KR102482204B1 - Laser device and method for manufacturing the same - Google Patents

Abstract

An embodiment includes a lower reflective layer; a laser cavity including an active layer disposed on the lower reflective layer; an oxide layer disposed over the laser cavity; and an upper reflective layer disposed on the oxide layer, wherein the upper reflective layer includes a plurality of upper reflective structures spaced apart from each other and an edge structure surrounding the plurality of upper reflective structures, wherein the oxide layer comprises a plurality of upper reflective structures disposed apart from each other. Disclosed is a laser device disposed between a structure and the laser cavity and not disposed between the frame structure and the laser cavity, and a manufacturing method thereof.

Description

Laser device and its manufacturing method {LASER DEVICE AND METHOD FOR MANUFACTURING THE SAME}

An embodiment relates to a vertical cavity surface emitting laser and a manufacturing method thereof.

A Vertical Cavity Surface Emitting Laser (VCSEL) is capable of oscillating in a single longitudinal mode of a narrow spectrum and has a small radiation angle and high coupling efficiency.

Recently, research into a technology for manufacturing a light source matrix by patterning vertical cavity surface emitting lasers (VCSELs) into a two-dimensional array has been actively conducted. A three-dimensional image of an object can be constructed by irradiating an object with a light source matrix patterned in the form of a two-dimensional array and analyzing a pattern of reflected light.

Significant advances in commercially currently used vertical cavity surface emitting lasers (VCSELs) have been made by the introduction of oxide apertures. The oxide aperture is the result of chemical reaction with the AlGaAs material as the H ₂ O molecule diffuses inside the AlGaAs layer as the AlGaAs layer is exposed to the high-temperature N ₂ and H ₂ O mixed gas atmosphere. It can be formed by an oxidation process that transforms it into the AlOx:As form.

Since this chemical oxidation process is highly dependent on processing conditions such as the Al content of the AlGaAs layer, the water vapor content, and the temperature of the reaction chamber, it is difficult to precisely control the shape and size of the oxide aperture in the transverse direction.

In addition, since there is an oxidized portion on the edge of the chip, the chip is easily broken or peeled off, resulting in defects.

Embodiments provide a laser device and a method of manufacturing the same, in which defects such as cracking or peeling of the edge of a chip are improved.

The problem to be solved in the embodiment is not limited thereto, and it will be said that the solution to the problem described below or the purpose or effect that can be grasped from the embodiment is also included.

A laser device according to one feature of the present invention includes a lower reflective layer; a laser cavity including an active layer disposed on the lower reflective layer; an oxide layer disposed over the laser cavity; and an upper reflective layer disposed on the oxide layer, wherein the upper reflective layer includes a plurality of upper reflective structures spaced apart from each other and an edge structure surrounding the plurality of upper reflective structures, wherein the oxide layer comprises a plurality of upper reflective structures disposed apart from each other. It is disposed between the structure and the laser cavity, and is not disposed between the rim structure and the laser cavity.

A capping layer may be disposed between the oxide layer and the upper reflective structure, and the capping layer may have a lower aluminum composition than the oxide layer.

The oxide layer may include a first hole disposed at the center of the plurality of upper reflective structures.

A height of an uppermost surface of the frame structure may be lower than a height of an uppermost surface of the plurality of upper reflective structures.

A height of an uppermost surface of the frame structure may be the same as a height of an uppermost surface of the plurality of upper reflective structures.

and an intermediate layer disposed between the oxide layer and the laser cavity, and a dopant type of the intermediate layer may be the same as that of the upper reflection layer.

The intermediate layer may overlap the plurality of upper reflective structures and an edge structure surrounding the plurality of upper reflective structures.

A laser device manufacturing method according to one aspect of the present invention includes forming an oxide layer and a mask on a laser cavity; forming a plurality of first holes in the oxide layer; forming an upper reflective layer on the oxide layer; and forming a plurality of upper reflective structures and an edge structure by etching the upper reflective layer.

