Surface-emitting laser device

Abstract

A semiconductor substrate of this surface-emitting laser device comprises a substrate upper surface and a substrate lower surface. A first electrode is provided on the substrate lower surface. A first light-reflecting layer is provided on the substrate upper surface. A light-generation layer is provided on the first light-reflecting layer. A second light-reflecting layer is provided on the light-generation layer. A second electrode is provided on the second light-reflecting layer. A current constriction layer is provided between an active layer and the second light-reflecting layer. The light-generation layer includes the active layer and cladding layers which are disposed with the active layer sandwiched therebetween. A protection layer is disposed between the active layer and the current constriction layer to protect the active layer.

Description

Surface-emitting laser device

[0001] The present disclosure relates to a surface-emitting laser device.

[0002] Patent Document 1 discloses a surface-emitting laser device, which includes a pair of distributed Bragg reflectors and an active layer interposed between the pair of distributed Bragg reflectors.

[0003] Japanese Patent Application Laid-Open No. 2020-21879

[0004] In a surface-emitting laser device including an active layer and a pair of distributed Bragg reflectors as described above, the characteristics of the active layer may deteriorate.

[0005] A surface-emitting laser device according to one aspect of the present disclosure includes a semiconductor substrate having an upper surface and a lower surface, a first electrode provided on the lower surface of the substrate, a first light-reflecting layer of a first conductivity type provided on the upper surface of the substrate, a light-generating layer provided on the first light-reflecting layer, a second light-reflecting layer of a second conductivity type provided on the light-generating layer, a second electrode provided on the second light-reflecting layer, and a current-confining layer disposed between the first electrode and the second electrode and including a current-confining portion formed of an oxide layer, wherein the light-generating layer includes an active layer and cladding layers disposed to sandwich the active layer, and further includes a first protective layer disposed between the active layer and the current-confining layer to protect the active layer.

[0006] a first electrode disposed on the lower surface of the substrate; a first light-reflecting layer of a first conductivity type disposed on the upper surface of the substrate; a light-generating layer disposed on the first light-reflecting layer; a second light-reflecting layer of a second conductivity type disposed on the light-generating layer; a second electrode disposed on the second light-reflecting layer; and a current-confining layer disposed between the first electrode and the second electrode and including a current-confining portion formed of an oxide layer, the oxide layer containing Al; the light-generating layer including an active layer and cladding layers disposed to sandwich the active layer; and a first protective layer disposed between the active layer and the current-confining layer and made of a material containing InGaP to protect the active layer.

[0007] According to the surface-emitting laser device of one aspect of the present disclosure, it is possible to suppress deterioration in the characteristics of the active layer.

[0008] FIG. 1 is a schematic plan view showing a surface-emitting laser device according to a first embodiment. FIG. 2 is a schematic cross-sectional view showing the layer structure of the surface-emitting laser device of FIG. 1. FIG. 3 is a schematic cross-sectional view showing an example of the layer structure of the light generation layer of FIG. 2. FIG. 4 is an explanatory diagram showing an example of the band gap energy in the light generation layer of FIG. 2. FIG. 5 is a schematic cross-sectional view showing a surface-emitting laser device according to a second embodiment. FIG. 6 is a schematic cross-sectional view showing an example of the layer structure of the light generation layer of FIG. 5. FIG. 7 is a schematic cross-sectional view showing a surface-emitting laser device according to a third embodiment. FIG. 8 is a schematic cross-sectional view showing an example of the layer structure of the light generation layer of FIG. 7. FIG. 9 is a schematic cross-sectional view showing a surface-emitting laser device according to a fourth embodiment. FIG. 10 is a schematic cross-sectional view showing an example of the layer structure of the light generation layer of FIG. 9. FIG. 11 is a schematic cross-sectional view showing a surface-emitting laser device according to a fifth embodiment. FIG. 12 is a schematic cross-sectional view showing an example of the layer structure of the light generation layer of FIG. 11. FIG. 13 is a schematic cross-sectional view showing a surface-emitting laser device according to a sixth embodiment. FIG. 14 is a schematic cross-sectional view showing an example of the layer structure of the light generation layer of FIG. 13.

[0009] Hereinafter, several embodiments of the surface-emitting laser device of the present disclosure will be described with reference to the accompanying drawings. Note that for simplicity and clarity of description, components shown in the drawings are not necessarily drawn to scale. Also, for ease of understanding, hatching lines may be omitted in cross-sectional views. The accompanying drawings merely illustrate embodiments of the present disclosure and should not be considered to limit the present disclosure. Terms such as "first," "second," and "third" in the present disclosure are used merely to distinguish between objects and not to rank the objects.

[0010] The following detailed description includes devices, systems, and methods embodying exemplary embodiments of the present disclosure. This detailed description is merely illustrative in nature and is not intended to limit the embodiments of the present disclosure or the application and uses of such embodiments.

[0011] First Embodiment (Schematic Configuration of Surface-Emitting Laser Device) FIG. 1 is a schematic plan view showing a surface-emitting laser device.

[0012] The surface-emitting laser device 10 is a semiconductor laser device known as a VCSEL (Vertical Cavity Surface Emitting Laser). The surface-emitting laser device 10 is formed in a substantially rectangular parallelepiped shape.

[0013] The surface-emitting laser device 10 includes a front surface 11, a rear surface 12, and multiple side surfaces 13, 14, 15, and 16. The front surface 11 and the rear surface 12 face in opposite directions. The direction in which the front surface 11 faces is defined as the thickness direction Z. Two axial directions that are perpendicular to the thickness direction Z and perpendicular to each other are defined as the first direction X and the second direction Y. The surface-emitting laser device 10 of the first embodiment is viewed from the thickness direction Z as a plan view. In one example, the surface-emitting laser device 10 is formed in a rectangular shape in plan view, with its length in the first direction X being longer than its length in the second direction Y. The shape of the surface-emitting laser device 10 in plan view can be changed as desired. The side surfaces 13 and 14 face opposite each other in the first direction X. The side surfaces 15 and 16 face opposite each other in the second direction Y.

[0014] The surface-emitting laser device 10 has a first electrode 21 provided on the rear surface 12 of the device, and a second electrode 22 provided on the front surface 11 of the device. The first electrode 21 is, for example, an n-type electrode. The second electrode is, for example, a p-type electrode. The first electrode 21 can be provided, for example, on the entire rear surface 12 of the device. The second electrode 22 is, for example, formed in a rectangular shape in a plan view. The second electrode 22 includes electrode portions 22A of the multiple light-emitting portions 23 and a rectangular external connection portion 22C extending along the side surface 16 of the device. A conductor such as a bonding wire is connected to the external connection portion 22C. Note that an external terminal may be connected to the external connection portion 22C, and a conductor such as a bonding wire may be connected to the external terminal.

[0015] The surface-emitting laser device 10 includes a light-emitting unit 23 formed on the element surface 11 and emitting laser light in the thickness direction Z. The surface-emitting laser device 10 of the first embodiment includes a plurality of light-emitting units 23. The light-emitting units 23 are formed at intervals in the first direction X and the Y direction in a plan view. The light-emitting units 23 are arranged inside a frame-shaped second electrode 22. The light-emitting units 23 are arranged at intervals in the first direction X and the second direction Y in a plan view. In one example, the light-emitting units 23 are arranged in a staggered pattern in a plan view. More specifically, the light-emitting units 23 are arranged such that one light-emitting unit 23 is located at each of the three vertices of a triangle (e.g., an equilateral triangle) in a plan view. It can also be said that the light-emitting units 23 are arranged such that one light-emitting unit 23 is located at each of the six vertices of a hexagon (e.g., a regular hexagon) in a plan view. The light emitting units 23 may be arranged in any manner, such as in a matrix or in a radial pattern (concentric circles).

[0016] (Layer Structure of Surface-Emitting Laser Device) Fig. 2 is a schematic cross-sectional view showing the layer structure of an exemplary surface-emitting laser device according to the first embodiment, illustrating the layer structure of one light-emitting section 23. Fig. 3 is a cross-sectional view showing an example of the layer structure of light-generating layer 33. Fig. 4 shows an example of the band gap energy in light-generating layer 33.

[0017] 2 , surface-emitting laser device 10 includes a semiconductor substrate 31, a first light reflecting layer 32, a light generating layer 33, and a second light reflecting layer 34. First light reflecting layer 32, light generating layer 33, and second light reflecting layer 34 are provided on semiconductor substrate 31. First light reflecting layer 32 is provided on semiconductor substrate 31 and is in contact with semiconductor substrate 31. Light generating layer 33 is provided on first light reflecting layer 32 and is in contact with first light reflecting layer 32. Second light reflecting layer 34 is provided on light generating layer 33 and is in contact with light generating layer 33.

[0018] (Substrate) The semiconductor substrate 31 includes, for example, a compound semiconductor material. The semiconductor substrate 31 includes, for example, a single crystal of a compound semiconductor material that forms a tetragonal crystal system. The compound semiconductor material may be a III-V semiconductor material. The semiconductor substrate 31 is made of, for example, a GaAs single crystal containing n-type impurities. The n-type impurities may be, for example, Si (silicon). The semiconductor substrate 31 includes a substrate upper surface 31S and a substrate lower surface 31R that face opposite each other in the thickness direction Z. The substrate lower surface 31R constitutes the device back surface 12.

[0019] (First Electrode, Second Electrode) The first electrode 21 is provided on the substrate lower surface 31R. The first electrode 21 forms ohmic contact with the substrate lower surface 31R of the semiconductor substrate 31. The first electrode 21 may include multiple electrode films. Alternatively, the first electrode 21 may be composed of a single electrode film. The first electrode 21 may include, for example, Ni (nickel), Au (gold), Ge (germanium), Ti (titanium), In (indium), Zn (zinc), or the like. In one example, the first electrode 21 is composed of a stack of an AuGe layer, a Ni layer, and an Au layer. The second electrode 22 may include multiple electrode films. Alternatively, the second electrode 22 may be composed of a single electrode film. The second electrode 22 may include, for example, Au, Ti, or the like. In one example, the second electrode 22 is composed of a stack of a Ti layer and an Au layer. The surface-emitting laser device 10 may include a contact layer interposed between the second light-reflecting layer 34 and the second electrode 22 .

