JP3944677B2 - Manufacturing method of surface emitting semiconductor laser - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a surface emitting semiconductor laser that emits laser light perpendicular to a semiconductor substrate.
[0002]
[Background]
A surface emitting semiconductor laser is a semiconductor laser that emits laser light perpendicular to a semiconductor substrate, and a resonator is provided on the semiconductor substrate in a vertical direction. This resonator emits laser light after being oscillated, and is configured by sequentially stacking a reflective layer, an active layer, and a reflective layer.
[0003]
Surface-emitting semiconductor lasers can be easily arrayed (a large number of lasers can be placed on the same semiconductor substrate), have a small threshold current, have a stable oscillation wavelength, and have an isotropic laser emission angle compared to edge lasers. And has excellent characteristics such as small size. Therefore, the surface emitting semiconductor laser is expected to be applied to optical parallel communication, optical parallel computation, a laser beam printer, and the like as a semiconductor laser capable of two-dimensional integration.
[0004]
On the other hand, when an optical device is constructed using a semiconductor laser, devices such as a polarizer and a beam splitter are often used. In devices such as a polarizer and a beam splitter, the reflectance depends on the polarization direction. For this reason, when a semiconductor laser is incorporated in an optical device and used, if the control of the polarization direction of the laser beam is insufficient, problems such as a change in the light intensity depending on the direction may occur. It is important to control.
[0005]
[Problems to be solved by the invention]
However, in the surface emitting semiconductor laser, since the resonator has an isotropic structure, the radiation angle of the laser beam emitted from the resonator is isotropic, so it is difficult to control the polarization direction of the laser beam. Met. For this reason, attempts have been made to control the polarization direction of laser light in surface emitting semiconductor lasers. For example, surface emitting semiconductor lasers are disclosed in Japanese Patent Application Laid-Open Nos. 8-116130 and 6-224515. A technique relating to the control of the polarization direction of the light is disclosed.
[0006]
An object of the present invention is to provide a method of manufacturing a surface emitting semiconductor laser capable of controlling the polarization direction of laser light.
[0007]
[Means for Solving the Problems]
The surface emitting semiconductor laser according to the present invention is
A surface emitting semiconductor laser in which a resonator is formed in a vertical direction on a semiconductor substrate and emits laser light in a direction perpendicular to the semiconductor substrate from the resonator,
The semiconductor substrate and the resonator have a function of controlling the polarization direction of laser light.
[0008]
According to this surface-emitting type semiconductor laser, not only the active layer that contributes to the emission of laser light in a surface-emitting laser, but also the function of controlling the polarization direction of the laser light is provided to the semiconductor substrate and the resonator. The polarization direction of the laser light in the active layer can be controlled more reliably.
[0009]
(1) In this case, it is desirable that the semiconductor substrate and the resonator have an anisotropic strain, and the polarization direction of the laser light is controlled by the anisotropic strain.
[0010]
Here, the anisotropic distortion referred to in the present invention refers to distortion in a specific direction. Therefore, in the surface emitting semiconductor laser of the present invention, the semiconductor substrate and the resonator have an anisotropic strain, and the anisotropic strain is also added to the active layer. The gain anisotropy is manifested. That is, the polarization direction of the laser light is controlled by anisotropic distortion in the semiconductor substrate or the resonator. As a result, since the laser beam having a specific polarization direction can be preferentially amplified and oscillated, the polarization direction of the laser beam can be controlled to a specific direction.
[0011]
(2) Further, in this case, it is desirable that the semiconductor substrate and the resonator have a curvature, and the anisotropic strain is caused by the curvature.
[0012]
Here, the curvature referred to in the present invention means that the semiconductor substrate and the resonator have a curvature that is convex or concave in the laser beam emission direction, and the semiconductor substrate and the resonator have a laser beam emission direction. It means that it is bent like a tile. Therefore, in the surface-emitting type semiconductor laser of the present invention, the semiconductor substrate and the resonator have a curvature, and the anisotropic strain is caused by the curvature. Since the active layer is reliably added, the polarization direction of the laser light can be strictly controlled in a specific direction.
