching stop layer 412 and GaAs, so that the surface of the etching stop layer 412 is exposed as shown in FIG. 4D. As a result, on the I layer 421, a thin p
The GaAs layer 413 having the shape is arranged.

Then, the photoluminescence spectrum (PL) of the Pin type diode was measured. As a result of this measurement, as shown in FIG. 4 (e), strong light emission at a long wavelength of 1.78 μm, which cannot be obtained when GaInAs is formed by crystal growth on a GaAs substrate, was observed. In addition, GaAs of this Pin type diode structure
The layer 413 is processed into a cylindrical shape having a diameter of about 20 μm, and electrodes are formed to form a photodiode, and the photodiode is reverse-biased at 5 V to have a thickness of 1.5 μm.
When the above light was incident, a light receiving sensitivity of 0.3 A / W was confirmed. To form a photodiode, a ring-shaped electrode made of AuZnNi was formed as a p-side electrode on the cylindrical upper portion, and a metal film made of AuGeNi that was an n-side electrode was formed on the back surface of the substrate 401.

When the characteristics of the surface emitting semiconductor laser of this embodiment described above were examined, the current-optical output characteristics and the current-voltage characteristics shown in FIG. 5 were obtained.
In FIG. 5, the broken line indicates GaInAsP as in the conventional case.
The result of the surface emitting semiconductor laser which formed the active layer which consists of, and was formed by sticking DBR on both surfaces is shown. As is clear from this result, the surface emitting semiconductor laser according to the present embodiment oscillates at a wavelength of 1.55 μm, has a smaller threshold current oscillated by the laser than the conventional one, and has the same value. It can be seen that a larger light output is obtained at the current value.

In the above embodiment, As is externally applied.
However, it is not limited to this.
In addition to As, P is also made to diffuse from the outside, and Ga
The active layer may be made of a semiconductor made of InAsP. However, when this GaInAsP is used for the active layer, the temperature characteristic becomes worse than that of GaInAs, so from the viewpoint of obtaining more stable laser oscillation,
It is better to use InAs or GaInAs for the active layer.

[0026]

As described above, according to the present invention, first, the first distributed feedback mirror of the first conductivity type is formed on the first substrate having the first conductivity type. A metal film made of indium is formed on the feedback mirror. On the other hand, the second distributed feedback mirror of the second conductivity type is formed on the second substrate. Then, the metal film and the second distributed feedback mirror are bonded by heating and melting the metal film in a state where the surface of the metal film and the surface of the second distributed feedback mirror are in contact with each other. After that, arsenic is diffused from the side surface to the bonded metal film to form an active layer composed of a semiconductor layer of a compound of indium and arsenic, and the active layer is formed by the first distributed feedback mirror and the second distributed feedback. It is in a state of being sandwiched between the type reflector. Then, the second substrate is removed, and the first substrate and the second distributed feedback mirror are provided with the first and second substrates.
Electrodes were formed. Since the first distributed feedback mirror and the second distributed feedback mirror are formed in such a manner that one material forming the active layer is sandwiched between the first distributed feedback mirror and the second distributed feedback mirror, the active layer is formed. The layers are completed. Therefore, since the active layer is not formed at the bonding stage, the problem of deterioration of the active layer due to bonding does not occur. Further, it becomes possible to easily form an active layer made of a material that does not lattice match with the distributed feedback mirror. As a result, according to the present invention, it is possible to obtain an excellent effect that a laser having a long wavelength required for long-distance optical communication can be stably obtained with a high output for a long period of time.

Further, according to the present invention, the first distributed feedback reflector of the first conductivity type is formed on the first substrate having the first conductivity type, and is formed on the first distributed feedback reflector. An active layer made of a semiconductor made of a compound of indium and arsenic, a second distributed feedback mirror of the second conductivity type formed on the active layer, and a first electrode formed on the back surface of the substrate, Second
And a second electrode formed on the distributed feedback reflection mirror, and the first and second distributed feedback reflection mirrors are made of a material that is not lattice-matched with the active layer. As a result, the semiconductor forming the active layer is formed in a state not having a single crystal structure. This is because the active layer is made of a material capable of obtaining long-wavelength laser oscillation, and the first and second distributed feedback mirrors capable of stably obtaining laser oscillation are combined. A long-wavelength laser required for optical communication can be stably obtained with high output for a long period of time.

[Brief description of drawings]

FIG. 1 is a process chart for explaining a method for manufacturing a surface emitting semiconductor laser according to an embodiment of the present invention.

FIG. 2 is a process diagram for explaining the method for manufacturing the surface emitting semiconductor laser according to the embodiment of the present invention, which is subsequent to FIG.

FIG. 3 is a process diagram for explaining the method for manufacturing the surface emitting semiconductor laser according to the embodiment of the present invention, which is subsequent to FIG. 2;

FIG. 4 is a process diagram showing a manufacturing process of a Pin-type diode manufactured for verifying the present invention, and a characteristic diagram showing its characteristics.

