JP2003218467A - Semiconductor distribution bragg reflecting mirror, manufacturing method therefor, surface light-emitting type semiconductor laser, optical communication module and optical communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor distribution Bragg reflecting mirror, with a characteristic that does not deteriorate, which comprises a contact layer that stably grows even when a contact layer of a p-type semiconductor requiring high doping concentration is contained. <P>SOLUTION: An outermost surface of a p-type semiconductor multilayer film reflecting mirror 7 consists of a GaAs layer that grows after doped with Zn by 1.0 E 10 cm<SP>-3</SP>with the use of, for example, DMZn (dimethyl zinc) as a dopant. The DMZn does not make a growth rate of GaAs significantly vary even when the DMZn is used as a dopant for Zn of higher concentration, and further a surface morphology does not get rough. Since only the outermost surface is doped with the Zn, there is little time for occurring diffusion by heat, so that no problem occurs. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor distributed Bragg reflector, a method for manufacturing the same, a surface emitting semiconductor laser, an optical communication module, and an optical communication system.

[0002]

2. Description of the Related Art A surface emitting semiconductor laser is a semiconductor laser that emits light in a direction perpendicular to a substrate and is used as a light source for optical interconnection, a light source for an optical pickup, and the like. More specifically, the surface-emitting type semiconductor laser is
It has a structure in which an active region including an active layer that generates light is sandwiched by reflecting mirrors. As the reflecting mirror, a semiconductor distributed Bragg reflecting mirror in which a low refractive index layer and a high refractive index layer are alternately laminated is widely used. It is used. As a material for the semiconductor distributed Bragg reflector, a material that does not absorb light generated from the active layer (generally, a material having a wider band gap than the active layer)
However, a material that is lattice-matched to the substrate is used in order to prevent lattice relaxation.

In the surface-emitting type semiconductor laser, the reflectance of the semiconductor distributed Bragg reflector must be extremely high at 99% or more. The reflectance of the semiconductor distributed Bragg reflector is increased by increasing the number of stacked layers. However, when the number of stacked layers increases, it becomes difficult to manufacture a semiconductor distributed Bragg reflector. Therefore, it is preferable that the difference in refractive index between the low refractive index layer and the high refractive index layer is large. The AlGaAs-based material has AlAs and GaAs as termination materials, has a lattice constant almost the same as that of GaAs which is a substrate, has a large difference in refractive index, and can obtain high reflectance with a small number of stacked layers. It is often used in Bragg reflectors.

AlGaAs grown by MOCVD method
When making a semiconductor distributed Bragg reflector using a system material,
Z is an element doped to obtain a p-type semiconductor.
There are n, C (carbon) and Mg. In particular, C (carbon) can achieve a relatively high doping concentration and has a small diffusion coefficient in the semiconductor. Even in a semiconductor distributed Bragg reflector using an AlGaAs-based material, several tens or more layers are required to obtain a sufficient reflectance, so the growth time is inevitably long. However, even when the semiconductor Bragg reflector is grown, C (carbon) has a small diffusion coefficient, and the doping profile in the semiconductor is unlikely to change during the growth time. Relatively preferred. On the other hand, Zn can be easily doped in MOCVD by using an organic metal raw material, but it is very likely to diffuse. Therefore, when Zn is doped, in the growth of a semiconductor distributed Bragg reflector, which requires long-term growth, a change in the doping profile may occur due to diffusion due to temperature during growth, which is not preferable. It is well known that when Zn is doped at a position near the active layer, the diffusion of Zn into the active layer may cause a decrease in luminous efficiency of the active layer. In JP-A-11-4044, diffusion of Zn into the active layer is mentioned as one of the causes for increasing the threshold current density of a laser diode or a light emitting diode, and C (carbon) doping is used as a solution thereof. Is proposing that.

For the above reasons, AlGaAs
MOCVD of a semiconductor distributed Bragg reflector using a base material
In the case of growing by the method, it is relatively common to dope C (carbon) when growing a p-type crystal, especially when growing GaAs.

This C (carbon) is used as A in the MOCVD method.
When doping 1GaAs or GaAs, halomethane, especially CBr _4, is often used as a dopant and reported (for example, the document “NI Buchan et al. J.
See CrystalGrowth 110 (1991) 405). This is C
This is because when Br ₄ is used as a p-type dopant in the MOCVD method, the range in which the doping concentration can be controlled is relatively wide.

