KR20200023874A - A surface-emitting laser device and light emitting device including the same - Google Patents

Abstract

According to an embodiment of the present invention, provided are a surface-emitting laser element and a light emitting device including the same. According to an embodiment of the present invention, the surface-emitting laser element may comprise: a first reflective layer; an active region disposed on the first reflective layer; a plurality of aperture regions disposed on the active region and including apertures and insulating regions; a second reflective layer disposed on the aperture region; and a first electrode and a second electrode electrically connected to the first reflective layer and the second reflective layer, respectively. An outer periphery of the insulating region in the aperture region may be circular, and an outer periphery of the aperture may be polygonal.

Description

Surface-emitting laser device and light emitting device including the same {A SURFACE-EMITTING LASER DEVICE AND LIGHT EMITTING DEVICE INCLUDING THE SAME}

Embodiments relate to a semiconductor device, and more particularly, to a surface emitting laser device and a light emitting device including the same.

A semiconductor device including a compound such as GaN, AlGaN, etc. has many advantages, such as having a wide and easy-to-adjust band gap energy, and can be used in various ways as a light emitting device, a light receiving device, and various diodes.

Particularly, light emitting devices such as light emitting diodes or laser diodes using semiconductors of Group 3-5 or Group 2-6 compound semiconductors have been developed through the development of thin film growth technology and device materials. Various colors such as blue and ultraviolet light can be realized, and efficient white light can be realized by using fluorescent materials or combining colors, and low power consumption, semi-permanent life, and quick response compared to conventional light sources such as fluorescent and incandescent lamps. It has the advantages of speed, safety and environmental friendliness.

In addition, when a light-receiving device such as a photodetector or a solar cell is also manufactured using a group 3-5 or group 2-6 compound semiconductor material of a semiconductor, the development of device materials absorbs light in various wavelength ranges to generate photocurrent As a result, light in various wavelength ranges, from gamma rays to radio wavelength ranges, can be used. It also has the advantages of fast response speed, safety, environmental friendliness and easy control of device materials, making it easy to use in power control or microwave circuits or communication modules.

Therefore, a white light emitting device that can replace a fluorescent light bulb or an incandescent bulb that replaces a Cold Cathode Fluorescence Lamp (CCFL) constituting a backlight of a liquid crystal display (LCD) display device, a transmission module of an optical communication means. Applications are expanding to diode lighting devices, automotive headlights and traffic lights, and sensors that detect gas or fire.

In addition, applications can be extended to high frequency application circuits, other power control devices, and communication modules. For example, in the conventional semiconductor light source device technology, there is a vertical-cavity surface-emitting laser (VCSEL), which is used for optical communication, optical parallel processing, optical connection, and the like. On the other hand, the laser diode used in such a communication module is designed to operate at a low current.

On the other hand, the response speed was important in the structure of the existing data optical communication, but recently applied to the high power package (High Power PKG) for the sensor, the optical output and voltage efficiency becomes an important characteristic.

For example, a 3D sensing camera is a camera capable of capturing depth information of an object, and has recently been in the spotlight in conjunction with augmented reality. On the other hand, a depth sensor of the camera module is equipped with a separate sensor, it is divided into two types of structured light (SL) method and ToF (Time of Flight) method.

In the structured light (SL) method, a laser of a specific pattern is emitted to a subject, the depth of the pattern is analyzed according to the shape of the subject surface, the depth is calculated, and then synthesized with the photograph taken by the image sensor to obtain a 3D photographing result.

In contrast, the ToF method calculates the depth by measuring the time when the laser is reflected back to the subject, and then synthesizes it with the photograph taken by the image sensor to obtain a 3D photographing result.

As a result, the SL method has an advantage in mass production in that the laser has to be positioned very accurately, whereas the ToF technology relies on an improved image sensor, and one or both methods can be adopted in one mobile phone. It may be.

For example, a 3D camera called True Depth can be implemented in the SL method on the front of the mobile phone and can be applied in the ToF method on the back.

On the other hand, when the VCSEL is applied to a structured light sensor, a time of flight (ToF) sensor, or a laser diode autofocus (LDAF), the VCSEL operates at a high current, so that the light output is decreased or the threshold current is increased. A problem occurs.

As described above, in the VCSEL package technology, the ToF method calculates the time difference of the reflected pulse beam by using a flash type pulse projection through a VCSEL chip as a light source and a diffuser. Depth is extracted.

For example, FIG. 1 illustrates an example of determining a field of interest (FOI) and a field of view (FOV) based on a combination of beam divergence and diffuser beam angle in a VCSEL chip. to be. Accordingly, control of beam divergence in the VCSEL chip is important for determining the FOI and FOV.

Next, FIG. 2A shows mode change data according to aperture size in the prior art.

In the prior art, the aperture size is increasing in accordance with the demand of a high output VCSEL package.

In VCSEL technology, small size apertures, e.g., apertures of less than 3 μm in diameter (r _A ) are preferred for single fundamental mode stabilization, but large size apertures in high-output VCSEL packages (large size aperture) is required.

On the other hand, as shown in FIG. 2A, when the aperture size, for example, the diameter r _A of the aperture increases, a change in emission mode or divergence angle due to mode hopping occurs.

Specifically, referring to FIG. 2A, when the diameter r _A of the aperture increases, the divergence mode changes, and thus a higher mode shift occurs.

For example, in the prior art, as the aperture size increases, LP ₀₁ (r _A = 2 μm), LP ₂₁ (r _A = 4 μm), LP ₄₁ (r _A = 6 μm) changes to higher order mode (higher). mode shift) phenomenon occurs.

However, the phenomenon of changing to the higher-order mode causes a problem in that the beam pattern increases the divergence angle of beams of the split or emitted beam.

For example, FIG. 2B is beam profile data in a far field of a conventional VCSEL, and a beam pattern of an exit beam is split as the applied current increases. For example, FIG. 2B shows an applied current of 1.2 mA (b1) in a VICSEL having an aperture having a diameter r _A of 4.5 μm in a circular shape under the condition that the threshold current I _th is 1.2 mA. It can be seen that as the oscillation mode is changed to the higher order mode as the increase to 3.0 mA (b2) and 5.0 mA (b3), respectively, the beam pattern of the exit beam is split.