[0020] (First Light Reflecting Layer, Second Light Reflecting Layer) First light reflecting layer 32 and second light reflecting layer 34 are arranged in thickness direction Z to sandwich light generating layer 33. First light reflecting layer 32 is provided on substrate upper surface 31S of semiconductor substrate 31. Light generating layer 33 is provided on first light reflecting layer 32. Second light reflecting layer 34 is provided on light generating layer 33. Second electrode 22 is provided on second light reflecting layer 34. Second electrode 22 on second light reflecting layer 34 may be formed, for example, in a ring shape.

[0021] The first light reflecting layer 32 is composed of a first conductivity type DBR (Distributed Bragg Reflector) layer. The first conductivity type is, for example, n-type. The first light reflecting layer 32 contains impurities of the first conductivity type. The impurities of the first conductivity type may be, for example, at least one of Si and Te (tellurium). The first light reflecting layer 32 has a refractive index that changes periodically along the thickness direction Z, and resonantly reflects specific wavelength components.

[0022] The first light reflecting layer 32 has a laminated structure in which a first reflecting layer and a second reflecting layer containing Al are laminated. The first reflecting layer and the second reflecting layer have different refractive indices. The first light reflecting layer 32 includes a plurality of first reflecting layers and a plurality of second reflecting layers. The first reflecting layer is an Al layer having an Al composition α1. α１ Ga （１－α１） The second reflective layer may contain As. α２ Ga （１－α２） It may contain As. The Al composition α1 of the first reflective layer may be greater than 0 and less than or equal to 0.2. The Al composition α2 of the second reflective layer is higher than the Al composition α1 of the first reflective layer. The Al composition α2 of the second reflective layer may be greater than or equal to 0.85 and less than or equal to 0.97. The higher the Al composition, the wider the energy gap and the lower the refractive index. Therefore, the refractive index of the first reflective layer and the second reflective layer are different from each other.

[0023] The second light reflecting layer 34 is composed of a DBR layer of a second conductivity type. The second conductivity type is, for example, p-type. The second light reflecting layer 34 contains impurities of the second conductivity type. The impurities of the second conductivity type may be, for example, at least one of C (carbon), Zn, and Mg (magnesium). The second light reflecting layer 34 has a refractive index that changes periodically along the thickness direction Z and resonantly reflects specific wavelength components.

[0024] The second light reflecting layer 34 has a laminated structure in which a third reflecting layer and a fourth reflecting layer containing an Al composition are laminated. The third reflecting layer and the fourth reflecting layer have different refractive indices. The second light reflecting layer 34 of the first embodiment includes a plurality of third reflecting layers and a plurality of fourth reflecting layers. The third reflecting layer is an Al layer having an Al composition α3. α３Ga （１－α３） The fourth reflective layer may contain Al having an Al composition α4. α４ Ga （１－α４） The third reflective layer may contain As. The Al composition α3 of the third reflective layer may be 0.85 or more and 0.97 or less. The Al composition α4 of the fourth reflective layer is lower than the Al composition α3 of the third reflective layer. The Al composition α3 of the third reflective layer may be greater than 0 and equal to or less than 0.2. Therefore, the refractive index of the third reflective layer and the refractive index of the fourth reflective layer are different from each other.

[0025] Each light-emitting section 23 of the surface-emitting laser device 10 emits laser light of a specific wavelength component that is reflected by the first light-reflecting layer 32 and the second light-reflecting layer 34 of the respective light-emitting section 23. The wavelength of the laser light is assumed to be λ. It can be said that each light-emitting section 23 generates laser light of wavelength λ due to the first light-reflecting layer 32 and the second light-reflecting layer 34.

[0026] (Active Layer) The light generating layer 33 includes an active layer 51. The active layer 51 is disposed in the thickness direction Z, i.e., between the first light reflecting layer 32 and the second light reflecting layer 34. The active layer 51 may have a QW (Quantum Well) structure including quantum well layers and barrier layers. The active layer 51 may have, for example, an MQW (Multi Quantum Well) structure in which quantum well layers and barrier layers are alternately stacked at an arbitrary period. The quantum well layer may include GaAs, AlGaAs, or InGaAs. The quantum well layer may be undoped. The barrier layer has a band gap larger than that of the quantum well layer.

[0027] (Cladding Layer) The cladding layers 61 and 62 are arranged to sandwich the active layer 51. The cladding layer 61 arranged on the first light reflecting layer 32 side of the active layer 51 is a first cladding layer containing impurities of a first conductivity type. The impurities of the first conductivity type may be, for example, at least one of Si and Te. The first cladding layer 61 is made of Al having an Al composition γ. γ Ga （１－γ）The cladding layer 62 disposed on the second light reflecting layer 34 side of the active layer 51 is a second cladding layer containing impurities of the second conductivity type. The impurities of the second conductivity type may be, for example, at least one of C, Zn, and Mg. The second cladding layer 62 is an Al cladding layer having an Al composition γ of 0.2 or more and 0.8 or less. γ Ga （１－γ） Contains As.

[0028] (Current Confinement Layer) The surface-emitting laser device 10 includes a current confinement layer 71. The current confinement layer 71 may be disposed between the first electrode 21 and the second electrode 22. In the surface-emitting laser device 10 of the first embodiment, the current confinement layer 71 is provided between the active layer 51 and the second electrode 22. In one example, the current confinement layer 71 is disposed between the second cladding layer 62, which sandwiches the active layer 51, and the second optical reflection layer 34. An adjustment layer 62A is provided between the current confinement layer 71 and the second optical reflection layer 34. The adjustment layer 62A adjusts the position of the current confinement layer 71. In one example, the adjustment layer 62A may have the same composition as the second cladding layer 62. The current confinement layer 71 confines the current supplied to the active layer 51.

[0029] The current confinement layer 71 includes a current passing portion 71A and a current confinement portion 71B. The current passing portion 71A may be made of a material containing Al. For example, the current passing portion 71A may be made of AlAs (Al ｘ Ga （１－ｘ） The current passing portion 71A is made of a material containing As and Al (composition x is 0.95 or more and 1.00 or less). The current passing portion 71A may contain impurities of the second conductivity type. The current passing portion 71A is provided in the inner portion of each light emitting portion 23. For example, in a plan view, the current passing portion 71A is disposed in the center of each light emitting portion 23. For example, the current passing portion 71A is formed in a circular shape in a plan view.

[0030] The current confinement portion 71B has insulating properties. The current confinement portion 71B is made of an oxide layer. The current confinement portion 71B includes an oxide layer containing Al. The oxide layer containing Al is, for example, Al ２ O ３(alumina). The oxide layer may contain Ga or As. The current confinement portion 71B is disposed on the side of each light-emitting portion 23 relative to the current passing portion 71A. For example, in a plan view, the current confinement portion 71B is formed in a ring shape (e.g., annular) surrounding the current passing portion 71A. For example, the current confinement portion 71B is formed by oxidizing the periphery of a layer containing AlAs. In one example, the current confinement portion 71B can be formed by performing a heat treatment in water vapor. The film thickness (physical thickness) of the current confinement layer 71 can be, for example, 15 nm or more and 100 nm or less.

[0031] The current confinement layer 71 includes an opening 71C formed by an annular current confinement portion 71B. The opening 71C is formed in an arc shape such that the center portion of the current confinement portion 71B in the thickness direction Z bulges toward the current passing portion 71A. This current confinement portion 71B confines the current flowing between the first electrode 21 and the second electrode 22 in each light-emitting portion 23. The current flowing between the first electrode 21 and the second electrode 22 passes through the current passing portion 71A inside the opening 71C. The region of the first active layer 51 facing this current passing portion 71A is the light-emitting region. The current confinement layer 71 increases the current density in the active layer 51. This improves the luminous efficiency of light generated in the active layer 51.

[0032] (Protective Layer) The surface-emitting laser device 10 includes a protective layer 81. The protective layer 81 is disposed between the active layer 51 and the current confinement layer 71. The protective layer 81 of the first embodiment is disposed within the second cladding layer 62. The protective layer 81 is disposed closer to the current confinement layer 71 than the active layer 51. The distance L21 (see FIG. 3 ) between the active layer 51 and the protective layer 81 may be 150 nm or less, for example. The thickness of the protective layer 81 may be, for example, 5 nm or more and 100 nm or less. In one example, the thickness of the protective layer 81 is 30 nm.

[0033] The protective layer 81 is made of a material containing InGaP. The protective layer 81 is configured so that the band gap energy of the protective layer 81 is equal to the band gap energy of the second cladding layer 62 around the protective layer 81. The protective layer 81 is made of InGaP having an In composition β1. β１ Ga （１－β１）The protective layer 81 may contain P. For example, when the Al composition γ of the second cladding layer 62 is 0.30 or more and 0.70 or less, the In composition β1 may be 0.48 or more and 0.60 or less. The protective layer 81 may contain impurities of the second conductivity type. The impurity concentration in the protective layer 81 may be equal to the impurity concentration in the second cladding layer 62.

[0034] (Insulating Film) The surface-emitting laser device 10 includes an insulating film 91 that covers the light-emitting section 23. In the first embodiment, the insulating film 91 is formed to cover the surface of the first light-reflecting layer 32, the side surfaces of the light-generating layer 33, and the side surfaces of the second light-reflecting layer 34. The insulating film 91 is made of, for example, SiO ２ , silicon oxide such as SiO, SiN (silicon nitride), SiON, ZrO ２ (zirconium oxide) or TiO (titanium oxide). The insulating film 91 includes a covering portion 92 that covers the upper surface of the second light reflecting layer 34 in each light emitting portion 23. The covering portion 92 covers the upper surface of the second light reflecting layer 34 that is exposed from the second electrode 22.

[0035] (Position of Each Layer in the Light-Generating Layer) FIG. 3 is a schematic cross-sectional view showing an example of the relationship between the layer configuration of the light-generating layer 33 constituting the light-emitting section 23 and the waveform of the laser light LW.