[0007]

However, this C
When halomethane such as Br ₄ is used as a dopant, for example, a high concentration (1.0
If C (carbon) is attempted to be doped with E19 cm ⁻³ ), there is a problem that the growth rate of GaAs becomes unstable and becomes slower than the normal growth rate.

Further, the semiconductor by etching action is to apply a high concentration of doped as used as a contact layer must significantly increase the supply amount of halomethanes, derived from a number comes to a halogen group supply such CBr ₄ The morphology on the surface of the membrane may be deteriorated.

In particular, when a semiconductor distributed Bragg reflector made of a p-type semiconductor is used as an upper reflector of a surface-emitting type semiconductor laser and the p-side contact layer for current injection is the same as the surface from which laser light is taken out, the reflector is It is not preferable that the thickness of the outermost surface film becomes difficult to control. Since the outermost surface of the reflecting mirror determines the position of the end of the optical cycle, if the thickness is deviated, the reflection band of the reflecting mirror is deviated and the maximum reflectance of the reflecting mirror is also decreased, which is not preferable.
Further, it is not preferable that the surface morphology of the contact layer that serves as a window for taking out the laser beam is deteriorated.

Furthermore, when a large amount of CBr ₄ or the like is supplied to perform such high concentration C (carbon) doping, halomethane has a property of being relatively easily adsorbed.
It easily remains in the reaction tubes and pipes inside the equipment. When CBr ₄ or the like remains in this way, when the active layer of a semiconductor laser is grown in the same device immediately after that, the luminous efficiency of the active layer may be deteriorated.

The present invention provides a semiconductor distributed Bragg reflector having a contact layer capable of stable growth even when it includes a p-type semiconductor contact layer requiring a high doping concentration, and its characteristics are not deteriorated. A method, a surface emitting semiconductor laser, an optical communication module, and an optical communication system are provided.

[0012]

In order to achieve the above object, the invention according to claim 1 uses halomethane as a dopant and GaAs or Al doped with carbon (C).
GaAs is grown by MOCVD,
Alternatively, in a method of manufacturing a semiconductor distributed Bragg reflector formed by stacking p-type semiconductor layers containing AlGaAs, it is preferable to use an organometallic compound containing Zn as a dopant of a layer to be highly doped including at least a contact layer. It has a feature.

The invention according to claim 2 is characterized in that, in the method for manufacturing a semiconductor distributed Bragg reflector according to claim 1, halomethane is CBr ₄ .

The invention according to claim 3 is characterized by being manufactured by the method for manufacturing a semiconductor distributed Bragg reflector according to claim 1 or 2.

According to a fourth aspect of the present invention, there is provided a surface-emitting type semiconductor laser having a resonator structure including reflecting mirrors provided above and below an active layer for obtaining laser light. The semiconductor distributed Bragg reflector described above is used as an upper reflector, and at least a layer adjacent to the active layer side of the p-type semiconductor layer forming the upper reflector is doped with carbon (C).

According to a fifth aspect of the present invention, in the surface emitting semiconductor laser according to the fourth aspect, the active layer is GaIn.
It is characterized by being made of As or GaInNAs.

According to a sixth aspect of the invention, there is provided an optical communication module using the surface emitting semiconductor laser according to the fifth aspect.

The invention according to claim 7 is the optical communication system using the optical communication module according to claim 6.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In the semiconductor distributed Bragg reflector of the present invention, GaAs or AlGaAs doped with carbon (C) is grown by MOCVD using halomethane as a dopant, and a p-type semiconductor layer containing GaAs or AlGaAs is laminated. Formed by the
It is characterized in that an organometallic compound containing Zn is used as a dopant for a layer to be doped at a high concentration including at least a contact layer.

Here, the halomethane is CBr ₄ .

In the present invention, halomethane is used as a dopant and GaAs or AlG doped with carbon (C) is used.
When a semiconductor distributed Bragg reflector is formed by growing aAs by the MOCVD method and stacking the p-type semiconductor layers containing GaAs or AlGaAs, Zn is used as a dopant of a layer to be doped at a high concentration including at least a contact layer. Since an organometallic compound containing is used,
It is possible to prevent the growth rate of GaAs from decreasing due to the effect of high-concentration halomethane when growing a highly-doped layer including the contact layer, and preventing the deterioration of morphology. It is possible to prevent deterioration of the performance of the reflecting mirror and stably manufacture a good quality semiconductor distributed Bragg reflecting mirror.