[0013]
As a preferred embodiment of the surface emitting semiconductor laser,
A surface emitting semiconductor laser in which a resonator is formed in a vertical direction on a semiconductor substrate and emits laser light in a direction perpendicular to the semiconductor substrate from the resonator,
The semiconductor substrate and the resonator have a curvature,
There is a surface-emitting type semiconductor laser capable of controlling the polarization direction of laser light by anisotropic distortion generated in the semiconductor substrate and the resonator due to the bending.
[0014]
According to this surface emitting semiconductor laser, the above-described effects can be obtained.
[0015]
The surface emitting semiconductor laser according to the present invention can be obtained by a manufacturing method including the following steps (a) to (c).
[0016]
(A) forming a stripe-shaped uneven portion on the back surface of the semiconductor substrate;
(B) forming a semiconductor deposition layer including at least an active layer on the surface of the semiconductor substrate at a predetermined temperature; and
(C) forming a resonator that emits laser light in a direction perpendicular to the semiconductor substrate from the semiconductor deposition layer;
[0017]
The back surface of the semiconductor substrate referred to in the present invention primarily means a surface of the semiconductor substrate opposite to a surface on which a resonator is formed in a later step. Further, the surface of the semiconductor substrate referred to in the present invention refers to a surface of the semiconductor substrate on which the resonator is formed.
[0018]
According to this manufacturing method, since the semiconductor substrate and the resonator can be curved, anisotropic distortion occurs in the semiconductor substrate and the resonator, and the active layer is formed in that state. As a result, anisotropy appears in the optical gain of the laser beam, and the laser beam in a specific polarization direction can be preferentially amplified and oscillated. A surface emitting semiconductor laser capable of strictly controlling the direction to a specific direction can be obtained.
[0019]
Here, as the step (a), the following step (1) or step (2) is preferable.
[0020]
(1) A step of forming the concavo-convex portion by etching a back surface of the semiconductor substrate to provide a stripe-shaped groove.
[0021]
According to the step (1), the degree of anisotropic strain applied to the semiconductor substrate and the resonator is changed by changing the width, depth, or interval of the groove forming the uneven portion formed on the semiconductor substrate. Can be controlled.
[0022]
(2) The process of forming the said uneven part by providing a stripe-shaped convex part in the back surface of the said semiconductor substrate.
[0023]
According to the step (2), in addition to the effect of the step (1), the protrusions and depressions are formed on the back surface of the semiconductor substrate by forming the protrusions with a material different from that of the semiconductor substrate. The convex portion can be formed by appropriately changing the material of the convex portion constituting the. As a result, the anisotropic strain applied to the semiconductor substrate and the resonator can also be adjusted by changing the material used for forming the convex portion.
[0024]
In the step (2), it is preferable that the convex portion is made of an oxide film or a nitride film. These materials can withstand the process of forming a semiconductor deposition layer later and can maintain the shape of the convex portion. For this reason, a surface emitting semiconductor laser having a function of controlling the polarization direction of the laser beam can be obtained by forming the convex portion from an oxide film or a nitride film so that the semiconductor substrate and the resonator can be curved. Can do. In this case, the convex portion is more preferably made of a material containing at least one of silicon dioxide, titanium dioxide, and silicon nitride.
[0025]
The surface-emitting type semiconductor laser according to the present invention can be obtained by a manufacturing method including the following steps (d) and (e).
