JP2018125404A - Surface emitting laser element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase light emission efficiency in a surface emitting laser element in which a nitride semiconductor is used for an active layer.SOLUTION: A surface emitting laser element in which a nitride semiconductor is used for an active layer has: a laminate including a lower Bragg reflector, the active layer and an upper Bragg reflector; and a tunnel junction structure provided between the active layer and the upper Bragg reflector. The tunnel junction structure includes a first nitride compound semiconductor layer doped with a p-type dopant at 5×10atoms/cmor more, a non-doped second nitride compound semiconductor layer, and a third nitride compound semiconductor layer doped with an n-type dopant at 5×10atoms/cmor more and having a band gap larger than that of the first nitride compound semiconductor layer, which are laminated from a side closer to the active layer in turn. Further, the surface emitting laser element has a current constriction structure between the active layer and the tunnel junction structure.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a surface emitting laser element.

  A surface emitting laser element (VCSEL: Vertical Cavity Surface Emitting LASER) forms a resonator structure by arranging reflectors above and below a semiconductor layer including an active layer that generates light, and has a predetermined wavelength of laser oscillation. It is a laser element that extracts light in a direction perpendicular to the substrate.

  In recent years, nitride semiconductor light emitting devices have been widely used as semiconductor light emitting devices, and surface emitting laser devices using nitride semiconductors have been developed. When growing p-type GaN on a gallium nitride (GaN) single crystal substrate or sapphire substrate using MOCVD, it is common to dope mainly with Mg as an acceptor.

  At this time, as the source gas, a gas containing hydrogen such as ammonia is often used. The source gas containing hydrogen is decomposed during the growth, and the hydrogen generated at that time inactivates Mg, resulting in high resistance of p-type GaN. Also, even if hydrogen is removed by thermal annealing to activate Mg, the resistivity of p-type GaN is extremely higher than that of a p-type compound semiconductor such as GaAs.

  A surface emitting laser element generally has a current confinement structure in which a current injection region is constricted by some method to improve efficiency. In a GaAs surface emitting laser element, a resonator structure using a DBR (Bragg reflector) structure made of an AlGaAs compound semiconductor is used. By appropriately doping the DBR and using it as a current path, It has succeeded in minimizing the effect of increasing the resistance of the entire device.

  However, in a surface emitting laser element using a nitride semiconductor as an active layer, a current-carrying DBR having an appropriate resistance cannot be realized at present. Also, an oxide confinement structure on the p side, which is a current confinement structure effective in a GaAs surface emitting laser element, has not been realized.

  In a surface emitting laser element using a nitride semiconductor, for example, a semiconductor DBR made of AlInN / GaN is used for the lower DBR, but this semiconductor DBR is not energized. The n-side electrode is taken out from the lateral direction using an n-GaN cavity layer provided between the semiconductor DBR and the active layer.

  In the current confinement, a part of the p-GaN cavity between the active layer and the upper DBR is passivated with a dielectric other than the energized part and joined to the ITO film via the energized part. The upper DBR is formed on the ITO film.

  The upper DBR is a dielectric DBR, which also has a structure that does not carry electricity. Current injection on the p side uses a current injection structure from the lateral direction through the ITO film. As described above, the current injection structure on the p side has a current injection structure from the lateral direction because a current-carrying DBR is not realized, and since p-GaN has a high resistance, a method of using an ITO film as a current path is currently mainstream. (For example, see Non-Patent Document 1).

  However, the ITO film absorbs a small amount of light from near ultraviolet light to blue light used in nitride semiconductor lasers. This is absorption that cannot be ignored as a laser device, and has been a factor of lowering light emission efficiency in the nitride surface emitting laser element.

  The present invention has been made in view of the above, and an object thereof is to improve the light emission efficiency in a surface emitting laser element using a nitride semiconductor as an active layer.

The surface-emitting laser element is a surface-emitting laser element using a nitride semiconductor as an active layer, and includes a laminated body including a lower Bragg reflector, an active layer, and an upper Bragg reflector, the active layer and the A tunnel junction structure is provided between the upper Bragg reflector and the tunnel junction structure is doped with p-type doping of 5 × 10 ¹⁹ atoms / cm ³ or more, which are sequentially stacked from the side close to the active layer. The first nitride compound semiconductor layer, the undoped second nitride compound semiconductor layer, and n-type doping of 5 × 10 ¹⁹ atoms / cm ³ or more are made, and the band gap of the first nitride compound semiconductor layer A third nitride compound semiconductor layer having a larger band gap, and having a current confinement structure between the active layer and the tunnel junction structure .