2C shows beam profile data in a far field of a conventional VCSEL. When the aperture diameter r _A is 6.0 μm, the oscillation is started immediately after lasing. As the current increases, multi-mode oscillation becomes even worse.

On the other hand, in this application, the measurement of the beam profile (Far field Beam profile) of the surface emitting laser device was used a beam profiler measuring instrument 8050M-GE-TE (Thorlabs, Inc.) (8050M-GE-TE specification information: 8 Megapixel Monochrome Scientific CCD Camera, Hermetically Sealed Cooled Package, GigE Interface. However, the measuring device of the far field beam profile is not limited thereto.

Next, FIG. 3 shows near field image data according to an increase in applied current in the conventional VCSEL, and also shows divergence angle of beams according to each applied current. Referring to FIG. 3, as the applied current increases from 3 mA (d1) to 5 mA (d2), 7.5 mA (d3), and 12 mA (d4), mode splitting occurs as the light emitting point increases. The divergence angle of beams increased sharply to 21.0 °, 25.0 °, and 31.0 °, respectively.

That is, according to the related art, when high current is applied, damage of the aperture, which is a laser emission area, may occur when current crowding occurs at the aperture edge. As the high current is applied while the oscillation mode is started, an optical problem in which the divergence angle of the beams is increased due to the higher mode oscillation is generated.

In particular, according to the prior art, there is a problem of changing wavelength and divergence angle due to divergence mode hopping, and in order to stabilize the divergence mode, an aperture diameter is preferably less than about 5.0 μm. Although a large aperture is required, a technical contradiction occurs in the divergence angle of beams due to the instability of oscillation mode in an aperture of a large size of 5.0 µm or larger.

The embodiment prevents an increase in the divergence angle of beams or the beam pattern splitting due to a higher mode shift despite high current application or an increase in aperture size. The present invention provides a surface emitting laser device and a light emitting device including the same.

The surface emitting laser device according to the embodiment includes a first reflective layer, an active region disposed on the first reflective layer, an aperture region 241 and an insulating region 242 disposed on the active region. And a plurality of aperture regions 240, a second reflective layer disposed on the aperture region, and first and second electrodes electrically connected to the first reflective layer and the second reflective layer, respectively. .

In the aperture region 240, an outer portion of the insulating region 242 may be circular, and an outer portion of the aperture 241 may have a polygonal shape.

The outer periphery of the aperture 241 may be one of a polygonal shape of a triangular shape to a seventh shape.

The size S1 of the aperture 241, which is the length of the diagonal of the long axis of the polygon, may be 6.0 μm to 12 μm.

The current density of the aperture 241 may be 8.3kA / cm ³ to 30.0 kA / cm ³ .

In an embodiment, the distance D between each of the closest aperture centers in the plurality of aperture regions may be greater than two times and less than three times the radius R of each of the aperture regions 240A and 240B.

The size R of the aperture region is equal to half S2 of the size of the aperture 241 and the shortest distance S2 from the polygon edge of the aperture 241 to the outside of the insulation region 242. It may be combined.

The divergence angle of the aperture may be 20 ° to 27 °.

The light emitting device of the embodiment may include the surface emitting laser device.

Embodiments provide a problem in which the divergence angle of beams increases or the beam pattern splits due to a higher mode shift despite high current application or an increase in aperture size. It is possible to provide a surface emitting laser device and a light emitting device including the same.

For example, according to the exemplary embodiment, the optical confinement is performed at the edge of the polygon of the aperture 241 having excellent crystal quality, thereby controlling the available mode, thereby delaying the higher mode shift. There is a special technical effect that the mode is maintained.

1 is a diagram illustrating a method of determining a field of interest (FOI) and a field of view (FOV) based on a combination of beam divergence and diffuser beam angle in a VCSEL chip.
FIG. 2A shows mode change data according to aperture size in the prior art. FIG.
FIG. 2B shows beam profile data in a far field as the applied current of a conventional VCSEL increases. FIG.
FIG. 2C shows beam profile data in a far field when the diameter r _A of the aperture of the conventional VCSEL is about 6.0 μm. FIG.
FIG. 3 illustrates near field image data according to an increase in applied current and divergence angle of beams according to each applied current in the conventional VCSEL.
4 is a plan view of a surface emitting laser device according to an embodiment;
FIG. 5 is an enlarged view of the first region C1 of the surface light emitting laser device according to the embodiment shown in FIG. 4.
6A is a first cross-sectional view taken along line A1-A2 of the surface emitting laser device according to the embodiment shown in FIG. 5;
6B is a second cross-sectional view taken along line A3-A4 of the surface emitting laser device according to the embodiment shown in FIG. 5;
FIG. 7 is a cross-sectional view of a first portion B1 of the surface emitting laser device according to the embodiment shown in FIG. 6A.
FIG. 8A is a top conceptual view of the aperture region of the surface emitting laser device according to the embodiment shown in FIG. 6A; FIG.
8B is an IR micrograph of an aperture region of the surface emitting laser device according to the embodiment shown in FIG. 6A.
FIG. 8C is near field image data of an aperture region of the surface emitting laser device according to the embodiment of FIG. 6A; FIG.
9A illustrates a low Miller index plane of GaAs in the surface emitting laser device according to the embodiment.
9B is another IR micrograph of an aperture region of the surface emitting laser device according to the embodiment.
10A is an IR micrograph of the aperture region in the comparative example.
10B is a cross-sectional photograph of the aperture region in the comparative example.
11A is a second enlarged view of an aperture region in the surface emitting laser device according to the embodiment;
FIG. 11B illustrates near field image data according to aperture shape and current and divergence angle of beams according to each applied current in the surface emitting laser device according to Comparative Example and Example. FIG.
FIG. 12 illustrates near field image data according to aperture size and current density and divergence angle of beams according to each applied current in the surface emitting laser device according to the embodiment; FIG.
FIG. 13A illustrates orientation angle change data according to current density for each aperture size in the data of FIG. 12. FIG.
FIG. 13B is directed angle change data according to current (Current) for each aperture size in the data of FIG. 12. FIG.
14a to 16b is a manufacturing process of the surface-emitting laser device according to the embodiment.
17 is a perspective view of a mobile terminal to which a surface emitting laser device is applied according to an embodiment;

DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the embodiments, when described as being formed on the "on or under" of each element, the on or under is It includes both the two elements are in direct contact with each other or one or more other elements are formed indirectly between the two elements. In addition, when expressed as "on" or "under", it may include the meaning of the downward direction as well as the upward direction based on one element.

