JP2009246194A - Surface-emitting semiconductor laser element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-emitting laser for realizing single lateral mode oscillation. <P>SOLUTION: A surface-emitting laser includes a lower clad 103 for constituting a laser resonance section, an active layer 104, and a pair of DBR mirrors 102 and 109 for interposing an upper clad layer 105. In an upper DBR mirror 106, there is formed a two-dimensional hole array 110 having a point defect at the center part. At the upper clad layer 105, a mesa part 106 is formed in the layer. The side face of the mesa part 106 is buried in a pair of current blocking layers 107 and 108 formed in the layer of the upper clad layer 105. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface emitting semiconductor laser element, and more particularly to a surface emitting semiconductor laser element that realizes fundamental transverse mode oscillation.

  A vertical cavity surface emitting semiconductor laser element (VCSEL: Vertical-Cavity Surface-Emitting Laser, hereinafter simply referred to as a surface emitting laser), as its name suggests, the resonance direction of light is perpendicular to the substrate surface, It is attracting attention as a light source for communication including optical interconnection and as a device for various applications such as sensor applications.

  The reason for this is that surface emitting lasers can be easily formed in a two-dimensional array of elements as compared to conventional edge emitting semiconductor laser elements, and can be tested at the wafer level because there is no need to cleave to provide a mirror. Further, since the volume of the active layer is remarkably small, it is possible to oscillate at a low threshold and to have advantages such as low power consumption.

  In particular, the surface emitting laser has an advantage that the fundamental mode oscillation can be easily obtained in the longitudinal mode of the oscillation spectrum because the resonator length is extremely short. On the other hand, since the horizontal mode does not have a control mechanism, a plurality of higher-order modes tend to oscillate. The laser light oscillated by the plurality of higher-order transverse modes causes significant deterioration in proportion to the transmission distance during optical transmission, particularly during high-speed modulation. Therefore, various structures have been proposed for surface emitting lasers that realize laser oscillation in the fundamental transverse mode.

The simplest method for obtaining the fundamental transverse mode is to employ a structure in which the area of the light emitting region is reduced to such an extent that only the fundamental mode can oscillate. For example, in the case of an AlAs layer selective oxidation confinement type (oxidation confinement type) surface emitting laser having an oscillation wavelength band of 1300 nm, the difference in refractive index between the AlAs layer and the oxide layer (Al ₂ O ₃ ) is large. In order to obtain the above, the size of the light emitting region needs to be about 30 μm ² . Here, in the oxidation confinement type surface emitting laser, the current confinement width for controlling the size of the area of the light emitting region is generally determined by the oxide layer that selectively oxidizes the outer edge of the AlAs layer. However, in order to obtain the inner diameter of the oxide layer so that the area of the current opening is about 30 μm ² , precise oxidation process control is required, resulting in a low product yield. In addition, stress distortion is generated by selective oxidation, and there is a serious drawback that the reliability of the element is impaired, for example, the laser element is broken during the oscillation due to the stress distortion.

  On the other hand, as a highly reliable current confinement technique, a buried type employed in an edge-emitting semiconductor laser element is known (Patent Document 1). This is, for example, a method in which a part of a stack including an active layer is processed into a mesa stripe by etching, and then the side surface of the mesa stripe is embedded with an n-type current blocking layer and a p-type current blocking layer. This technique is widely used in edge emitting semiconductor lasers in the optical communication wavelength band.