  According to the disclosed technique, the emission efficiency can be improved in a surface emitting laser element using a nitride semiconductor as an active layer.

It is a figure explaining the tunnel junction structure concerning this Embodiment. It is sectional drawing which illustrates the surface emitting laser element which concerns on 1st Embodiment. FIG. 6 is a diagram (part 1) illustrating a manufacturing process of the surface emitting laser element according to the first embodiment; FIG. 6 is a diagram (part 2) illustrating a manufacturing process of the surface emitting laser element according to the first embodiment; It is sectional drawing which illustrates the surface emitting laser element which concerns on the modification 1 of 1st Embodiment. It is sectional drawing which illustrates the surface emitting laser element which concerns on the modification 2 of 1st Embodiment. It is a figure which illustrates the manufacturing process of the surface emitting laser element which concerns on the modification 2 of 1st Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

(Tunnel junction structure)
FIG. 1 is a diagram for explaining a tunnel junction structure according to the present embodiment. The normal tunnel structure has a characteristic that the depletion layer becomes thin due to the contact between the highly doped p layer and the highly doped n layer, and a tunnel current flows through the thinned depletion layer.

  On the other hand, as shown in FIG. 1A, the tunnel junction structure 120 according to the present embodiment is thinner than the highly doped p-type nitride compound semiconductor layer 108 (first nitride compound semiconductor layer). It has a stacked structure of an undoped layer 109 (second nitride compound semiconductor layer) and a highly doped n-type nitride compound semiconductor layer 110 (third nitride compound semiconductor layer). That is, in tunnel junction structure 120 according to the present embodiment, undoped layer 109 is provided between p-type nitride compound semiconductor layer 108 and n-type nitride compound semiconductor layer 110.

  As the p-type nitride compound semiconductor layer 108, for example, p-GaN can be used. As the undoped layer 109, for example, GaN can be used. As the n-type nitride compound semiconductor layer 110, for example, n-AlGaN can be used.

  FIG. 1B simply shows a band diagram of the tunnel junction structure. In the tunnel junction structure 120, when the above materials are used, n-AlGaN constituting the n-type nitride compound semiconductor layer 110 on the c-plane which is a polar surface of the GaN-based material, and a band gap of n-AlGaN. When the small undoped layer 109 of GaN is adjacent, a band bending due to piezoelectric polarization occurs at the interface, and a two-dimensional electron gas G is generated as shown in FIG.

  Since the two-dimensional electron gas G can move in the undoped layer 109 with almost no resistance, a current can flow with a very low resistance in the lateral direction. Here, when the undoped layer 109 is relatively thin (for example, about 10 to 20 nm) and the highly doped p-type nitride compound semiconductor layer 108 is provided below the undoped layer 109, the depletion layer is more than a normal tunnel junction. Becomes wider. Therefore, although the resistance against the tunnel current is higher than the structure without the undoped layer 109, a structure having the two-dimensional electron gas G in the tunnel junction can be obtained.

Here, the high doping means that the p-type nitride compound semiconductor layer or the n-type nitride compound semiconductor layer is doped with 5 × 10 ¹⁹ atoms / cm ³ or more. The reason why the p-type nitride compound semiconductor layer or the n-type nitride compound semiconductor layer requires doping of 5 × 10 ¹⁹ atoms / cm ³ or more is that a depletion layer is sufficient to form a tunnel junction and flow a tunnel current. This is because it must be made thinner. When the doping is less than 5 × 10 ¹⁹ atoms / cm ³ , the depletion layer becomes wide, so that a sufficient tunnel current does not flow.

  In the tunnel junction structure 120, a current can flow perpendicularly to the c-plane by a tunnel current, and at the same time, a current flows with low resistance while using a semiconductor layer in the horizontal direction, so that the resistance of the element can be reduced in total. Further, by applying the tunnel junction structure 120 to a surface emitting laser element, a surface emitting laser element using a nitride semiconductor as an active layer without using an absorbing material such as ITO can be realized.