Further, when CBr ₄ is used as the halomethane, since a range in which the doping concentration of C (carbon) as the p-type dopant in the MOCVD method can be controlled is relatively wide, a good semiconductor distributed Bragg reflector can be manufactured. .

Further, according to the present invention, in a surface emitting semiconductor laser having a resonator structure including reflecting mirrors provided above and below an active layer for obtaining a laser beam, the semiconductor produced as described above. The distributed Bragg reflector may be the upper reflector, and at least the layer adjacent to the active layer side of the p-type semiconductor layer forming the upper reflector may be C (carbon) -doped.

As described above, the semiconductor distributed Bragg reflector manufactured as described above is used as the upper reflector, and at least the layer close to the active layer side of the p-type semiconductor layer forming the upper reflector is C (carbon). ) In the case of a doped semiconductor, a stable and high-quality semiconductor distributed Bragg reflector that does not cause deterioration of the luminous efficiency of the active layer due to diffusion of the doped element and prevents deterioration of the performance of the reflector Can be produced, and MOCVD with the use of a large amount of halomethane
Since the adsorption of halomethane inside the device is suppressed, deterioration of the active layer due to residual halomethane can be avoided even when the laser is continuously grown, and a stable and high-quality surface-emitting type semiconductor laser can be manufactured.

In this surface-emitting type semiconductor laser, the active layer is made of GaInAs or GaInNAs. As described above, when the active layer is made of GaInAs or GaInNAs, the upper reflecting mirror is formed by using a p-type semiconductor that can be easily grown on the active layer made of GaInAs or GaInNAs at a temperature at which thermal deterioration does not occur. In this case, the luminous efficiency of the active layer does not decrease due to the diffusion of the doped element, the deterioration of the performance of the reflecting mirror is prevented, and a good quality semiconductor distributed Bragg reflecting mirror can be stably manufactured, which is stable and high. A surface-emitting type semiconductor laser of high quality can be provided.

FIG. 1 is a diagram showing a structural example of a surface emitting semiconductor laser including a semiconductor distributed Bragg reflector manufactured by the present invention. Referring to FIG. 1, this surface-emitting type semiconductor laser includes an n-type GaAs substrate 1, an n-type semiconductor multilayer film reflecting mirror 2, a GaAs lower spacer layer 3, and a GaInN layer.
An As / GaAs multiple quantum well active layer 4, a GaAs upper spacer layer 5, an AlAs layer 6, and a p-type semiconductor multilayer film reflecting mirror 7 are sequentially formed.

Then, this laminated structure is cylindrically etched until it reaches the n-type semiconductor multilayer film reflecting mirror 2 to form a mesa structure. Mesa size has a diameter of 30 μm
Has become. Then, the AlAs layer 6 is selectively oxidized from the side surface where the surface is exposed by etching to form an AlO _x insulating region, thereby forming a current constriction structure. In this case, the current is concentrated in the oxide opening region having a diameter of about 5 μm by the AlO _x insulating region and injected into the active layer 4.

Further, in the example of FIG. 1, a ring-shaped p-side electrode 9 is formed on the surface of the p-type semiconductor multilayer film reflecting mirror 7 (on the p-type GaAs contact layer 7a), and an n-type is formed. G
An n-side electrode 10 is formed on the back surface of the aAs substrate 1.

Here, the GaInNAs / GaAs multiple quantum well active layer 4 has a bandgap wavelength of 1.3 μm band. The GaAs lower spacer layer 3 to the GaAs upper spacer layer 5 form a λ resonator.

It is known that, when GaInAs and GaInNAs as materials for the active layer 4 are annealed at a temperature higher than 700 ° C. after growth, their crystals are deteriorated and the luminous efficiency is lowered. . In particular, when AlGaAs is grown by the MOCVD method, if it is attempted to grow it at a temperature lower than 700 ° C., a large amount of C (carbon) derived from an organometallic raw material is likely to be introduced as an acceptor. Therefore, the n-type semiconductor multilayer film reflecting mirror is set to AlGa
When trying to grow with an As-based material, growth at high temperature is inevitably desired. Therefore, when the upper semiconductor multilayer film reflecting mirror 7 to be grown after the growth of GaInAs and GaInNAs is made of an AlGaAs material, the p-type is preferable because it is easy to grow at a low temperature.

In the example of FIG. 1, the n-type semiconductor multilayer film reflecting mirror 2
Is an n-type GaAs high refractive index layer and n-type Al _0.8 Ga _0.2 As
It is composed of a distributed Bragg reflector in which low refractive index layers are alternately laminated. Similarly, the p-type semiconductor multilayer film reflecting mirror 7
It is composed of a distributed Bragg reflector in which p-type GaAs high refractive index layers and p-type Al _0.8 Ga _0.2 As low refractive index layers are alternately laminated.

The p-type GaAs high refractive index layer contains a dopant and
Then CBr_FourIs grown by using p-type AlGaA
s It is C (carbon) doped together with the low refractive index layer. C
Br _FourIs a p-type dopant in the MOCVD method.
When used as C, the doping concentration when C (carbon) is doped
It is suitable because the controllable range is relatively wide.
It

Since C (carbon) has a small diffusion coefficient, p
The doping profile does not change when the type semiconductor multilayer film is grown, and the emission characteristics of the laser are not deteriorated by diffusion into the active region.

In the example of FIG. 1, the p-type semiconductor multilayer film reflecting mirror 7 is used.
The outermost surface of is composed of a GaAs layer grown by using, for example, DMZn (dimethylzinc) as a dopant and doping with Zn of 1.0E19 cm ^-3 . DMZn, even when used as a dopant for high-concentration Zn, has GaA
There is no significant change in the growth rate of s,
Moreover, the surface morphology does not become rough. Since Zn is doped only on the outermost surface, there is almost no time for thermal diffusion to occur, so no problem occurs.

Further, in this example, as shown in FIG.
The contact layer 7a is formed by doping Zn into the entire GaAs layer having a thickness of 1 / 4.lamda., Which is the outermost surface of the type semiconductor multilayer film reflecting mirror 7, but the present invention is particularly limited to Ga having a thickness of 1 / 4.lamda.
It is not limited to doping all of the As layer with Zn. For example, in the 1.3 μm band, the thickness of GaAs corresponding to ¼λ is slightly less than 100 nm, but when the surface is used as the contact layer 7a, for example, as shown in FIG. The contact layer 7
In order to function as a, only the GaAs layer having a thickness of 50 nm from the surface is highly doped with Zn and the remaining GaA
The s layer may be doped with C (carbon) at a normal concentration. At this time, the contact layer 7a has a thickness of 50 nm, but the outermost GaAs layer has a Zn-doped portion of the contact layer 7a and C.
As long as the combined length with the (carbon) -doped portion is 1 / 4λ, there is no particular problem as a reflecting mirror.

In the surface-emitting type semiconductor laser of FIG. 1, GaI
The light emitted from the nNAs / GaAs multiple quantum well active layer 4 is reflected and amplified by the upper and lower semiconductor multilayer film reflecting mirrors 2 and 7, and emits a 1.3 μm band laser light in a direction perpendicular to the substrate 1.

As the semiconductor multilayer film reflecting mirrors 2 and 7 on the GaAs substrate 1, the AlGaAs / GaAs laminated type is the easiest to manufacture a high-performance reflecting mirror, and the selective oxidation process of AlAs can be used, and It is easy to use because it has good lattice matching. In fact, the 0.85 μm band and 0.
The surface-emitting type semiconductor laser of the 98 μm band is AlGaAs /
It is actually manufactured and sold using a GaAs laminated semiconductor multilayer film reflecting mirror, and it can be said that this AlGaAs / GaAs laminated semiconductor multilayer film reflecting mirror is essential for a surface emitting semiconductor laser on a GaAs substrate. is there. When only halomethane such as CBr ₄ is used as the p-type dopant as in the conventional case, the growth rate of GaAs is lowered when the p-type contact layer 7a is grown,
Deterioration of the surface morphology and the like sometimes caused the performance of the semiconductor distributed Bragg reflector to deteriorate. Also, DMZn
When only such an organometallic compound containing Zn as a dopant is used as a dopant, the diffusion of Zn due to heat may cause a change in the doping profile, or the diffusion of Zn into the active region may cause a decrease in light emission efficiency. However, in the present invention, since the contact layer 7a is Zn-doped and the other p-type semiconductor distributed Bragg reflector 7 is C (carbon) -doped, deterioration of the performance of the reflector is prevented, and the reflector of good quality is stably provided. Can be manufactured, and using this, a surface emitting semiconductor laser can be manufactured.

As a material for the active layer, GaInAs is used.
In the case of using GaInNAs and GaInNAs, a p-type semiconductor multilayer film reflecting mirror that is easy to grow at a temperature lower than n-type is often used as the upper reflecting mirror in order to avoid deterioration of the active layer due to high temperature. Therefore, inevitably, the outermost surface G, which is the light emission port
The high-refractive-index layer made of aAs or the like is also used as a contact layer for conducting electricity, and thus must be highly doped p-type. The example of FIG. 1 solves the problem when the p-type semiconductor distributed Bragg reflector is used as the upper reflector, so that such a structure must be adopted.
It is suitable for manufacturing a surface emitting semiconductor laser using As and GaInNAs.

Further, when a large amount of halomethane such as CBr ₄ is introduced during the reaction due to the high concentration of C (carbon) doping and grown, CBr ₄ or the like is adsorbed into the inside of the apparatus, and continuous growth occurs. Then, when a semiconductor laser or the like is grown, the luminous efficiency of the active layer may decrease. In the present invention, C is used only as a dopant in a portion other than the contact layer.
Br ₄ is used, and the C (carbon) doping concentration of the portion other than the contact layer is 1/10 of that of the contact layer.
Since a concentration lower than 1.0E18 cm ⁻³ below is sufficient, the amount of CBr ₄ or the like introduced during the reaction can be minimized. Therefore, even when a semiconductor laser as shown in the example of FIG. 1 is continuously manufactured, adsorption of CBr ₄ or the like to the reaction tube or pipe in the apparatus is suppressed to the minimum, and C to the active layer 4 is absorbed.
The adverse effect of Br ₄ etc. is minimized.

FIG. 4 is a view showing another structural example of a surface emitting semiconductor laser including a semiconductor distributed Bragg reflector manufactured according to the present invention. In FIG. 4, the same parts as those in FIG. 1 are designated by the same reference numerals. Referring to FIG. 4, this surface-emitting type semiconductor laser has an n-type GaAs substrate 1 on which n
-Type semiconductor multilayer film reflecting mirror 2 and GaAs lower spacer layer 3
And GaInNAs / GaAs multiple quantum well active layer 4
, GaAs upper spacer layer 5, AlAs layer 6, p
The type semiconductor multilayer film reflecting mirror 17 is sequentially formed.

Then, this laminated structure is etched into a cylindrical shape until it reaches the n-type semiconductor multilayer film reflecting mirror 2 to form a mesa structure. Mesa size has a diameter of 30 μm
Has become. Then, the AlAs layer 6 is selectively oxidized from the side surface where the surface is exposed by etching to form an AlO _x insulating region, thereby forming a current constriction structure. In this case, the current is concentrated in the oxide opening region having a diameter of about 5 μm by the AlO _x insulating region and injected into the active layer 4.

Further, in the example of FIG. 4, the surface of the p-type semiconductor multilayer film reflecting mirror 17 is (p-type GaAs contact layer 17a).
(Above), a ring-shaped p-side electrode 9 is formed, and n-type Ga is formed.
An n-side electrode 10 is formed on the back surface of the As substrate 1.

Here, the GaInNAs / GaAs multiple quantum well active layer 4 has a bandgap wavelength of 1.3 μm band. The GaAs lower spacer layer 3 to the GaAs upper spacer layer 5 form a λ resonator.

As described above, the basic configuration of FIG.
In the surface-emitting type semiconductor laser of FIG. 4, the Zn-doped layer is not only the contact layer 17a on the outermost surface but also the GaAs forming the multilayer mirror as shown in FIG. Of the layers, Zn is doped into a plurality of layers close to the surface, and the side close to the active layer 4 is C (carbon).
It is different from the surface emitting semiconductor laser of FIG. 1 in that it is doped.

That is, in the configuration examples of FIGS. 4 and 5, CBr ₄ is used as a dopant for the GaAs layer on the lower side of the p-type semiconductor multilayer film reflecting mirror 17 close to the active layer 4, and the C concentration is relatively low. Doping is performed so as to avoid adverse effects on the active layer 4 due to diffusion of the doped element. AlGa
As is, for example, TMA (trimethyl Al) as an Al raw material.
(C) accompanying the decomposition of the organometallic raw material during growth
C (carbon) is introduced by the automatic doping of C (carbon) utilizing the incorporation of carbon. On the upper side of the p-type semiconductor multilayer film reflecting mirror 17, the GaAs layer is doped with Zn using DMZn as a dopant, and the AlGaAs layer is C (carbon) -doped by autodoping. With such a configuration, it is possible to avoid the adverse effect on the active layer 4 due to the diffusion of the doped element (particularly Zn) in the portion of the p-type semiconductor multilayer film reflecting mirror 17 near the active layer 4.