(Example)

4 is a plan view of the surface emitting laser device 201 according to the embodiment, and FIG. 5 is an enlarged view of the first region C1 of the surface emitting laser device according to the embodiment shown in FIG. 4.

Referring to FIG. 4, the surface emitting laser device 201 according to the embodiment may include a light emitting part E and a pad part P. The light emitting part E includes a plurality of light emitting emitters as shown in FIG. 5. Emitters E1, E2, E3 can be arranged.

Referring to FIG. 5, in the embodiment, the surface emitting laser device 201 has a second electrode 280 disposed in a region other than the aperture 241, which is an opening, and a passivation layer on the surface corresponding to the aperture 241. 270 may be disposed.

Next, FIG. 6A is a first cross-sectional view taken along line A1-A2 of the surface emitting laser device according to the embodiment shown in FIG. 5, and FIG. 6B is A3- of the surface emitting laser device according to the embodiment shown in FIG. 5. 2nd sectional drawing along the A4 line.

6A and 6B, in the embodiment, the surface emitting laser device 201 may include the first electrode 215, the substrate 210, the first reflective layer 220, the active region 230, and the aperture region 240. ), The second reflective layer 250, the second electrode 280, and the passivation layer 270.

The aperture region 240 may include an aperture 241 and an insulating region 242. The region 242 may be referred to as an oxide layer, and the aperture region 240 may be referred to as an oxide region, but is not limited thereto.

The second electrode 280 may include a contact electrode 282 and a pad electrode 284.

Next, FIG. 7 is an enlarged cross-sectional view of the first portion B1 of the surface light emitting laser device according to the embodiment shown in FIG. 6A.

Hereinafter, technical features of the surface emitting laser device 201 according to the embodiment will be described with reference to FIGS. 6A and 7, and the technical effects will be described with reference to the accompanying drawings. In the drawings of the embodiment, the direction of the x-axis may be a direction parallel to the longitudinal direction of the substrate 210, the y-axis may be a direction perpendicular to the x-axis.

<Substrate, first electrode>

Referring to FIG. 6A, in an embodiment, the substrate 210 may be a conductive substrate or a non-conductive substrate. In the case of using a conductive substrate, a metal having excellent electrical conductivity may be used, and a heat generating GaAs substrate, a metal substrate, or silicon (Si ) Substrates and the like can be used.

In the case of using a non-conductive substrate, an AlN substrate, a sapphire (Al ₂ O ₃ ) substrate, or a ceramic substrate may be used.

In an embodiment, the first electrode 215 may be disposed under the substrate 210, and the first electrode 215 may be disposed in a single layer or multiple layers with a conductive material. For example, the first electrode 215 may be a metal and at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). Including a single layer or a multi-layer structure to improve the electrical properties can increase the light output.

<1st reflective layer, 2nd reflective layer>

Referring to FIG. 7, the first reflective layer 220 may be doped with a first conductivity type. For example, the first conductivity type dopant may include an n type dopant such as Si, Ge, Sn, Se, Te, or the like.

In addition, the first reflective layer 220 may include a gallium-based compound, for example, AlGaAs, but is not limited thereto. The first reflective layer 220 may be a distributed Bragg reflector (DBR). For example, the first reflective layer 220 may have a structure in which a first layer and a second layer made of materials having different refractive indices are alternately stacked at least once.

For example, as illustrated in FIG. 7, the first reflective layer 220 may include a first group first reflective layer 221 disposed on the substrate 210 and a first group first reflective layer 221 disposed on the first group first reflective layer 221. The second group first reflection layer 222 may be included.

The first group first reflective layer 221 and the second group first reflective layer 222 may include a plurality of layers made of a semiconductor material having a compositional formula of Al _x Ga _(1-x) As (0 <x <1). As the Al in each layer increases, the refractive index of each layer may decrease, and as Ga increases, the refractive index of each layer may increase.

In addition, the thickness of each layer may be λ / 4n, λ may be a wavelength of light generated in the active region 230, and n may be a refractive index of each layer with respect to light having the aforementioned wavelength. Here, λ may be 650 to 980 nanometers (nm), and n may be the refractive index of each layer. The first reflective layer 220 having such a structure may have a reflectance of 99.999% for light in a wavelength region of about 940 nanometers.

The thickness of the layer in each first reflective layer 220 may be determined according to the refractive index and the wavelength λ of the light emitted from the active region 230.

In addition, as shown in FIG. 7, the first group first reflective layer 221 and the second group first reflective layer 222 may also be formed of a single layer or a plurality of layers, respectively.

For example, the first group first reflective layer 221 may include about 30-40 pairs of the first group first-first layer 221a and the first group first-second layer 221b. have. The first group 1-1 layer 221a may be formed thicker than the first group 1-2 layer 221b. For example, the first group first-first layer 221a may be formed at about 40 to 60 nm, and the first group first-2 layer 221b may be formed at about 20-30 nm.

In addition, the second group first reflective layer 222 may also include about 5 to 15 pairs of the second group first-first layer 222a and the second group first-second layer 222b. The second group first-first layer 222a may be formed thicker than the second group first-second layer 222b. For example, the second group 1-1 layer 222a may be formed at about 40 nm to about 60 nm, and the second group 1-2 layer 222 b may be formed at about 20 nm to about 30 nm.

In addition, as shown in FIG. 7, the second reflective layer 250 may include a gallium-based compound, for example, AlGaAs, and the second reflective layer 250 may be doped with a second conductivity type dopant. The second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. Meanwhile, the first reflective layer 220 may be doped with a p-type dopant, and the second reflective layer 250 may be doped with an n-type dopant.

The second reflective layer 250 may also be a distributed Bragg reflector (DBR). For example, the second reflective layer 250 may have a structure in which a plurality of layers made of materials having different refractive indices are alternately stacked at least once.