  That is, it is possible to reduce the resistance of lateral current injection in a surface emitting laser element using a nitride semiconductor as an active layer, and to reduce absorption by ITO or the like. It is possible to further improve the luminous efficiency.

  Hereinafter, specific embodiments of the surface emitting laser element including the tunnel junction structure 120 will be described.

<First Embodiment>
(Outline of surface emitting laser element)
FIG. 2 is a cross-sectional view illustrating the surface emitting laser element according to the first embodiment. As shown in FIG. 2, the surface emitting laser element 10 has a mesa 150 having a columnar structure. The shape of the mesa 150 viewed from the top of the surface emitting laser element 10 may be a circle, an ellipse, a square, a rectangle, or the like. In the surface emitting laser element 10, laser light is emitted on the side opposite to the substrate 101 (in the direction of arrow L in FIG. 1). The oscillation wavelength λ of the surface emitting laser element 10 can be, for example, a wavelength band from near ultraviolet light to blue.

  In the surface emitting laser element 10, a semiconductor Bragg reflector 102 (hereinafter referred to as a semiconductor DBR 102) that is a lower Bragg reflector is formed on a substrate 101. DBR is an abbreviation for Distributed Bragg Reflector.

  As the substrate 101, for example, a GaN substrate can be used. The semiconductor DBR 102 has a structure made of, for example, AlInN / GaN, and is designed to have a film thickness that matches the oscillation wavelength of an active layer 105 described later.

  A lower cavity 103 is formed on the semiconductor DBR 102. The lower cavity 103 can be formed from, for example, n-GaN. A first n-side electrode 104 is formed on the outer edge of the lower cavity 103 exposed at the periphery of the mesa 150.

  An active layer 105 using a nitride semiconductor is formed on the lower cavity 103. As the active layer 105, for example, an InGaN / GaN multiple quantum well structure can be used. InGaN is suitable as an active layer of a blue laser, and the wavelength can be adjusted to some extent by adjusting the composition.

  An upper cavity 106 is formed on the active layer 105. The upper cavity 106 can be formed of, for example, p-GaN. A current confinement layer 113 is formed in the upper peripheral portion of the upper cavity 106. The current confinement layer 113 is a high resistance region, and the inside of the current confinement layer 113 is a low resistance region.

  A carrier block layer 107 is formed on the current confinement layer 113 and on the upper cavity 106 located inside the current confinement layer 113. As the carrier block layer 107, for example, a superlattice structure of AlN / GaN or the like can be used. The carrier block layer 107 has a function of suppressing carrier overflow from the active layer 105 and increasing the recombination probability in the active layer 105.

  A tunnel junction structure 120 through which a tunnel current can flow is formed on the carrier block layer 107. The tunnel junction structure 120 includes a p-type nitride compound semiconductor layer 108, an undoped layer 109, and an n-type nitride compound semiconductor layer 110, which are sequentially stacked from the side close to the active layer 105.

The p-type nitride compound semiconductor layer 108 can be formed of, for example, p-GaN doped with Mg at a high concentration. The doping amount of Mg is preferably 5 × 10 ¹⁹ atoms / cm ³ or more, for example, 1 × 10 ²⁰ atoms / cm ³ .

  The undoped layer 109 can be formed from, for example, GaN. The thickness of the undoped layer 109 can be, for example, about 10 nm. If the undoped layer 109 is too thin, it is difficult to form a two-dimensional electron gas. Therefore, the thickness of the undoped layer 109 needs to be 5 nm or more, and preferably 10 nm or more. That the thickness of the undoped layer 109 is required to be 5 nm or more can be estimated from a simple band calculation.

  However, if the undoped layer 109 is made too thick, the depletion layer becomes thick and the resistance becomes high. Therefore, it is not desirable to unnecessarily increase the thickness of the undoped layer 109. Although the resistance varies depending on the doping concentration of the front and rear layers, the thickness of the undoped layer 109 is preferably 100 nm or less in order not to increase the resistance unnecessarily.

The n-type nitride compound semiconductor layer 110 has a band gap larger than that of the p-type nitride compound semiconductor layer 108. The n-type nitride compound semiconductor layer 110 can be formed of, for example, n-AlGaN doped with Si at a high concentration. The doping amount of Si is preferably 5 × 10 ¹⁹ atoms / cm ³ or more, for example, 1 × 10 ²⁰ atoms / cm ³ .