[0036] The waveform of the laser light LW shown in Fig. 3 indicates the electric field intensity of the laser light LW. Note that the waveform of the laser light LW in Fig. 3 is shown as a constant length with respect to the wavelength λ.

[0037] The light generating layer 33 includes an active layer 51. The active layer 51 is located at an antinode position of the laser light LW generated by the active layer 51, the first light reflecting layer 32, and the second light reflecting layer 34. The current confinement layer 71 is located at a position with respect to the laser light LW that is different from the antinode position of the laser light LW. The current confinement layer 71 is preferably located at an optical distance λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layer 51. The light emitting section 23 of the first embodiment includes one active layer 51 and one current confinement layer 71.

[0038] The optical distance L11 between the current confinement layer 71 and the active layer 51 is λ / 4. That is, the current confinement layer 71 can be said to be located at a position that is an optical distance L11 of λ / 4 away from the first active layer 51 that is closer to the first optical reflection layer 32. The active layer 51 is located at an antinode position of the laser light LW in the light-emitting unit 23. The current confinement layer 71 can be said to be located at a node position of the laser light LW. The antinode position of the laser light LW is a position where the electric field strength is highest, and the node position is a position where the electric field strength is lowest. Note that if the difference between the current confinement layer 71 and a position that is an optical distance of λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layer 51 is, for example, λ / 8 or less, the current confinement layer 71 can be said to be located at a position that is an optical distance of λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layer 51, and can be said to be located at a node position.

[0039] (Operation) Next, the operation of the surface-emitting laser device 10 of the first embodiment will be described. The surface-emitting laser device 10 includes a first electrode 21, a second electrode 22, a semiconductor substrate 31, a first light-reflecting layer 32 of a first conductivity type, a light-generating layer 33, a second light-reflecting layer 34 of a second conductivity type, a current-confining layer 71, and a protective layer 81. The semiconductor substrate 31 includes a substrate upper surface 31S and a substrate lower surface 31R. The first electrode 21 is provided on the substrate lower surface 31R. The first light-reflecting layer 32 is provided on the substrate upper surface 31S. The light-generating layer 33 is provided on the first light-reflecting layer 32. The second light-reflecting layer 34 is provided on the light-generating layer 33. The second electrode 22 is provided on the second light-reflecting layer 34. The current-confining layer 71 is provided between the active layer 51 and the second light-reflecting layer 34. The light generating layer 33 includes an active layer 51 and cladding layers 61 and 62 disposed to sandwich the active layer 51. The protective layer 81 is disposed between the active layer 51 and the current confinement layer 71.

[0040] The current confinement layer 71 includes a current confinement portion 71B made of an oxide layer. This current confinement portion 71B is smaller than the current passing portion 71A constituting the current confinement layer 71. This causes stress around the current confinement layer 71. This stress can cause deterioration in the characteristics of the second cladding layer 62 and the active layer 51 in contact with the second cladding layer 62. This deterioration in characteristics includes degradation over time. The deterioration in the characteristics of the active layer leads to a decrease in the output of the laser light LW from the surface-emitting laser device 10.

[0041] The surface-emitting laser device 10 of the first embodiment includes a protective layer 81 disposed between the active layer 51 and the current confinement layer 71. This protective layer 81 relieves stress caused by the current confinement portion 71B of the current confinement layer 71. In other words, this protective layer 81 can protect the active layer 51. Therefore, in the surface-emitting laser device 10 of the first embodiment, the protective layer 81 can suppress deterioration in the characteristics of the active layer 51. Furthermore, by suppressing deterioration in the characteristics of the active layer 51, it is possible to suppress a decrease in the output of laser light LW in the surface-emitting laser device 10.

[0042] As shown in Figure 4, the protective layer 81 is configured so that its bandgap energy is equal to that of the second cladding layer 62 surrounding the protective layer 81. The difference in bandgap energy can cause an increase in resistance. This resistance reduces the current flowing through the active layer 51, thereby reducing the intensity of the laser light LW generated by the surface-emitting laser device 10. In contrast, by making the bandgap energy of the protective layer 81 equal to that of the second cladding layer 62, the increase in resistance can be suppressed. Therefore, the reduction in the intensity of the laser light LW generated by the surface-emitting laser device 10 can be suppressed.

[0043] The protective layer 81 is preferably disposed closer to the current confinement layer 71 than to the active layer 51. By disposing the protective layer 81 closer to the current confinement layer 71 than to the active layer 51, the active layer 51 can be better protected.

[0044] Surface-emitting laser device 10 includes a light-generating layer 33 and a first light-reflecting layer 32 of a first conductivity type and a second light-reflecting layer 34 of a second conductivity type, which are arranged to sandwich light-generating layer 33. Light-generating layer 33 includes an active layer 51 and first and second cladding layers 61 and 62. Active layer 51 is arranged between first light-reflecting layer 32 and second light-reflecting layer 34 in a direction from first light-reflecting layer 32 to second light-reflecting layer 34. First cladding layer 61 is arranged on the first light-reflecting layer 32 side of each active layer 51. Second cladding layer 62 is arranged on the second light-reflecting layer 34 side of each active layer 51.

[0045] The surface-emitting laser device 10 of the first embodiment includes a current confinement layer 71 disposed between the active layer 51 and the second optical reflection layer 34. The current confinement layer 71 includes a current confinement portion 71B forming an opening 71C, and a current passing portion 71A disposed inside the opening 71C. The current passing portion 71A is formed of a material containing AlAs. The second cladding layer 62 between the active layer 51 and the second optical reflection layer 34 is made of AlAs having an Al composition γ. γ Ga （１－γ） The current passing portion 71A contains As. Therefore, it can be said that the current passing portion 71A has a higher Al composition than the Al composition γ of the second cladding layer 62. The current passing portion 71A has a low resistance due to a high impurity concentration of a second conductivity type impurity (e.g., C). Therefore, the current passing portion 71A is more likely to absorb the laser light LW than the cladding layers 61, 62. Therefore, the current confinement layer 71 can cause a loss in the optical intensity of the laser light LW generated by the light emitting portion 23. The higher the electric field intensity of the laser light LW that forms a standing wave, the greater the loss. Therefore, by locating the current confinement layer 71 at a position different from the antinode position of the laser light LW, the loss of the laser light LW due to the current confinement layer 71 can be reduced.

[0046] In the surface-emitting laser device 10, the current confinement layer 71 is disposed at an optical distance L11 of λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layer 51. Therefore, the current confinement layer 71 is disposed at a node position of the laser light LW, that is, at a position where the electric field strength is low. This makes it possible to further reduce the loss of the laser light LW due to the current confinement layer 71.

[0047] (Effects) The surface-emitting laser device 10 of the first embodiment has the following effects. (1-1) The surface-emitting laser device 10 includes a semiconductor substrate 31, a first light-reflecting layer 32 of a first conductivity type, a light-generating layer 33, a second light-reflecting layer 34 of a second conductivity type, a first electrode 21, a second electrode 22, a current-confining layer 71, and a protective layer 81. The semiconductor substrate 31 includes a substrate upper surface 31S and a substrate lower surface 31R. The first electrode 21 is provided on the substrate lower surface 31R. The first light-reflecting layer 32 is provided on the substrate upper surface 31S. The light-generating layer 33 is provided on the first light-reflecting layer 32. The second light-reflecting layer 34 is provided on the light-generating layer 33. The second electrode 22 is provided on the second light-reflecting layer 34. The current-confining layer 71 is provided between the active layer 51 and the second light-reflecting layer 34. The light generating layer 33 includes an active layer 51 and cladding layers 61 and 62 disposed to sandwich the active layer 51. The protective layer 81 is disposed between the active layer 51 and the current confinement layer 71.

[0048] The current confinement layer 71 includes a current confinement portion 71B formed of an oxide layer. Stress is generated in the light generation layer 33 due to contraction of the current confinement portion 71B. The protective layer 81 disposed between the active layer 51 and the current confinement layer 71 relieves the stress generated by the current confinement portion 71B. In other words, the protective layer 81 can protect the active layer 51. Therefore, in the surface-emitting laser device 10 of the first embodiment, the protective layer 81 can suppress deterioration in the characteristics of the active layer 51.

[0049] (1-2) The protective layer 81 is configured so that the band gap energy of the protective layer 81 is equal to the band gap energy of the second cladding layer 62 around the protective layer 81. This makes it possible to suppress an increase in the resistance components in the second cladding layer 62 and the protective layer 81. This makes it possible to suppress a decrease in the light intensity of the laser light LW generated by the surface-emitting laser device 10.

[0050] (1-3) The surface-emitting laser device 10 of the first embodiment includes a current confinement layer 71 disposed between the active layer 51 and the second optical reflection layer 34. The current confinement layer 71 includes a current confinement portion 71B forming an opening 71C, and a current passing portion 71A disposed inside the opening 71C. The current passing portion 71A is formed of a material containing AlAs. The second cladding layer 62 between the active layer 51 and the second optical reflection layer 34 is made of AlAs having an Al composition γ. γ Ga （１－γ） The current passing portion 71A contains As. Therefore, it can be said that the current passing portion 71A has a higher Al composition than the Al composition γ of the second cladding layer 62. The current passing portion 71A has a low resistance due to a high impurity concentration of a second conductivity type impurity (e.g., C). Therefore, the current passing portion 71A is more likely to absorb the laser light LW than the cladding layers 61, 62. Therefore, the current confinement layer 71 can cause a loss in the optical intensity of the laser light LW generated by the light emitting portion 23. The higher the electric field intensity of the laser light LW that forms a standing wave, the greater the loss. Therefore, by locating the current confinement layer 71 at a position different from the antinode position of the laser light LW, the loss of the laser light LW due to the current confinement layer 71 can be reduced.

[0051] (1-4) In the surface-emitting laser device 10, the current confinement layer 71 is disposed at an optical distance L11 of λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layer 51. Therefore, the current confinement layer 71 is disposed at a node position of the laser light LW, that is, at a position where the electric field strength is low. This makes it possible to further reduce the loss of the laser light LW due to the current confinement layer 71.