In the forming of the plurality of first holes, an oxide layer of an area where the first holes are to be formed and an area where the border structure is to be formed may be removed together.

In the laser device according to the embodiment, defects in which edges of chips are cracked or peeled off can be improved. Thus, the apparent yield of chips can be improved.

Various advantageous advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the process of describing specific embodiments of the present invention.

1 is a plan view of a laser device according to an embodiment of the present invention;
Figure 2a is a cross-sectional view of a laser device according to an embodiment of the present invention,
Figure 2b is a modified example of Figure 2a,
3 is a plan view of a conventional laser device;
Figure 4 is a cross-sectional view of Figure 3,
5 is a plan view showing a state in which an oxide layer and a mask are formed on a laser cavity;
6 is a cross-sectional view showing a state in which an oxide layer and a mask are formed on a laser cavity;
7 is a plan view showing a state in which an oxide layer is patterned;
8 is a cross-sectional view showing a state in which an oxide layer is patterned;
9 is a plan view showing a state in which a planarization layer is entirely formed on an oxide layer;
10 is a cross-sectional view showing a state in which a planarization layer is entirely formed on an oxide layer;
11 is a plan view showing a state in which an upper reflective layer is entirely formed on an oxide layer;
12 is a cross-sectional view showing a state in which an upper reflective layer is entirely formed on an oxide layer;
13 is a plan view showing a state in which an upper reflective layer and an oxide layer are patterned;
14 is a cross-sectional view showing a state in which an upper reflective layer and an oxide layer are patterned;
15 is a cross-sectional view showing a state in which an upper electrode is formed on an upper reflective layer.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second and first may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be termed a first element, and similarly, a first element may be termed a second element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings, but the same or corresponding components regardless of reference numerals are given the same reference numerals, and overlapping descriptions thereof will be omitted.

1 is a plan view of a laser device according to an embodiment of the present invention, FIG. 2a is a cross-sectional view of a laser device according to an embodiment of the present invention, FIG. 2b is a modified example of FIG. 2a, and FIG. 3 is a conventional laser device. A plan view, and FIG. 4 is a cross-sectional view of FIG. 3 .

1, the laser device according to the embodiment includes a lower reflective layer 20, a laser cavity 30 including an active layer disposed on the lower reflective layer 20, and an oxide layer disposed on the laser cavity 30 ( 51), and an upper reflective layer 40 disposed on the oxide layer 51.

The semiconductor structure of the laser device is formed using Metal-Organic Chemical Vapor Deposition (MOCVD), Liquid Phase Epitaxy (LPE), and Molecular Beam Epitaxy (MBE). It can be manufactured, but is not necessarily limited thereto.

Substrate 10 may be a semi-insulating or conductive substrate. For example, the substrate 10 is a GaAs substrate having a high doping concentration, and the doping concentration may be about 1×10 ¹⁷ cm ⁻³ to 1×10 ¹⁹ cm ⁻³ . If necessary, a semiconductor buffer layer such as an AlGaAs or GaAs thin film may be further disposed on the substrate 10, but is not necessarily limited thereto.

The lower reflective layer 20 may include a Distributed Bragg Reflector (DBR) having an n-type superlattice structure. The lower reflective layer 20 may be epitaxially deposited on the substrate 10 by a technique such as MOCVD or MBE described above.

The lower reflective layer 20 may perform an internal reflection function in the VCSEL structure. The lower reflective layer 20 may be formed by alternately stacking a plurality of first lower reflective layers 21 and a plurality of second lower reflective layers 22 . Both the first lower reflective layer 21 and the second lower reflective layer 22 may be AlGaAs, but the aluminum composition of the first lower reflective layer 21 may be higher.

The first lower reflective layer 21 and the second lower reflective layer 22 constituting the lower reflective layer 20 preferably have an effective optical thickness that is about 1/4 of the wavelength of light generated by the VCSEL, and For high internal reflection, it is desirable to have a reflectance of about 100% overall, if possible.