[0026]
(D) forming a semiconductor deposition layer including at least an active layer at a predetermined temperature on the surface of the semiconductor substrate in a curved state; and
(E) forming a resonator that emits laser light in a direction perpendicular to the semiconductor substrate from the semiconductor deposition layer;
[0027]
According to this manufacturing method, since the semiconductor substrate and the resonator can be curved, an anisotropic strain is generated in the semiconductor substrate and the resonator, so that an anisotropic strain is also applied to the active layer. Anisotropy appears in the optical gain of the laser beam, and the laser beam having a specific polarization direction can be preferentially amplified and oscillated. Therefore, it is possible to obtain a surface emitting semiconductor laser capable of strictly controlling the polarization direction of the laser light in a specific direction. In addition, since the semiconductor deposition layer and the semiconductor substrate can be curved without performing any special treatment on the semiconductor substrate, the manufacturing process can be shortened. Thereby, manufacturing cost can be reduced.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0029]
(First embodiment)
(Device structure)
FIG. 1 is a cross-sectional view of a surface-emitting type semiconductor laser 100 (hereinafter referred to as “surface-emitting laser”) according to the first embodiment of the present invention, cut along line AA in FIG. FIG. 2 is a diagram schematically showing a principal part of a plane when the surface emitting laser shown in FIG. 1 is viewed from the side facing the laser beam exit.
[0030]
The structure of the surface emitting laser 100 shown in FIGS. 1 and 2 will be described. The surface emitting laser 100 is formed on a semiconductor substrate 101, a buffer layer 102 made of n-type GaAs formed on the semiconductor substrate 101, a vertical resonator (hereinafter referred to as “resonator”) 120, and the resonator 120. The vertical cavity surface emitting laser includes a contact layer 109 made of p-type GaAs.
[0031]
The resonator 120 is formed on the buffer layer 102, and includes an n-type AlAs layer and an n-type Al. _0.15 Ga _0.85 30.5 pairs of distributed reflection type multilayer mirrors (hereinafter referred to as “lower mirrors”) 103, n-type Al, alternately laminated with As layers _0.5 Ga _0.5 N-type cladding layer 104 made of As, GaAs well layer and Al _0.3 Ga _0.7 A multi-well active layer 105 composed of an As barrier layer and having three well layers, Al _0.5 Ga _0.5 P-type cladding layer 106 made of As and p-type Al _0.89 Ga _0.11 As layer and p-type Al _0.15 Ga _0.85 25 pairs of distributed reflection type multilayer mirrors (hereinafter referred to as “upper mirrors”) 108 in which As layers are alternately stacked are sequentially stacked. In addition, one of the layers constituting the upper mirror 108 is replaced with a current confinement layer 107 made of p-type AlAs and a dielectric layer 111 formed around the current confinement layer 107.
[0032]
The upper mirror 108 is made p-type by doping with Zn, and the lower mirror 103 is made n-type by doping with Se. Therefore, a pin diode is formed by the upper mirror 108, the active layer 105 not doped with impurities, and the lower mirror 103.
[0033]
Further, a columnar portion 110 is formed by etching in a circular shape when viewed from the laser light emitting side from the laser light emitting side of the surface emitting laser 100 to just above the surface of the p-type cladding layer 106. In this embodiment, the planar shape of the columnar section 110 is circular, but this shape can take any shape. Further, a silicon oxide film (SiO 2) is formed so as to cover a part of the side surface of the columnar part 110 and the upper surface of the lower mirror 103. ₂ An insulating layer 112 made of a film is formed.
[0034]
Further, an upper electrode 113 is formed on the upper surfaces of the columnar part 110 and the insulating layer 112. At the center of the upper surface of the columnar portion 110, an opening 116 serving as a laser beam exit is formed. Further, a lower electrode 115 is formed on the surface of the semiconductor substrate 101 opposite to the side on which the resonator 120 is formed.
[0035]
In order to concentrate the current from the upper electrode 113 on the central portion of the columnar portion 110, a dielectric layer 111 made of aluminum oxide is formed in a region about several μm from the periphery of the current confinement portion layer 107.
[0036]
(Device operation)
When a forward voltage is applied to the pin diode between the upper electrode 113 and the lower electrode 115, recombination of electrons and holes occurs in the active layer 105, and light emission due to the recombination occurs. When the generated light reciprocates between the upper mirror 108 and the lower mirror 103, stimulated emission occurs, and the light intensity is amplified. Here, when the optical gain exceeds the optical loss, laser oscillation occurs, and laser light is emitted from the opening of the upper electrode 113 in a direction perpendicular to the semiconductor substrate 101.
[0037]
(effect)
With reference to FIG. 1 and FIG. 2, the effect of the surface emitting laser according to the first embodiment will be described.
