JP2008177341A - Surface emitting semiconductor laser and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-emitting laser device with an accurately controlled current blocking layer without reducing the productivity. <P>SOLUTION: The light-emitting semiconductor laser device comprises a first reflection mirror 12, an active layer 13, the current blocking layer 16 made of a material containing aluminum, and a second reflection mirror 17, which are formed on a substrate 11 in this order from bottom. The current blocking layer 16 includes a conductive portion 16A, a high-resistance portion 16B which is an oxidized layer formed around the conductive portion 16A, and a high impurity concentration region 19 which is formed in a boundary region between the conductive portion 16A and the high-resistance portion 16B and is more heavily doped with impurities than the other regions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vertical cavity surface emitting semiconductor laser device, and more particularly to a surface emitting semiconductor laser device having a current confinement layer formed by a selective oxidation method.

  In recent years, vertical cavity surface emitting laser (VCSEL) devices have been developed that are expected to reduce operating current, improve integration, and reduce costs compared to edge emitting semiconductor laser devices. Progressing. In particular, surface-emitting semiconductor laser devices using gallium arsenide (GaAs) compound semiconductor materials with a wavelength of 850 nm are researched and developed for high-speed, high-capacity optical communication or optical interconnection over short distances such as gigabit data communication. Is being promoted and commercialized.

  The surface-emitting semiconductor laser device employs a structure in which a quantum well active layer serving as a light-emitting region is sandwiched from above and below by a high-reflectance mirror made of a multilayer film. In a surface emitting semiconductor laser device, in order to improve current efficiency by reducing the oscillation threshold current density and realize high-speed modulation, it is necessary to provide a current confinement structure that limits the current path.

  As a method of forming a current confinement structure of a surface emitting semiconductor laser, there is a selective oxidation method in which a high resistance region is formed by selectively oxidizing an AlGaAs layer having a high aluminum (Al) composition ratio provided in the vicinity of a quantum well active layer. is there. The selective oxidation method has an advantage over other current confinement methods in laser characteristics such as oscillation threshold current density, and is becoming mainstream as a leading current confinement technique.

  However, due to the slight thickness variation and Al composition ratio variation that occur when growing an AlGaAs layer having a high Al composition ratio and slight variations in oxidation conditions, the oxidation controllability of the AlGaAs layer is greatly changed, resulting in a high resistance region. Will vary in size. A slight variation in the size of the high-resistance region greatly changes the characteristics of the laser, so that oxidation control is required to form the current confinement structure with high reproducibility and high accuracy (see, for example, Non-Patent Document 1). reference.).

As a method for forming a current confinement structure with high accuracy, a method for forming an oxidation monitor region is known (see, for example, Patent Document 1). As shown in FIG. 7, together with the post portion 100 serving as a surface emitting semiconductor laser device, a monitor post portion 110 </ b> A and a post portion 110 </ b> B having a smaller diameter than the post portion 100 are formed on the substrate. When the AlGaAs layer 106 having a high Al composition ratio to be a current confinement layer is oxidized in an oxidizing atmosphere, the reflectance of the post part 100, the post part 110A, and the post part 110B is continuously measured. As the AlGaAs layer 106 is oxidized, the reflectance changes. When the AlGaAs layer 106 is completely oxidized, the reflectance does not change. Therefore, by monitoring the change in reflectance, it is possible to detect the time until the mesa 110A and the post 110B are completely oxidized for monitoring. Since the accurate oxidation rate of the AlGaAs layer 106 can be calculated based on the obtained time, the current confinement layer can be formed on the post portion 100 with high reproducibility and high accuracy.
Carl Wilmsen, et al., “Vertical-Cavity Surface-Emitting Lasers”, Cambridge University Press, 1999, p. 193-232 JP 2004-95934 A

  However, since the conventional method for forming a current confinement layer needs to form a region for monitoring the oxidation state separately from a portion to be a surface emitting optical semiconductor laser device, the surface emitting optical semiconductor laser device per wafer is required. The production number of will decrease. For this reason, there exists a problem that the manufacturing cost of a surface emitting optical semiconductor laser device rises.

  Further, since it is necessary to continuously measure the refractive index in the oxidation process, there are problems that the manufacturing apparatus becomes complicated and the throughput of the process is lowered.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to realize a surface emitting laser device having an accurately controlled current confinement layer without reducing productivity.