Each layer of the second reflective layer 250 may include AlGaAs, and in detail, may be formed of a semiconductor material having a compositional formula of Al _x Ga _(1-x) As (0 <x <1). Herein, when Al increases, the refractive index of each layer may decrease, and when Ga increases, the refractive index of each layer may increase. In addition, each layer of the second reflective layer 250 may have a thickness of λ / 4n, λ may be a wavelength of light emitted from the active layer, and n may be a refractive index of each layer with respect to light having the aforementioned wavelength.

The second reflective layer 250 having such a structure may have a reflectance of 99.9% with respect to light in a wavelength region of about 940 nanometers.

The second reflective layer 250 may be formed by alternately stacking layers, and the number of pairs of layers in the first reflective layer 220 may be greater than the number of pairs of layers in the second reflective layer 250. In this case, as described above, the reflectance of the first reflective layer 220 may be about 99.999%, which may be greater than 99.9% of the reflectance of the second reflective layer 250.

In an embodiment, the second reflective layer 250 is spaced apart from the first region second reflecting layer 251 and the first group second reflecting layer 251 adjacent to the active region 230 in the active region 230. The second group second reflective layer 252 may be disposed.

As illustrated in FIG. 7, the first group second reflective layer 251 and the second group second reflective layer 252 may also be formed of a single layer or a plurality of layers, respectively.

For example, the first group second reflective layer 251 may include about 1 to 5 pairs of the first group 2-1 layer 251a and the first group 2-2 layer 251b. have. The first group 2-1 layer 251a may be formed thicker than the first group 2-2 layer 251b. For example, the first group 2-1 layer 251a may be formed at about 40 to 60 nm, and the first group 2-2 layer 251b may be formed at about 20 to 30 nm.

In addition, the second group second reflection layer 252 may also include about 5 to 15 pairs of the second group 2-1 layer 252a and the second group 2-2 layer 252b. The second group 2-1 layer 252a may be formed thicker than the second group 2-2 layer 252b. For example, the second group 2-1 layer 252a may be formed at about 40 to 60 nm, and the second group 2-2 layer 252b may be formed at about 20 to 30 nm.

<Active area>

7, the active region 230 may be disposed between the first reflective layer 220 and the second reflective layer 250.

The active region 230 may include an active layer 232 and at least one cavity 231 and 233. For example, the active region 230 may include an active layer 232, a first cavity 231 disposed under the active layer 232, and a second cavity 233 disposed above. The active region 230 of the embodiment may include both the first cavity 231 and the second cavity 233, or may include only one of the two.

The active layer 232 may include any one of a single well structure, a multi well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum line structure.

The active layer 232 may include a quantum well layer 232a and a quantum wall layer 232b using a compound semiconductor material of a group III-V element. The quantum well layer 232a may be formed of a material having an energy band gap smaller than the energy band gap of the quantum wall layer 232b. The active layer 232 may be formed in a 1 to 3 pair structure such as InGaAs / AlxGaAs, AlGaInP / GaInP, AlGaAs / AlGaAs, AlGaAs / GaAs, GaAs / InGaAs, but is not limited thereto. Dopants may not be doped in the active layer 232.

Next, the first cavity 231 and the second cavity 233 may be formed of Al _y Ga _(1-y) As (0 <y <1) material, but is not limited thereto. For example, the first cavity 231 and the second cavity 233 may each include a plurality of layers made of Al _y Ga _(1-y) As.

For example, the first cavity 231 may include a first-first cavity layer 231a and a first-second cavity layer 231b. The first-first cavity layer 231a may be further spaced apart from the active layer 232 than the first-second cavity layer 231b. The first-first cavity layer 231a may be formed thicker than the first-second cavity layer 231b, but is not limited thereto.

For example, the first-first cavity layer 231a may be formed at about 60-70 nm, and the 1-2th cavity layer 231b may be formed at about 40-55 nm, but is not limited thereto.

In addition, the second cavity 233 may include a 2-1 cavity layer 233a and a 2-2 cavity layer 233b. The 2-2 cavity layer 233b may be further spaced apart from the active layer 232 than the 2-1 cavity layer 233a. The 2-2 cavity layer 233b may be formed thicker than the 2-1 cavity layer 233a, but is not limited thereto. For example, the second-2 cavity layer 233b may be formed to about 60 to 70 nm, and the second-1 cavity layer 233a may be formed to about 40 to 55 nm, but is not limited thereto.

<Aperture area>

Referring back to FIG. 6A, in the embodiment, the aperture region 240 may include an insulation region 242 and an aperture 241. The aperture 241 may be referred to as an opening, and the aperture region 240 may be referred to as an opening region.

The insulating region 242 may be formed of an insulating layer, for example, aluminum oxide, to serve as a current blocking region, and the aperture 241 may be defined by the insulating region 242.

For example, when the aperture region 240 includes aluminum gallium arsenide (AlGaAs), AlGaAs of the aperture region 240 reacts with H ₂ O to change the edge to aluminum oxide (Al ₂ O ₃ ). The insulating region 242 may be formed, and the central region that does not react with H ₂ O may be an aperture 241 made of AlGaAs.

According to an embodiment, the light emitted from the active region 230 through the aperture 241 may be emitted to the upper region, and the light transmittance of the aperture 241 may be superior to that of the insulating region 242. have.

Referring to FIG. 7, the insulating region 242 may include a plurality of layers. For example, the insulating region 242 may include a first insulating layer 242a and a second insulating layer 242b. Can be. The first insulating layer 242a may have a thickness that is the same as or different from that of the second insulating layer 242b.

One of the technical problems of the embodiment is that the divergence angle of the beams increases due to the higher mode shift or the beam pattern is broken despite the application of a high current or an increase in the aperture size. It is an object of the present invention to provide a surface emitting laser device and a light emitting device including the same.

FIG. 8A is a schematic conceptual view of an aperture region 240 of the surface emitting laser device according to the embodiment shown in FIG. 6A, and FIG. 8B is an aperture region 240 of the surface emitting laser device according to the embodiment shown in FIG. 6A. 8C is near field image data of the aperture region of the surface emitting laser device according to the embodiment of FIG. 6A.

8A and 8B, in the embodiment, the aperture region 240 may include an insulation region 242 and an aperture 241, and the aperture 241 may include a polygonal horizontal cross section.