[0038]
(1) In the surface emitting laser according to the present embodiment, the semiconductor substrate 101 and the resonator 120 have a function of controlling the polarization direction of the laser light. In the surface emitting laser, the active layer 105 contributes to the light emission of the laser beam. By providing the semiconductor substrate 101 and the resonator 120 with a function of controlling the polarization direction of the laser beam, the laser beam in the active layer 105 is obtained. The polarization direction can be controlled more reliably.
[0039]
For example, by adding anisotropic strain to the semiconductor substrate 101 and the resonator 120, the semiconductor substrate 101 and the resonator 120 can be provided with a function of controlling the polarization direction of the laser light. Here, anisotropic distortion refers to distortion in a specific direction. Since the semiconductor substrate 101 and the resonator 120 have an anisotropic strain, the anisotropic strain is also applied to the active layer 105 in the resonator 120, and the anisotropic gain of the laser beam due to the anisotropic strain is increased. Sex is expressed. As a result, since the laser beam having a specific polarization direction can be preferentially amplified and oscillated, the polarization direction of the laser beam can be controlled to a specific direction.
[0040]
One means for applying anisotropic strain to the semiconductor substrate 101 and the resonator 120 is to bend the surface of the semiconductor substrate 101 where the resonator 120 is formed. In this case, the term “curved” means that the semiconductor substrate 101 and the resonator 120 have a curvature such that the semiconductor substrate 101 and the resonator 120 are convex or concave in the laser beam emission direction and are bent in a tile shape. Since the semiconductor substrate 101 and the resonator 120 have an anisotropic strain due to the curvature, the anisotropic strain is more reliably applied to the active layer 105 particularly in the formation process thereof. As a result, the anisotropic distortion applied to the active layer 105 causes anisotropy in the optical gain of the laser beam, and the laser beam having a specific polarization direction can be preferentially amplified and oscillated. The polarization direction of light can be strictly controlled in a specific direction. In the present embodiment, the case where the semiconductor substrate 101 and the resonator 120 are bent in a tile shape so as to be convex in the laser beam emission direction is shown. However, the semiconductor substrate 101 and the resonator 120 are bent in a tile shape so as to be concave. The same effect can be obtained even when
[0041]
(2) In the surface emitting laser according to the present embodiment, not only the active layer 105 is anisotropically strained, but also a layer other than the active layer 105, for example, other than the active layer 105 in the resonator 120. A surface emitting laser in which an anisotropic strain is applied to the layer and the semiconductor substrate 101 can be obtained. As described above, when a strain in a certain direction is applied to a layer other than the active layer 105 in the resonator 120, particularly a distributed reflection type multilayer mirror (upper mirror 108, lower mirror 103), the refractive index is increased in the direction in which the strain is applied. Thus, a difference in refractive index occurs between the direction in which distortion is applied and the direction perpendicular thereto. In a medium having such a refractive index distribution, only light having a certain polarization component can be propagated due to the refractive index difference. Therefore, in the surface emitting laser according to the present embodiment, for example, an elliptical core fiber which is a kind of polarization-maintaining fiber (the major axis direction and the minor axis of the ellipse are obtained by making the planar shape of the core elliptical). An effect similar to that of a fiber in which a difference in refractive index between the direction and the direction is generated.
[0042]
(Device manufacturing process)
Next, a method for manufacturing the surface emitting laser 100 according to the present embodiment will be described with reference to FIGS.
[0043]
3 and 5 to 7 are cross-sectional views schematically showing the steps of the method for manufacturing the surface emitting laser 100 according to the present embodiment. FIG. 4 is a perspective view schematically showing the steps of the method for manufacturing the surface emitting laser 100 according to the present embodiment.