[0052] Second Embodiment (Layer Structure of Surface-Emitting Laser Device) FIG. 5 is a schematic cross-sectional view showing the layer structure of an exemplary surface-emitting laser device 110 according to a second embodiment, illustrating the layer structure of one light-emitting section 123. FIG. 6 is a schematic cross-sectional view showing an example of the relationship between the layer structure of the light-generating layer 133 constituting the light-emitting section 123 and the waveform of the laser light LW. In FIGS. 5 and 6, the same components as those in the surface-emitting laser device 10 according to the first embodiment are denoted by the same reference numerals. Below, components different from those in the first embodiment will be described. Note that some or all of the description of components similar to those in the first embodiment may be omitted.

[0053] 5 , surface-emitting laser device 110 of the second embodiment includes semiconductor substrate 31, first light reflecting layer 32, light generating layer 133, and second light reflecting layer 34. First light reflecting layer 32, light generating layer 133, and second light reflecting layer 34 are provided on semiconductor substrate 31. First light reflecting layer 32 is provided on semiconductor substrate 31 and is in contact with semiconductor substrate 31. Light generating layer 133 is provided on first light reflecting layer 32 and is in contact with first light reflecting layer 32. Second light reflecting layer 34 is provided on light generating layer 133 and is in contact with light generating layer 133.

[0054] The light generating layer 133 of the second embodiment includes a first active layer 51 and a second active layer 52. The first active layer 51 and the second active layer 52 are arranged in this order in the thickness direction Z, i.e., from the second light reflecting layer 34 toward the first light reflecting layer 32. The second active layer 52 may have a QW structure including quantum well layers and barrier layers. The second active layer 52 may have an MQW structure in which quantum well layers and barrier layers are alternately stacked at any period. The quantum well layers may contain GaAs. The quantum well layers may be undoped. The barrier layers may have a band gap larger than the band gap of the quantum well layers.

[0055] The light generating layer 133 of the second embodiment includes cladding layers 61, 62, 63, and 64. The cladding layers 61, 62 are arranged to sandwich the second active layer 52, and the first active layer 51 is also arranged to sandwich the cladding layers 63, 64. The cladding layers 61, 63, which are arranged on the first light reflecting layer 32 side of the active layers 51, 52, are first cladding layers containing impurities of the first conductivity type. The impurities of the first conductivity type may be, for example, Si. The first cladding layers 61, 63 are Al having an Al composition γ. γ Ga （１－γ） The cladding layers 62 and 64 arranged on the second light reflecting layer 34 side of the active layers 51 and 52 are second cladding layers containing impurities of the second conductivity type. The impurities of the second conductivity type may be, for example, C. The second cladding layers 62 and 64 are Al cladding layers having an Al composition γ of 0.2 or more and 0.7 or less. γ Ga （１－γ） The first cladding layers 61 and 63 and the second cladding layers 62 and 64 have the same Al composition.

[0056] The light generating layer 133 includes a tunnel junction layer 67. The tunnel junction layer 67 is disposed between adjacent cladding layers in the thickness direction Z, i.e., the first cladding layer 61 and the second cladding layer 64, in which the active layers 51 and 52 are disposed. The tunnel junction layer 67 allows a tunnel current to flow due to the tunnel effect.

[0057] The tunnel junction layer 67 includes a first tunnel layer 67A of a first conductivity type and a second tunnel layer 67B of a second conductivity type. The second tunnel layer 67B is disposed on the second light reflecting layer 34 side of the first tunnel layer 67A. The first tunnel layer 67A and the second tunnel layer 67B are in contact with each other. The first tunnel layer 67A is in contact with the second cladding layer 64. The second tunnel layer 67B is in contact with the first cladding layer 61.

[0058] The surface-emitting laser device 110 includes a current confinement layer 71. The current confinement layer 71 is provided between the first active layer 51 and the second electrode 22. The surface-emitting laser device 110 includes an adjustment layer 62A interposed between the current confinement layer 71 and the second light reflecting layer 34.

[0059] The surface-emitting laser device 110 includes a protective layer 81. The protective layer 81 is provided between the first active layer 51 and the current confinement layer 71. (Position of Each Layer in the Light-Generating Layer) FIG. 6 is a cross-sectional view showing an example of the relationship between the layer configuration of the light-generating layer 133 constituting the light-emitting section 123 and the waveform of the laser light LW. The laser light LW shown in FIG. 6 is the waveform of the laser light LW and indicates the electric field intensity. Note that the waveform of the laser light LW in FIG. 6 is shown as a constant length for each wavelength λ.

[0060] In the light generating layer 133, the optical distance L01 between the first active layer 51 and the second active layer 52 is preferably λ×k1 / 2 (k1 is a natural number). In the surface-emitting laser device 110 of the second embodiment, the optical distance L01 between the first active layer 51 and the second active layer 52 is λ. The first active layer 51 and the second active layer 52 are located at antinode positions of the laser light LW.

[0061] The current confinement layer 71 is disposed at a position with respect to the laser light LW that is different from the antinode position of the laser light LW. The current confinement layer 71 is preferably disposed at a position that is an optical distance λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layers 51 and 52. The light emitting section 123 of the second embodiment includes two active layers 51 and 52 and one current confinement layer 71.

[0062] The optical distance L11 between the current confinement layer 71 and the first active layer 51 closest to the second optical reflection layer 34 is λ / 4. In other words, the current confinement layer 71 is located at an optical distance L11 of λ / 4 from the first active layer 51 closest to the first optical reflection layer 32. The active layers 51 and 52 are located at antinode positions of the laser light LW in the light-emitting section 123. The current confinement layer 71 is located at a node position of the laser light LW. The antinode positions of the laser light LW are positions where the electric field strength is highest, and the node positions are positions where the electric field strength is lowest. Furthermore, if the difference between the current confinement layer 71 and a position that is an optical distance λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layers 51 and 52 is, for example, λ / 8 or less, then the current confinement layer 71 can be said to be located at a position that is an optical distance λ×(2×k3−1) / 4 (k3 is a natural number) away from the active layers 51 and 52, and can be said to be located at a nodal position.

[0063] The tunnel junction layer 67 is disposed at a position with respect to the laser light LW that is different from the antinode position of the laser light LW. The tunnel junction layer 67 is preferably disposed at a position optically separated from the active layers 51 and 52 by λ×(2×k2−1) / 4 (k2 is a natural number). For example, the tunnel junction layer 67 is disposed such that a predetermined position within the tunnel junction layer 67 is optically separated from the active layers 51 and 52 by λ×(2×k2−1) / 4 (k2 is a natural number) in the thickness direction of the tunnel junction layer 67. It can be said that the tunnel junction layer 67 is located at a node position of the laser light LW. In addition, if the difference between a predetermined position inside the tunnel junction layer 67 and a position that is an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the active layers 51 and 52 is, for example, λ / 8 or less, then the tunnel junction layer 67 can be said to be located at a position that is an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the active layers 51 and 52, and can be said to be located at a nodal position.

[0064] The first tunnel layer 67A contains impurities of a first conductivity type. The first tunnel layer 67A is doped with a high concentration of impurities of the first conductivity type. The second tunnel layer 67B contains impurities of a second conductivity type. The second tunnel layer 67B is doped with a high concentration of impurities of the second conductivity type. The impurity concentration of the first tunnel layer 67A is higher than the impurity concentration of the second tunnel layer 67B. The film thickness of the first tunnel layer 67A can be, for example, 10 nm or more and 30 nm or less. The film thickness of the second tunnel layer 67B can be, for example, 10 nm or more and 30 nm or less.

[0065] In the second embodiment, the optical distance L31 between the first tunnel layer 67A and the first active layer 51 is λ / 4. That is, the first tunnel layer 67A is disposed at a position that is an optical distance of λ / 4 away from the first active layer 51. For example, the first tunnel layer 67A is disposed at a position in the thickness direction of the first tunnel layer 67A such that the center of the first tunnel layer 67A is an optical distance of λ×(2×k2−1) / 4 (k2 is a natural number) away from the first active layer 51. The first tunnel layer 67A is disposed at a node position of the laser light LW.

[0066] Furthermore, the optical distance L32 between the first tunnel layer 67A and the second active layer 52 is λ×3 / 4. That is, the first tunnel layer 67A is disposed at a position that is an optical distance λ×3 / 4 away from the second active layer 52. For example, the first tunnel layer 67A is disposed at a position in the thickness direction of the first tunnel layer 67A such that the center of the first tunnel layer 67A is an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the second active layer 52. The first tunnel layer 67A is disposed at a node position of the laser light LW. Furthermore, if the difference between the center of the first tunnel layer 67A and a position that is an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the active layers 51 and 52 is, for example, λ / 8 or less, then the first tunnel layer 67A can be said to be positioned at a position that is an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the active layers 51 and 52, and can be said to be located at a node position.

[0067] (Function) Next, a description will be given of the function of the surface-emitting laser device 110 of the second embodiment. The surface-emitting laser device 110 of the second embodiment includes a protective layer 81 disposed between the first active layer 51 and the current confinement layer 71. The protective layer 81 relieves stress generated by the current confinement portion 71B of the current confinement layer 71 and protects the first active layer 51 and the second active layer 52.

[0068] In the light-emitting section 123 of the surface-emitting laser device 110 of the second embodiment, the light-generating layer 50 includes a first active layer 51 and a second active layer 52. Therefore, the light intensity of the laser light LW emitted from the light-emitting section 123 can be improved compared to the light-emitting section 23 of the first embodiment.

[0069] The tunnel junction layer 67 is disposed between the first cladding layer 61 and the second cladding layer 64 between two adjacent active layers 52, 51 in the direction from the first light reflecting layer 32 toward the second light reflecting layer 34. Furthermore, when the wavelength of the laser light LW is λ, the tunnel junction layer 67 is disposed at an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the active layers 51, 52.