The first lower reflective layer 21 and the second lower reflective layer 22 have an effective optical thickness (effective optical thickness = target light wavelength / (4 x material refractive index)) that is about 1/4 of the wavelength of light generated by the VCSEL. can have It is also desirable to have a reflectance of about 100% for high internal reflection of the VCSEL.

The reflectance of the lower reflective layer 20 is determined by the difference in refractive index between the first lower reflective layer 21 and the second lower reflective layer 22 constituting the inside thereof, and the first lower reflective layer 21 and the second lower reflective layer 22 may depend on the number of layers of Therefore, in order to obtain a high reflectance, the greater the difference in refractive index and the greater the number of layers, the better.

In addition, in order to reduce the electrical resistance, the Al composition ratio of the first lower reflective layer 21 and the second lower reflective layer 22 between the first lower reflective layer 21 and the second lower reflective layer 22 is one-dimensionally or two-dimensionally It is also possible to place an Al graded AlGaAs layer continuously changed to .

The laser cavity 30 may include an active layer composed of one or more quantum well layers and a barrier layer. Any one of GaAs, AlGaAs, AlGaAsSb, InAlGaAs, AlInGaP, GaAsP, or InGaAsP may be selected for the quantum well layer, and any one of AlGaAs, InAlGaAs, InAlGaAsP, AlGaAsSb, GaAsP, GaInP, AlInGaP, or InGaAsP may be selected for the barrier layer. It can be.

The laser cavity 30 may be designed to provide sufficient optical gain of the laser device. Illustratively, the laser cavity 30 according to the embodiment may have a quantum well layer having an appropriate thickness and composition ratio at the center to emit light in a wavelength range of about 850 nm or about 980 nm. However, the wavelength band of the laser output from the quantum well layer is not particularly limited.

The laser cavity 30 may include a first semiconductor layer (not shown) disposed below the active layer and a second semiconductor layer (not shown) disposed above the active layer. The first semiconductor layer may be an n-type semiconductor layer and the second semiconductor layer may be a p-type semiconductor layer, but is not necessarily limited thereto. The first semiconductor layer and the second semiconductor layer may not be doped with a dopant. Illustratively, the first semiconductor layer and the second semiconductor layer may be AlGaAs, but are not necessarily limited thereto.

An oxide layer 51 may be disposed on the laser cavity 30 . The oxide layer 51 may be doped with the same type of dopant as the upper reflective layer 40 . For example, the oxide layer 51 may be doped with a p-type dopant at a concentration of about 10 ¹⁸ cm ^-3 , but is not necessarily limited thereto.

The oxide layer 51 may include a semiconductor compound containing aluminum, for example, AlAs, AlGaAs, InAlGaAs, or the like. A first hole h1 may be disposed in the center of the oxide layer 51 according to the embodiment. That is, the oxide layer 51 may have a donut shape with a hole formed in the center.

Since the oxide layer 51 has a relatively high resistance and a relatively low refractive index, current can pass through the first hole h1 and laser light can be focused to the center of the device.

According to the embodiment, since the diameter of the opening of the oxide layer is already determined by the first hole h1, an oxidation process requiring precise control can be quickly performed. However, it is not necessarily limited thereto, and openings may be formed by adjusting the degree of oxidation as in the prior art.

The aluminum composition of the oxide layer 51 may be 80% to 100%. When the aluminum composition of the oxide layer 51 is 80% or less, the oxidation rate slows down and the process lengthens.

A capping layer 52 may be disposed on the oxide layer 51 . The capping layer 52 may prevent the oxide layer 51 from being exposed to an external environment during or after the process.

The oxide layer 51 may be designed to have a high aluminum composition and a high doping concentration so that it can be easily oxidized. Therefore, in the absence of the capping layer 52, the oxidation layer 51 may already be oxidized before the oxidation process is performed.

Since it is difficult to grow a semiconductor layer on the already oxidized oxide layer 51 , it may be difficult to grow the upper reflective layer 40 . Accordingly, the capping layer 52 may prevent the oxidation layer 51 from being oxidized before the oxidation process.