[0044]
(A) First, after applying a photoresist on the back surface of the semiconductor substrate 101 made of n-type GaAs shown in FIG. 3, the photoresist is patterned by photolithography to thereby form a resist having a stripe pattern (not shown). And then etching the back surface of the semiconductor substrate 101 using the resist as a mask, selectively removing a portion of the semiconductor substrate 101 where the resist is not applied, and then removing the resist. As shown in FIG. 4, a stripe-shaped uneven portion 142 is formed by forming a stripe-shaped groove 140 on the back surface of the semiconductor substrate 101. Here, the back surface of the semiconductor substrate 101 refers to a surface of the semiconductor substrate 101 opposite to the surface on which the resonator 120 is formed in a later step. The striped uneven portion 142 is an uneven portion formed by the grooves 140 and the convex portions 141 and formed in parallel in the same direction.
[0045]
(B) Next, as shown in FIG. 5, a semiconductor deposition layer 150 is formed on the surface of the semiconductor substrate 101 by epitaxial growth while modulating the composition. Here, the semiconductor deposition layer 150 includes the buffer layer 102 made of n-type GaAs, the n-type AlAs layer, and the n-type Al. _0.15 Ga _0.85 Lower mirror 103 in which As layers are alternately stacked, n-type Al _0.5 Ga _0.5 N-type cladding layer 104 made of As, GaAs well layer and Al _0.3 Ga _0.7 A multi-well active layer 105 composed of an As barrier layer and having three well layers, Al _0.5 Ga _0.5 P-type cladding layer 106 made of As, p-type Al _{0. 89} Ga _0.11 As layer and p-type Al _0.15 Ga _0.85 The upper layer 108 including the AlAs layer and the contact layer 109 made of p-type GaAs are stacked alternately with the As layer, and these layers are sequentially stacked on the semiconductor substrate 101 to form the semiconductor deposition layer 150. To do. Here, the p-type AlAs layer constituting the upper mirror 108 is used as the current confinement layer 107, and the dielectric layer 111 is formed from a part of the current confinement layer 107 in a later step. The surface of the semiconductor substrate 101 refers to a surface of the semiconductor substrate 101 on the side where the resonator 120 is formed in a later step.
[0046]
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 deposition layer 150 to be formed, but is generally preferably 700 ° C. to 800 ° C. Further, the time required for performing the epitaxial growth is also appropriately determined in the same manner as the temperature. As a method for epitaxial growth, a metal-organic vapor phase epitaxy (MOVPE) method, an MBE method (Molecular Beam Epitaxy) method, or an LPE method (Liquid Phase Epitaxy) can be used.
[0047]
(C) Subsequently, a photoresist (not shown) is applied on the contact layer 109 and then patterned by photolithography to form a resist layer (not shown) having a predetermined pattern. Next, by performing reactive ion etching using this resist layer as a mask, as shown in FIG. 6, the contact layer 109, the upper mirror 108, and the current confinement portion layer 107 are etched to form the columnar portion 110.
[0048]
Next, the current confinement layer 107 made of a p-type AlAs layer is exposed to a water vapor atmosphere at about 400 ° C. for an appropriate time, for example, in the range of 20 to 90 minutes, so that the AlAs layer is oxidized inward from the exposed surface. As a result, aluminum oxide, which is a dielectric, is formed. That is, the outer peripheral portion of the current confinement layer 107 is oxidized to form a dielectric layer 111 made of aluminum oxide as shown in FIG. As described above, the resonator 120 is formed on the semiconductor substrate 101.
[0049]
Subsequently, the upper electrode 113 and the lower electrode 115 are installed in the obtained resonator 120.
[0050]
First, a silicon oxide film is formed on the side surfaces and upper surfaces of the lower mirror 103 and the columnar portion 110 by atmospheric pressure CVD using monosilane gas and oxygen gas and nitrogen gas as a carrier gas. Then, the insulating layer 112 is formed by removing a part of the side surface of the columnar part 110 and the silicon oxide film on the upper surface of the columnar part 110 by photolithography and dry etching.
[0051]
Next, in order to install the lower electrode 116 on the back surface of the semiconductor substrate 101 in a later process, the uneven portion 142 formed on the back surface of the semiconductor substrate 101 is removed by etching, and the back surface of the semiconductor substrate 101 is flattened. .