  In order to achieve the above object, the present invention has a surface emitting semiconductor laser device in which a high concentration impurity region is formed in an interface region between a conductive portion and a high resistance portion in a current confinement layer.

  A surface-emitting semiconductor laser device according to the present invention includes a first reflecting mirror formed on a substrate, an active layer formed on the first reflecting mirror, and a conductive material that is formed on the active layer and through which an electric current flows. A current confinement layer including a conductive portion and a high resistance portion which is an oxide layer formed around the conductive portion, and a second reflecting mirror formed on the current confinement layer. A high-concentration impurity region into which impurities are introduced at a higher concentration than other regions is formed in the interface region with the resistance portion.

  According to the surface emitting semiconductor laser device of the present invention, the interface region between the conductive portion and the high resistance portion is formed with a high concentration impurity region in which impurities are introduced at a higher concentration than other regions. When the current confinement layer is formed by oxidation, the oxidation can be stopped in the high concentration impurity region. This is because disorder occurs in the high concentration impurity region and the Al composition ratio is reduced. Therefore, since the size of the conductive portion can be determined by the size of the high concentration impurity region, the control when forming the current confinement layer becomes easy, and the current confinement layer can be formed with high accuracy and good reproducibility. It becomes. Further, since there is no need to provide a monitor post, the number of surface emitting laser devices produced per wafer does not decrease.

In the surface emitting semiconductor laser device of the present invention, the current confinement layer is made of a compound whose general formula is represented by Al _x Ga _1-x As (where 0 <x ≦ 1). The aluminum composition ratio is preferably lower than that in the region.

  In the surface emitting semiconductor laser device of the present invention, the high concentration impurity region is preferably formed so as to penetrate the second reflecting mirror and reach the current confinement layer from the upper surface of the second reflecting mirror.

  In the surface emitting semiconductor laser device of the present invention, the second reflecting mirror is formed by alternately laminating low-refractive index layers and high-refractive index layers having different aluminum composition ratios, and a high-concentration impurity region in the second reflecting mirror. In the portion where is formed, the aluminum composition ratio of the low refractive index layer and the aluminum composition ratio of the high refractive index layer are preferably averaged. With such a configuration, the resistance of the heterointerface can be reduced in the high-concentration impurity region of the second reflecting mirror, so that the series resistance of the reflecting mirror can be reduced. Also, the stability of the light output mode can be improved.

  The surface-emitting semiconductor laser device of the present invention preferably further includes an electrode formed on the second reflecting mirror, and the electrode is in contact with the high concentration impurity region. With such a configuration, the contact resistance of the electrode can be reduced.

  In the surface emitting semiconductor laser device of the present invention, it is preferable that the portion of the second reflecting mirror where the high-concentration impurity region is formed has a smaller reflectance than the other portions. With such a configuration, the stability of the light output mode can be improved.

  In the surface emitting semiconductor laser device of the present invention, the oscillation mode is preferably single transverse mode oscillation.

  In the surface emitting semiconductor laser of the present invention, the impurity is preferably zinc, magnesium or beryllium.

  In the surface emitting semiconductor laser of the present invention, the impurity is preferably silicon, germanium, selenium or sulfur.

  A method of manufacturing a surface emitting semiconductor laser device according to the present invention includes a step (a) of sequentially forming a first reflecting mirror, an active layer, a current confinement layer forming layer, and a second reflecting mirror from below on a substrate; By selectively introducing impurities from the upper surface of the second reflecting mirror toward the current confinement layer forming layer, a planar ring-shaped high concentration impurity region penetrating the second reflecting mirror and reaching the current confining layer forming layer is formed. By selectively removing the step (b), a part of the first reflector, the active layer, the current confinement layer forming layer, and the second reflector, the side surface of the current confinement layer forming layer is exposed. And a step (c) of forming a post portion concentrically formed with the high-concentration impurity region, and oxidizing the current confinement layer formation layer in an oxidizing atmosphere, whereby the side surface of the current confinement layer formation layer is changed to the high-concentration impurity region The current confinement layer is formed by selectively increasing the resistance of each region. It characterized in that it comprises a step (d) of that.