  Further, the Al composition in n-AlGaN constituting the n-type nitride compound semiconductor layer 110 is preferably about 0.2. If the Al composition is too high, the n-type nitride compound semiconductor layer 110 tends to have a high resistance and the strain on GaN increases, so it is necessary to adjust the composition and film thickness within a range that allows growth by lattice matching.

In the tunnel junction structure 120, a two-dimensional electron gas having a carrier density of about 1 × 10 ²⁰ atoms / cm ³ can be formed in the vicinity of the interface between the undoped layer 109 and the n-type nitride compound semiconductor layer 110, for example.

  A second n-side electrode 111 is formed on the outer edge of the n-type nitride compound semiconductor layer 110.

A dielectric DBR 112, which is an upper Bragg reflector, is formed on the center side of the second n-side electrode 111 on the n-type nitride compound semiconductor layer 110. The dielectric DBR 112 can have, for example, a TiO ₂ / SiO ₂ multilayer structure. However, the dielectric DBR 112 may be made of other materials.

(Method for manufacturing surface-emitting laser element)
3 and 4 are diagrams illustrating a manufacturing process of the surface emitting laser element according to the first embodiment. First, in the step shown in FIG. 3A, a stacked body of semiconductor layers is formed on a substrate 101 (wafer). The laminated body can be grown on the substrate 101 using, for example, MOVPE (Metal-Organic Vapor Phase Epitaxy).

  Specifically, for example, the semiconductor DBR 102 is grown on a substrate 101 (wafer) made of GaN. The semiconductor DBR 102 can be formed from, for example, AlInN / GaN. The band of the semiconductor DBR 102 is grown with a thickness designed in accordance with the oscillation wavelength of the active layer 105.

  Further, a lower cavity 103 made of, for example, n-GaN is grown on the semiconductor DBR 102, and then an active layer 105 having, for example, an InGaN / GaN multiple quantum well structure is grown on the lower cavity 103. Further, an upper cavity 106 made of, for example, p-GaN is grown on the active layer 105.

  Thereafter, the growth is temporarily stopped, and the current confinement layer 113 is selectively formed in the peripheral portion on the upper side of the upper cavity 106. The current confinement layer 113 can be formed, for example, by increasing the resistance by injecting B atoms excessively into the upper cavity 106. However, the current confinement layer 113 is not limited to atom implantation, and may be formed by other methods.

  Next, in the step shown in FIG. 3B, a carrier block layer 107 such as an AlN / GaN superlattice structure is formed on the current confinement layer 113 and on the upper cavity 106 located inside the current confinement layer 113. Form. Then, a tunnel junction structure 120 in which a p-type nitride compound semiconductor layer 108, an undoped layer 109, and an n-type nitride compound semiconductor layer 110 are sequentially stacked is formed on the carrier block layer 107. The doping amount of the p-type nitride compound semiconductor layer 108 and the n-type nitride compound semiconductor layer 110 and the thickness of the undoped layer 109 are as described above.

  The doping of the p-type nitride compound semiconductor layer 108 and the n-type nitride compound semiconductor layer 110 requires, for example, a dopant source such as Cp2Mg for p-type and monosilane for n-type during growth of MOCVD. It is done by introducing at a proper concentration. The dopant raw material and concentration can be changed as necessary.

Next, in the step shown in FIG. 4A, the mesa 150 is formed. Specifically, first, a mask pattern for forming the mesa 150 is formed on the n-type nitride compound semiconductor layer 110. For example, the mask pattern is formed by forming a SiO ₂ film, a SiN film or the like on the entire upper surface of the n-type nitride compound semiconductor layer 110 by a CVD method or the like, patterning with a photoresist or the like, and then removing unnecessary portions by etching. Can be formed.

  Thereafter, using the mask pattern as an etching mask, the mesa 150 is formed by a dry etching method such as a reactive ion beam etching method or an inductively coupled plasma etching method. For example, the etching of the mesa 150 is stopped in the lower cavity 103. In this case, the lower cavity 103 is exposed around the mesa 150. After the mesa 150 is etched, the mask pattern is removed.