[0052]
Subsequently, an alloy layer made of gold and zinc is formed on the insulating layer 112, the side surfaces of the columnar portion 110, and the upper surface of the columnar portion 110 by vacuum deposition, and then the alloy layer is patterned using a photolithography method. As a result, the opening 116 is formed. The upper electrode 113 is formed by the above process. Subsequently, a lower electrode 115 made of an alloy layer made of gold and germanium is formed on the back surface of the semiconductor substrate 101 by vacuum deposition. Through the above process, the surface emitting laser 100 shown in FIGS. 1 and 2 is formed.
[0053]
(effect)
Next, effects in the method for manufacturing the surface emitting laser according to the first embodiment will be described.
[0054]
(1) As shown in FIG. 4, after forming the groove 140 on the back surface of the semiconductor substrate 101, the semiconductor deposition layer 150 is formed on the surface of the semiconductor substrate 101 by epitaxial growth while modulating the composition. As described above, the formation of the semiconductor deposition layer 150 by epitaxial growth is generally performed under a high temperature condition of 700 ° C. to 800 ° C. Therefore, during the epitaxial growth, the semiconductor substrate 101 has a longitudinal direction ( The degree of thermal expansion differs between the direction Y in FIG. 4 and the direction orthogonal to the concavo-convex portion 142 (direction X in FIG. 4). That is, since the uneven portion 142 is formed, the expansion of the semiconductor substrate 101 is larger in the direction orthogonal to the uneven portion 142 than in the longitudinal direction of the uneven portion 142.
[0055]
Further, when the substrate is allowed to cool after the semiconductor deposition layer 150 is formed, the entire substrate contracts, so that the entire substrate is curved in a convex shape at the laser light emission port. Since the semiconductor substrate 101 has expanded more in the direction orthogonal to the uneven portion 142 than in the longitudinal direction of the uneven portion 142, the contraction of the substrate causes the semiconductor substrate 101 to be orthogonal to the uneven portion 142 rather than the longitudinal direction of the uneven portion 142. The shrinkage in the direction increases. For this reason, it has a convex curve in the laser beam emission direction, and anisotropic distortion in the direction orthogonal to the concavo-convex portion 142 occurs in the semiconductor substrate 101. This anisotropic strain is also applied to the semiconductor deposition layer 150, and in particular, this anisotropic strain is applied to the active layer 105, whereby anisotropy appears in the gain of the laser beam. As a result, laser light having a specific polarization direction can be preferentially amplified and oscillated, so that the polarization direction of the laser light can be controlled to a specific direction. Therefore, according to the surface emitting laser manufacturing method according to the present embodiment, a surface emitting laser in which the polarization direction of laser light is controlled to a specific direction can be easily obtained by the above method.
[0056]
(2) In the method of manufacturing the surface emitting laser according to the present embodiment, not only the active layer 105 is anisotropically strained, but also a layer other than the active layer 105, for example, the active layer 105 in the semiconductor deposition layer 150. A surface emitting laser in which an anisotropic strain is applied to the other layers and the semiconductor substrate 101 can be obtained.
[0057]
(3) The degree of anisotropic strain applied to the semiconductor substrate 101 and the resonator 120 can be controlled by changing the width, depth, or interval of the groove 140 formed on the semiconductor substrate 101.
[0058]
(Second Embodiment)
(Device structure and operation)
The structure and operation of the surface emitting semiconductor laser according to the present embodiment are the same as the structure and operation of the surface emitting semiconductor laser according to the first embodiment. Therefore, the description is omitted.
[0059]
(Device manufacturing process)
The manufacturing method of the surface emitting semiconductor laser according to the second embodiment is basically the same as the steps (b) and (c) in the manufacturing method of the surface emitting semiconductor laser according to the first embodiment. Yes, a surface emitting semiconductor laser can be manufactured by using the following step (a ′) instead of the step (a). That is, in the first embodiment, the concavo-convex portion 142 is formed directly on the back surface of the semiconductor substrate 101 by etching the back surface of the semiconductor substrate 101. However, in the second embodiment, The uneven portion 242 is formed on the back surface using another material.