[0070] The tunnel junction layer 67 has an impurity concentration higher than that of the cladding layers 61 to 64. Such a tunnel junction layer 67 is more likely to absorb the laser light LW generated by the active layers 51 and 52 than the cladding layers 61 to 64. Therefore, the tunnel junction layer 67 can cause a loss in the optical intensity of the laser light LW generated by the light emitting portion 123. The higher the electric field intensity of the laser light LW that forms a standing wave, the greater the loss. Therefore, by locating the tunnel junction layer 67 at a position different from the antinode position of the laser light LW, the loss of the laser light LW due to the tunnel junction layer 67 can be reduced.

[0071] Furthermore, by locating the tunnel junction layer 67 at a node position of the laser light LW, i.e., a position where the electric field strength is low, the loss of the laser light LW can be further reduced. The active layers 51 and 52 are located at antinode positions where the electric field strength is lowest in the waveform of the laser light LW. Therefore, by locating the tunnel junction layer 67 at a position optically distant from the active layers 51 and 52 by λ×(2×k2−1) / 4 (k2 is a natural number), the loss of the laser light LW due to the tunnel junction layer 67 can be further reduced.

[0072] The tunnel junction layer 67 includes a first tunnel layer 67A of a first conductivity type and a second tunnel layer 67B of a second conductivity type. The impurity concentration of the first tunnel layer 67A is higher than the impurity concentration of the second tunnel layer 67B. Therefore, the first tunnel layer 67A is more likely to absorb the laser light LW than the second tunnel layer 67B. Therefore, by locating the first tunnel layer 67A at an optical distance of λ×(2×k2−1) / 4 (k2 is a natural number) from the active layers 51 and 52, the loss of the laser light LW due to the tunnel junction layer 67 can be further reduced.

[0073] (Effects) The surface-emitting laser device 110 of the second embodiment has the following effects: (2-1) The surface-emitting laser device 110 of the second embodiment has the same effects as the surface-emitting laser device 10 of the first embodiment.

[0074] (2-2) Surface-emitting laser device 110 includes light generating layer 133, first light reflecting layer 32 of a first conductivity type, and second light reflecting layer 34 of a second conductivity type, which are arranged to sandwich light generating layer 133. Light generating layer 133 includes active layers 51 and 52, first cladding layers 61 and 63, second cladding layers 62 and 64, and tunnel junction layer 67. Therefore, the light intensity of laser light LW emitted from surface-emitting laser device 110 can be improved compared to a surface-emitting laser device that includes a single active layer in the light generating layer of the light-emitting section.

[0075] (2-3) The tunnel junction layer 67 is disposed between the first cladding layer 61 and the second cladding layer 64 between two adjacent active layers 52, 51 in the direction from the first light reflecting layer 32 toward the second light reflecting layer 34. Furthermore, when the wavelength of the laser light LW is λ, the tunnel junction layer 67 is disposed at an optical distance λ×(2×k2−1) / 4 (k2 is a natural number) away from the active layers 51, 52.

[0076] By locating the tunnel junction layer 67 at a node position of the laser light LW, i.e., at a position where the electric field strength is low, the loss of the laser light LW can be further reduced. The active layers 51 and 52 are located at antinode positions where the electric field strength is highest in the waveform of the laser light LW. Therefore, by locating the tunnel junction layer 67 at a position optically distant from the active layers 51 and 52 by λ×(2×k2−1) / 4 (k2 is a natural number), the loss of the laser light LW due to the tunnel junction layer 67 can be further reduced.

[0077] (2-4) The tunnel junction layer 67 includes a first tunnel layer 67A of a first conductivity type and a second tunnel layer 67B of a second conductivity type. The impurity concentration of the first tunnel layer 67A is higher than the impurity concentration of the second tunnel layer 67B. Therefore, the first tunnel layer 67A is more likely to absorb the laser light LW than the second tunnel layer 67B. Therefore, by arranging the first tunnel layer 67A at an optical distance of λ×(2×k2−1) / 4 (k2 is a natural number) from the active layers 51 and 52, the loss of the laser light LW due to the tunnel junction layer 67 can be further reduced.

[0078] Third Embodiment (Layer Structure of Surface-Emitting Laser Device) FIG. 7 is a schematic cross-sectional view showing the layer structure of an exemplary surface-emitting laser device 210 according to a third embodiment, illustrating the layer structure of one light-emitting section 223. FIG. 8 is a cross-sectional view showing an example of the relationship between the layer structure of the light-generating layer 250 constituting the light-emitting section 223 of the surface-emitting laser device 210 of FIG. 7 and the waveform of the laser light LW. In FIGS. 7 and 8, the same components as those in the surface-emitting laser device 110 according to the second embodiment are denoted by the same reference numerals. In the following, a description of the same components as those in the second embodiment will be omitted, and only components different from those in the second embodiment will be described.

[0079] (Current Confinement Layer) The surface-emitting laser device 210 of the third embodiment includes two current confinement layers 71 and 72. The first current confinement layer 71 is disposed between the first active layer 51 and the second electrode 22 (12A). More specifically, the first current confinement layer 71 is disposed between the first active layer 51 and the second light reflecting layer 34.

[0080] The second current confinement layer 72 can be disposed between the second active layer 52 and the second electrode 22 (12A). More specifically, the second current confinement layer 72 can be disposed between the second active layer 52 and the first active layer 51. In the surface-emitting laser device 210 shown in Fig. 7, the second current confinement layer 72 is disposed between the second active layer 52 and the tunnel junction layer 67. That is, in the surface-emitting laser device 210 of the third embodiment, the current confinement layers 71 and 72 are disposed on the second electrode 22 (12A) side of the active layers 51 and 52, respectively.

[0081] The second current confinement layer 72 is disposed between the second cladding layer 64 and the tunnel junction layer 67, which sandwich the second active layer 52. An adjustment layer 64A is interposed between the second current confinement layer 72 and the tunnel junction layer 67. The adjustment layer 64A adjusts the positions of the second current confinement layer 72 and the tunnel junction layer 67. In one example, the adjustment layer 64A may have the same composition as the second cladding layer 64.

[0082] The second current confinement layer 72 includes a second current passing portion 72A and a second current confinement portion 72B. The second current passing portion 72A may be formed of a material containing Al. The second current passing portion 72A may be formed of, for example, AlAs (Al ｘ Ga （１－ｘ） The second current passing portion 72A is made of a material containing As and Al (composition x is 0.95 or more and 1.00 or less). The second current passing portion 72A may contain impurities of the second conductivity type. The second current passing portion 72A is provided in the inner portion of each light emitting portion 123. For example, in a plan view, the second current passing portion 72A is disposed in the center of each light emitting portion 123. For example, the second current passing portion 72A is formed in a circular shape in a plan view.

[0083] The second current confinement portion 72B has insulating properties. The second current confinement portion 72B is made of an oxide layer. The second current confinement portion 72B includes an oxide layer containing Al. The oxide layer containing Al is, for example, Al ２ O ３ The oxide layer may contain Ga or As. The second current confinement portion 72B is disposed on the side of each light-emitting portion 123 relative to the second current passing portion 72A. For example, in a plan view, the second current confinement portion 72B is formed in a ring shape (e.g., annular) surrounding the second current passing portion 72A. For example, the second current confinement portion 72B is formed by oxidizing the periphery of a layer containing AlAs. The film thickness (physical thickness) of the second current confinement layer 72 can be, for example, 15 nm or more and 100 nm or less.

[0084] The second current confinement layer 72 includes a second opening 72C formed by an annular second current confinement portion 72B. The second opening 72C is formed in an arc shape, with the center of the second current confinement portion 72B in the thickness direction Z expanding toward the second current passing portion 72A. This second current confinement portion 72B confines the current flowing between the first electrode 21 and the second electrode 22 in each light-emitting portion 123. The current flowing between the first electrode 21 and the second electrode 22 passes through the second current passing portion 72A inside the second opening 72C. The region of the second active layer 52 facing this second current passing portion 72A is the light-emitting region. The second current confinement layer 72 increases the current density in the second active layer 52, thereby improving the luminous efficiency of light generated in the second active layer 52.

[0085] (Protective Layer) The surface-emitting laser device 210 of the third embodiment includes two protective layers 81 and 82. The protective layers 81 and 82 of the third embodiment correspond to first protective layers disposed between the active layers 51 and 52 and the current confinement layers 71 and 72.

[0086] The first protective layer 81 is disposed between the first active layer 51 and the first current confinement layer 71. The second protective layer 82 is disposed between the second active layer 52 and the second current confinement layer 72. The second protective layer 82 is disposed within the second cladding layer 64. The second protective layer 82 is disposed closer to the second current confinement layer 72 than the second active layer 52. The distance L22 (see FIG. 8 ) between the second active layer 52 and the second protective layer 82 may be, for example, 150 nm or less. The thickness of the second protective layer 82 may be, for example, 5 nm or more and 100 nm or less. In one example, the thickness of the second protective layer 82 is 30 nm.

[0087] The second protective layer 82 is made of a material containing InGaP. The second protective layer 82 is configured so that the band gap energy of the second protective layer 82 is equal to the band gap energy of the second cladding layer 64 around the second protective layer 82. The second protective layer 82 is made of InGaP having an In composition β2. β２ Ga （１－β２） The second protective layer 82 may contain impurities of the second conductivity type. The impurity concentration in the second protective layer 82 may be equal to the impurity concentration in the second cladding layer 64. For example, when the Al composition γ of the second cladding layer 64 is set to 0.30 or more and 0.70 or less, the In composition β2 may be 0.48 or more and 0.60 or less. The second protective layer 82 may contain impurities of the second conductivity type. The impurity concentration in the second protective layer 82 may be equal to the impurity concentration in the second cladding layer 64.

[0088] (Position of Each Layer in the Light-Generating Layer) The waveform of the laser light LW shown in Fig. 8 indicates the electric field intensity. Note that the waveform of the laser light LW in Fig. 8 is shown as a constant length for the wavelength λ.

[0089] The light generating layer 233 includes a second active layer 52 and a first active layer 51. The optical distance L01 between the second active layer 52 and the first active layer 51 is preferably λ×k1 / 2 (k1 is a natural number). In the surface-emitting laser device 210 of the third embodiment, the optical distance L01 between the second active layer 52 and the first active layer 51 is λ. The second active layer 52 and the first active layer 51 are located at antinode positions of the laser light LW.