Further, as a means for widening the emission area and obtaining fundamental transverse mode oscillation in a surface emitting laser, for example, a structure as shown in Patent Document 2 has been proposed. In this structure, a periodic two-dimensional hole array having a point defect region at the center is formed in the upper DBR mirror. The two-dimensional hole array slightly lowers the refractive index perceived by light, acts as a cladding for the central point defect region, and realizes transverse mode control by weak refractive index confinement. This lateral mode control can increase the area of the light emitting region when only the fundamental transverse mode is oscillated. A surface emitting laser having this structure is called a photonic crystal surface emitting laser.
JP-A-8-195523 Special table 2007-502029 gazette

  As a current confinement structure in a photonic crystal surface emitting laser, an AlAs selective oxidation confinement type and an ion implantation type are known so far. The AlAs selective oxidation confinement type has a large refractive index difference between AlAs and AlOx oxidized AlAs, which affects the weak refractive index confinement mode due to photonic crystals and is unstable during high current injection and high-speed modulation. There was a case. Further, as described above, there is a drawback that the reliability of the element is impaired by stress strain. On the other hand, in the ion implantation type, since there is almost no difference in refractive index due to the current confinement structure, the refractive index confinement mode by the photonic crystal is not affected. In this case, the device resistance is increased.

  In view of the above, the present invention improves the current confinement structure and the optical confinement structure in the conventional surface emitting laser, oscillates in a single transverse mode, and improves the reliability of the laser element while suppressing an increase in element resistance. An object of the present invention is to provide a surface emitting laser.

  In order to solve the above-mentioned problem, the present inventor embeds the periphery of the mesa portion in a buried type confined surface emitting laser by embedding the periphery of the mesa portion with a current blocking layer having a refractive index equivalent to the refractive index of the mesa portion. The surface light emitting laser was conceived in which a layered structure having no refractive index distribution was formed, and a light confinement structure with a photonic crystal structure was formed thereon.

That is, according to the first aspect of the present invention, in the first aspect, the first reflecting mirror formed of a multilayer film, the first cladding layer of the first conductivity type, the active layer, the second conductivity type, which are sequentially formed on the semiconductor substrate. In the surface emitting semiconductor laser device having a laminated structure including the second cladding layer and the second reflecting mirror made of a multilayer film,
The second cladding layer has a flat portion having a uniform thickness and a mesa portion projecting upward from the flat portion at a central portion of the flat portion, and a side surface of the mesa portion is formed on the flat portion. Embedded with a first conductivity type first current blocking layer and a second conductivity type second current blocking layer sequentially stacked;
The refractive index of the mesa portion and the equivalent refractive index of the first and second current blocking layers are substantially equal,
There is provided a surface emitting semiconductor laser device characterized in that the upper reflector structure is formed with a two-dimensional hole array having a point defect having no holes in the central part above the mesa part.

According to the second aspect of the present invention, in the second aspect, the first reflecting mirror formed of a multilayer film, the first contact layer of the first conductivity type, the active layer, and the second conductivity type are sequentially formed on the semiconductor substrate. In the surface emitting semiconductor laser device having a laminated structure including the second contact layer and the second reflecting mirror made of a dielectric multilayer film,
The second contact layer has a flat portion having a uniform thickness and a mesa portion protruding upward from the flat portion at a central portion of the flat portion, and a side surface of the mesa portion is formed on the flat portion. Embedded with a first conductivity type first current blocking layer and a second conductivity type second current blocking layer sequentially stacked;
The refractive index of the mesa portion and the equivalent refractive index of the first and second current blocking layers are substantially equal,
In the dielectric multilayer film, a two-dimensional distribution of a periodic refractive index is formed in the laminated surface except for a predetermined region above the mesa portion in the laminated surface, and the two-dimensional distribution of the refractive index is It is formed by forming a plurality of other layers of the dielectric multilayer film on one layer of the dielectric multilayer film in which holes are periodically formed in a region excluding the predetermined region. A surface emitting semiconductor laser device is provided.

  In the surface-emitting laser elements of the first and second aspects, the main surface of the substrate is a (100) plane, and the cross section of the mesa portion is between the <011> direction or the <01-1> direction. A substantially square structure having four sides with an angle of 45 degrees is preferable.