[0060]
FIG. 8 is a perspective view schematically showing the steps of the method for manufacturing the surface emitting laser according to the second embodiment.
[0061]
(A ′) First, a groove forming layer (not shown) is formed on the back surface of the n-type GaAs semiconductor substrate 101 shown in FIG. 3, and a photoresist is applied on the groove forming layer. Then, a photoresist (not shown) having a predetermined pattern is formed by patterning the photoresist by photolithography. Subsequently, after performing reactive ion etching or the like, striped convex portions 241 are formed by removing the resist. As described above, the uneven portion 242 is provided on the back surface of the semiconductor substrate 101. The subsequent steps are the same as those in the method of manufacturing the surface emitting semiconductor laser according to the first embodiment. After the resonator 120 is formed on the surface of the semiconductor substrate 101, the lower electrode 115 is formed on the back surface of the semiconductor substrate 101. Prior to installation, the uneven portion 242 is removed by etching.
[0062]
As a material for forming the convex portion 241, any material can be used as long as it can withstand a subsequent process of forming the semiconductor deposition layer 150. For example, silicon dioxide, titanium dioxide, or silicon nitride can be used.
[0063]
(effect)
The effect of the surface emitting laser manufacturing method according to the second embodiment is the same as the effect of the surface emitting laser manufacturing method according to the first embodiment. Furthermore, in the second embodiment, the convex portion 241 is made of a material by forming a striped convex portion 241 with a material different from that of the semiconductor substrate 101 on the back surface of the semiconductor substrate 101 to provide the concave and convex portion 242. The uneven portion 242 can be formed as appropriate. Therefore, anisotropic distortion applied to the semiconductor substrate 101 and the resonator 120 can be adjusted also by changing the material used for the convex portion 241.
[0064]
(Third embodiment)
(Device structure and operation)
The structure and operation of the surface emitting semiconductor laser according to the present embodiment are the same as the structure and operation of the surface emitting semiconductor laser according to the first embodiment and the second embodiment. Therefore, the description is omitted.
[0065]
(Device manufacturing process)
The surface emitting semiconductor laser manufacturing method according to the third embodiment is shown below in place of steps (a) and (b) in the method of manufacturing the surface emitting semiconductor laser according to the first embodiment. Step (d) is used, and step (e) is used subsequent to step (d). Here, since the step (e) is the same as the step (c) in the method for manufacturing the surface emitting semiconductor laser according to the first embodiment, the description thereof is omitted.
[0066]
FIG. 9 is a plan view schematically showing an apparatus used in one step of the method of manufacturing the surface-emitting laser according to the third embodiment, and FIG. 10 shows the apparatus of FIG. 9 along the line BB. It is sectional drawing.
[0067]
(D) First, as shown in FIGS. 9 and 10, the semiconductor substrate 101 is placed on the surface of the semiconductor substrate 101 in a state where the semiconductor substrate 101 is placed on the substrate placement surface 191 of the holder 190 having the convexly curved substrate placement surface 191. The semiconductor deposition layer 150 is formed by epitaxial growth while modulating the composition. The subsequent steps are the same as those in the method for manufacturing the surface emitting semiconductor laser according to the first embodiment and the second embodiment.
[0068]
(effect)
The effect of the surface emitting laser manufacturing method according to the third embodiment is that a surface emitting laser in which not only the active layer 105 but also the semiconductor deposition layer 150 and the semiconductor substrate 101 are anisotropically strained can be obtained. This is the same as the effect in the method for manufacturing the surface emitting laser according to the first embodiment and the second embodiment. In the first embodiment and the second embodiment, the step of forming the semiconductor deposited layer 150 by epitaxial growth on the surface of the semiconductor substrate 101 after forming the concavo-convex portions 142 and 242 on the back surface of the semiconductor substrate 101, respectively. The semiconductor deposition layer 150 and the semiconductor substrate 101 are anisotropically strained. However, in the third embodiment, the semiconductor substrate 101 has the same structure as the first embodiment and the second embodiment. Without performing special treatment, the semiconductor deposition layer 150 and the semiconductor substrate 101 can be anisotropically strained, so that the manufacturing process can be shortened. Thereby, manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a cross section of a surface emitting semiconductor laser according to a first embodiment of the present invention;
FIG. 2 is a diagram schematically showing a main part of a plane when the surface-emitting type semiconductor laser shown in FIG. 1 is viewed from the side facing a laser beam emission port.