[0090] The first current confinement layer 71 is disposed at a position with respect to the laser light LW that is different from the position of the antinode of the laser light LW. The first current confinement layer 71 is preferably disposed at a position optically separated from the active layers 51, 52 by λ×(2×k3−1) / 4 (k3 is a natural number). In the surface-emitting laser device 210 of the third embodiment, the optical distance L11 between the first current confinement layer 71 and the first active layer 51 closest to the second optical reflecting layer 34 is λ / 4. If the difference between the position of the current confinement layer 71 and the position optically separated from the active layers 51, 52 by λ×(2×k3−1) / 4 (k3 is a natural number) is, for example, λ / 8 or less, then the current confinement layer 71 can be said to be disposed at a position optically separated from the active layers 51, 52 by λ×(2×k3−1) / 4 (k3 is a natural number), and can be said to be located at a node position.

[0091] The second current confinement layer 72 is disposed at a position with respect to the laser light LW that is different from the position of the antinode of the laser light LW. The second current confinement layer 72 is preferably disposed at a position optically separated from the active layers 51, 52 by λ×(2×k3−1) / 4 (k3 is a natural number). In the surface-emitting laser device 210 of the third embodiment, the optical distance L12 between the second current confinement layer 72 and the second active layer 52 closest to the first optical reflecting layer 32 is λ / 4. If the difference between the position of the current confinement layer 72 and the position optically separated from the active layers 51, 52 by λ×(2×k3−1) / 4 (k3 is a natural number) is, for example, λ / 8 or less, then the current confinement layer 72 can be said to be disposed at a position optically separated from the active layers 51, 52 by λ×(2×k3−1) / 4 (k3 is a natural number), and can be said to be located at a node position.

[0092] In the surface-emitting laser device 210 of the third embodiment, the optical distance L31 between the tunnel junction layer 67 and the first active layer 51 is λ / 4. On the other hand, the optical distance L32 between the tunnel junction layer 67 and the second active layer 52 is λ×3 / 4.

[0093] (Effects) The surface-emitting laser device 210 of the third embodiment has the following effects: (3-1) The surface-emitting laser device 210 of the third embodiment has the same effects as the surface-emitting laser device 110 of the second embodiment.

[0094] (3-2) In the surface-emitting laser device 210, the light-generating layer 250 of the light-emitting section 223 includes current confinement layers 71 and 72 arranged on the second electrode 22 (12A) side of the active layers 51 and 52, respectively. The first current confinement layer 71 includes a first current passing portion 71A and a first current confinement portion 71B. The region of the first active layer 51 facing the first current passing portion 71A is the light-emitting region. The second current confinement layer 72 includes a second current passing portion 72A and a second current confinement portion 72B. The region of the second active layer 52 facing the second current passing portion 72A is the light-emitting region. In this way, the current confinement layers 71 and 72 arranged for the active layers 51 and 52 can increase the current density in the active layers 51 and 52, thereby improving the light-emitting efficiency of the active layers 51 and 52.

[0095] (3-3) The light-emitting section 223 of the surface-emitting laser device 210 includes a first protective layer 81 disposed between the first active layer 51 and the first current confinement layer 71, and a second protective layer 82 disposed between the second active layer 52 and the second current confinement layer 72. The first current confinement layer 71 includes a first current confinement portion 71B formed of an oxide layer. The first protective layer 81 relieves stress caused by the first current confinement portion 71B. The first protective layer 81 can protect the first active layer 51.

[0096] The second current confinement layer 72 includes a second current confinement portion 72B formed of an oxide layer. The second protective layer 82 relieves stress caused by the second current confinement portion 72B. The second protective layer 82 can protect the second active layer 52.

[0097] (Fourth Embodiment) (Layer Structure of Surface-Emitting Laser Device) Fig. 9 is a schematic cross-sectional view showing the layer structure of an exemplary surface-emitting laser device 310 according to a fourth embodiment, illustrating the layer structure of one light-emitting section 323. Fig. 10 is a cross-sectional view showing an example of the relationship between the layer structure of the light-generating layer 333 constituting the light-emitting section 323 of the surface-emitting laser device 310 of Fig. 9 and the waveform of the laser light LW. In Figs. 9 and 10, the same components as those in the surface-emitting laser device 210 according to the third embodiment are denoted by the same reference numerals. Below, a description of the same components as those in the third embodiment will be omitted, and only components different from those in the third embodiment will be described.

[0098] The surface-emitting laser device 310 of the fourth embodiment further includes two protective layers 83 and 84. The protective layers 83 and 84 of the fourth embodiment correspond to third protective layers arranged on the opposite side of the active layers 51 and 52 from the protective layers 81 and 82.

[0099] The third protective layer 83 is disposed on the opposite side of the first active layer 51 from the first protective layer 81. The third protective layer 83 is disposed between the first active layer 51 and the tunnel junction layer 67. The third protective layer 83 is disposed within the first cladding layer 61. That is, the first active layer 51 of the fourth embodiment is sandwiched between the first protective layer 81 and the third protective layer 83 in the thickness direction Z. The distance L23 between the first active layer 51 and the third protective layer 83 may be, for example, 150 nm or less. The thickness of the third protective layer 83 may be, for example, 5 nm or more and 100 nm or less. In one example, the thickness of the third protective layer 83 is 30 nm.

[0100] The third protective layer 83 is made of a material containing InGaP. The third protective layer 83 is configured so that the band gap energy of the third protective layer 83 is equal to the band gap energy of the first cladding layer 61 around the third protective layer 83. The third protective layer 83 is made of InGaP having an In composition β3. β３ Ga （１－β３） The third protective layer 83 may contain P. For example, when the Al composition γ of the first cladding layer 61 is set to be 0.30 or more and 0.70 or less, the In composition β3 may be 0.48 or more and 0.60 or less. The third protective layer 83 may contain an impurity of the first conductivity type. The impurity concentration in the third protective layer 83 may be equal to the impurity concentration in the first cladding layer 61.

[0101] The fourth protective layer 84 is disposed on the opposite side of the second active layer 52 from the second protective layer 82. The fourth protective layer 84 is disposed between the second active layer 52 and the first optical reflecting layer 32. The fourth protective layer 84 is disposed within the first cladding layer 63. That is, the second active layer 52 of the fourth embodiment is sandwiched between the second protective layer 82 and the fourth protective layer 84 in the thickness direction Z. The distance L24 between the second active layer 52 and the fourth protective layer 84 may be, for example, 150 nm or less. The thickness of the fourth protective layer 84 may be, for example, 5 nm or more and 100 nm or less. In one example, the thickness of the fourth protective layer 84 is 30 nm.

[0102] The fourth protective layer 84 is made of a material containing InGaP. The fourth protective layer 84 is configured so that the band gap energy of the fourth protective layer 84 is equal to the band gap energy of the first cladding layer 63 around the fourth protective layer 84. The fourth protective layer 84 is made of InGaP having an In composition β4. β４ Ga （１－β４） The fourth protective layer 84 may contain P. For example, when the Al composition γ of the first cladding layer 63 is set to be 0.30 or more and 0.70 or less, the In composition β4 may be 0.48 or more and 0.60 or less. The fourth protective layer 84 may contain an impurity of the first conductivity type. The impurity concentration in the fourth protective layer 84 may be equal to the impurity concentration in the first cladding layer 63.

[0103] (Effects) The surface-emitting laser device 310 of the fourth embodiment has the following effects: (4-1) The surface-emitting laser device 310 of the fourth embodiment has the same effects as the surface-emitting laser device 210 of the third embodiment.

[0104] (4-2) The surface-emitting laser device 310 includes a third protective layer 83 and a fourth protective layer 84. The third protective layer 83 is disposed on the opposite side of the first active layer 51 from the first protective layer 81. The first active layer 51 is sandwiched between the first protective layer 81 and the third protective layer 83 in the thickness direction Z. This protects the first active layer 51 from stress on the side of the first current confinement layer 71 and stress on the side of the tunnel junction layer 67. Therefore, the first protective layer 81 and the third protective layer 83 can further protect the first active layer 51.

[0105] The fourth protective layer 84 is disposed on the opposite side of the second active layer 52 from the second protective layer 82. The second active layer 52 is sandwiched between the second protective layer 82 and the fourth protective layer 84 in the thickness direction Z. Therefore, the second active layer 52 is protected from stress on the side of the second current confinement layer 72 and stress on the side of the first light reflecting layer 32. Therefore, the second active layer 52 can be further protected by the second protective layer 82 and the fourth protective layer 84.

[0106] Fifth Embodiment (Layer Structure of Surface-Emitting Laser Device) Fig. 11 is a schematic cross-sectional view showing the layer structure of an illustrative surface-emitting laser device 410 according to a fifth embodiment, illustrating the layer structure of one light-emitting section 423. Fig. 12 is a cross-sectional view showing an example of the relationship between the layer structure of the light-generating layer 433 constituting the light-emitting section 423 of the surface-emitting laser device 410 of Fig. 11 and the waveform of the laser light LW. In Figs. 11 and 12, the same components as those in the surface-emitting laser device 310 according to the fourth embodiment are denoted by the same reference numerals. In the following, a description of the same components as those in the fourth embodiment will be omitted, and only components different from those in the fourth embodiment will be described.

[0107] The surface-emitting laser device 410 of the fifth embodiment differs from the surface-emitting laser device 310 of the fourth embodiment in the positions of the two protective layers 83 and 84. The protective layers 83 and 84 of the fifth embodiment correspond to second protective layers that are arranged on the opposite side of the protective layers 81 and 82 with respect to the current confinement layers 71 and 72.