Next, in the step shown in FIG. 4B, thermal annealing is performed to activate p-GaN. Then, the first n-side electrode 104 is formed on the outer edge of the lower cavity 103 exposed at the periphery of the mesa 150. A second n-side electrode 111 is formed on the outer edge of the n-type nitride compound semiconductor layer 110. Further, for example, TiO ₂ / SiO ₂ is alternately laminated on the center side of the second n-side electrode 111 on the n-type nitride compound semiconductor layer 110 to form a dielectric DBR 112 having a multilayer structure. Through the above steps, the surface emitting laser element 10 is completed.

  In the surface emitting laser element 10, carrier injection into the active layer 105 is performed as follows. Electrons are supplied from the first n-side electrode 104 to the lower cavity 103, and further electrons are supplied to the active layer 105 via the lower cavity 103.

  On the other hand, electrons are supplied from the second n-side electrode 111 to the n-type nitride compound semiconductor layer 110, and further, electrons are injected from the n-type nitride compound semiconductor layer 110 into the undoped layer 109 in which a two-dimensional electron gas is formed.

  The electrons injected into the undoped layer 109 move in the lateral direction, and carriers are injected into the p-type nitride compound semiconductor layer 108 side through a tunnel junction at a portion where the current confinement layer 113 is not present. The formed carriers become holes and are injected into the upper cavity 106 through a portion where the current confinement layer 113 is not provided, and further injected into the active layer 105. In this way, carriers can be emitted from the active layer 105.

  As described above, in the surface emitting laser element 10 using the nitride semiconductor as the active layer 105, the tunnel junction structure 120 capable of forming a two-dimensional electron gas is used, so that carriers are injected into the upper cavity 106 with low resistance. Therefore, the luminous efficiency can be improved. Further, in the structure of the surface emitting laser element 10, it is not necessary to use a material having high absorption such as ITO, so that the light emission efficiency can be improved also in this respect.

  Note that in this embodiment mode, the light emission efficiency is the ratio of the laser output to the energy injected into the device, and the higher the light emission efficiency, the better.

<Variation 1 of the first embodiment>
Modification 1 of the first embodiment shows an example in which a contact layer is provided on an n-type nitride compound semiconductor layer. In the first modification of the first embodiment, the description of the same components as those of the already described embodiments may be omitted.

  FIG. 5 is a cross-sectional view illustrating a surface emitting laser element according to Modification 1 of the first embodiment. The surface emitting laser element 10A shown in FIG. 5 is the surface emitting laser element in that the contact layer 214 is provided on the n-type nitride compound semiconductor layer 110, and the second n-side electrode 111 is provided on the contact layer 214. 10 (see FIG. 2). The contact layer 214 can be formed by, for example, p-GaN.

When the n-type nitride compound semiconductor layer 110 is formed of n-AlGaN, it may be difficult to form the second n-side electrode 111 on the n-type nitride compound semiconductor layer 110 depending on the Al composition. Therefore, on the n-type nitride compound semiconductor layer 110, for example, p-GaN is formed with a doping amount of about 1 × 10 ¹⁹ atoms / cm ³ , and the second n-side electrode 111 is provided thereon. In this case, carriers are injected into the tunnel junction structure 120 after passing through the forward direction of the pn junction.

  Thus, by providing the contact layer 214 on the n-type nitride compound semiconductor layer 110, the composition degree of freedom of the n-type nitride compound semiconductor layer 110 (for example, the degree of freedom of Al composition) can be improved. it can.

<Modification 2 of the first embodiment>
The second modification of the first embodiment shows an example in which a dielectric DBR is provided as the lower DBR instead of the semiconductor DBR. In the second modification of the first embodiment, the description of the same components as those of the already described embodiment may be omitted.

  FIG. 6 is a cross-sectional view illustrating a surface emitting laser element according to Modification 2 of the first embodiment. The surface emitting laser element 10B shown in FIG. 6 differs from the surface emitting laser element 10 (see FIG. 2) in that the substrate 101 is replaced with a heat dissipation substrate 301 and the semiconductor DBR 102 is replaced with a dielectric DBR 302.

As the heat dissipation substrate 301, for example, a substrate such as SiC having excellent heat dissipation characteristics can be used. The heat dissipation substrate has a higher thermal conductivity than sapphire, and other materials can be used as long as the substrate has excellent heat dissipation characteristics. The dielectric DBR 302 can have, for example, a TiO ₂ / SiO ₂ multilayer structure. The heat dissipation substrate 301 is disposed directly below the dielectric DBR 302.