As described above, in the structures shown in FIGS. 4 and 5, when it is desired to increase the carrier concentration in the contact layer, the C-doping using halomethane (particularly CBr ₄ ) alone does not cause the above-mentioned problems. By using DMZn instead of halomethane for Zn doping, a high carrier concentration can be obtained without problems. Further, since Zn is not used near the active layer, Zn diffusion does not adversely affect the active layer.

An optical communication module can be constructed using the surface emitting semiconductor laser of the present invention as described above. FIG. 6 is a diagram showing a configuration example of an optical communication (optical transmission / reception) module according to the present invention. In the example of FIG. 6, the optical communication module is configured by combining a surface emitting semiconductor laser element 21, a receiving photodiode 22 and an optical fiber 23.

Here, the surface-emitting type semiconductor laser device 21 has been described above (see FIGS. 1, 2 and 3 or FIGS. 4 and 5).
The surface-emitting type semiconductor laser device of the present invention (for example, the surface-emitting type semiconductor laser device in the 1.3 μm band) is used.

High strain GaInAs or GaInNAs
The surface emitting semiconductor laser using is 1.2 to 1.3 μm.
It is an element that can obtain oscillation in a band, and is said to be suitable as a light source for communication because of its small loss with respect to a silica-based optical fiber at these wavelengths. Furthermore, fluorine-doped POF (plastic fiber) and GaInN, which have low loss particularly in the long wavelength band of 1.3 μm and the like,
When combined with a surface-emitting type semiconductor laser using As as the active layer, the cost of the fiber is low, and since the diameter of the fiber is large and the coupling with the fiber is easy and the mounting cost can be reduced, the cost is extremely low. A cost module can be realized. In addition, GaInNAs does not require a strong cooling structure because of its excellent temperature characteristics. Therefore, the cost for cooling can be reduced and an inexpensive optical communication module can be obtained.

An optical communication system can be constructed by using the optical communication module of the present invention as described above.

As described above, according to the present invention, since the upper reflecting mirror can be grown with a high quality p-type semiconductor multilayer film, a 0.85 μm surface-emitting type semiconductor laser device using a GaAs substrate can be used. A proven AlGaAs-based semiconductor multilayer film distributed Bragg reflector and a current narrowing structure by selective oxidation of AlAs can be applied, and it becomes easier to manufacture a surface-emitting type semiconductor laser device as in the above-mentioned example. It is possible to realize a high-performance long-wavelength surface-emitting type semiconductor laser device for communication, and by using these devices,
Optical communication systems such as low-cost optical fiber communication systems and optical interconnection systems can be realized.

[0053]

As described above, according to the first aspect of the present invention, halomethane is used as a dopant, and carbon (C) -doped GaAs or AlGaAs is added as M.
GaAs or AlG grown by OCVD method
In a method of manufacturing a semiconductor distributed Bragg reflector formed by stacking p-type semiconductor layers containing aAs, since an organometallic compound containing Zn is used as a dopant of a layer to be highly doped including at least a contact layer,
It is possible to prevent the growth rate of GaAs from decreasing due to the effect of high-concentration halomethane when growing a highly-doped layer including the contact layer, and preventing the deterioration of morphology. It is possible to prevent deterioration of the performance of the reflecting mirror and stably manufacture a good quality semiconductor distributed Bragg reflecting mirror.

According to the second aspect of the invention, by using CBr ₄ as the halomethane in the first aspect of the invention, the doping concentration of C (carbon) as a p-type dopant in the MOCVD method can be controlled. Is relatively wide, a high-quality semiconductor distributed Bragg reflector can be manufactured.