  In the surface emitting laser of the present invention, the current confinement structure employs a buried structure that does not have a refractive index distribution associated with the current confinement structure as seen in the AlAs selective oxidation confinement type, and the optical confinement structure uses a photonic structure. A two-dimensional periodic structure (hereinafter referred to as a pseudo-photonic crystal structure) having a crystal structure or a structure similar to the photonic crystal structure is employed. For this reason, since the current confinement structure does not have an optical confinement function, an optical confinement function using only a photonic crystal structure or a pseudo photonic crystal structure is realized. Therefore, stable single transverse mode oscillation is possible even during high current injection or high speed modulation. Further, since the buried structure is adopted, the thickness of the current confinement structure can be made thinner than that of the ion implantation type, and a surface emitting laser having a low element resistance can be obtained. Furthermore, since the oxide constriction structure is not employed, the reliability of the device does not deteriorate due to oxidation strain.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a partial cross-sectional perspective view of a surface emitting laser according to a first embodiment of the present invention. The surface emitting laser is designed so that the oscillation wavelength is 1300 nm. The surface emitting laser 100 is formed on an n-type GaAs substrate 101, and includes a lower DBR mirror 102, an n-type lower cladding layer 103, a p-type upper cladding layer 105, a lower cladding layer 103, and an upper cladding layer. The active layer 104 is formed between the upper DBR mirror 109, the upper electrode 111 formed on the upper DBR mirror, and the lower electrode 112 formed on the back surface of the n-type GaAs substrate 101. In this surface emitting laser, the lower clad layer 103, the active layer 104, and the upper clad layer constitute a laser resonance part, and the laser resonance part is sandwiched between the lower DBR mirror 102 and the upper DBR mirror 109. Have a structured.

  The upper clad layer 105 includes a flat portion having a uniform thickness and a mesa portion 106 protruding upward from the flat portion at a central portion of the flat portion. The side surface of the mesa portion 106 has an n-conductivity type first current block layer (n-type current block layer) 107 and a p-conductivity type second current block layer (which are sequentially stacked on the surface of the flat portion. embedded in the p-type current blocking layer 108. The top surface of the mesa unit 106 is in the same plane as the surface of the p-type current blocking layer 108. A current confinement structure is realized by the pnp junction of the p-type upper cladding layer 105, the n-type current blocking layer 107, and the p-type current blocking layer 108. In addition, a photonic crystal structure is formed inside the upper DBR mirror 109, and there is a hole in the central portion of the two-dimensional hole array 110 constituting the photonic crystal structure above the mesa unit 106. A point defect is not formed. An optical confinement structure is formed by the photonic crystal structure.

  In this embodiment, the current confinement structure does not have an optical confinement function because the refractive index of the mesa portion and the equivalent refractive indexes of the first and second current blocking layers are substantially equal. Therefore, the optical confinement function can be obtained only by the photonic crystal structure formed in the upper DBR mirror 109. Therefore, stable single transverse mode oscillation is possible even during high current injection or high-speed modulation, and the thickness of the current confinement structure can be made thinner than that of the ion-implanted type. Is obtained. Furthermore, since the oxide constriction structure is not employed, the reliability of the device does not deteriorate due to oxidation strain.

The structure of the said embodiment is obtained by the following manufacturing processes, for example. First, on the surface of the n-type GaAs substrate 101 having the (100) plane as the principal surface, the thickness is λ / 4n (where λ is the oscillation wavelength and n is the refractive index) by MBE or MOCVD. Al _0.2 Ga _0.8 As layers and AlAs layers are alternately stacked to form the lower DBR mirror 102 composed of 35.5 pairs of multilayer films. The carrier density of each layer is, for example, 1 × 10 ¹⁸ cm ⁻³ . Next, an n-type GaAs lower clad layer 103, three GaInNAs / GaAs multiple quantum well (MQW) active layers 104, and p-type GaAs upper clad layer 105 are formed on the stacked layers. Laminate sequentially (FIG. 2).

  Next, after a SiNx film is formed on the surface of the laminated structure using a plasma CVD method, the SiNx film is formed into a substantially square shape with a side length of 10 μm by photolithography using a normal photoresist thereon. To process. The square shape is formed so that the angle between each side and the <011> direction or the <01-1> direction is 45 degrees. By wet etching using this SiNx film as a mask, the upper clad layer 105 is processed into a film shape having a flat portion and a mesa portion protruding upward from the flat portion by etching only the surface portion while leaving the bottom portion of the upper clad layer 105. (FIG. 3). The formed mesa portion 106 has a truncated pyramid shape with a substantially square top surface.