  According to the method of manufacturing the surface emitting semiconductor laser device of the present invention, the impurity is selectively introduced from the upper surface of the second reflecting mirror toward the current confining layer forming layer, thereby penetrating the second reflecting mirror and current confining. Since a step of forming a planar ring-shaped high-concentration impurity region reaching the layer formation layer is provided, a region from the exposed portion to the high-concentration impurity region is selectively oxidized when the current confinement layer is formed by oxidation. be able to. Therefore, it becomes easy to control when forming the current confinement layer by oxidation, and the current confinement layer can be formed with high accuracy and good reproducibility.

  In the method for manufacturing a surface emitting semiconductor laser device according to the present invention, in the step (b), an impurity material layer containing an impurity is formed on the second reflecting mirror in a planar ring shape, and then a second heat treatment is performed. A step of diffusing into the reflecting mirror and the current confinement layer forming layer is preferable.

  In the method for manufacturing a surface emitting semiconductor laser device of the present invention, the step (b) is preferably a step of selectively ion-implanting impurities.

  In the method for manufacturing a surface emitting semiconductor laser device of the present invention, the impurity is preferably zinc, magnesium or beryllium.

  In the method for manufacturing a surface emitting semiconductor laser device of the present invention, the impurity is preferably silicon, germanium, selenium, or sulfur.

  According to the semiconductor light emitting device and the method for manufacturing the same according to the present invention, a surface emitting laser device including an accurately controlled current confinement layer can be realized without reducing productivity.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional configuration of a surface emitting semiconductor laser device according to an embodiment.

  As shown in FIG. 1, the surface emitting laser device according to this embodiment includes an n-type first reflecting mirror 12, a first spacer layer 13, an active layer 14, and a second spacer on a substrate 11 made of n-type GaAs. The layer 15, the current confinement layer 16, the p-type second reflecting mirror 17, and the p-type contact layer 18 are sequentially formed from the lower side.

In the first reflecting mirror 12, a low refractive index layer 12A made of n-type doped Al _0.9 Ga _0.1 As and a high refractive index layer 12B made of Al _0.12 Ga _0.88 As are alternately stacked for 22.5 periods. The low refractive index layer 12A and the high refractive index layer 12B are formed to have a thickness of λ / 4n (where λ is the oscillation wavelength and n is the refractive index). What is necessary is just to form the 1st reflective mirror 12 so that a reflectance may be 99% or more.

  The first spacer layer 13 is an AlGaAs layer having a gradient composition in which the Al composition ratio gradually decreases from the first reflecting mirror 12 side toward the active layer 14 side, and the Al composition ratio on the first reflecting mirror 12 side is 0. 6 and the Al composition ratio on the active layer 14 side is 0.3.

The active layer 14 is a quantum well active layer in which well layers made of undoped GaAs and barrier layers made of undoped Al _0.3 Ga _0.7 As are alternately stacked.

  The second spacer layer 15 is an AlGaAs layer having a gradient composition in which the Al composition ratio gradually increases from the active layer 14 side toward the second reflecting mirror 17 side, and the Al composition ratio on the active layer 14 side is 0.3. The Al composition ratio on the second reflecting mirror 17 side is 0.6.

The current confinement layer 16 is a layer having a high Al composition made of Al _0.98 Ga _0.02 As. The central portion of the current confinement layer 16 is a conductive portion 16A through which a current flows, and a high resistance portion 16B formed by oxidation surrounds the conductive portion 16A. As a result, the current path is narrowed by the conductive portion 16 </ b> A provided at the center of the current confinement layer 16, and the laser light can be emitted from the laser emission region 25. In the surface emitting laser device of this embodiment, a high concentration impurity region 19 described later is formed in an interface region between the conductive portion 16A and the high resistance portion 16B.

In the second reflecting mirror 17, p-type doped low refractive index layers 17A made of Al _0.9 Ga _0.1 As and high refractive index layers 17B made of Al _0.12 Ga _0.88 As are alternately stacked for 34.5 periods. What is necessary is just to form the 2nd reflective mirror 17 so that a reflectance may become 99% or more. The p-type contact layer 18 formed on the second reflecting mirror 17 is made of p-type doped GaAs.

A part of the first reflecting mirror 12, the first spacer layer 13, the active layer 14, the second spacer layer 15, the current confinement layer 16, the second reflecting mirror 17, and the p-type contact layer 18 are selectively etched to be conductive. A cylindrical post portion centering on the sex portion 16A is formed. A buried insulating film 24 made of benzocyclobutene (BCB), which is a low dielectric constant film, is buried around the post portion with a passivation film 23 made of silicon oxide (SiO ₂ ) interposed therebetween.