The capping layer 52 may be selected from at least one of GaAs, AlGaAs, InAlGaAs, AlGaAsSb, AlGaAsP, GaInP, InGaAsP, and AlInGaP, but is not necessarily limited thereto.

When the capping layer 52 includes aluminum, the aluminum composition of the capping layer 52 may be smaller than the aluminum composition of the oxide layer 51 . For example, the aluminum composition of the capping layer 52 may be 0% to 60%. When the aluminum composition of the capping layer 52 is greater than 60%, a problem in that the surface of the capping layer 52 is exposed to air and oxidized may occur during the process, and even after the upper reflection layer 40 is formed, the oxide layer ( When 51) is oxidized, there may be a problem in that the capping layer 52 is oxidized together.

The capping layer 52 may have a thickness of 2.5 Å to 5000 Å. When the thickness of the capping layer 52 is less than 2.5 Å, the capping layer 52 is too thin to effectively block the permeation of oxygen. There is a problem that it is difficult to form a uniform interface due to the large size.

The upper reflective layer 40 may be disposed on the oxide layer 51 . The upper reflective layer 40 may include a first upper reflective layer 41 and a second upper reflective layer 42 like the lower reflective layer 20 .

Both the first upper reflective layer 41 and the second upper reflective layer 42 may have a composition of AlGaAs, but the aluminum composition of the first upper reflective layer 41 may be higher.

The upper reflective layer 40 may be doped to have a polarity different from that of the lower reflective layer 20 . For example, if the lower reflective layer 20 and the substrate 10 are doped with an n-type dopant, the upper reflective layer 40 may be doped with a p-type dopant.

The upper reflective layer 40 may have fewer layers than the lower reflective layer 20 in order to reduce reflectance from the VCSEL. That is, the reflectance of the upper reflective layer 40 may be smaller than that of the lower reflective layer 20 .

The upper reflective layer 40 may include a plurality of upper reflective structures 40a spaced apart from each other and an edge structure 40b surrounding the plurality of upper reflective structures 40a.

The plurality of upper reflective structures 40a may be spaced apart from each other, and the number is not particularly limited. Illustratively, the number of the plurality of upper reflective structures 40a in the chip may be 100 to 500.

On a plane, the plurality of upper reflective structures 40a may have circular shapes, but are not limited thereto and may have various polygonal shapes.

The edge structure 40b of the upper reflective layer 40 may be disposed to surround the plurality of upper reflective structures 40a. For example, the edge structure 40b may have a rectangular frame shape surrounding the plurality of upper reflective structures 40a. At this time, some of the square frame shapes may be formed with a wide area, and the electrode pads 62 may be disposed thereon.

The oxide layer 51 according to the embodiment is disposed between the plurality of upper reflective structures 40a and the laser cavity 30, but may not be disposed between the edge structure 40b and the laser cavity 30. That is, by removing the oxide layer 51 from the lower portion of the edge structure 40b, it is possible to improve the problem of the edge structure 40b being separated from the chip.

The height of the edge structure 40b may have a difference d1 from the height of the upper reflective structure 40a. That is, since the oxide layer 51 is removed from the lower portion of the edge structure 40b, the height of the upper reflection structure 40a disposed above the oxide layer 51 may be higher. However, the height of the frame structure 40b and the height of the upper reflection structure 40a may be substantially equal to each other.

Referring to FIGS. 3 and 4 , when the oxide layer 51 is formed on both the lower portion of the plurality of upper reflective structures 40a and the lower portion of the edge structure 40b, the edge structure 40b is broken or peeled off even with a small impact. risk may increase.

The oxide layer 51 may change into an amorphous crystal structure while being oxidized. Accordingly, since the crystal structure is different from that of the intermediate layers 43 and 44 disposed under the oxide layer 51 and the upper reflective layer 40 disposed thereon, stress is generated.