  Thereafter, a current blocking layer 107 made of n-type GaAs and a current blocking layer 108 made of p-type GaAs are sequentially stacked around the mesa portion 106 by MOCVD using the previous SiNx film as a selective growth mask (FIG. 4). Here, as both current blocking layers, GaAs, which is the same material as the upper clad layer 105, is embedded flatly, so that an equivalent refractive index difference is almost generated in the stacking direction between the mesa portion 106 and the embedded portion. No structure is obtained. For this reason, the embedded structure itself does not exhibit the light confinement function, and a surface emitting laser in which only the refractive index distribution by the photonic crystal structure described later has the light confinement function can be realized. If such an optical confinement structure can be realized, the mesa unit 106 is not limited to a substantially square shape.

Thereafter, the SiNx film is removed, and p-type Al _0.8 Ga _0.2 As layers and p-type Al _0.2 Ga _0.8 As layers each having a thickness of λ / 4n are alternately laminated, An upper DBR mirror 109 consisting of 30 pairs is formed. The carrier concentration of each layer is, for example, 1 × 10 ¹⁸ cm ⁻³ .

  Next, a new SiNx film is formed on the surface of the laminated structure using a plasma CVD method. The obtained SiNx film is etched using photolithography using a normal photoresist and RIE (reactive ion etching) to form a two-dimensional periodic hole arrangement hard mask.

Next, using the two-dimensional hole array structure formed in the SiNx film as a mask, ICP (inductively coupled plasma) dry etching using Cl ₂ is used to form a stacked structure of the DBR mirror 109 under the SiNx film to a depth of about 4 μm. The hole arrangement structure is formed. The two-dimensional hole array has a point defect (point defect region) in which no hole (circular hole) is present at the center, and has a triangular lattice shape with a hole array period of 5 μm and a diameter of each hole of 3 μm. A two-dimensional hole array structure is adopted. Note that the point defect is not limited to the one in which one hole is removed from the two-dimensional hole array as in the present embodiment, and may be one in which a plurality of (for example, seven) holes are removed.

  Next, a new SiNx film is formed on the surface of the laminated structure using the plasma CVD method, and this SiNx film is selectively removed by photolithography and RIE using a normal photoresist. A ring-shaped opening is formed. For example, AuZn is vapor-deposited in the opening from which the SiNx film has been removed to form the ring-shaped upper electrode 111. Thereafter, the n-type GaAs substrate 101 is polished from the back surface so that the substrate thickness is about 200 μm, and Ti / Pt / Au, for example, is deposited on the polished back surface to form the lower electrode 112. Thus, the surface emitting laser according to the present embodiment is obtained.

Embodiment 2
Next, a surface emitting laser element according to the second embodiment of the present invention will be described. In the surface emitting laser element of this embodiment, the upper DBR mirror is a dielectric multilayer mirror, the point that adopts an intracavity contact structure, a stacked layer including an active layer, a current blocking layer, and a p-type contact layer. The second embodiment is different from the first embodiment in that a mesa post is formed and a two-dimensional refractive index distribution having a pseudo-photonic crystal structure is formed in the upper dielectric multilayer mirror. Details will be described below.

  5 and 6 are diagrams showing a configuration of a surface emitting laser according to the second embodiment of the present invention. 5 is a plan view, and FIG. 6 is a cross-sectional view taken along line VI-VI shown in FIG. As shown in these drawings, the surface emitting laser 200 includes, for example, a semiconductor lower DBR mirror 202, an n-type contact layer 203, an active layer 204, current blocking layers 207 and 208 stacked on a semi-insulating GaAs substrate 201, The p-type contact layer 205 includes an upper DBR mirror 209 made of a dielectric material including a lowermost layer 210 serving as a starting point of a two-dimensional periodic array, a p-side electrode 211, and an n-side electrode 212. Among these, the active layer 204, the current blocking layers 207 and 208, and the p-type contact layer 205 stacked on the n-type contact layer 203 constitute a mesa post 213 formed in a columnar shape by an etching process or the like.