[0108] The third protective layer 83 is disposed on the opposite side of the first current confinement layer 71 from the first protective layer 81. The third protective layer 83 is disposed between the first current confinement layer 71 and the second light reflecting layer 34. The third protective layer 83 is disposed within the adjustment layer 62A. That is, the first current confinement layer 71 of the fourth embodiment is sandwiched between the first protective layer 81 and the third protective layer 83 in the thickness direction Z. The distance between the first current confinement layer 71 and the third protective layer 83 may be equal to the distance between the first current confinement layer 71 and the first protective layer 81. Note that the distance between the first current confinement layer 71 and the third protective layer 83 and the distance between the first current confinement layer 71 and the first protective layer 81 may be different from each other. The third protective layer 83 of the fifth embodiment may contain impurities of the second conductivity type. The impurity concentration in the third protective layer 83 may be equal to the impurity concentration in the adjustment layer 62A.

[0109] The fourth protective layer 84 is disposed on the opposite side of the second current confinement layer 72 from the second protective layer 82. The fourth protective layer 84 is disposed between the second current confinement layer 72 and the tunnel junction layer 67. The fourth protective layer 84 is disposed within the adjustment layer 64A. That is, the second current confinement layer 72 of the fourth embodiment is sandwiched between the second protective layer 82 and the fourth protective layer 84 in the thickness direction Z. The distance between the second current confinement layer 72 and the fourth protective layer 84 may be equal to the distance between the second current confinement layer 72 and the third protective layer 83. Note that the distance between the second current confinement layer 72 and the fourth protective layer 84 and the distance between the second current confinement layer 72 and the third protective layer 83 may be different from each other. The fourth protective layer 84 of the fifth embodiment may contain impurities of the second conductivity type. The impurity concentration in the fourth protective layer 84 may be equal to the impurity concentration in the adjustment layer 64A.

[0110] (Effects) The surface-emitting laser device 410 of the fifth embodiment has the following effects: (5-1) The surface-emitting laser device 410 of the fifth embodiment has the same effects as the surface-emitting laser device 210 of the third embodiment.

[0111] (5-2) The surface-emitting laser device 310 includes a third protective layer 83 and a fourth protective layer 84. The third protective layer 83 is disposed on the opposite side of the first current confinement layer 71 from the first protective layer 81. The first current confinement layer 71 is sandwiched between the first protective layer 81 and the third protective layer 83 in the thickness direction Z. The first protective layer 81 and the third protective layer 83 relieve stress caused by the first current confinement layer 71. This reduces the effect of stress from the first current confinement layer 71 in the thickness direction Z of the light-emitting section 523.

[0112] The fourth protective layer 84 is disposed on the opposite side of the second current confinement layer 72 from the second protective layer 82. The second current confinement layer 72 is sandwiched between the second protective layer 82 and the fourth protective layer 84 in the thickness direction Z. The second protective layer 82 and the fourth protective layer 84 relieve stress caused by the second current confinement layer 72. This reduces the effect of stress from the second current confinement layer 72 in the thickness direction Z of the light emitting section 523.

[0113] Sixth Embodiment (Layer Structure of Surface-Emitting Laser Device) FIG. 13 is a schematic cross-sectional view showing the layer structure of an illustrative surface-emitting laser device 510 according to a sixth embodiment, illustrating the layer structure of one light-emitting section 523. FIG. 14 is a cross-sectional view showing an example of the relationship between the layer structure of the light-generating layer 533 constituting the light-emitting section 523 of the surface-emitting laser device 510 of FIG. 13 and the waveform of the laser light LW. In FIGS. 13 and 14 , the same components as those in the surface-emitting laser device 210 according to the third embodiment are denoted by the same reference numerals. In the following, a description of the same components as those in the third embodiment will be omitted, and only components different from those in the third embodiment will be described.

[0114] The surface-emitting laser device 510 of the sixth embodiment differs from the surface-emitting laser device 210 of the third embodiment in the positions of the second current confinement layer 72 and the second protective layer 82. The second current confinement layer 72 is disposed between the second active layer 52 and the first optical reflection layer 32. In the sixth embodiment, the second current confinement layer 72 is disposed between the first cladding layer 63 and the first optical reflection layer 32, sandwiching the second active layer 52 therebetween. An adjustment layer 63A is interposed between the second current confinement layer 72 and the first optical reflection layer 32. The adjustment layer 63A adjusts the position of the second current confinement layer 72. In one example, the adjustment layer 63A may have the same composition as the first cladding layer 63.

[0115] The second protective layer 82 is disposed between the second active layer 52 and the second current confinement layer 72. In the sixth embodiment, the second protective layer 82 is disposed in the first cladding layer 63 between the second active layer 52 and the first light reflecting layer 32. The second protective layer 82 may contain impurities of the first conductivity type. The impurity concentration in the second protective layer 82 may be equal to the impurity concentration in the first cladding layer 63.

[0116] (Effects) The surface-emitting laser device 510 of the sixth embodiment has the following effects: (6-1) The surface-emitting laser device 510 of the sixth embodiment has the same effects as the surface-emitting laser device 210 of the third embodiment.

[0117] (Modifications) The above embodiment can be modified, for example, as follows. The above embodiment and each of the following modifications can be combined with each other as long as no technical contradiction occurs. In the following modifications, parts that are common to the above embodiment will be assigned the same reference numerals as in the above embodiment, and their description will be omitted.

[0118] The second conductivity type impurity may be changed as appropriate. For example, a material containing Zn, Mg, or the like may be used as the second conductivity type impurity. The number of active layers included in the light generating layer 133 may be three or more. In this case, the tunnel junction layer 67 is disposed between two adjacent active layers in the thickness direction Z and between the adjacent second cladding layer and first cladding layer.

[0119] The number of light-emitting portions 123 may be any number equal to or greater than 1. The shape of the second electrode 22 shown in Fig. 1 may be changed as appropriate depending on the number, arrangement, etc. of the light-emitting portions 123.

[0120] The positions of the active layer and other layers included in the light generating layer may be changed as appropriate. For example, in the surface-emitting laser device 110 according to the second embodiment shown in FIGS. 5 and 6, the optical distance between the tunnel junction layer 67 and the second active layer 52 may be set to λ / 4.

[0121] The term "on" as used in this disclosure includes both the meanings of "on" and "above," unless the context clearly indicates otherwise. Thus, the phrase "a first layer is formed on a second layer" is intended to mean that in some embodiments, the first layer may be disposed directly on the second layer in contact with the second layer, while in other embodiments, the first layer may be disposed above the second layer without contacting the second layer. In other words, the term "on" does not exclude a structure in which another layer is formed between the first and second layers.

[0122] The Z-axis direction used in this disclosure does not necessarily have to be the vertical direction, nor does it have to completely coincide with the vertical direction. Therefore, various structures according to this disclosure (for example, the structure shown in FIG. 1 ) are not limited to the "up" and "down" in the Z-axis direction described herein being "up" and "down" in the vertical direction. For example, the X-axis direction may be the vertical direction, or the Y-axis direction may be the vertical direction.

[0123] (Supplementary Notes) The technical ideas that can be understood from the present disclosure are described below. Note that, for the purpose of aiding understanding and not intending to be limiting, the components described in the Supplementary Notes are given the reference symbols of the corresponding components in the embodiments. The reference symbols are shown as examples to aid understanding, and the components described in each Supplementary Note should not be limited to the components indicated by the reference symbols.

[0124] (Supplementary Note 1) A semiconductor substrate (31) including a substrate upper surface (31S) and a substrate lower surface (31R), a first electrode (21) provided on the substrate lower surface (31R), a first light-reflecting layer (32) of a first conductivity type (n-type) provided on the substrate upper surface (31S), a light-generating layer (33) provided on the first light-reflecting layer (32), a second light-reflecting layer (34) of a second conductivity type (p-type) provided on the light-generating layer (33), a second electrode (22) provided on the second light-reflecting layer (34), and current-confining layers (71, 72) disposed between the first electrode (21) and the second electrode (22), the current-confining layers including current-confining portions (71B, 72B) formed of oxide layers, wherein the light-generating layer (33) includes active layers (51, 52), a first protection layer (81, 82) disposed between the active layer (51, 52) and the current confinement layer (71, 72) to protect the active layer (51, 52).

[0125] (Supplementary Note 2) The surface-emitting laser device according to Supplementary Note 1, wherein the first protective layer (81, 82) is disposed within the cladding layer (62, 64).

[0126] (Supplementary Note 3) The surface-emitting laser device according to Supplementary Note 1 or Supplementary Note 2, wherein the first protective layers (81, 82) are arranged closer to the current confinement layers (71, 72) than the active layers (51, 52).

[0127] (Supplementary Note 4) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the first protective layers (81, 82) are spaced from the active layers (51, 52) by 150 nm or less.

[0128] (Supplementary Note 5) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 4, wherein the thickness of the first protective layer (81, 82) is greater than the thickness of the current confinement layer (71, 72).

[0129] (Note 6) The cladding layers (61 to 64) are Al having an Al composition γ. γ Ga （１－γ）The first protective layer (81) contains In having an In composition β1. β１ Ga （１－β１） The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 5, further comprising: P; the Al composition γ is 0.30 or more and 0.70 or less; and the In composition β1 is 0.48 or more and 0.60 or less.

[0130] (Supplementary Note 7) The surface-emitting laser device according to any one of Supplementary Notes 1 to 6, wherein the first protective layer (81, 82) has a thickness of 5 nm to 100 nm.

[0131] (Supplementary Note 8) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 7, wherein the first protective layers (81, 82) have the same band gap as the cladding layers (62, 64).

[0132] (Supplementary Note 9) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 8, wherein the active layer (51, 52) is one of a plurality of active layers (51, 52), the light generation layer (33) includes the plurality of active layers (51, 52), the current confinement layer (71, 72) is disposed on the second light reflective layer (34) side of each of the plurality of active layers (51, 52), and the first protective layer (81, 82) is disposed between each of the plurality of active layers (51, 52) and the plurality of current confinement layers (71, 72).

[0133] (Supplementary Note 10) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 9, further comprising second protective layers (83, 84) disposed on the opposite side of the active layer (51, 52) to the first protective layers (81, 82).

[0134] (Supplementary Note 11) The surface-emitting laser device according to Supplementary Note 10, wherein the second protective layers (83, 84) are spaced apart from the active layers (51, 52) by 150 nm or less.