However, since the oxide layer 51 disposed below the upper reflective structure 40a has an unoxidized region in the center, a relatively stable bonding state may be maintained even when stress occurs. Alternatively, when the first hole h1 is formed in the center of the oxide layer 51, the upper reflective structure 40a regrows inside the first hole h1, so that it is in a relatively stable bonding state even when stress occurs during the oxidation process. can keep However, since the edge structure 40b is formed on the upper surface of the oxide layer 51 or the capping layer 52, the bonding state may be relatively unstable.

Therefore, since the stress due to the lattice mismatch is high between the frame structure 40b and the oxide layer 51, when thermal shock for ohmic formation or impact by ultrasonic cleaning occurs, the frame structure 40b is cracked or peeled off. there is a problem.

However, according to the embodiment, since the oxide layer 51 is removed from the lower portion of the frame structure 40b, the frame structure 40b is formed on the intermediate layers 43 and 44 having the same crystal structure, so that the oxide layer 51 is oxidized. The amorphous crystal structure can be avoided, thus freeing from stress due to the oxidized amorphous crystal structure. Therefore, even when thermal shock or impact by ultrasonic cleaning occurs, the problem of cracking or peeling of the frame structure 40b can be improved. Thus, the apparent yield of chips can be improved.

The intermediate layers 43 and 44 may be disposed between the upper reflective layer 40 and the intermediate layers 43 and 44 . This structure has the advantage of being able to protect the laser cavity 30 .

In general, when the oxide layer 51 is oxidized, the material becomes amorphous, and the film quality may be somewhat deteriorated. Accordingly, if an amorphous layer having a somewhat inferior film quality is directly bonded to a laser cavity in which light is generated, reliability of the device may be deteriorated. Accordingly, the intermediate layers 43 and 44 may be formed before the oxide layer to prevent direct contact of the amorphous layer with the laser cavity.

The intermediate layers 43 and 44 may have the same composition as the upper reflective layer 40 . Illustratively, the composition of the first intermediate layer 43 may be the same as that of the first upper reflective layer 41 , and the composition of the second intermediate layer 44 may be the same as that of the second upper reflective layer 42 . That is, the intermediate layers 43 and 44 may be part of the upper reflective layer 40 . Accordingly, the total reflectance of the upper reflective layer 40 can be controlled including the thickness of the intermediate layers 43 and 44 .

The first electrode 61 may be disposed on the upper reflective layer 40 , and the second electrode 11 may be disposed below the substrate 10 . However, it is not necessarily limited thereto, and after exposing the upper part of the substrate 10 of the second electrode 11, the second electrode 11 may be disposed in the exposed area.

The first electrode 61 and the second electrode 11 include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), and indium gallium zinc oxide (IGZO). ), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, or Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, It may be formed including at least one of Ru, Mg, Zn, Pt, Au, and Hf, but is not limited to these materials.

Illustratively, the first electrode 61 may have a plurality of metal layers (eg, Ti/Pt/Au). In this case, the thickness of Ti may be about 100 angstroms to 400 angstroms, and the thickness of Au may be about 3000 angstroms to 20000 angstroms, but is not necessarily limited thereto.

The second electrode 11 may have a plurality of metal layers (eg, AuGe/Ni/Au). In this case, the thickness of AuGe may be 1000 angstroms, the thickness of Ni may be 100 angstroms, and the thickness of Au may be 2000 angstroms, but is not necessarily limited thereto.

An ohmic layer (not shown) may be further disposed between the first electrode 61 and the upper reflective layer 40 . The ohmic layer may include a material having a band gap equal to or lower than that of the GaAs substrate and equal to or lower than the energy of the emitting laser light, for low ohmic resistance. For example, the ohmic layer may be one of AlInGaAs, InGaAs, GaAs, AlInGaAsSb, AlInGaAsPSb, InGaAsP, InGaAsPSb, GaAsSb, InGaAsSb, InAsSb, AlGaAsSb, AlGaAsP, and AlGaInAsP.

5 is a plan view showing a state in which an oxide layer and a mask are formed on a laser cavity, FIG. 6 is a cross-sectional view showing a state in which an oxide layer and a mask are formed on a laser cavity, and FIG. 7 is a plan view showing a state in which an oxide layer is patterned. 8 is a cross-sectional view showing a state in which the oxide layer is patterned.