For example, in an embodiment, the polygonal cross section of the aperture 241 may have a shape of any one of a triangular shape to a seven-corner shape. For example, the outer angle of the aperture 241 may be any one of a triangular shape, a tetragonal shape, a pentagonal shape, a hexagonal shape, or a hexagonal shape, and the outer shape of the aperture 241 in FIG. 8A is hexagonal. The case is illustrated but is not limited thereto.

In addition, in an embodiment, an outer portion of the insulating region 242 of the aperture region 240 may be circular.

In an embodiment the size S1 of the aperture 241 may be diagonal in polygon. For example, when the shape of the aperture 241 is hexagonal as in FIG. 8A, the length of the maximum or long axis diagonal may be the size S1 of the aperture 241. Meanwhile, half of the size of the aperture 241 may be represented by S2.

In an embodiment, the size R of the aperture region 240 including the aperture 241 and the insulation region 242 is equal to half of the size of the aperture 241 (S2) and the polygonal edge of the aperture 241. In this case, the shortest distance S2 to the outside of the insulating region 242 may be added together.

As described above, one of the technical problems of the embodiment is that the beam pattern or an increase in the divergence angle of the beams due to a higher mode shift despite the application of a high current or an increase in the aperture size An object of the present invention is to provide a surface light emitting laser device and a light emitting device including the same.

Referring to FIG. 8C, in the surface light emitting laser device according to the embodiment, the oxidation condition is controlled in a circular mesa state to form an aperture having an outline shape of the polygon so that the polygon may be formed at the time of application of a high current or an increase in the aperture size. Pinning at the edges of the aperture is suppressed to increase the point of light emission, increasing the divergence angle of beams or beam pattern due to higher mode shift. There is a technical effect that can prevent this splitting problem.

For example, FIG. 9A illustrates a low Miller index plane of GaAs in the surface emitting laser device according to the embodiment, and FIG. 9B is another IR micrograph of an aperture region of the surface emitting laser device according to the embodiment.

9A is an exemplary diagram of a GaAs (Zinc-blende crystal) low Miller index plane in the surface emitting laser device according to the embodiment. In the zinc-blende structure, low Miller index planes appear at intervals of 45 ° based on the (001) plane surface. . The low Miller index plane features low bond density and can be chemically and mechanically stable.

As a result, the Low Miller index plane has a low etching rate or a slow growth rate, so easy cleavage and low surface defect density.

Accordingly, referring to FIG. 9B, an aperture of a quadrilateral shape may be formed by {110} side-wall termination, but the external shape is not limited to the quadrangle, and as illustrated in FIG. 8B, the hexagonal shape is provided. One aperture may be formed.

According to the embodiment, by designing a mesa (circle) to form an aperture region in a circular shape to increase the symmetry, it is possible to suppress the occurrence of local stress or defect increase, and the speed contrast Control allows you to control the aperture shape in polygonal form.

10A is an IR micrograph of the aperture region in the comparative example, and FIG. 10B is a cross-sectional photograph of the aperture region in the comparative example.

10A and 10B are photographs of a closed comparative example, and show that there is a problem that a crack occurs in an aperture when using polygonal mesa for mode control.

According to the comparative example, when the hexagonal mesa is formed to realize the closed packed structure, the side wall is formed by the combination of high and low index, and the surface quality is increased by the defect on the high index plane surface. There is a problem in that a reliability issue occurs due to a difference in stress and a crack due to stress concentration due to defect propagation during aperture oxidation. have.

Accordingly, according to the embodiment, the outer portion of the insulating region 242 in the aperture region 240 is circular, the outer portion of the aperture 241 is controlled in a polygonal shape, in particular the polygon edge of the aperture 241 Because of its excellent crystal quality, the divergence angle of the beams increases or the beam pattern splits due to higher mode shift, even when high current is applied or the aperture size is increased. It is possible to provide a surface emitting laser device and a light emitting device including the same, which can prevent the problem.

According to an embodiment, an increase in light emission point is suppressed by pinning by an aperture of a corner of a polygon having excellent crystal quality and a higher order mode shift is achieved by controlling an available mode due to such optical confinement. There is a special technical effect that the mode shift is delayed and the mode is maintained.

For example, according to the exemplary embodiment, the optical confinement is performed at the edge of the polygon of the aperture 241 having excellent crystal quality, thereby controlling the available mode, thereby delaying the higher mode shift. There is a special technical effect that the mode is maintained.

Accordingly, according to the embodiment, despite the increase in the aperture size, even when a high current is applied, the beam mode is controlled so that the beam pattern of the output beam is split due to a higher mode shift. It is possible to provide a surface emitting laser device and a light emitting device including the same, which can solve a problem and a problem of increasing the divergence angle.

Next, FIG. 11A is a second enlarged view C2 of the aperture region in the surface emitting laser device according to the embodiment.

According to the embodiment, by increasing the symmetry of the Mesa for forming the aperture region in a circular manner, it is possible to suppress the occurrence of local stress or defect increase, and to oxidize by controlling the distance between adjacent patcher regions. Speed contrast may be controlled to form an aperture shape in a polygonal shape.

For example, referring to FIG. 11A, the distance D between the closest aperture centers in the plurality of aperture regions is controlled to be greater than two times and less than three times the radius R of each aperture region to control adjacent apertures. Aperture shapes may be formed in a polygonal shape by allowing a relatively slow oxidation rate between the aperture regions.

For example, the first aperture region 204A includes the first insulating region 242A and the first aperture 241A, and the size of the first aperture region 240A is R as described in FIG. 8A. The size of the first aperture region 240A may mean a radius, but is not limited thereto.

In addition, the second aperture region 240B adjacent to the first aperture region 204A includes a second insulating region 242B and a second aperture 241B, and the size of the second aperture region 240B. May be R.

At this time, according to the embodiment, the distance D between the closest first aperture 241A and the second aperture 241B is controlled to be greater than two times and less than three times the radius R of each aperture region to control the adjacent aperture. Aperture shapes may be formed in a polygonal shape by allowing a relatively slow oxidation rate between the aperture regions.

Next, FIG. 11B illustrates near field image data according to aperture shape and current and divergence angle of beams according to each applied current in the surface emitting laser device according to Comparative Examples and Examples. .

The comparator has a circular type aperture, and the divergence angle occurs as the light emission mode splits as the light emission point increases as the current increases from 0.5 A to 1 A and 2 A. It increased rapidly from 19.5˚ to 26.0˚ and 32.5˚.