  A p-side electrode 21 made of titanium, platinum, and gold is formed on a region extending from the outer edge of the p-type contact layer 18 to the buried insulating film 24 with a passivation film 23 interposed therebetween. An n-side electrode 22 made of gold, germanium, and nickel is formed on the surface (back surface) opposite to the first reflecting mirror 12 of the substrate 11.

  In the surface emitting semiconductor laser device of this embodiment, a high concentration impurity region in which a p-type impurity such as zinc (Zn) is introduced at a high concentration in an interface region between the conductive portion 16A of the current confinement layer 16 and the high resistance portion 16B. 19 is formed. The high concentration impurity region 19 is formed so as to penetrate not only the current confinement layer 16 but also the second reflector 17 and the current confinement layer 16 from the upper surface of the p-type contact layer 18 to reach the second spacer layer 15.

The high-concentration impurity region 19 contains, for example, about 4 × 10 ¹⁹ cm ⁻³ of Zn, and the impurity concentration is very high compared to other regions. In this way, by introducing high-concentration Zn, in-concentration diffusion increases in the high-concentration impurity region 19. Therefore, in the high concentration impurity region 19, the Al composition ratio is averaged among the p-type contact layer 18, the low refractive index layer 17A, the high refractive index layer 17B, the current confinement layer 16, and the second spacer layer 15. . For this reason, the Al composition ratio is lower in the portion of the high concentration impurity region 19 in the current confinement layer 16 than in the other portion of the current confinement layer 16.

  The oxidation rate when oxidizing the AlGaAs layer varies depending on the Al composition ratio, and the oxidation rate decreases as the Al composition ratio decreases. Therefore, in the surface emitting laser device of this embodiment, when the high resistance portion 16B is formed by oxidizing the AlGaAs layer having a high Al composition ratio from the outside, the oxidation rate in the portion of the high concentration impurity region 19 having the low Al composition ratio. Decreases significantly, and oxidation does not proceed any further. As a result, the region inside the high concentration impurity region 19 is not oxidized and becomes the conductive portion 16A, and the region outside the high concentration impurity region 19 is oxidized and becomes the high resistance portion 16B. Thus, since the size of the conductive portion 16A can be determined by the size of the high concentration impurity region 19, the current confinement layer 16 can be formed with high accuracy and good reproducibility.

  Further, if the p-side electrode 21 is formed so as to be in contact with the portion of the p-type contact layer 18 where the high-concentration impurity region 19 is formed, an effect that the contact resistance of the p-side electrode 21 can be reduced is obtained. In addition, since the resistance of the portion where the high-concentration impurity region 19 is formed in the second reflecting mirror 17 is reduced, the effect of reducing the series resistance of the surface emitting semiconductor laser device can be obtained. Further, the reflectance of the portion of the second reflecting mirror 17 where the high-concentration impurity region 19 is formed is lowered due to disordering. For this reason, only a limited region of the laser emission region 25 has a resonator structure, and a basic single transverse mode operation can be realized in the optical oscillation mode.

  Below, the manufacturing method of the surface emitting laser apparatus of this embodiment is demonstrated with reference to drawings. 2 to 7 show a method of manufacturing the surface emitting laser device according to this embodiment in the order of steps.

  First, as shown in FIG. 2, an n-type first reflecting mirror 12, a first spacer layer 13, an active layer 14, a second spacer layer 15, and a p-type current confinement are formed on a substrate 11 made of n-type GaAs. The layer forming layer 46, the p-type second reflecting mirror 17, and the p-type contact layer 18 are sequentially formed using a metal organic chemical vapor deposition (MOCVD) method.

In the present embodiment, as a raw material for epitaxial growth by MOCVD, Group III raw materials Ga and Al include organometallic materials such as trimethyl gallium (TMG) and trimethyl aluminum (TMA). Is used. In addition, for example, arsine (AsH ₃ ) is used as the group V material As. Further, silicon doping is performed on the n-type layer using, for example, silane (SiH ₄ ), and carbon doping is performed on the p-type layer using, for example, carbon tetrabromide (CBr ₄ ).