  The surface emitting laser 200 of the above embodiment is manufactured by the following manufacturing process, for example. First, on a semi-insulating GaAs substrate 201 having a (100) plane as a main surface, the thickness of each layer is λ / 4n (λ is an oscillation wavelength and n is a refractive index) by MBE or MOCVD. For example, A plurality of composite semiconductor layers composed of GaAs / AlAs pair layers are stacked to form a lower DBR mirror 202 composed of a semiconductor multilayer film reflecting mirror. Next, an active layer 204 having a multiple quantum well structure in which, for example, an n-type contact layer 203 made of n-GaAs, for example, a composite semiconductor layer made of GaInNAs / GaAs, is stacked on the lower DBR mirror 202, and For example, a part of the p-type contact layer 205 made of p-GaAs is sequentially stacked.

  Next, after a SiNx film is formed on the surface of the laminated structure by a plasma CVD method, the SiNx film is formed into a square having a predetermined size by a lithography technique using a photoresist and RIE (reactive ion etching). Process. This square is formed so that the angle between each side and the <011> direction or the <01-1> direction is 45 degrees. Thereafter, a part of the p-type contact layer 205 is processed into a square mesa portion 206 by wet etching using the square SiNx film as a mask. Subsequently, the current block layer 207 made of n-type GaAs and the current block layer 208 made of p-type GaAs are stacked around the square mesa portion 206 by MOCVD using the above-described square SiNx film as a selective growth mask. . Thereafter, after removing the SiNx film, the remainder of the p-type contact layer 205 is further laminated by MOCVD. As described above, by using GaAs, which is the same material as that of the p-type contact layer 205, as the current blocking layer, the equivalent refractive index difference hardly occurs in the stacking direction between the mesa portion and the buried portion. I am doing so. Note that the mesa portion 206 is not limited to a substantially square shape as long as the above-described embedded shape can be realized.

  Next, after a new SiNx film is formed on the surface of the laminated structure using the plasma CVD method, the SiNx film is etched by a lithography technique using an ordinary photoresist and RIE, and a two-dimensional hole array is formed. A hole forming layer 210 having the structure is formed. The two-dimensional hole array is a triangular lattice-shaped two-dimensional hole array having a point defect in which no hole is present at the center, a two-dimensional period of holes being 5 μm, and a diameter of each hole being 3 μm. Further, the etching depth is set to a depth smaller than the film thickness of the lowermost layer, for example, 50 nm. The arrangement period, hole diameter, depth, etc. of the holes are such that the fundamental transverse mode oscillation can be obtained by the difference between the average refractive index of the portion where the holes are formed and the average refractive index of the point defect having no holes. It is adjusted appropriately.

  In this embodiment, a pseudo-photonic crystal structure in which a two-dimensional refractive index distribution obtained by etching at a depth of 50 nm in one layer of the dielectric multilayer film is applied to the dielectric multilayer film on the upper layer is employed. With this configuration, the depth controllability is excellent and light scattering loss is less likely to occur compared to the first embodiment having a photonic crystal structure in which holes are formed deeply in most of the semiconductor multilayer mirror. Is obtained.

  Subsequently, SiNx is removed by photolithography and RIE using a normal photoresist to form a ring-shaped opening. For example, AuZn is vapor-deposited on the portion from which the SiNx film has been removed to form a ring-shaped p-side electrode 211. As described above, the p-side electrode 211 is stacked on the p-type contact layer 205, and in a ring shape so as to surround a part of the upper DBR mirror 209 immediately above the current injection region 204a along the stacked surface. It is formed. Thereafter, the peripheral portions of the p-type contact layer 205, the current blocking layers 207 and 208, and the active layer 204 are etched until they reach the n-type contact layer, and processed into a circular mesa post 213.

Next, 12 pairs of dielectric layers made of, for example, a SiO ₂ / SiNx pair layer are laminated on the lowermost layer 210 of the upper multilayer film reflecting mirror 209 in which holes are formed, using a plasma CVD method, and the dielectric multilayer An upper DBR mirror 209 made of a film is laminated. Through this process, the two-dimensional hole array formed in the lowermost layer 210 made of the SiNx film is transmitted to the upper stack while holding the shape of the hole array at least partially starting from the lowermost layer 210. . In this way, the upper DBR mirror 209 is formed with a two-dimensional array structure of refractive index throughout the stack having a function similar to that of the photonic crystal structure. The hole forming layer that is the starting point of the two-dimensional refractive index distribution is not necessarily limited to the lowermost layer 210 of the upper multilayer mirror 209. Moreover, it is not limited to one layer, For example, it is good also considering a layer of about 2 pairs as a hole formation layer.

The upper DBR mirror 209 of the dielectric multilayer film composed of the SiO ₂ / SiNx pair layer has a light transmittance with a predetermined transmittance as a whole. In the surface emitting laser 200, by using the dielectric multilayer film as the upper multilayer mirror in this way, the light absorption loss in the upper DBR mirror 209 is significantly reduced as compared with the case where the semiconductor multilayer film is used. .

  Next, the upper DBR mirror 209 formed on the mesa post 213 will be described. As shown in FIGS. 5 and 6, the upper DBR mirror 209 is formed in a range including the mesa post 213, and is integrally formed with the mesa post 213 so as to cover it. The upper DBR mirror 209 is roughly composed of an emission window portion 209a and a lower layer portion 209b having a smaller number of layers than the emission window portion 209a.

  The exit window 209a is located immediately above the current injection region 204a provided in the active layer 204, and resonates spontaneously emitted light emitted from the current injection region 204a in cooperation with the lower DBR mirror 202. A part is emitted as laser light. That is, the exit window portion 209a is provided as a portion that actually functions as a DBR mirror in the upper DBR mirror 209. On the other hand, the low layer portion 209b is a region including the side surface 213a of the mesa post 213 and is formed in a peripheral region other than the portion directly above the current injection region 204a, and functions as a protective film that protects the side surface portion 213a from the outside air.

  The upper DBR mirror 209 having the above configuration forms, for example, a dielectric multilayer film having a predetermined number of layers in a range including the mesa post 213, and a peripheral region other than the portion directly above the current injection region 204a in the dielectric multilayer film. It is formed by etching. Specifically, as shown by a broken line in FIG. 6, the annular etching portion 209c of the formed dielectric multilayer film is removed by etching.

As the dielectric multilayer film, for example, 12 composite dielectric layers made of SiO ₂ / SiNx pair layers are laminated, and 8 composite dielectric layers out of the 12 layers are etched as the etching portion 209c. With this configuration, the exit window portion 209a is formed of 12 composite dielectric layers, and the low layer portion 209b is formed of 4 composite dielectric layers. In addition, the number of lamination | stacking of the exit window part 209a and the low layer part 209b is not limited to this example, Various lamination structures are applicable.

  Thereafter, an n-side electrode 212 made of, for example, Ti / Au is formed on the n-type contact layer 203. The n-side electrode 212 is laminated on the n-type contact layer 203 and is formed in a U shape or a C shape so as to surround the bottom surface portion of the mesa post 213 along the laminated surface. The p-side electrode 211 and the n-side electrode 212 are electrically connected to an external circuit (current supply circuit) (not shown) by a p-side extraction electrode 214 and an n-side extraction electrode 215, respectively. Thus, the surface emitting laser according to the present embodiment is obtained.

  In each of the above-described embodiments, an example in which a GaAs substrate is used as the substrate has been described. However, another substrate such as InP can be used as the substrate. An example in which a square mesa portion is formed in the upper cladding layer or the upper (p-type) contact layer has been shown. However, if a mesa portion having another shape can be formed by employing an appropriate growth method, such a mesa portion can be formed. Mesa is enough. Although an example in which the upper clad layer and the contact layer and the current blocking layer are formed of the same material has been described, different materials can be employed if the refractive index difference between the two is small.

  Although the present invention has been described based on the preferred embodiment, the surface emitting laser of the present invention is not limited to the configuration of the above embodiment, and various modifications and changes can be made from the configuration of the above embodiment. Those subjected to are also included in the scope of the present invention.

1 is a partial cross-sectional perspective view of a surface emitting laser element according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional perspective view showing one step in the manufacturing process of the surface emitting laser element of FIG. 1. FIG. 2 is a partial cross-sectional perspective view showing one step in the manufacturing process of the surface emitting laser element of FIG. 1. FIG. 2 is a partial cross-sectional perspective view showing one step in the manufacturing process of the surface emitting laser element of FIG. 1. The top view of the surface emitting laser element which concerns on the 2nd Embodiment of this invention. Sectional drawing of the surface emitting laser element which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

101: Substrate 102: Lower DBR mirror 103: Lower cladding layer 104: Active layer 105: Upper cladding layer 106: Mesa 107: Current blocking layer 108: Current blocking layer 109: Upper DBR mirror 110: Two-dimensional hole array 111: Upper electrode 112: Lower electrode 201: Substrate 202: Lower DBR mirror 203: n-type contact layer 204: active layer 205: p-type contact layer 206: mesa portion 207: current blocking layer 208: current blocking layer 209: upper DBR mirror 210 : Two-dimensional hole array 211: p-side electrode 212: n-side electrode 213: mesa post 214: p-side extraction electrode 215: n-side extraction electrode

Claims (3)

From a first reflecting mirror composed of a multilayer film, a first conductivity type first cladding layer, an active layer, a second conductivity type second cladding layer, and a multilayer film, which are sequentially formed on a semiconductor substrate In the surface emitting semiconductor laser device having a laminated structure including the second reflecting mirror,
The second cladding layer has a flat portion having a uniform thickness and a mesa portion projecting upward from the flat portion at a central portion of the flat portion, and a side surface of the mesa portion is formed on the flat portion. Embedded with a first conductivity type first current blocking layer and a second conductivity type second current blocking layer sequentially stacked;
The refractive index of the mesa portion and the equivalent refractive index of the first and second current blocking layers are substantially equal,
2. The surface emitting semiconductor laser device according to claim 1, wherein the upper reflector structure is formed with a two-dimensional hole array having a point defect having no holes in the central part above the mesa part. A first reflecting mirror comprising a multilayer film, a first contact layer of a first conductivity type, an active layer, a second contact layer of a second conductivity type, and a dielectric multilayer, which are sequentially formed on a semiconductor substrate In a surface emitting semiconductor laser device having a laminated structure including a second reflecting mirror made of a film,
The second contact layer has a flat portion having a uniform thickness and a mesa portion protruding upward from the flat portion at a central portion of the flat portion, and a side surface of the mesa portion is formed on the flat portion. Embedded with a first conductivity type first current blocking layer and a second conductivity type second current blocking layer sequentially stacked;
The refractive index of the mesa portion and the equivalent refractive index of the first and second current blocking layers are substantially equal,
In the dielectric multilayer film, a two-dimensional distribution of a periodic refractive index is formed in the laminated surface except for a predetermined region above the mesa portion in the laminated surface, and the two-dimensional distribution of the refractive index is It is formed by forming a plurality of other layers of the dielectric multilayer film on one layer of the dielectric multilayer film in which holes are periodically formed in a region excluding the predetermined region. Surface emitting semiconductor laser device.   The main surface of the substrate is a (100) plane, and the cross section of the mesa portion is a substantially square having four sides each having an angle of 45 degrees with the <011> direction or the <01-1> direction. The surface emitting semiconductor laser device according to claim 1, wherein the surface emitting semiconductor laser device has a structure.

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