On the other hand, in the embodiment, when the polygon is provided with a hexagonal aperture, for example, pinning occurs at the edge of the archer, thereby increasing the emission point, thereby suppressing mode splitting. It is possible to reduce the amount of increase in the divergence angle.

For example, in the embodiment, even if the current increases from 0.5 A to 1 A and 2 A, there is a technical effect that the divergence angle is controlled from 19.0 ° to 23.5 ° and 27.5 ° by preventing light emission mode splitting ( H standard).

That is, according to the embodiment, pinning occurs at the edge of the archer due to optical confinement by the aperture having polygonal edges having excellent crystal quality, thereby increasing the emission point. By controlling the available mode through this, there is a special technical effect that the higher mode shift is delayed and the mode is maintained.

In addition, according to the embodiment, even when a high current is applied, the beam mode is controlled so that the beam pattern of the output beam is split and the divergence angle is increased according to the higher mode shift. It is possible to provide a surface emitting laser device and a light emitting device including the same.

Next, FIG. 12 illustrates near field image data according to aperture size and current density and divergence angle of beams according to each applied current in the surface emitting laser device according to the embodiment.

In addition, FIG. 13A is data indicating direction angle changes according to current density for each aperture size in the data of FIG. 12, and FIG. 13B shows current for each aperture size in the data of FIG. 12. ) Is the orientation angle change data.

According to the embodiment, there is a special technical effect that the oscillation mode and the divergence angle can be stably controlled according to the current range IE according to the aperture size in the wavelength region of about 810 nm to 980 nm.

For example, Fig. 12 and Figs. 13a to see if the 6.0㎛ 12㎛ size (S1) of the aperture in the embodiment, when the current density is controlled in the case of 8.3kA / cm ³ to 30.0 kA / cm ³ There is a special technical effect that the oscillation mode and the divergence angle can be controlled stably.

In the embodiment, the orientation angle of the surface-emitting laser device was measured using an LEDGON-100 goniophotometer (Instrument Systems Optische Messtechnik GmbH, Germany), but is not limited thereto.

For example, when it is controlled to 12, 13a and Referring to Figure 13b, when the size (S1) of the aperture is 6.0㎛ In an embodiment, the current density of 8.3kA / cm ³ to 30.0 kA / cm ³ The oscillation mode was stably controlled in the current region (7 mA) with the secondary mode and the divergence angle approximately 20 degrees.

In addition, when one size (S1) of the aperture is 8.0㎛ In an embodiment, if the current density is controlled to 8.3kA / cm ³ to 30.0 kA / cm ^3, the current (current) in the 7mA, 9mA, 12mA, 14mA There is a special technical effect that the oscillation mode is controlled in the secondary mode and the divergence angle is approximately 21 degrees even if it is changed.

In addition, when one size (S1) of the aperture is 10.0㎛ In an embodiment, if the current density is controlled to 8.3kA / cm ³ to 30.0 kA / cm ^3, the current (current) in the 7mA, 9mA, 12mA, 14mA There is a special technical effect that the oscillation mode is controlled in the secondary mode and the divergence angle is approximately 25 ° even if it is changed.

In addition, when the size (S1) of the aperture is 12.0㎛ one time, the current density is controlled to 8.3kA / cm ³ to 30.0 kA / cm ³ in the embodiment, the current (current) may be changed to a 9mA, 12mA, 14mA There is a special technical effect that the oscillation mode is stably controlled as the secondary mode and the divergence angle is about 27 °.

Accordingly, the embodiment may increase the divergence angle of the beams or the beam pattern due to the higher mode shift despite the increase of the aperture size or the aperture size. It is possible to provide a surface emitting laser device and a light emitting device including the same, which can prevent the problem.

In addition, the embodiment suppresses the increase of the light emission point by pinning at the aperture of the polygonal edge having excellent crystal quality despite the increase of the aperture size or the application of high current, thereby increasing the higher mode shift. According to the present invention, there is provided a surface emitting laser device capable of preventing an increase in divergence angle of beams or a splitting of a beam pattern, and a light emitting device including the same.

<Second electrode, ohmic contact layer, passivation layer>

Referring back to FIG. 6A, the surface emitting laser device 201 may be mesa-etched from the second reflective layer 250 to the aperture region 240 and the active region 230 to define an emitter. In addition, even a part of the first reflective layer 220 may be mesa etched.

The second electrode 280 may be disposed on the second reflective layer 250, and the second electrode 280 may include a contact electrode 282 and a pad electrode 284.

The passivation layer 270 may be disposed in a region where the second reflective layer 250 is exposed in the region between the contact electrodes 282, and may correspond to the aperture 241 and the upper and lower sides. The contact electrode 282 may improve ohmic contact between the second reflective layer 250 and the pad electrode 284.

The second electrode 280 may be made of a conductive material, for example, may be a metal. For example, the second electrode 280 may include at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). It may be formed into a structure.

In FIG. 6A, a passivation layer 270 may be disposed on the side and top surfaces of the mesa-etched light emitting structure and the top surface of the first reflective layer 220. The passivation layer 270 may also be disposed on the side surface of the surface emitting laser device 201 separated by device units to protect and insulate the surface emitting laser device 201. The passivation layer 270 may be made of an insulating material, for example, nitride or oxide. For example, the passivation layer 270 may include at least one of polyimide, silica (SiO ₂ ), or silicon nitride (Si ₃ N ₄ ).

The passivation layer 270 may have a thickness at an upper surface of the light emitting structure to be thinner than that of the contact electrode 282, thereby exposing the contact electrode 282 to the upper portion of the passivation layer 270. The pad electrode 284 may be disposed in electrical contact with the exposed contact electrode 282. The pad electrode 284 may be disposed to extend over the passivation layer 270 to receive current from the outside.

(Production Method of Example)

Hereinafter, a method of manufacturing a surface emitting laser device according to an embodiment will be described with reference to FIGS. 14A to 16B.

First, as shown in FIG. 14A, a light emitting structure including a first reflective layer 220, an active region 230, and a second reflective layer 250 is formed on a substrate 210.

The substrate 210 may be formed of a material suitable for growing a semiconductor material or a carrier wafer, may be formed of a material having excellent thermal conductivity, and may include a conductive substrate or an insulating substrate.