[0135] (Supplementary Note 12) The surface-emitting laser device according to Supplementary Note 10 or Supplementary Note 11, wherein the second protective layers (83, 84) have a thickness greater than that of the current confinement layer (71).

[0136] (Note 13) The second protective layer (83, 84) is an In having an In composition β2. β２ Ga （１－β２） 13. The surface-emitting laser device according to claim 10, further comprising P, wherein the In composition β2 is 0.48 or more and 0.60 or less.

[0137] (Supplementary Note 14) The surface-emitting laser device according to any one of Supplementary Note 10 to Supplementary Note 13, wherein the second protective layer (83, 84) has a thickness of 5 nm to 100 nm.

[0138] (Supplementary Note 15) The surface-emitting laser device according to any one of Supplementary Note 10 to Supplementary Note 14, wherein the second protective layers (83, 84) have the same band gap as the cladding layers (61, 63).

[0139] (Supplementary Note 16) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 15, further comprising a third protective layer (83, 84) disposed on the opposite side of the active layer (51, 52) to the first protective layer (81, 82).

[0140] (Supplementary Note 17) The surface-emitting laser device according to Supplementary Note 16, wherein the thickness of the third protective layer (83, 84) is greater than the thickness of the current confinement layer (71).

[0141] (Note 18) The third protective layer (83, 84) is an In having an In composition β3. β３ Ga （１－β３） 18. The surface-emitting laser device according to claim 16, further comprising P, wherein the In composition β3 is 0.48 or more and 0.60 or less.

[0142] (Supplementary Note 19) The surface-emitting laser device according to any one of Supplementary Note 16 to Supplementary Note 18, wherein the third protective layer (83, 84) has a thickness of 5 nm to 100 nm.

[0143] (Supplementary Note 20) The surface-emitting laser device according to any one of Supplementary Note 16 to Supplementary Note 19, wherein the third protective layers (83, 84) have the same band gap as the cladding layers (61 to 64).

[0144] (Supplementary Note 21) The surface-emitting laser device according to any one of Supplementary Note 1 to Supplementary Note 20, wherein the cladding layers (61 to 64) include a first cladding layer (61, 63) of a first conductivity type arranged on the first optical reflecting layer (32) side with respect to the active layer (51, 52), and a second cladding layer (62, 64) of a second conductivity type arranged on the second optical reflecting layer (34) side with respect to the active layer (51, 52), and a tunnel junction layer (67) arranged between the second cladding layer (64) and the first cladding layer (61) adjacent to each other in a direction from the first optical reflecting layer (32) to the second optical reflecting layer (34).

[0145] (Supplementary Note 22) A semiconductor substrate (31) including a substrate upper surface (31S) and a substrate lower surface (31R), a first electrode (n-type electrode) provided on the substrate lower surface (31R), a first light-reflecting layer (32) of a first conductivity type (n-type) provided on the substrate upper surface (31S), a light-generating layer (33) provided on the first light-reflecting layer (32), a second light-reflecting layer (34) of a second conductivity type (p-type) provided on the light-generating layer (33), a second electrode (22) (p-type electrode) provided on the second light-reflecting layer (34), and a current-confining layer (71) disposed between the first electrode (21) and the second electrode (22), the current-confining layer (71) including a current-confining portion (71B) formed of an oxide layer, the oxide layer including Al, and the light-generating layer (33) including: active layers (51, 52); a first protective layer (81) that is disposed between the active layer (51, 52) and the current confinement layer (71), the first protective layer (81) being made of a material containing InGaP and protecting the active layer (51, 52).

[0146] The above description is merely illustrative. Those skilled in the art will recognize that many more possible combinations and permutations are possible other than the components and methods (manufacturing processes) listed for the purpose of illustrating the technology of the present disclosure. The present disclosure is intended to embrace all alternatives, modifications, and variations that fall within the scope of the present disclosure, including the claims.

[0147] REFERENCE SIGNS LIST 10 Surface-emitting laser device 11 Element front surface 12 Element rear surface 13 Element side surface 14 Element side surface 15 Element side surface 16 Element side surface 21 First electrode 22 Second electrode 22A Electrode portion 22B Peripheral portion 22C External connection portion 23 Light-emitting portion 31 Semiconductor substrate 31R Substrate lower surface 31S Substrate upper surface 32 First light-reflecting layer 33 Light-generating layer 34 Second light-reflecting layer 50 Light-generating layer 51 Active layer, first active layer 52 Active layer, second active layer 61 Cladding layer, first cladding layer 62 Cladding layer, second cladding layer 63 Cladding layer, first cladding layer 64 Cladding layer, second cladding layer 67 Tunnel junction layer 67A First tunnel layer 67B Second tunnel layer 71 Current confinement layer, first current confinement layer 71A Current passing portion, first current passing portion 71B Current confinement portion, first current confinement portion 71C Opening 72 Second current confinement layer 72A Second current passing portion 72B Second current confinement portion 72C Second opening 81 First protective layer 82 Second protective layer 83 Third protective layer 84 Fourth protective layer 91 Insulating film 92 Covering portion 110 Surface-emitting laser device 123 Light-emitting portion 133 Light-generating layer 210 Surface-emitting laser device 223 Light-emitting portion 250 Light-generating layer 310 Surface-emitting laser device 323 Light-emitting portion 333 Light-generating layer 410 Surface-emitting laser device 423 Light-emitting portion 433 Light-generating layer 510 Surface-emitting laser device 523 Light-emitting portion 533 Light-generating layer λ Wavelength α1~α4 Al composition β1~β4 In composition γ Al composition L01 Optical distance L11, L12 Optical distance L21~L24 Distance L31, L32 Optical distance LW Laser light X First direction Y Second direction Z Thickness direction

Claims

1. a semiconductor substrate including an upper substrate surface and a lower substrate surface; a first electrode provided on a lower surface of the substrate; a first light-reflecting layer of a first conductivity type provided on an upper surface of the substrate; a light generating layer disposed on the first light reflecting layer; a second light reflective layer of a second conductivity type disposed on the light generating layer; a second electrode provided on the second light-reflecting layer; a current confinement layer disposed between the first electrode and the second electrode and including a current confinement portion formed of an oxide layer; Including, The photogenerating layer comprises: an active layer; cladding layers arranged to sandwich the active layer; Including, a first protective layer disposed between the active layer and the current confinement layer to protect the active layer; Surface-emitting laser device.

2. the first protective layer is disposed within the cladding layer; 2. The surface-emitting laser device according to claim 1.

3. the first protective layer is disposed closer to the current confinement layer than the active layer; 2. The surface-emitting laser device according to claim 1.

4. the first protective layer is located at a distance of 150 nm or less from the active layer; 2. The surface-emitting laser device according to claim 1.

5. The thickness of the first protective layer is greater than the thickness of the current confinement layer.

2. The surface-emitting laser device according to claim 1.

6. The cladding layer is an Al layer having an Al composition γ. γ Ga （１－γ） Contains As fruit, The first protective layer is an In layer having an In composition β1. β１ Ga （１－β１） Contains P, the Al composition γ is 0.30 or more and 0.70 or less, the In composition β1 is 0.48 or more and 0.60 or less; 2. The surface-emitting laser device according to claim 1.

7. The thickness of the first protective layer is 5 nm or more and 100 nm or less.

2. The surface-emitting laser device according to claim 1.

8. the first protective layer has the same bandgap as the cladding layer; 2. The surface-emitting laser device according to claim 1.

9. the active layer is one of a plurality of active layers; the light generating layer includes the plurality of active layers; the current confinement layer is disposed on the second light reflective layer side with respect to each of the plurality of active layers, the first protective layers are disposed between the active layers and the current confinement layers, respectively; 2. The surface-emitting laser device according to claim 1.

10. a second protective layer disposed on the opposite side of the current confinement layer from the first protective layer; 2. The surface-emitting laser device according to claim 1.

11. The thickness of the second protective layer is greater than the thickness of the current confinement layer. The surface-emitting laser device according to claim 10.

12. The second protective layer is an In layer having an In composition β2. β２ Ga （１－β２） Contains P, the In composition β2 is 0.48 or more and 0.60 or less; The surface-emitting laser device according to claim 10.

13. The thickness of the second protective layer is 5 nm or more and 100 nm or less. The surface-emitting laser device according to claim 10.

14. the second protective layer has the same bandgap as the cladding layer; The surface-emitting laser device according to claim 10.

15. a third protective layer disposed on the opposite side of the active layer from the second protective layer; The surface-emitting laser device according to claim 10.

16. the third protective layer is located at a distance of 150 nm or less from the active layer; 16. The surface-emitting laser device according to claim 15.

17. The thickness of the third protective layer is greater than the thickness of the current confinement layer.

16. The surface-emitting laser device according to claim 15.

18. The third protective layer is an In layer having an In composition β3. β３ Ga （１－β３） Contains P, the In composition β3 is 0.48 or more and 0.60 or less; 16. The surface-emitting laser device according to claim 15.

19. the cladding layer includes a first cladding layer of a first conductivity type arranged on the first light reflecting layer side of the active layer, and a second cladding layer of a second conductivity type arranged on the second light reflecting layer side of the active layer, a tunnel junction layer disposed between the second cladding layer and the first cladding layer adjacent to each other in a direction from the first light reflecting layer toward the second light reflecting layer; 19. The surface-emitting laser device according to claim 1.

20. a semiconductor substrate including an upper substrate surface and a lower substrate surface; a first electrode provided on a lower surface of the substrate; a first light-reflecting layer of a first conductivity type provided on an upper surface of the substrate; a light generating layer disposed on the first light reflecting layer; a second light reflective layer of a second conductivity type disposed on the light generating layer; a second electrode provided on the second light-reflecting layer; a current confinement layer disposed between the first electrode and the second electrode and including a current confinement portion formed of an oxide layer; Including, the oxide layer contains Al; The photogenerating layer comprises: an active layer; cladding layers arranged to sandwich the active layer; Including, a first protective layer disposed between the active layer and the current confinement layer, the first protective layer being made of a material containing InGaP and protecting the active layer; Surface-emitting laser device.