FIG. 5 is a characteristic diagram showing surface emitting semiconductor laser characteristics according to the embodiment of the present invention.

FIG. 6 is a configuration diagram showing a partial configuration of a conventional surface emitting semiconductor laser.

[Explanation of symbols]

101 ... Substrate, 102 ... N-type distributed feedback reflector, 103
... Spacer layer, 104 ... Barrier layer, 105 ... Metal layer, 10
6 ... Substrate, 107 ... P-type distributed feedback reflector, 107a ...
Layer, 107b ... High resistance region, 108 ... Spacer layer, 11
0 ... Insulating layer, 111 ... Insulating film, 112 ... P-side electrode, 11
3 ... N side electrode, 115 ... Active layer.

Front Page Continuation (72) Inventor Toshiaki Kagawa 3-19-3 Nishishinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Main tax Amano 3-19-3 Nishishinjuku, Shinjuku-ku, Tokyo Date In this telegraph telephone company (56) Reference JP-A-7-335967 (JP, A) Electronics Letters, 1996, 32 [16], p. 1483-1484 IEEE Journal of Q Quantum Electronics, 1998, 34 [10], p. 1904-1913 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 5/183 H01L 33/00

Claims (10)

(57) [Claims] 1. A first substrate on a first substrate having a first conductivity type.
Forming a conductive type first distributed feedback reflection mirror; forming a metal film made of indium on the first distributed feedback reflection mirror; and forming a second conductive type reflection film on the second substrate. Forming a second distributed feedback mirror, and heating and melting the metal film in a state where the surface of the metal film and the surface of the second distributed feedback mirror are in contact with each other, Bonding a metal film and the second distributed feedback mirror to each other, and diffusing arsenic from the side surface of the bonded metal film to form an active layer composed of a semiconductor layer of a compound of indium and arsenic. A step in which the active layer is sandwiched between the first distributed feedback mirror and the second distributed feedback mirror; a step of removing the second substrate; and a rear surface of the first substrate And the first and second distributed feedback mirrors VCSEL manufacturing method characterized by comprising at least a step of forming a pole. 2. The method for manufacturing a surface emitting semiconductor laser according to claim 1, wherein the metal film contains gallium in addition to indium. 3. The method for manufacturing a surface emitting semiconductor laser according to claim 1, wherein a barrier layer is formed on the first distributed feedback mirror, and then the metal film is formed on the barrier layer. A method for manufacturing a surface emitting semiconductor laser, wherein the active layer has a quantum well structure including the barrier layer and the semiconductor layer. 4. The method of manufacturing a surface emitting semiconductor laser according to claim 3, wherein after forming a plurality of recesses in the barrier layer, the metal film is formed on the barrier layer, and the active layer is the barrier layer. 2. A method of manufacturing a surface emitting semiconductor laser, comprising a quantum well structure including a quantum box formed of the semiconductor layer formed in the recess of the. 5. The method for manufacturing a surface emitting semiconductor laser according to claim 1, wherein the first and second distributed feedback mirrors are made of a compound of aluminum, gallium and arsenic. The first semiconductor layer and the first semiconductor layer are formed by alternately laminating the second semiconductor layer having a refractive index different from that of the first semiconductor layer by changing the composition ratio of aluminum and gallium. A method for manufacturing a surface emitting semiconductor laser, comprising: 6. A first distributed feedback reflector of a first conductivity type formed on a first substrate having a first conductivity type, and indium formed on the first distributed feedback reflector. An active layer formed of a semiconductor of a compound of arsenic and arsenic; a second distributed feedback mirror of the second conductivity type formed on the active layer; a first electrode formed on the back surface of the substrate; A second electrode formed on a second distributed feedback mirror, wherein the first and second distributed feedback mirrors are made of a material that is not lattice-matched with the active layer. A characteristic surface emitting semiconductor laser. 7. The surface emitting semiconductor laser according to claim 6, wherein the active layer is composed of a semiconductor made of a compound containing gallium in addition to indium and arsenic. 8. The surface emitting semiconductor laser according to claim 6, wherein the active layer has a quantum well structure including a barrier layer and a well layer made of the semiconductor. 9. The surface emitting semiconductor laser according to claim 8, wherein the barrier layer has a plurality of recesses, the semiconductor layer is formed so as to fill the recesses, and the active layer fills the recesses with the semiconductor. A surface-emitting semiconductor laser having a quantum well structure composed of quantum boxes made of layers. 10. The surface emitting semiconductor laser according to claim 6, wherein the first and second distributed feedback mirrors are made of a compound of aluminum, gallium and arsenic.
And a second semiconductor layer having a refractive index different from that of the first semiconductor layer by alternately changing the composition ratio of aluminum and gallium in the first semiconductor layer. A surface emitting semiconductor laser comprising: