JP2003258378A - Surface-emitting semiconductor laser and method of manufacturing the same, optical module, optical transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-emitting semiconductor laser having good device characteristics and a high operation speed and a method of manufacturing the same, and also to provide an optical module and an optical transmission device including the surface-emitting semiconductor laser. <P>SOLUTION: The surface-emitting laser 100 includes a resonator 120 formed on a semiconductor substrate 101, and can emit light in a direction vertical to the semiconductor substrate 101. The resonator 120 includes a first multilayer reflection film 102, an active layer 103, and a second multilayer reflection film 104. At least in either of the first and the second multilayer reflection films 102 and 104, a current narrowing layer 105 is formed. The current narrowing layer 105 at least includes an aperture section 105a. A cross-sectional area of the current narrowing layer 105 when cut by a face parallel to the semiconductor substrate 101 is smaller than a cross-sectional area of other layers constituting the resonator 120 when cut by a face parallel to the semiconductor substrate 101. <P>COPYRIGHT: (C)2003,JPO

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, a method for manufacturing the same, an optical module and an optical transmission device including the surface emitting semiconductor laser.

[0002]

BACKGROUND ART A surface emitting semiconductor laser is a semiconductor laser that emits laser light perpendicularly to a semiconductor substrate. In this surface-emitting type semiconductor laser, a resonator is provided in a vertical direction on a semiconductor substrate. The resonator has a function of causing laser light to oscillate and then emitting the laser light, and is configured by sequentially stacking a multilayer reflective film, an active layer, and a multilayer reflective film. FIG. 14 shows a cross-sectional structure of a general surface emitting semiconductor laser.

In such a surface-emitting type semiconductor laser 900, a vertical resonator 920 including a columnar section 910 is formed on a semiconductor substrate 901. The resonator 920 is formed by laminating a first multilayer reflective film 902, an active layer 903, and a second multilayer reflective film 904.

One of the excellent features of the surface emitting semiconductor laser is that the laser emission angle is isotropic as compared with the edge laser,
And it is small. Therefore, the surface-emitting type semiconductor laser is expected to be applied as a light source in optical fiber communication and optical parallel information processing. Above all, when using surface-emitting type semiconductor lasers for optical fiber communication,
Considering the transmission loss, which is one of the characteristics of the optical fiber,
It is required that a high output can be obtained in the single mode with better coupling efficiency.

Therefore, for example, as shown in FIG.
When each of the layers forming the multilayer reflective film 902, the active layer 903, and the second multilayer reflective film 904 is a layer containing Al, Ga, and As as a main component, the second reflective multilayer film 904 is formed from a layer having a high Al composition. After inserting the current constriction forming layer 905c, the current constriction forming layer 905c is oxidized into a donut shape from the surroundings, and as shown in FIG.
A current confinement layer 905 including a and the oxide confinement portion 905b is formed. That is, in the current confinement layer 905, the portion that remains in the center without being oxidized by the layer having a high Al composition is the aperture portion 905a. Further, the portion formed around the aperture portion 905a by oxidation is the oxidized constriction portion 905.
b. In this surface-emitting type semiconductor laser 900, an electric current is concentratedly supplied to the aperture section 905a to increase the output power of the laser light.

However, in the surface-emitting type semiconductor laser 900, the formation of the oxide confinement portion 905b increases the capacitance of the entire device. The increase in capacity generally hinders high-speed driving for devices that require high-speed driving. For example, FHPeters et al, IEEE PHO
TONICS TECHNOLOGY LETTERS, vol.13, NO.7, JULY 2001
It has been pointed out that most of the capacitance of the surface-emitting type semiconductor laser is due to the oxide confinement portion forming the current confinement layer.

On the other hand, in the surface-emitting type semiconductor laser 900 shown in FIG. 14, the diameter of the columnar section 910 can be reduced to reduce the oxide confinement section 905b and the capacitance of the device. However, in this case, by reducing the diameter of the columnar section 910, the columnar section 910 is reduced.
Since the contact area of the first electrode 907 formed on the upper surface of the is small, the contact resistance may increase and the device characteristics may deteriorate.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a surface emitting semiconductor laser having good device characteristics and capable of high speed operation, and a method for manufacturing the same.

Another object of the present invention is to provide an optical module and an optical transmission device including the surface emitting semiconductor laser.

[0010]

(Surface emitting semiconductor laser) A surface emitting semiconductor laser of the present invention includes a resonator formed on a semiconductor substrate and emits light in a direction perpendicular to the semiconductor substrate. A surface-emitting type semiconductor laser capable of:
The resonator includes a first multilayer reflective film, an active layer, and a second multilayer reflective film, and a current constriction layer is formed on at least one of the first and second multilayer reflective films. Is at least an aperture portion, and the cross-sectional area when the current confinement layer is cut along a plane parallel to the semiconductor substrate is a plane parallel to the semiconductor substrate and cuts another layer forming the resonator. It is smaller than the area of the cross section in the case.

Here, the term "perpendicular to the semiconductor substrate" means
It means a direction perpendicular to the surface of the semiconductor substrate, and the “surface of the semiconductor substrate” means the surface of the semiconductor substrate on which the resonator is formed. Further, the “plane parallel to the semiconductor substrate” means a plane parallel to the surface of the semiconductor substrate.

According to the surface-emitting type semiconductor laser of the present invention,
The current confinement layer includes at least an aperture portion, and the cross-sectional area when the current constriction layer is cut along a plane parallel to the semiconductor substrate is another layer that constitutes the resonator on a plane parallel to the semiconductor substrate. Since it is smaller than the area of the cross section in the case where is cut, the capacitance of the element can be reduced while maintaining the resistance of the element. This allows
High-speed operation becomes possible.

The surface-emitting type semiconductor laser of the present invention can have the following aspects (1) to (4).

(1) The other layer may include layers constituting the first multilayer reflective film, the active layer, and the second multilayer reflective film.

(2) The current constriction layer may further include an oxide constriction portion formed around the aperture portion.

(3) Further, a columnar portion may be included in a part of the resonator.

In this case, the current confinement layer can be formed in the columnar portion. In this case, the area of the cross section when the current confinement layer is cut along the plane parallel to the semiconductor substrate is the cross section when the other layers constituting the resonator are cut along the plane parallel to the semiconductor substrate. Can be smaller than the area.

In this case, an insulating layer can be formed around the columnar portion.

(4) The first multilayer reflective film is made of Al _x Ga.
_1-X As and Al _Y Ga _1-Y As are alternately laminated, and the aperture portion forming the current constriction layer is made of Al _Z.
Ga _1-Z As, and X, Y, and Z are 0 ≦ X <Y
<Z ≦ 1 can be satisfied.

(Method for Manufacturing Surface Emitting Semiconductor Laser) A method for manufacturing a surface emitting semiconductor laser according to the present invention includes a resonator formed on a semiconductor substrate and emits light in a direction perpendicular to the semiconductor substrate. A method of manufacturing a surface-emitting type semiconductor laser capable of including the following step (a) and step (b).

(A) A step of forming a resonator including a first multilayer reflective film, an active layer, and a second multilayer reflective film on the semiconductor substrate, wherein the first and second multilayer reflective films are formed. Forming a current confinement forming layer on at least one of the above, and (b) removing a part of the current confinement forming layer to form a current confinement layer including at least an aperture portion.

According to the method of manufacturing a surface-emitting type semiconductor laser of the present invention, a surface-emitting laser having good device characteristics and capable of high-speed operation can be formed by a simple method.

The surface-emitting type semiconductor laser manufacturing method of the present invention can take the following aspects (1) to (4).

(1) In the step (b), by removing a part of the current constriction forming layer, the area of the cross section when the current constriction layer is cut by a plane parallel to the semiconductor substrate becomes The current constriction layer can be formed so as to have a smaller area than the cross-sectional area when the other layers forming the resonator are cut along a plane parallel to the semiconductor substrate.

In this case, the other layer may include layers constituting the first multilayer reflective film, the active layer, and the second multilayer reflective film.

(2) Further, the following step (c) can be included.

(C) A step of oxidizing a part of the current constriction forming layer to form an oxidized constriction portion around the aperture portion.

(3) The step (a) may further include the following step (d).

(D) A step of forming a columnar portion on a part of the resonator.

In this case, in the step (a), the current confinement forming layer can be formed on the layer for forming the columnar portion of the resonator. Also in this case,
In the step (b), by removing a part of the current constriction forming layer, the cross-sectional area when the current constriction layer is cut along a plane parallel to the semiconductor substrate is a plane parallel to the semiconductor substrate. It is possible to form the current constriction layer so that the area is smaller than the area of the cross section when the other layer forming the columnar portion is cut. further,
In this case, the method may include the step (e) of forming an insulating layer around the columnar portion.

(4) In the step (a), Al _X G
a _1-X As and Al _Y Ga _1-Y As are alternately laminated to form the first multilayer reflective film; and a step of forming the current constriction forming layer made of Al _Z Ga _1-Z As. Including and
X, Y, and Z can satisfy 0 ≦ X <Y <Z ≦ 1.

(Optical Module and Optical Transmission Device) The present invention can be applied to an optical module including the surface emitting semiconductor laser of the present invention and an optical waveguide. Further, it can be applied to an optical transmission device including the optical module.

[0033]

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

[First Embodiment] (Device Structure) FIG. 1 is a sectional view schematically showing a surface-emitting type semiconductor laser 100 according to a first embodiment of the present invention. FIG. 2 is a plan view schematically showing the surface emitting semiconductor laser 100 according to the first embodiment to which the present invention is applied. FIG. 1 is a view showing a cross section taken along the line AA of FIG.

The surface-emitting type semiconductor laser 10 of the present embodiment
0 (hereinafter also referred to as “surface emitting laser”) is a semiconductor substrate (GaAs substrate in this embodiment) 10 as shown in FIG.
1 and a vertical resonator (hereinafter referred to as “resonator”) 120 formed on the semiconductor substrate 101. This resonator 12
Reference numeral 0 denotes a columnar semiconductor deposited body (hereinafter referred to as “columnar portion”) 11
Including 0.

Next, each component of the surface emitting laser 100 will be described.

The surface emitting laser 100 is, for example, an n-type GaA.
The semiconductor substrate 101 made of s and the resonator 120 formed on the semiconductor substrate 101 are included.

A columnar portion 110 is formed on the resonator 120. Here, the columnar section 110 is a part of the resonator 120, and is a columnar semiconductor deposited body including at least the second multilayer reflective film 104. Further, the first electrode 107 is formed on the columnar section 110, and the emission surface 108 is formed on the upper surface.
Is installed.

The resonator 120 is made of, for example, n-type Al._0.9G
a_0.1As layer and n-type Al_0.1Ga_0.9Alternating with As layer
38 pairs of distributed reflection type multilayer mirrors (hereinafter referred to as “first
"Multilayer reflective film" 102, n-type Al_0.5Ga_0.5A
n-type clad layer (not shown) composed of s layer, i-GaA
Active layer 103 using s layer as well layer, p-type Al_0.5Ga_0
.FiveA p-type clad layer (not shown) made of an As layer, and
p-type Al_0.9Ga_0.1As layer and p-type Al_0.1Ga_0.9As layer
24.5 pairs of distributed reflection multi-layer film
(Hereinafter referred to as “second multilayer reflective film”) 104
It is configured by stacking. Here, the first multilayer reflective film 1
N-type Al forming 02_0.9Ga_0.1As layer and n-type Al
_0.1Ga_0.9The As layer and the second multilayer reflective film 104 are formed.
P-type Al formed_0.9Ga_0.1As layer and p-type Al_0.1Ga_0.9
Each As layer has a film thickness of 1 of the in-medium wavelength λ of the laser light.
It is formed to be / 4. The resonator 120
The composition and number of layers of each layer are not limited to this.
Not only.

The second multilayer reflective film 104 is made p-type by, for example, being doped with C, and the first multilayer reflective film 1 is formed.
02 is made n-type by doping Si, for example. Therefore, the second multilayer reflective film 104, the active layer 103 not doped with impurities, and the first multilayer reflective film 102 form a pin diode.

The surface emitting laser 1 of the resonator 120 is also used.
The portion of the laser beam 00 from the laser light emitting side to the middle of the first multilayer reflective film 102 is etched into a circular shape as viewed from the laser light emitting side to form the columnar portion 110. In addition, in the present embodiment, the planar shape of the columnar section 110 is circular, but this shape can take any shape.

Further, the current confinement layer 105 is formed in a region near the active layer 103 among the layers forming the second multilayer reflective film 104.
Are formed. The current constriction layer 105 includes at least the aperture portion 105a. In the surface emitting laser 100 according to the present embodiment, as shown in FIG. 1, the current confinement layer 105 is cut along a plane parallel to the semiconductor substrate 101 (a plane parallel to the XY plane in FIG. 1). The cross-sectional area of the semiconductor substrate 1 is different from that of the other layers constituting the resonator 120.
01 is formed so as to be smaller than the cross-sectional area when cut along a plane parallel to 01 (plane parallel to the XY plane in FIG. 1). Here, the other layers constituting the resonator 120 are each layer constituting the first multilayer reflection film 102, the active layer 103, the second multilayer reflection film 104, and the n-type clad layer and the p-type clad layer (both are shown in FIG. (Not shown). In the present embodiment, the current confinement layer 105 is the first
Although the case where it is formed on the multilayer reflective film 104 is shown, a current confinement layer may be formed on the first multilayer reflective film 102.

Further, in the present embodiment, the current confinement layer 105 is formed in the columnar section 110. Here, the area of the cross section when the current confinement layer 105 is cut along a plane parallel to the semiconductor substrate 101 (a plane parallel to the XY plane in FIG. 1) has a cross-sectional area other than the other layers constituting the semiconductor substrate 101. It is formed so as to be smaller than the area of the cross section when cut by a plane parallel to 101 (plane parallel to the XY plane in FIG. 1).

First multilayer reflective film 102 and current confinement layer 1
Aperture portion 105a constituting 05 is made of Al, Ga, A
In the case of a layer containing s as a main component (aperture portion 105
a also includes a layer containing Al and As as main components), and the first multilayer reflective film 102 has an Al _x Ga ₁ -x As layer and an A layer.
The 1 _Y Ga _1-Y As layers are alternately laminated to form an aperture portion 1
05a is made of an Al _Z Ga _1-Z As layer, and X, Y,
It is desirable that Z satisfies 0 ≦ X <Y <Z ≦ 1.

In the present embodiment, the current confinement layer 10
5 further includes an oxidized constriction portion 105b formed around the aperture portion 105a. This oxidation constriction portion 105b
Are formed in a ring shape. That is, the oxidized constricted portion 105b has a shape in which the cross section taken along a plane parallel to the XY plane in FIG. 1 is concentric.

The oxidation constriction portion 105b is formed by oxidizing a part of the current constriction forming layer 105c (see FIG. 6) from the side surface.

The first electrode 1 is formed on the columnar section 110.
07 are formed. Further, a portion (opening) where the first electrode 107 is not formed is provided in the central portion of the upper surface of the columnar portion 110. This portion is the emission surface 108. The emission surface 108 serves as an emission port for laser light. First
The electrode 107 is composed of, for example, a laminated film of an alloy of Au and Zn and Au.

Further, a second electrode 109 is formed on the back surface of the semiconductor substrate 101. Here, the semiconductor substrate 1
The back surface of 01 is the resonator 12 in the semiconductor substrate 101.
The surface opposite to the surface on which 0 is formed (surface 101a). That is, in the surface emitting laser 100 shown in FIG.
The first electrode 107 is bonded on the columnar section 110 and the second electrode 109 is bonded on the back surface of the semiconductor substrate 101. The active layer 10 is bonded by the first electrode 107 and the second electrode 109.
Current is injected into 3. The second electrode 109 is, for example, Au.
And a Ge alloy and a laminated film of Ni and Au.

(Operation of Device) The general operation of the surface emitting laser 100 of the present embodiment is shown below. The following method of driving the surface-emitting type semiconductor laser is an example, and various modifications can be made without departing from the spirit of the present invention.

First, when a forward voltage is applied to the pin diode between the first electrode 107 and the second electrode 109, recombination of electrons and holes occurs in the active layer 103,
Luminescence is generated by such recombination. When the generated light reciprocates between the first multilayer reflective film 102 and the second multilayer reflective film 104, stimulated emission occurs and the intensity of light is amplified.
When the optical gain exceeds the optical loss, laser oscillation occurs, and the semiconductor substrate 1 is emitted from the emitting surface 108 on the upper surface of the columnar section 110.
Laser light is emitted in the direction perpendicular to 01 (Z direction shown in FIG. 1). Here, the “direction perpendicular to the semiconductor substrate 101” means the surface 101a of the semiconductor substrate 101 (X-Y in FIG. 1).
A direction (Z direction in FIG. 1) perpendicular to the plane parallel to the plane). Further, the front surface 101a of the semiconductor substrate 101 is the same as that shown in FIG.
As shown in FIG.
Refers to the surface on which is formed.

(Device Manufacturing Process) Next, the surface emitting laser 100 according to the first embodiment to which the present invention is applied.
An example of the manufacturing method will be described with reference to FIGS. 3 to 7 are cross-sectional views schematically showing one manufacturing process of the surface emitting laser 100 of the present embodiment shown in FIGS. 1 and 2, each of which corresponds to the cross section shown in FIG.

(1) First, a semiconductor made of n-type GaAs
Epitaxy on the surface of substrate 101 with varying composition
As shown in FIG.
The multilayer film 150 is formed. Here, the semiconductor multilayer film 150
Is, for example, n-type Al_0.9Ga_{0 .1}As layer and n-type Al_0.1G
a_0.938 pairs of the first multi-layered film in which As layers are alternately laminated
Spray film 102, n-type Al_0.5Ga_0.5N-type layer consisting of As layer
Rad layer (not shown) and i-GaAs layer as well layers
Active layer 103, p-type Al_0.5Ga_0.5P consisting of As layer
-Type cladding layer (not shown) and p-type Al_0.9Ga_0.1
As layer and p-type Al _0.1Ga_0.9As layers were alternately laminated
24.5 pairs of second multilayer reflective films 104 are sequentially stacked.
The composition and film thickness of each layer are described in the device structure section.
It is as follows. These layers are sequentially deposited on the semiconductor substrate 101.
The semiconductor multilayer film 150 is formed by stacking layers.
It In addition, as shown in FIG.
When growing, the current constriction forming layer 105c is formed in the vicinity of the active layer.
To form. The current constriction forming layer 105c is the first multilayer
Layers constituting the reflective film 102 and the second multilayer reflective film 104
Is a layer having a higher Al composition than that of, for example, an AlAs layer or
Is an AlGaAs layer having an Al composition of 0.95 or more. This
The current constriction forming layer 105c of FIG.
Oxidation causes a part of it to become the oxidation constriction portion 105b.
A current including the aperture part 105a and the oxidation constriction part 105b
It becomes the narrowing layer 105. In addition, the second multilayer reflective film 104
The surface layer has a high carrier density and is used for electrodes (
It is easy to make ohmic contact with 1 electrode 107)
You can

The temperature at which the epitaxial growth is performed is appropriately determined depending on the type of the semiconductor substrate 101 or the type and thickness of the semiconductor multilayer film 150 to be formed, but it is generally preferably 600 ° C. to 800 ° C. Further, the time required for performing the epitaxial growth is appropriately determined like the temperature. Further, as a method for epitaxial growth, metal organic vapor phase epitaxy (MOVPE: Metal) is used.
-Organic Vapor Phase Epit
axy) method and MBE method (Molecular Beam)
The Epitaxy) method can be used.

(2) Subsequently, as shown in FIG. 4, a photoresist (not shown) is applied on the semiconductor multilayer film 150, and then the photoresist is patterned by a photolithography method to form a predetermined pattern. A resist layer R100 is formed. Then, this resist layer R
Using 100 as a mask, the second multilayer reflective film 104, the active layer 103, and the first
Part of the multilayer reflective film 102 is etched to form a columnar semiconductor deposited body (columnar portion) 110 as shown in FIG. Through the above steps, the resonator 120 including the columnar section 110 is formed on the semiconductor substrate 101. Then, the resist layer R100 is removed.

(3) Then, as shown in FIG. 6, the current constriction forming layer 105c is etched from the side surface to the middle.
In the step of etching the current confinement forming layer 105c, an etching solution that can selectively remove the current confinement forming layer 105c is used. As in this embodiment,
When the current constriction forming layer 105c is composed of a layer having a higher Al composition than the other layers constituting the resonator 120, an etching solution having a higher Al composition and a higher etching rate can be used. An example of such an etching solution is a diluted HF solution (for example, 0.1% to 1%).

For example, when the columnar section 110 is cut along a plane parallel to the XY plane shown in FIG.
In the case of 0 μm, the current confinement forming layer 105c is formed from the side surface by
The current confinement forming layer 105c having a diameter of about 20 μm is formed by etching about μm.

(4) Then, as shown in FIG. 7, at a temperature of, for example, about 420 ° C., in a nitrogen atmosphere containing water vapor,
The semiconductor substrate 101 on which the resonator 120 has been formed by the above process is put in to oxidize the current confinement forming layer 105c from the side surface. As a result, the current confinement layer 105 including the aperture portion 105a and the oxidation constriction portion 105b is formed.
That is, in this step, the oxidized portion becomes the oxidized constriction portion 105b, and the central portion left unoxidized becomes the aperture portion 105a.

Here, the oxidation rate depends on the temperature of the furnace, the supply amount of water vapor, the Al composition and the film thickness of the layer to be oxidized (current confinement forming layer 105c). In the surface emitting laser 100 including the current confinement layer 105, when driven, a current flows only in the aperture portion 105a. Therefore, in the step of forming the current confinement layer 105 by oxidation, the current density can be controlled by controlling the range of the oxidized constriction portion 105b formed by oxidation.

For example, when the diameter of the current constriction forming layer 105c is about 20 μm, the current constriction forming layer 105c is oxidized from the side surface by about 5 μm to form the oxidized constriction portion 105b, and the aperture portion 105a has a diameter of about 10 μm. it can.

In this step, the current confinement forming layer 105
After oxidizing a part of c to form the oxide constriction portion 105b,
The current confinement layer 105 (see FIG. 7) may be formed by etching the formed oxide confinement portion 105b.

When the diameters of the formed aperture portions 105a are the same, a part of the current constriction forming layer 105c is oxidized to form the oxidized constriction portion 105b, and then the formed oxidized constriction portion 105b is etched. Compared to the case
When the current constriction forming layer 105c is etched and then a part of the current constriction forming layer 105c is oxidized to form the oxidized constriction part 105b, the volume of the oxidized constriction part 105b formed is smaller. Therefore, the latter is better than the oxidized constricted portion 10.
It takes less time to form 5b. Therefore, in the present embodiment, from the viewpoint of processing time, the latter method is used, that is, the current confinement forming layer 105c is etched and then a part of the current confinement forming layer 105c is oxidized to form the oxidized constriction portion 105b. It is desirable to form.

Through the above steps, the portion of the surface emitting laser 100 that functions as a light emitting element (excluding the emission surface 108 and the electrodes 107 and 109) is formed.

(5) Next, a process of forming the first electrode 107 and the second electrode 109 for injecting a current into the active layer 103, and the laser light emitting surface 108 will be described.

First, the first electrode 107 and the second electrode 10
Before forming 9, the upper surface of the columnar section 110 is washed using a dry etching method or the like, if necessary. As a result, an element having more stable characteristics can be formed.
Subsequently, a stacked film (not shown) of, for example, an alloy of Au and Zn and Au is formed on the upper surface of the columnar section 110 by, for example, a vacuum evaporation method, and then the columnar section 110 is formed by a lift-off method.
A portion where the laminated film is not formed is formed on the upper surface of. This portion becomes the emission surface 108. In the above process, a dry etching method can be used instead of the lift-off method.

On the back surface of the semiconductor substrate 101, for example, an alloy of Au and Ge, Ni and A are formed by, for example, a vacuum evaporation method.
A laminated film (not shown) with u is formed. Next, for example, annealing treatment is performed in a nitrogen atmosphere at 400 ° C. Through the above steps, the first electrode 107 and the second electrode 109 are formed.

Through the above process, the surface emitting laser 100 shown in FIG. 1 is obtained.

(Operation and Effect) The surface emitting laser 100 according to the present embodiment has the following operation and effect.

(1) Surface-emitting laser 100 of this embodiment
According to this, the current confinement layer 105 includes at least the aperture portion 105a, and the cross-sectional area when the current confinement layer 105 is cut along the plane parallel to the semiconductor substrate 101 has the resonator 120 on the plane parallel to the semiconductor substrate 101. Since the area is smaller than the area of the cross section when the other layers constituting the element are cut, the capacitance of the element can be reduced while maintaining the resistance of the element. This enables high speed operation.

Further, the surface emitting laser 10 according to the present embodiment.
At 0, the columnar portion 110 is formed in a part of the resonator 120. Further, the current constriction layer 105 includes an aperture portion 105a and an oxidized constriction portion 105b formed around the aperture portion 105a. In this case, the area of the cross section when the current confinement layer 105 is cut along the plane parallel to the semiconductor substrate 101 is smaller than the cross section when the other layer forming the columnar section 110 is cut along the plane parallel to the semiconductor substrate 101. Smaller than the area. This allows the semiconductor substrate 10 to be processed like a general surface emitting laser 900 (see FIG. 14).
When the area of the cross section when the current confinement layer 105 is cut along the plane parallel to 1 is the same as the area of the cross section when the other layers forming the columnar section 110 are cut along the plane parallel to the semiconductor substrate 101. The area of the oxide constricted portion can be reduced as compared with That is, when the surface emitting laser 100 and the surface emitting laser 900 according to the present embodiment have the same diameter of the columnar portion 110 and the diameter of the aperture portion 105a, the area of the oxide constriction portion can be reduced. As a result, it is possible to reduce the capacitance of the element while maintaining the resistance of the element, which enables high-speed operation.

(2) Surface emitting laser 100 according to the present embodiment
According to the manufacturing method of 1., it is possible to form a surface-emitting laser having good device characteristics and capable of high-speed operation by a simple method.

(Modification) FIG. 8 is a sectional view schematically showing a modification 100a of the surface emitting laser according to the present embodiment.

The surface emitting laser 100a has a columnar portion 11
0 has the same structure as the surface emitting laser 100 according to the present embodiment, except that the insulating layer 118 is provided so as to cover the side surface of 0 and the upper surface of the first multilayer reflective film 102. Therefore, components having substantially the same functions as those of the surface emitting laser 100 according to the present embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The insulating layer 118 may use either an inorganic material or an organic material. Examples of the inorganic material include a silicon oxide layer and a silicon nitride layer. Examples of the organic material include polyimide resin, fluorine resin, acrylic resin, epoxy resin, and the like.
In particular, it is desirable to use a polyimide resin or a fluorine-based resin from the viewpoint of ease of processing and insulating properties. In this case, the insulating layer 118 is formed by irradiation with energy such as heat or light, or by curing the resin precursor by a chemical reaction.

The operation, action and effect of this surface emitting laser 100a are similar to those of the surface emitting laser 100 according to the present embodiment. In addition, in the surface emitting laser 100a, the shape of the columnar section 110 can be maintained because the insulating layer 118 is formed around the columnar section 110.

[Second Embodiment] (Device Structure) FIG. 9 is a sectional view schematically showing a surface emitting laser 200 according to a second embodiment of the invention.

The surface emitting laser 200 according to the present embodiment.
Is the surface emitting laser 1 according to the first embodiment except that the current confinement layer 105 mainly includes the aperture portion 105a.
It has almost the same structure as 00. Therefore, components having substantially the same functions as those of the surface emitting laser 100 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The surface emitting laser 200 according to the present embodiment.
As described above, the current constriction layer 105 mainly includes the aperture portion 105a. That is, this surface emitting laser 2
00 is the surface emitting laser 100 of the first embodiment described above.
In the process of manufacturing the current confinement forming layer 105c in the process of etching the current confinement forming layer 105c (see FIG. 6),
After forming 5a, it is formed without going through the step of forming an oxide constriction portion (see FIG. 7).

The surface emitting laser 200 according to the present embodiment.
The operation, action and effect of are the same as those of the surface emitting laser 100 according to the first embodiment. In addition, in the surface emitting laser 200, the current confinement layer 105 is mainly composed of the aperture portion 105a, so that the capacitance of the device can be further reduced.

[Third Embodiment] FIG. 10 is a diagram schematically illustrating an optical module according to a third embodiment of the present invention. The optical module according to the present embodiment includes a structure 1000 (see FIG. 10). This structure 1000 is the surface emitting laser 10 according to the first embodiment.
0 (see FIG. 1), platform 1120, first optical waveguide 1130 and actuator 1150. In addition, the structure 1000 has the second optical waveguide 13
Have 02. The second optical waveguide 1302 is the substrate 130.
Part of 0. The connection optical waveguide 1304 may be optically connected to the second optical waveguide 1302. The connection optical waveguide 1304 may be an optical fiber.

In the optical module of this embodiment, after the light is emitted from the surface emitting laser 100 (emission surface 108; see FIG. 1), the first and second optical waveguides 1130 and 1302 are provided.
This light is received by a light receiving element (not shown) through (and the connecting optical waveguide 1304).

[Fourth Embodiment] FIG. 11 is a diagram for explaining an optical transmission device according to a fourth embodiment of the present invention. In the present embodiment, the first optical waveguide 1130
And the light receiving element 210, a plurality of third optical waveguides 12
It has 30, 1310 and 1312. In addition, the optical transmission device according to the present embodiment has a plurality (two) of substrates 1314.
1316.

In this embodiment, the structure of the surface emitting laser 100 side (the surface emitting laser 100, the platform 112).
0, the first optical waveguide 1130, the second optical waveguide 131
8, including actuator 1150. ) And the light receiving element 2
10 side configuration (light receiving element 210, platform 12
20 and third optical waveguides 1230 and 1310. ) Between the third optical waveguide 1312 and the optical waveguide 1312. An optical fiber or the like can be used as the third optical waveguide 1312 to perform optical transmission between a plurality of electronic devices.

For example, referring to FIG. 12, the optical transmission device 11
Reference numeral 00 interconnects electronic devices 1102 such as a computer, a display, a storage device, and a printer. The electronic device 1102 may be an information communication device. The light transmission device 1100 has a cable 1104 including a third optical waveguide 1312 such as an optical fiber. The light transmission device 1100 includes a plug 11 at both ends of the cable 1104.
06 may be provided. The surface emitting laser 100 and the light receiving element 210 are provided in the respective plugs 1106.
A side configuration is provided. An electric signal output from one of the electronic devices 1102 is converted into an optical signal by the light emitting element, the optical signal is transmitted through the cable 1104, and converted into an electric signal by the light receiving element. The electric signal is input to another electronic device 1102. Thus, according to the optical transmission device 1100 according to the present embodiment, it is possible to transmit information of the electronic device 1102 by the optical signal.

FIG. 13 is a diagram showing a usage pattern of the optical transmission device according to the embodiment to which the present invention is applied. The light transmission device 1110 connects between the electronic devices 1112. As the electronic device 1112, a liquid crystal display monitor or a digital-compatible CRT (may be used in the fields of finance, mail order, medical care, and education), liquid crystal projector, plasma display panel (PDP), digital TV, retail store Examples include cash registers (for POS (Point of Sale Scanning)), videos, tuners, game machines, printers, and the like.

The third and fourth embodiments (see FIG. 1)
0 to 13), even when the surface emitting lasers 100a (see FIG. 8) and 200 (see FIG. 9) are used instead of the surface emitting laser 100, the same operation and effect can be obtained.

That is, the present invention is not limited to the above-described embodiment, but various modifications can be made.
For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations having the same function, method and result, or configurations having the same object and result).
Further, the invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Further, the present invention includes a configuration having the same effects as the configurations described in the embodiments or a configuration capable of achieving the same object. Further, the invention includes configurations in which known techniques are added to the configurations described in the embodiments.

For example, although the surface-emitting type semiconductor laser having one columnar portion has been described in the above embodiment, the configuration of the present invention is not impaired even if a plurality of columnar portions are provided in the substrate surface. Further, even when a plurality of surface-emitting type semiconductor lasers are arrayed, the same action and effect are obtained.

Further, for example, in the above embodiment,
It does not deviate from the gist of the present invention even if the p-type and the n-type in each semiconductor layer are interchanged. In the above embodiment,
Although the AlGaAs type has been described, other material types such as InGaAs type, Ga type, etc. may be used depending on the oscillation wavelength.
InP, ZnSSe, InGaN, GaInNA
It is also possible to use s-based or GaAsSb-based semiconductor materials.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a surface emitting semiconductor laser according to a first embodiment to which the present invention is applied.

FIG. 2 is a plan view schematically showing the surface emitting semiconductor laser according to the first embodiment to which the present invention is applied.

FIG. 3 is a cross-sectional view schematically showing one manufacturing process of the surface-emitting type semiconductor laser shown in FIGS. 1 and 2.

FIG. 4 is a cross-sectional view schematically showing one manufacturing process of the surface-emitting type semiconductor laser shown in FIGS. 1 and 2.

5 is a cross-sectional view schematically showing one manufacturing step of the surface-emitting type semiconductor laser shown in FIGS. 1 and 2. FIG.

FIG. 6 is a cross-sectional view schematically showing one manufacturing process of the surface-emitting type semiconductor laser shown in FIGS. 1 and 2.

FIG. 7 is a cross-sectional view schematically showing one manufacturing process of the surface-emitting type semiconductor laser shown in FIGS. 1 and 2.

8 is a sectional view schematically showing a modification of the surface-emitting type semiconductor laser shown in FIGS. 1 and 2. FIG.

FIG. 9 is a sectional view schematically showing a surface-emitting type semiconductor laser according to a second embodiment of the present invention.

FIG. 10 is a diagram schematically showing an optical module according to a third embodiment of the present invention.

FIG. 11 is a diagram showing an optical transmission device according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing an optical transmission device according to a fourth embodiment of the present invention.

FIG. 13 is a diagram showing a usage pattern of an optical transmission device according to a fourth embodiment of the present invention.

FIG. 14 is a sectional view schematically showing a general surface emitting semiconductor laser.

FIG. 15 is a cross-sectional view schematically showing one manufacturing process of a general surface emitting semiconductor laser.

FIG. 16 is a cross-sectional view schematically showing one manufacturing process of a general surface emitting semiconductor laser.

[Explanation of symbols]

100,100a, 200 surface emitting laser 101 semiconductor substrate 102 first multilayer reflective film 103 Active layer 104 second multilayer reflective film 105 Current constriction layer 105a aperture part 105b Current constriction part 105c Current constriction forming layer 107 first electrode 108 exit surface 109 second electrode 118 insulating layer 110 Column 120 resonator 150 semiconductor multilayer film 210 Light receiving element 1000 structures 1100, 1110 Optical transmission device 1102, 1112 electronic devices 1104 cable 1106 plug 1120, 1220 platform 1130 First optical waveguide 1150 Actuator 1152 cushion 1154 Energy source 1300 substrate 1302, 1318 second optical waveguide 1230, 1310, 1312 Third optical waveguide 1304 Optical waveguide for connection 1314, 1316 substrate R100 resist

Claims (19)

[Claims] 1. A surface emitting semiconductor laser including a resonator formed on a semiconductor substrate and capable of emitting light in a direction perpendicular to the semiconductor substrate, wherein the resonator comprises a first multilayer reflective film. An active layer and a second multilayer reflective film, a current confinement layer is formed on at least one of the first and second multilayer reflective films, the current constriction layer includes at least an aperture portion, and the semiconductor substrate The area of the cross section when the current confinement layer is cut by a plane parallel to the plane is smaller than the area of the cross section when the other layers constituting the resonator are cut by the plane parallel to the semiconductor substrate. Type semiconductor laser. 2. The surface emitting semiconductor laser according to claim 1, wherein the other layer includes a layer forming a first multilayer reflective film, an active layer, and a second multilayer reflective film. 3. The surface emitting semiconductor laser according to claim 1, wherein the current confinement layer further includes an oxide confinement portion formed around the aperture portion. 4. The surface emitting semiconductor laser according to claim 1, further comprising a columnar part in a part of the resonator. 5. The surface emitting semiconductor laser according to claim 4, wherein the current constriction layer is formed in the columnar portion. 6. The cross-sectional area when the current confinement layer is cut along a plane parallel to the semiconductor substrate according to claim 5, wherein another layer forming the resonator is formed on a plane parallel to the semiconductor substrate. A surface-emitting type semiconductor laser that is smaller than the cross-sectional area when cut. 7. The surface emitting semiconductor laser according to claim 4, wherein an insulating layer is formed around the columnar portion. 8. The first multilayer reflective film according to claim 1, wherein the first multilayer reflective film is Al _X Ga _1-X As and Al _Y Ga.
_1-Y As are alternately laminated, and the aperture portion forming the current confinement layer is made of Al _Z Ga.
_A surface-emitting type semiconductor laser which is composed of _1-Z As and in which X, Y, and Z satisfy 0 ≦ X <Y <Z ≦ 1. 9. An optical module comprising the surface-emitting type semiconductor laser according to claim 1 and an optical waveguide. 10. An optical transmission device comprising the optical module according to claim 9. 11. A method for manufacturing a surface-emitting type semiconductor laser including a resonator formed on a semiconductor substrate and capable of emitting light in a direction perpendicular to the semiconductor substrate, comprising the following steps (a) and (a): A method for manufacturing a surface-emitting type semiconductor laser including (b). (A) a step of forming a resonator including a first multilayer reflective film, an active layer, and a second multilayer reflective film on the semiconductor substrate, wherein at least one of the first and second multilayer reflective films A step of forming a current constriction forming layer, and (b) removing a part of the current constriction forming layer to form a current confinement layer including at least an aperture portion. 12. The cross section in the case where the current constriction layer is cut along a plane parallel to the semiconductor substrate by removing a part of the current constriction formation layer in the step (b). Manufacturing of a surface emitting semiconductor laser in which the current confinement layer is formed so that the area becomes smaller than the area of the cross section when the other layer forming the resonator is cut by a plane parallel to the semiconductor substrate. Method. 13. The method for manufacturing a surface-emitting type semiconductor laser according to claim 12, wherein the other layer includes a layer forming a first multilayer reflective film, an active layer, and a second multilayer reflective film. 14. The method for manufacturing a surface emitting semiconductor laser according to claim 11, further including the following step (c). (C) A step of oxidizing a part of the current constriction forming layer to form an oxidized constriction portion around the aperture portion. 15. The method for manufacturing a surface emitting semiconductor laser according to claim 11, wherein the step (a) further includes the following step (d). (D) A step of forming a columnar portion on a part of the resonator. 16. The current confinement forming layer according to claim 15, wherein in the step (a), the current constriction forming layer is formed on a layer for forming the columnar portion of the resonator.
Method of manufacturing surface-emitting type semiconductor laser. 17. The cross-section according to claim 16, wherein in the step (b), a part of the current constriction forming layer is removed to cut the current constriction layer along a plane parallel to the semiconductor substrate. Manufacturing of a surface-emitting type semiconductor laser in which the current confinement layer is formed so that the area becomes smaller than the area of the cross section in the case where another layer forming the columnar section is cut by a plane parallel to the semiconductor substrate. Method. 18. The method for manufacturing a surface-emitting type semiconductor laser according to claim 15, further including the following step (e). (E) A step of forming an insulating layer around the columnar portion. 19. The first multilayer reflective film according to claim 11, wherein in the step (a), Al _X Ga _1-X As and Al _Y Ga _1-Y As are alternately laminated. And a step of forming the current confinement forming layer made of Al _Z Ga _{1 -Z} As, wherein X, Y and Z satisfy 0 ≦ X <Y <Z ≦ 1. Laser manufacturing method.