  In order to manufacture the surface emitting laser element 10B, first, as shown in FIG. 7A, a lower cavity 103 made of, for example, n-GaN is grown on a sapphire substrate 451, and then the first embodiment is performed. Each layer is formed in the same manner as the form.

  Next, as shown in FIG. 7B, a holding substrate 452 is prepared. Then, the structure shown in FIG. 7A is fixed on the holding substrate 452 using the wax 453 in an upside down state, and the sapphire substrate 451 is removed. The removal of the sapphire substrate 451 can be performed by, for example, laser lift-off.

Thereafter, the surface of the lower cavity 103 is planarized, and a dielectric DBR 302 is formed on the lower cavity 103. The dielectric DBR 302 can be formed by, for example, alternately stacking TiO ₂ / SiO ₂ on the lower cavity 103. Thereafter, the heat radiation substrate 301 is bonded to the dielectric DBR 302, and the wax 453 is removed, thereby completing the surface emitting laser element 10B (see FIG. 6).

  In the surface emitting laser element 10B, since the upper and lower DBRs are both dielectric DBRs, the reflection band can be made wider than when a semiconductor DBR is used on one side. Thereby, the surface emitting laser element 10B having a more stable characteristic than the case where the semiconductor DBR is used for one side can be manufactured. The characteristics referred to here are, for example, an oscillation wavelength, an output, a threshold current, and the like.

  In the surface emitting laser element 10B, the dielectric DBR 302 is directly formed on the heat dissipation substrate 301. Therefore, heat can be directly radiated from the dielectric DBR 302 to the heat dissipation substrate 301. Therefore, the heat radiation characteristics can be improved as compared with the case where the surface emitting laser element 10B is improved. The characteristics referred to here are, for example, output and threshold current.

  The preferred embodiments and the like have been described in detail above, but the present invention is not limited to the above-described embodiments and the like, and various modifications can be made to the above-described embodiments and the like without departing from the scope described in the claims. Variations and substitutions can be added.

10, 10A, 10B Surface emitting laser element 101 Substrate 102 Semiconductor Bragg reflector (semiconductor DBR)
103 lower cavity 104 first n-side electrode 105 active layer 106 upper cavity 107 carrier block layer 108 p-type nitride compound semiconductor layer (first nitride compound semiconductor layer)
109 Undoped layer (second nitride compound semiconductor layer)
110 n-type nitride compound semiconductor layer (third nitride compound semiconductor layer)
111 2nd n-side electrode 112 Dielectric DBR
113 Current confinement layer 120 Tunnel junction structure 150 Mesa 214 Contact layer 301 Heat dissipation substrate 302 Dielectric DBR

APPLIED PHYSICS LETTERS 101, 151113 (2012)

Claims (5)

A surface-emitting laser element using a nitride semiconductor as an active layer,
Having a laminate comprising a lower Bragg reflector, an active layer, and an upper Bragg reflector;
A tunnel junction structure is provided between the active layer and the upper Bragg reflector;
The tunnel junction structure is laminated in order from the side close to the active layer,
a first nitride compound semiconductor layer made of p-type and doped with 5 × 10 ¹⁹ atoms / cm ³ or more;
An undoped second nitride compound semiconductor layer;
a third nitride compound semiconductor layer having a n-type doping of 5 × 10 ¹⁹ atoms / cm ³ or more and having a band gap larger than the band gap of the first nitride compound semiconductor layer,
A surface emitting laser element having a current confinement structure between the active layer and the tunnel junction structure. The first nitride compound semiconductor layer is formed of GaN;
The second nitride compound semiconductor layer is formed of GaN;
2. The surface emitting laser device according to claim 1, wherein the third nitride compound semiconductor layer is made of AlGaN.   The surface emitting laser element according to claim 1, wherein the second nitride compound semiconductor layer has a thickness of 5 nm or more.   4. The surface emitting laser element according to claim 1, wherein a contact layer made of p-GaN is provided in contact with the third nitride compound semiconductor layer. 5. The lower Bragg reflector and the upper Bragg reflector are formed of a dielectric,
The surface emitting laser element according to any one of claims 1 to 4, wherein the lower Bragg reflector is directly formed on a substrate having a higher thermal conductivity than sapphire.

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