5 and 6 , a lower reflective layer 20, a laser cavity 30, intermediate layers 43 and 44, an oxide layer 51, and a capping layer 52 may be sequentially formed on a substrate 10. . The second electrode 11 may be formed at this stage, but may also be formed together with the first electrode after fabrication of the chip is completed. The semiconductor structure of the laser device is formed using Metal-Organic Chemical Vapor Deposition (MOCVD), Liquid Phase Epitaxy (LPE), and Molecular Beam Epitaxy (MBE). It can be manufactured, but is not necessarily limited thereto.

A mask pattern P1 having a hole may be formed on the capping layer 52 . A plurality of mask patterns P1 may be disposed on the wafer. In the capping layer 52, a region h2 corresponding to the hole of the mask pattern and an edge region h3 disposed outside the mask may be exposed to the outside. The number of mask patterns P1 may be equal to the number of chips to be divided.

Referring to FIGS. 7 and 8 , the capping layer 52 exposed by the mask pattern P1 may be etched. Afterwards, the oxide layer 51 exposed by the mask pattern P1 may be etched. As a method of etching the capping layer 52 and the oxide layer 51, a general semiconductor process may be applied without limitation. For example, the capping layer 52 and the oxide layer 51 may be patterned by wet etching, but are not necessarily limited thereto.

In this process, an area corresponding to the hole of the mask pattern P1 and an edge area h3 disposed outside the mask may be removed from the oxide layer 51 . Accordingly, a plurality of first holes h1 may be formed in the oxide layer 51 and the edge portion may be removed.

9 is a plan view showing a state in which a planarization layer is entirely formed on an oxide layer, and FIG. 10 is a cross-sectional view showing a state in which a planarization layer is entirely formed on an oxide layer.

Referring to FIG. 9 , the planarization layer 41 may be re-grown. The planarization layer 41 may be re-grown in the first hole h1 and the edge region h3 from which the capping layer 52 is removed. The planarization layer 41 grown in the first hole h1 may evenly grow on top of the capping layer 52 . However, the re-grown planarization layer 41 in the edge region h3 may grow relatively lower than the planarization layer 41 formed on the oxide layer 51 . Since the planarization layer 41 is the first upper reflection layer, it may have the same composition as the intermediate layers 43 and 44 and the upper reflection layer 40 .

11 is a plan view showing a state in which an upper reflective layer is entirely formed on an oxide layer, FIG. 12 is a cross-sectional view showing a state in which an upper reflective layer is entirely formed on an oxide layer, and FIG. 13 is a plan view showing a state in which the upper reflective layer and the oxide layer are patterned. 14 is a cross-sectional view showing a state in which the upper reflective layer and the oxide layer are patterned, and FIG. 15 is a cross-sectional view showing a state in which an upper electrode is formed on the upper reflective layer.

Referring to FIGS. 11 and 12 , the remaining upper reflection layer 40 may be formed on the planarization layer 41 .

Both the first upper reflective layer 41 and the second upper reflective layer 42 may have a composition of AlGaAs, but the aluminum composition of the first upper reflective layer 41 may be higher.

The upper reflective layer 40 may be doped to have a polarity different from that of the lower reflective layer 20 . For example, if the lower reflective layer 20 and the substrate 10 are doped with an n-type dopant, the upper reflective layer 40 may be doped with a p-type dopant.

The upper reflective layer 40 may have fewer layers than the lower reflective layer 20 in order to reduce reflectance from the VCSEL. That is, the reflectance of the upper reflective layer 40 may be smaller than that of the lower reflective layer 20 .

Referring to FIGS. 13 and 14 , a plurality of light emitting structures may be formed by etching the upper reflective layer 40 , the capping layer 52 , the oxide layer 51 , and the intermediate layers 43 and 44 . In this process, the upper reflective layer 40 may be separated into a plurality of upper reflective structures 40a and an edge structure 40b. Various semiconductor etching processes may be used for this etching process without limitation.