For example, when the substrate 210 is a conductive substrate, a metal having excellent electrical conductivity may be used, and a GaAs substrate having high thermal conductivity may be used because it should be able to sufficiently dissipate heat generated when the surface emitting laser device 200 is operated. Alternatively, a metal substrate may be used, or a silicon (Si) substrate may be used.

In addition, when the substrate 210 is a non-conductive substrate, an AlN substrate, a sapphire (Al ₂ O ₃ ) substrate, or a ceramic substrate may be used.

In addition, in the exemplary embodiment, a substrate of the same type as the first reflective layer 220 may be used as the substrate 210. For example, when the substrate 210 is a GaAs substrate of the same type as the first reflective layer 220, the lattice constant coincides with the first reflective layer 210 so that a defect such as lattice mismatch does not occur in the first reflective layer 220. Can be.

Next, a first reflective layer 220 may be formed on the substrate 210, and FIG. 14B is an enlarged cross-sectional view of the second region B2 of the surface light emitting laser device according to the embodiment shown in FIG. 14A.

Hereinafter, a surface emitting laser device according to an exemplary embodiment will be described with reference to FIGS. 14A and 14B.

The first reflective layer 220 may be grown using a chemical vapor deposition method (CVD) or a molecular beam epitaxy (MBE) or a sputtering or hydroxide vapor phase epitaxy (HVPE).

The first reflective layer 220 may be doped with a first conductivity type. For example, the first conductivity type dopant may include an n type dopant such as Si, Ge, Sn, Se, Te, or the like.

The first reflective layer 220 may include a gallium-based compound, for example, AlGaAs, but is not limited thereto. The first reflective layer 220 may be a distributed Bragg reflector (DBR). For example, the first reflective layer 220 may have a structure in which layers made of materials having different refractive indices are alternately stacked at least one or more times.

For example, as shown in FIG. 14B, the first reflective layer 220 is disposed on the first group first reflective layer 221 and the first group first reflective layer 221 disposed on the substrate 210. The second group first reflective layer 222 may be included.

The first group first reflective layer 221 and the second group first reflective layer 222 may include a plurality of layers made of a semiconductor material having a compositional formula of Al _x Ga _(1-x) As (0 <x <1). If the Al in each layer increases, the refractive index of each layer may decrease, and if Ga increases, the refractive index of each layer may increase.

In addition, as shown in FIG. 14B, the first group first reflective layer 221 and the second group first reflective layer 222 may also be formed of a single layer or a plurality of layers. For example, the first group first reflective layer 221 may include about 30-40 pairs of the first group first-first layer 221a and the first group first-second layer 221b. have. In addition, the second group first reflective layer 222 may also include about 5 to 15 pairs of the second group first-first layer 222a and the second group first-second layer 222b.

Next, the active region 230 may be formed on the first reflective layer 220.

As shown in FIG. 14B, the active region 230 may include an active layer 232, a first cavity 231 disposed under the active layer 232, and a second cavity 233 disposed above. The active region 230 of the embodiment may include both the first cavity 231 and the second cavity 233, or may include only one of the two.

 The active layer 232 may include a quantum well layer 232a and a quantum wall layer 232b using a compound semiconductor material of a group III-V element. The active layer 232 may be formed in a 1 to 3 pair structure such as InGaAs / AlxGaAs, AlGaInP / GaInP, AlGaAs / AlGaAs, AlGaAs / GaAs, GaAs / InGaAs, but is not limited thereto. Dopants may not be doped in the active layer 232.

The first cavity 231 and the second cavity 233 may be formed of Al _y Ga _(1-y) As (0 <y <1) material, but is not limited thereto. For example, the first cavity 231 and the second cavity 233 may each include a plurality of layers made of Al _y Ga _(1-y) As.

For example, the first cavity 231 may include a first-first cavity layer 231a and a first-second cavity layer 231b. In addition, the second cavity 233 may include a 2-1 cavity layer 233a and a 2-2 cavity layer 233b.

Next, an AlGa-based layer 241a for forming the aperture region 240 may be formed on the active region 230. The AlGa-based layer 241a may include a plurality of layers. For example, the AlGa-based layer 241a may include a first AlGa-based layer 241a1 and a second AlGa-based layer 241a2.

The AlGa-based layer 241a may include a material such as Al _z Ga _(1-z) As (0 <z <1), but is not limited thereto.

The AlGa-based layer 241a may include a conductive material, and may include the same material as the first reflective layer 220 and the second reflective layer 250, but is not limited thereto.

For example, when the AlGa-based layer 241a includes an AlGaAs-based material, the AlGa-based layer 241a is a semiconductor material having a composition formula of Al _x Ga _(1-x) As (0 <x <1). It may be made, for example, but may have a composition formula of Al _0.98 Ga _0.02 As, but is not limited thereto.

Next, a second reflective layer 250 may be formed on the AlGa-based layer 241a.

The second reflective layer 250 may include a gallium-based compound, for example AlGaAs. For example, each layer of the second reflective layer 250 may include AlGaAs, and in detail, may be formed of a semiconductor material having a compositional formula of Al _x Ga _(1-x) As (0 <x <1). .

The second reflective layer 250 may be doped with a second conductivity type dopant. For example, the second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, Ba, or the like. Meanwhile, the first reflective layer 220 may be doped with a p-type dopant, and the second reflective layer 250 may be doped with an n-type dopant.

The second reflective layer 250 may also be a distributed Bragg reflector (DBR). For example, the second reflective layer 250 may have a structure in which a plurality of layers made of materials having different refractive indices are alternately stacked at least once.

For example, the second reflecting layer 250 may be disposed in the active region 230 than the first group second reflecting layer 251 and the first group second reflecting layer 251 disposed adjacent to the active region 230. The second group may include a second reflective layer 252 spaced apart from.

In addition, the first group second reflecting layer 251 and the second group second reflecting layer 252 may also be formed of a single layer or a plurality of layers, respectively. For example, the first group second reflective layer 251 may include about 1 to 5 pairs of the first group 2-1 layer 251a and the first group 2-2 layer 251b. In addition, the second group second reflective layer 252 may also include about 5 to 15 pairs of the second group 2-1 layer 252a and the second group 2-2 layer 252b. .