As an example of each layer, the first reflecting mirror 12 has an n-type doped low refractive index layer 12A made of Al _0.9 Ga _0.1 As and a high refractive index layer 12B made of Al _0.12 Ga _0.88 As alternately. What is necessary is just to laminate | stack 22.5 periods. The first spacer layer 13 has a gradient composition in which the Al composition ratio gradually decreases so that the Al composition ratio on the first reflecting mirror 12 side is 0.6 and the Al composition ratio on the active layer 14 side is 0.3. An undoped AlGaAs layer may be used.

The active layer 14 may be formed by alternately laminating well layers made of undoped GaAs and barrier layers made of undoped Al _0.3 GaAs. The second spacer layer 15 has a gradient composition in which the Al composition ratio gradually increases so that the Al composition ratio on the active layer 14 side is 0.3 and the Al composition ratio on the second reflecting mirror 17 side is 0.6. An undoped AlGaAs layer may be used. The current confinement layer 16 may be a high Al composition layer made of p-type doped Al _0.98 Ga _0.02 As.

The second reflecting mirror 17 may be formed by alternately laminating the p-type doped low refractive index layer 17A made of Al _0.9 Ga _0.1 As and the high refractive index layer 17B made of Al _0.12 Ga _0.88 As for 34.5 periods. The p-type contact layer 18 may be p-type doped GaAs.

  Note that a composition modulation layer or an impurity modulation doped layer may be provided inside the first reflecting mirror 12 and the second reflecting mirror 17 for the purpose of reducing the resistance at the heterointerface in the reflecting mirror.

  Next, as shown in FIG. 3, a ring-shaped impurity material layer 31 made of zinc oxide (ZnO) is formed on the p-type contact layer 18. The impurity material layer 31 may be formed in a ring shape by forming a ZnO film on the entire surface of the p-type contact layer 18 by sputtering, for example, and then performing photolithography and etching. In the method for manufacturing the surface emitting semiconductor laser device of this embodiment, the size of the laser emission region 25 is determined by the inner diameter of the impurity material layer 31. Therefore, in the case of a general surface emitting semiconductor laser device, the inner diameter of the impurity material layer 31 may be about 5 μm. Thereafter, a protective layer 32 made of silicon nitride (SiN) is formed so as to cover the impurity material layer 31 and the p-type contact layer 18. The protective layer 32 may be formed by a plasma CVD method or the like.

  Next, as shown in FIG. 4, the wafer after the formation of the impurity material layer 31 and the protective layer 32 is heat-treated, and solid diffusion is performed until Zn as a p-type impurity reaches the second spacer layer 15. As a result, a high-concentration impurity region 19 is formed from the p-type contact layer 18 through the second reflector 17 and the current confinement layer forming layer 46 to reach the second spacer layer 15. Note that the heat treatment time and temperature are controlled so that impurities do not reach the active layer 14.

In the high-concentration impurity region 19, so-called disorder occurs due to the diffusion of Zn, and AlGaAs having an average Al composition ratio is formed. That is, in the high-concentration impurity region 19, the characteristics of the second reflecting mirror 17 and the current confinement layer forming layer 46 before Zn diffusion are lost. In order to cause disordering, the Zn concentration in the high-concentration impurity region 19 may be about 4 × 10 ¹⁹ cm ⁻³ .

  Next, after removing the impurity material layer 31 and the protective layer 32 as shown in FIG. 5, the p-type contact layer 18, the second reflecting mirror 17, the current confinement layer forming layer 46, the second spacer layer 15, and the active layer 14. A part of the first spacer layer 13 and the first reflecting mirror 12 is selectively removed to form a columnar post portion 33. The post portion 33 has a planar shape concentric with the planar ring-shaped high concentration impurity region 19. Since the post portion 33 is a laser element portion of the surface emitting semiconductor laser device, the diameter may be about 10 μm in the case of a general surface emitting semiconductor laser device. The post part 33 may be formed by photolithography and etching.

  Next, as shown in FIG. 6, the current confinement layer forming layer 46 is removed from the side of the post portion by annealing the wafer on which the post portion 33 is formed in an oxidizing gas atmosphere such as nitrogen containing water vapor. The current confinement layer 16 in which the conductive portion 16A and the high resistance portion 16B surrounding the conductive portion 16A are formed is formed by oxidation.