According to a fourth aspect of the present invention, there is provided a surface emitting semiconductor laser having a resonator structure including reflecting mirrors provided above and below an active layer for obtaining laser light. The semiconductor distributed Bragg reflector according to 1 is used as an upper reflector, and at least a layer adjacent to the active layer side of the p-type semiconductor layer forming the upper reflector is C (carbon) -doped. The emission efficiency of the active layer does not decrease due to the diffusion of the above-mentioned elements, the deterioration of the performance of the reflector is prevented, and a stable and high-quality semiconductor distributed Bragg reflector can be manufactured, and a large amount of halomethane is used. Since the adsorption of halomethane inside the MOCVD equipment due to the above is suppressed, deterioration of the active layer due to residual halomethane can be avoided even when the laser is continuously grown, and it is stable and high. The quality of the surface-emitting type semiconductor laser can be produced.

According to a fifth aspect of the invention, in the surface emitting semiconductor laser of the fourth aspect, the active layer is G
By using aInAs or GaInNAs, even if the upper reflector is made of a p-type semiconductor that can be easily grown at a temperature that does not deteriorate due to heat, the luminous efficiency of the active layer is reduced due to the diffusion of the doped element. It is possible to provide a stable and high-quality surface-emitting type semiconductor laser, in which the deterioration of the performance of the reflecting mirror is prevented, a high-quality semiconductor distributed Bragg reflecting mirror can be stably manufactured.

According to the invention described in claim 6, since the surface emitting semiconductor laser according to claim 5 is used as the light source of the optical communication module, a high quality p-type semiconductor using an AlGaAs material is used. It is possible to provide a low-cost and small-sized optical communication module using a surface emitting semiconductor laser using a material having good matching with an optical fiber such as GaInAs or GaInNAs by using a distributed Bragg reflector as a light source.

According to the invention described in claim 7, by using the optical communication module described in claim 6, it is possible to provide a small-sized optical communication system at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a surface emitting semiconductor laser including a semiconductor distributed Bragg reflector.

FIG. 2 is a diagram showing a configuration example of a p-type semiconductor multilayer film reflecting mirror in the surface-emitting type semiconductor laser of FIG.

3 is a diagram showing another configuration example of a p-type semiconductor multilayer film reflecting mirror in the surface-emitting type semiconductor laser of FIG.

FIG. 4 is a diagram showing another configuration example of a surface-emitting type semiconductor laser including a semiconductor distributed Bragg reflector.

5 is a diagram showing a configuration example of a p-type semiconductor multilayer film reflecting mirror in the surface-emitting type semiconductor laser of FIG.

FIG. 6 is a diagram showing a configuration example of an optical communication module of the present invention.

[Explanation of symbols]

1 n-type GaAs substrate 2 n-type semiconductor multilayer film reflector 3 GaAs lower spacer layer 4 Active layer 5 GaAs upper spacer layer 6 AlAs layer 7 p-type semiconductor multilayer film reflector 7a Contact layer 9 p-side electrode 10 n side electrode 17 p-type semiconductor multilayer mirror 17a contact layer 21 Surface-emitting type semiconductor laser device 22 Photodiode for reception 23 optical fiber

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoto Shatani             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 5F073 AA52 AA55 AA74 AA89 AB17                       BA01 CA04 CB02 CB14 DA05                       EA28

Claims (7)

[Claims] 1. GaAs or AlGaAs doped with carbon (C) using halomethane as a dopant is M
GaAs or AlG grown by OCVD method
A method of manufacturing a semiconductor distributed Bragg reflector, which is formed by stacking p-type semiconductor layers containing aAs, characterized in that an organometallic compound containing Zn is used as a dopant of a high-concentration doping layer including at least a contact layer. Of manufacturing a semiconductor distributed Bragg reflector. 2. The method of manufacturing a semiconductor distributed Bragg reflector according to claim 1, wherein the halomethane is CBr ₄ . 3. A semiconductor distributed Bragg reflector, which is manufactured by the method for manufacturing a semiconductor distributed Bragg reflector according to claim 1 or 2. 4. A surface emitting semiconductor laser having a resonator structure including reflecting mirrors provided above and below an active layer for obtaining a laser beam, wherein the semiconductor distributed Bragg reflecting mirror according to claim 3 is used. A surface-emitting type semiconductor laser comprising an upper reflecting mirror, wherein at least a layer adjacent to the active layer side of the p-type semiconductor layer forming the upper reflecting mirror is doped with carbon (C). 5. The surface emitting semiconductor laser according to claim 4, wherein the active layer is GaInAs or GaInNAs.
1. A surface-emitting type semiconductor laser comprising: 6. An optical communication module using the surface emitting semiconductor laser according to claim 5. 7. An optical communication system using the optical communication module according to claim 6.