In this case, since the oxide layer 51 has already been removed from the edge region h3, the oxide layer 51 and the capping layer 52 may not be formed on the edge structure 40b. Thus, the apparent yield can be improved.

Thereafter, the oxide layer 51 may be oxidized by exposure to water vapor. The side surface of the exposed oxide layer 51 is oxidized so that the inside of the oxide layer 51 may be gradually oxidized. According to the embodiment, since the first hole h1 is already formed in the oxide layer 51, the oxidation process can be completed by oxidizing the entire oxide layer 51. Thus, the oxidation process can proceed quickly and accurately.

Referring to FIG. 15 , an insulating layer 60 may be formed on a plurality of light emitting structures. Thereafter, after forming a hole in the insulating layer 60 , the first electrode 61 may be formed to electrically connect to the upper reflective structure 40a. In addition, an electrode pad 62 may be formed on one side of the edge structure 40b.

The laser device according to the present embodiment may be used as a light source for 3D face recognition and 3D imaging technology. 3D face recognition and 3D imaging technologies require a patterned light source matrix in the form of a two-dimensional array. A light source matrix patterned in the form of a two-dimensional array may be irradiated onto an object and a pattern of reflected light may be analyzed. At this time, by analyzing the deformed states of the element lights reflected from the curved surface of each shape object among the light source matrix patterned in the form of a two-dimensional array, a three-dimensional image of the object can be constructed. If the structured light source patterned in the form of such a two-dimensional array is fabricated in the VCSEL array according to the embodiment, the structured light source in the form of a two-dimensional array in which the characteristics of each element light source are uniform matrix can be provided.

In addition, the laser device according to the present invention is an optical communication device, CCTV, night vision for automobiles, motion recognition, medical / treatment, communication device for IoT, heat tracking camera, thermal imaging camera, SOL (Solid State Laser) It can be used as a low-cost VCSEL light source in many applications, such as pumping and heating processes for bonding plastic films.

Although the above has been described with reference to the embodiments, these are merely examples and do not limit the present invention, and those skilled in the art to which the present invention belongs will not deviate from the essential characteristics of the present embodiment. It will be appreciated that various variations and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And the differences related to these modifications and applications should be construed as being included in the scope of the present invention as defined in the appended claims.

Claims (9)

a lower reflective layer;
a laser cavity including an active layer disposed on the lower reflective layer;
an oxide layer disposed over the laser cavity;
a capping layer disposed on the oxide layer;
An upper reflective layer disposed on the capping layer;
The upper reflective layer includes a plurality of upper reflective structures spaced apart from each other and an edge structure surrounding the plurality of upper reflective structures,
The oxide layer and the capping layer are disposed between the plurality of upper reflective structures and the laser cavity, and are not disposed between the edge structure and the laser cavity.
According to claim 1,
The capping layer has a lower aluminum composition than the oxide layer.
According to claim 1,
The oxide layer includes a first hole disposed in the center of the plurality of upper reflective structures.
According to claim 1,
A height of an uppermost surface of the frame structure is lower than a height of an uppermost surface of the plurality of upper reflective structures.
According to claim 1,
The height of the uppermost surface of the frame structure is the same as that of the uppermost surface of the plurality of upper reflective structures.
According to claim 1,
an intermediate layer disposed between the oxide layer and the laser cavity;
The dopant type of the intermediate layer is the same as the dopant of the upper reflective layer.
According to claim 6,
The intermediate layer overlaps with the plurality of upper reflective structures and an edge structure surrounding the plurality of upper reflective structures.
forming an oxide layer and a mask on the laser cavity;
forming a plurality of first holes in the oxide layer;
forming an upper reflective layer on the oxide layer; and
Etching the upper reflective layer to form a plurality of upper reflective structures and an edge structure;
In the forming of the plurality of first holes, the oxide layer of the region where the first holes are to be formed and the region where the border structure is to be formed are removed together.
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