Next, FIG. 15A is an enlarged view of the first region C1 of the surface light emitting laser device according to the embodiment, and FIG. 15B is a cross-sectional view along the line A1-A2 of the surface light emitting laser device according to the embodiment shown in FIG. 15A.

15B, the light emitting structure may be etched using a predetermined mask 300 to form a mesa region M. Referring to FIG. In this case, the mesa may be etched from the second reflective layer 250 to the AlGa series layer 241a and the active region 230, and may be mesa etched up to a portion of the first reflective layer 220. In mesa etching, the AlGa-based layer 241a and the active region 230 may be removed from the second reflective layer 250 in the peripheral region by an inductively coupled plasma (ICP) etching method. It can be etched.

Next, FIG. 16A is an enlarged view of the first region C1 of the surface light emitting laser device according to the embodiment, and FIG. 16B is a cross-sectional view taken along line A1-A2 of the surface light emitting laser device according to the embodiment shown in FIG. 16A.

According to an embodiment, as shown in FIG. 16B, the edge region of the AlGa series layer 241a may be changed to the insulating region 242, and may be changed to, for example, wet oxidation. As a result, the aperture region 240 including the insulating region 242 and the aperture 241 which is a non-oxidation region may be formed.

For example, when oxygen is supplied from an edge region of the AlGa-based layer 241a, AlGaAs of the AlGa-based layer may react with H ₂ O to form aluminum oxide (Al ₂ O ₃ ). At this time, by adjusting the reaction time, the center region of the AlGa-based layer does not react with oxygen, and only the edge region reacts with oxygen to form an insulating region 242 of aluminum oxide.

In addition, the embodiment may change the edge region of the AlGa series layer into the insulating region 242 through ion implantation, but is not limited thereto. During ion implantation, photons may be supplied with energy of 300 keV or more.

After the reaction process described above, conductive AlGaAs may be disposed in the central region of the aperture region 240 and non-conductive Al ₂ O ₃ may be disposed in the edge region. AlGaAs in the central region may be defined as the aperture 241 as a portion where the light emitted from the active region 230 proceeds to the upper region.

6A, a passivation layer 270 may be formed on an upper surface of the light emitting structure. The passivation layer 270 may include at least one of polymide, silica (SiO ₂ ), or silicon nitride (Si ₃ N ₄ ).

The passivation layer 270 may expose a portion of the second reflective layer 250 to be electrically connected to the second electrode 280 formed thereafter.

In addition, according to an embodiment, the contact electrode 282 may be formed on the second reflective layer 250, and a central region between the contact electrodes 282 may correspond to the aperture 241. The contact electrode 282 may improve ohmic contact with the second reflective layer 250.

Next, a pad electrode 284 may be formed to be in electrical contact with the contact electrode 282, and the pad electrode 284 may be disposed to extend over the passivation layer 270 to receive current from the outside. .

The contact electrode 282 and the pad electrode 284 may be made of a conductive material. For example, the contact electrode 282 and the pad electrode 284 include at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). It can be formed into a single layer or a multi-layer structure.

 Next, a first electrode 215 may be disposed under the substrate 210. Before disposing the first electrode 215, a portion of the bottom surface of the substrate 210 may be removed through a predetermined grinding process to improve heat dissipation efficiency. The first electrode 215 may be made of a conductive material, for example, metal. For example, the first electrode 215 may include at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). It may be formed into a structure.

 (Mobile terminal)

Next, FIG. 17 is a perspective view of a mobile terminal to which a surface emitting laser device is applied according to an embodiment.

As shown in FIG. 17, the mobile terminal 1500 of the embodiment may include a camera module 1520, a flash module 1530, and an auto focusing device 1510 provided at a rear surface thereof. Here, the auto focus device 1510 may include one of the packages of the surface emitting laser device according to the above-described embodiment as a light emitting unit.

The flash module 1530 may include a light emitting device that emits light therein. The flash module 1530 may be operated by camera operation of a mobile terminal or control of a user.

The camera module 1520 may include an image capturing function and an auto focus function. For example, the camera module 1520 may include an auto focus function using an image.

The auto focus device 1510 may include an auto focus function using a laser. The auto focus device 1510 may be mainly used in a condition in which the auto focus function using the image of the camera module 1520 is degraded, for example, in a proximity or dark environment of 10 m or less. The autofocus device 1510 may include a light emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor device, and a light receiving unit converting light energy such as a photodiode into electrical energy.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment, but are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be interpreted that the contents related to such combinations and modifications are included in the scope of the embodiments.

Although described above with reference to the embodiment, this is merely an example, not to limit the embodiment, those skilled in the art to which the embodiment belongs to various not illustrated above in the range without departing from the essential characteristics of the embodiment It will be appreciated that modifications and applications of the branches are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to these modifications and applications will have to be construed as being included in the scope of the embodiments set forth in the appended claims.

Claims (9)

A first reflective layer;
An active region disposed on the first reflective layer;
A plurality of aperture regions disposed on the active region and including an aperture and an insulating region;
A second reflective layer disposed on the aperture region; And
And first and second electrodes electrically connected to the first reflective layer and the second reflective layer, respectively.
The outer periphery of the insulation region in the plurality of aperture regions is circular,
The outer surface of the aperture is a polygonal surface-emitting laser device. The method of claim 1,
The outer periphery of the aperture
Surface-emitting laser device which is one of the triangular shape to polygonal shape. The method of claim 1,
And a size of the aperture, which is the length of the polygonal long axis diagonal, from 6.0 μm to 12 μm. The method of claim 3,
The current density of the aperture is 8.3kA / cm ³ to 30.0 kA / cm ³ Surface emitting laser device. The method of claim 4, wherein
And a distance between each of the closest aperture centers in the plurality of aperture regions is greater than two times and less than three times the radius of each aperture region. The method of claim 4, wherein
The size of the aperture region is
And a half of the aperture size and the shortest distance from the polygon edge of the aperture to the outside of the insulation region. The method of claim 4, wherein
The outer periphery of the aperture
Surface-emitting laser device which is one of the triangular shape to polygonal shape. The method of claim 4, wherein
The divergent angle of the aperture is 20 ° to 27 ° surface emitting laser device. A light emitting device comprising the surface emitting laser device of any one of claims 1 to 8.

Images