FIG. 3 is a perspective view schematically showing a first step of the method for manufacturing the surface emitting semiconductor laser according to the first embodiment of the invention.
FIG. 4 is a cross sectional view schematically showing a second step of the method for manufacturing the surface emitting semiconductor laser according to the first embodiment of the invention.
FIG. 5 is a cross sectional view schematically showing a third step of the method for manufacturing the surface emitting semiconductor laser according to the first embodiment of the invention.
FIG. 6 is a cross sectional view schematically showing a fourth step of the method for manufacturing the surface emitting semiconductor laser according to the first embodiment of the invention.
FIG. 7 is a cross sectional view schematically showing a fifth step of the method for manufacturing the surface emitting semiconductor laser according to the first embodiment of the invention.
FIG. 8 is a perspective view schematically showing one step of the method for manufacturing the surface emitting semiconductor laser according to the second embodiment of the invention.
FIG. 9 is a plan view schematically showing an apparatus used in one step of a method of manufacturing a surface emitting semiconductor laser according to a third embodiment of the present invention.
10 is a cross-sectional view of a portion of the device shown in FIG. 9 cut along line BB. FIG.
[Explanation of symbols]
100 Surface emitting semiconductor laser
101 Semiconductor substrate
102 Buffer layer
103 Lower mirror
104 n-type cladding layer
105 Active layer
106 p-type cladding layer
107 Current confinement layer
108 Upper mirror
109 Contact layer
110 Columnar part
111 Dielectric layer
112 Insulating layer
113 Upper electrode
115 Lower electrode
116 opening
120 resonator
140 ・ 240 groove
141 ・ 241 Convex
142 ・ 242 Concavity and convexity
150 Semiconductor deposition layer
190 Holder
191 Substrate installation surface

Claims (7)

A method of manufacturing a surface-emitting type semiconductor laser including the following steps (a) to (c).
(A) forming a stripe-shaped uneven portion on the back surface of the semiconductor substrate;
(B) forming a semiconductor deposition layer including at least an active layer on the surface of the semiconductor substrate at a predetermined temperature; and (c) a direction including the active layer and perpendicular to the semiconductor substrate from the semiconductor deposition layer. Forming a resonator that emits laser light and resonates perpendicularly to the semiconductor substrate. In claim 1,
The method (a) is a method of manufacturing a surface-emitting type semiconductor laser, wherein the uneven portion is formed by etching a back surface of the semiconductor substrate to provide a stripe-shaped groove. In claim 1 or 2,
The method (a) is a method of manufacturing a surface-emitting type semiconductor laser, which is a step of forming the concavo-convex portion by providing a stripe-shaped convex portion on the back surface of the semiconductor substrate. In claim 3,
The method of manufacturing a surface emitting semiconductor laser, wherein the convex portion is made of an oxide film or a nitride film. In claim 4,
The method for manufacturing a surface emitting semiconductor laser, wherein the convex portion is made of a material containing at least one of silicon dioxide, titanium dioxide, and silicon nitride. A method of manufacturing a surface-emitting type semiconductor laser including the following steps (d) and (e):
(D) A semiconductor substrate is placed on a convexly curved holder, and the semiconductor substrate is curved so as to be convex in a direction perpendicular to the semiconductor substrate, and at least an active layer is formed on the surface of the semiconductor substrate. And (e) emitting a laser beam in a direction perpendicular to the semiconductor substrate, including the active layer, and from the semiconductor substrate, and Forming a vertically resonating resonator. In any of claims 1 to 5,
A method of manufacturing a surface emitting semiconductor laser, further comprising the following step (f):
(F) A step of removing the concavo-convex portion from the semiconductor substrate after performing the steps (a) to (c).

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