  In the method for manufacturing the surface emitting semiconductor laser device of the present embodiment, the planar ring-shaped high concentration impurity region 19 is formed in the center of the current confinement layer forming layer 46 having a very high Al composition ratio. The region which is the high concentration impurity region 19 in the current confinement layer forming layer 46 has a lower Al composition ratio than other regions due to disordering by Zn. For example, when layers having an Al composition ratio of about 0.6 are formed above and below the current confinement layer formation layer 46 having an Al composition ratio of 0.98 as in the present embodiment, the height of the current confinement layer formation layer 46 is high. The Al composition ratio in the portion that becomes the concentration impurity region 19 is reduced to about 0.7.

  The Al composition ratio greatly affects the oxidation rate of the current confinement layer forming layer 46. When the Al composition ratio decreases, the oxidation rate rapidly decreases. For this reason, when the oxidation proceeds from the outer edge portion of the current confinement layer forming layer 46 at a substantially constant rate and the oxidation proceeds to the high-concentration impurity region 19, the oxidation rate is greatly reduced, and the oxidation does not proceed any further. Therefore, the size of the conductive portion 16A can be easily and stably adjusted to the size of the high concentration impurity region 19. That is, the current confinement layer 16 can be formed with high accuracy and good reproducibility.

Next, as shown in FIG. 7, the lower portion of the passivation film 23 made of SiO ₂ is formed so as to cover the upper surface of the first reflecting mirror 12 and the side surface of the post portion 33, and then the post portion 33 is formed. A buried insulating film 24 made of a BCB film is buried in the recess. Subsequently, the upper portion of the passivation film 23 made of SiO ₂ is formed so as to cover the outer edge portion of the p-type contact layer 18 and the upper surface of the buried insulating film 24.

  Next, the p-side electrode 21 is formed so as to cover the upper surface of the passivation film 23 and the upper surface of the p-type contact layer 18 except for the laser emission region 25, and the n-side electrode 22 is formed on the back surface of the substrate 11. At this time, the p-side electrode 21 is preferably formed so as to be in contact with the high concentration impurity region 19. Since the high-concentration impurity region 19 has a low resistance by impurity diffusion, the contact resistance of the p-side electrode can be reduced by bringing the p-side electrode and the high-concentration impurity region 19 into contact with each other.

  Further, since the high-concentration impurity region penetrates through the second reflecting mirror 17, the resistance of the heterointerface is also reduced in the second reflecting mirror 17 by increasing the Zn concentration and disordering the AlGaAs multilayer films having different compositions. Thus, the series resistance can be reduced. Accordingly, it is possible to realize a surface emitting semiconductor laser device that can reduce the operating current and consume less power. It is also advantageous for high-speed modulation. Further, in the disordered high-concentration impurity region, the reflectivity is lowered, and thus anti-waveguide action occurs in the outer peripheral portion of the laser emission region 25. As a result, basic single transverse mode operation can be realized in the optical oscillation mode.

In this embodiment, as a method for forming the high-concentration impurity region 19, an example is shown in which an impurity material layer made of ZnO is formed and Zn is thermally diffused. However, Zn ion implantation or Zn-based material such as ZnAs ₂ has been shown. Other methods such as thermal diffusion in a gas atmosphere may be used.

  Further, although Zn is used as an impurity for forming the high concentration impurity region 19, other p-type impurities such as magnesium (Mg) or beryllium (Be) may be used.

  In the present embodiment, a surface emitting semiconductor laser device having a configuration in which a p-type layer is disposed on the upper side is shown. However, the same effect can be obtained also in a surface emitting semiconductor laser device having a configuration in which an n-type layer is disposed on the upper side. Obtainable. In this case, an impurity for forming the high concentration impurity region may be n-type impurity such as silicon (Si), germanium (Ge), selenium (Se), or sulfur (S). Further, a p-type GaAs substrate may be used as the substrate.

  Further, the GaAs surface emitting semiconductor laser having an emission wavelength of 850 nm band has been described, but the same effect is expected for other material systems or surface emitting lasers having different wavelength bands.

  INDUSTRIAL APPLICABILITY The optical semiconductor device and the manufacturing method thereof according to the present invention can realize a surface emitting laser device having a precisely controlled current confinement layer without reducing productivity, and a vertical cavity surface emitting semiconductor laser device. In particular, it is useful as a surface emitting semiconductor laser device having a current confinement layer formed by a selective oxidation method.

It is sectional drawing which shows the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the surface emitting semiconductor laser apparatus which concerns on a prior art example.

Explanation of symbols

11 substrate 12 first reflecting mirror 12A low refractive index layer 12B high refractive index layer 13 first spacer layer 14 active layer 15 second spacer layer 16 current confinement layer 16A conductive portion 16B high resistance portion 17 second reflecting mirror 17A low refractive index Index layer 17B High refractive index layer 18 P-type contact layer 19 High-concentration impurity region 21 P-side electrode 22 n-side electrode 23 Passivation film 24 Insulating film 25 Laser emission region 31 Impurity material layer 32 Protective layer 33 Post part 46 Current confinement layer formation layer

Claims (14)

A first reflecting mirror formed on the substrate;
An active layer formed on the first reflector;
A current confinement layer formed on the active layer and including a conductive portion through which a current flows and a high resistance portion which is an oxide layer formed around the conductive portion;
A second reflecting mirror formed on the current confinement layer,
A surface emitting semiconductor laser device, wherein a high concentration impurity region into which impurities are introduced at a higher concentration than other regions is formed in an interface region between the conductive portion and the high resistance portion. The current confinement layer is made of a compound whose general formula is represented by Al _x Ga _1-x As (where 0 <x ≦ 1),
2. The surface emitting semiconductor laser device according to claim 1, wherein the high concentration impurity region has a lower aluminum composition ratio than other regions.   3. The surface emitting semiconductor laser device according to claim 1, wherein the high concentration impurity region is formed so as to penetrate the second reflecting mirror and reach the current confinement layer. In the second reflecting mirror, low refractive index layers and high refractive index layers having different aluminum composition ratios are alternately laminated,
The aluminum composition ratio of the low refractive index layer and the aluminum composition ratio of the high refractive index layer are averaged in the portion where the high concentration impurity region is formed in the second reflecting mirror. The surface emitting semiconductor laser device according to claim 3. An electrode formed on the second reflecting mirror;
5. The surface emitting semiconductor laser device according to claim 3, wherein the electrode is in contact with the high concentration impurity region.   6. The surface emitting semiconductor laser according to claim 3, wherein the portion of the second reflecting mirror where the high-concentration impurity region is formed has a smaller reflectance than other portions. 7. apparatus.   The surface emitting semiconductor laser device according to claim 6, wherein the light oscillation mode is single transverse mode oscillation.   8. The surface emitting semiconductor laser according to claim 1, wherein the impurity is zinc, magnesium, or beryllium.   8. The surface emitting semiconductor laser according to claim 1, wherein the impurity is silicon, germanium, selenium, or sulfur. A step (a) of sequentially forming a first reflecting mirror, an active layer, a current confinement layer forming layer, and a second reflecting mirror on the substrate from below;
By introducing impurities selectively from the upper surface of the second reflector toward the current confinement layer formation layer, a planar ring-shaped high-concentration impurity that penetrates the second reflector and reaches the current confinement layer formation layer Forming a region (b);
By selectively removing a part of the first reflecting mirror, the active layer, the current confinement layer forming layer, and the second reflecting mirror, side surfaces of the current confining layer forming layer are exposed and A step (c) of forming a post portion concentrically formed with the high concentration impurity region;
By oxidizing the current confinement layer forming layer in an oxidizing atmosphere, a region from the side surface of the current confinement layer forming layer to the high-concentration impurity region is selectively increased in resistance, and a current confinement layer that restricts a current path is formed. And a step (d) of forming a surface emitting semiconductor laser device.   In the step (b), the impurity material layer containing the impurity is formed on the second reflecting mirror in a planar ring shape, and then the heat treatment is performed to remove the impurity from the second reflecting mirror and the current confinement layer forming layer. The method of manufacturing a surface emitting semiconductor laser device according to claim 10, wherein the method is a step of diffusing into a surface.   The method of manufacturing a surface emitting semiconductor laser device according to claim 10, wherein the step (b) is a step of selectively ion-implanting the impurities.   The method for manufacturing a surface emitting semiconductor laser device according to claim 10, wherein the impurity is zinc, magnesium, or beryllium.   The method for manufacturing a surface emitting semiconductor laser device according to claim 10, wherein the impurity is silicon, germanium, selenium, or sulfur.

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