Laser device
阅读说明:本技术 激光器件 (Laser device ) 是由 崔元珍 金东焕 于 2019-09-04 设计创作,主要内容包括:本发明公开一种激光器件,其包括:基板;第一反射层叠体,其配置于上述基板上;有源层,其配置于上述第一反射层叠体上;氧化层,其配置于上述有源层上;第二反射层叠体,其配置于上述氧化层上;多个凹槽,其贯通上述第二反射层叠体、上述氧化层、上述有源层以及上述第一反射层叠体;第一电极层,其配置于上述第二反射层叠体上且与上述第二反射层叠体电连接;以及第二电极层,其配置于上述第二反射层叠体上并向上述多个凹槽的内部延伸而与上述第一反射层叠体电连接,上述第二反射层叠体的反射率高于上述第一反射层叠体的反射率。(The invention discloses a laser device, which comprises: a substrate; a first reflective laminate disposed on the substrate; an active layer disposed on the first reflective stack; an oxide layer disposed on the active layer; a second reflective laminate disposed on the oxide layer; a plurality of grooves penetrating the second reflective laminate, the oxide layer, the active layer, and the first reflective laminate; a first electrode layer disposed on the second reflective laminate and electrically connected to the second reflective laminate; and a second electrode layer disposed on the second reflective laminate and extending into the plurality of grooves to be electrically connected to the first reflective laminate, wherein the second reflective laminate has a reflectance higher than that of the first reflective laminate.)
1. A laser device, comprising:
a substrate;
a first reflective laminate disposed on the substrate;
an active layer disposed on the first reflective stack;
an oxide layer disposed on the active layer;
a second reflective laminate disposed on the oxide layer;
a plurality of grooves penetrating the second reflective laminate, the oxide layer, the active layer, and the first reflective laminate;
a first electrode layer disposed on the second reflective laminate and electrically connected to the second reflective laminate; and the number of the first and second groups,
a second electrode layer disposed on the second reflective laminate and extending into the plurality of grooves to be electrically connected to the first reflective laminate,
the reflectance of the second reflective laminate is higher than the reflectance of the first reflective laminate.
2. The laser device of claim 1,
further comprising a conductive layer disposed between the substrate and the first reflective stack,
the substrate is not doped with a dopant,
the conductive layer is doped with a dopant.
3. The laser device according to claim 2,
the dopant doped in the conductive layer is the same as the dopant doped in the first reflective stack,
the doping concentration of the conductive layer is higher than the doping concentration of the first reflective stack.
4. The laser device according to claim 3,
comprising a first insulating layer extending to the inside of the plurality of grooves,
the plurality of grooves and the first insulating layer expose a portion of the upper surface of the conductive layer.
5. The laser device according to claim 4,
the second electrode layer includes a contact portion extending into the plurality of grooves and electrically connected to the conductive layer.
6. The laser device of claim 1,
the second insulating layer is disposed between the first electrode layer and the second electrode layer.
7. The laser device of claim 1,
the laser light generated in the active layer is reflected by the second reflective laminate, passes through the substrate, and is emitted to the outside.
8. The laser device according to claim 5,
the oxide layer includes a plurality of non-oxidized regions,
each non-oxidized region is surrounded on a plane by the plurality of grooves.
9. The laser device according to claim 8,
each non-oxidized region is surrounded on a plane by the plurality of contact portions,
the plurality of contact portions are overlapped with the plurality of grooves on a plane.
10. A laser device, comprising:
a substrate;
a conductive layer disposed on the substrate;
a first reflective laminate disposed on the conductive layer;
an active layer disposed on the first reflective stack;
an oxide layer disposed on the active layer;
a second reflective laminate disposed on the oxide layer;
a plurality of grooves that penetrate the second reflective laminate, the oxide layer, the active layer, and the first reflective laminate and expose the conductive layer;
a first electrode layer disposed on the second reflective laminate;
a first insulating layer which is disposed on the first electrode layer and the plurality of grooves and includes an opening portion exposing the conductive layer;
a second electrode layer disposed on the first insulating layer, extending toward the opening, and contacting the conductive layer;
a second insulating layer disposed on the second electrode layer;
a first pad which penetrates the first insulating layer and the second insulating layer and is electrically connected to the first electrode layer; and the number of the first and second groups,
and a second pad which penetrates the second insulating layer and is electrically connected to the second electrode layer.
11. The laser device of claim 10,
the reflectance of the second reflective laminate is higher than the reflectance of the first reflective laminate.
12. The laser device of claim 11,
the laser light generated in the active layer is reflected by the second reflective laminate, passes through the substrate, and is emitted to the outside.
Technical Field
The invention relates to a laser device (LASER DEVICE).
Background
A Vertical Cavity Surface Emitting Laser (VCSEL) is capable of single longitudinal mode oscillation with a narrow spectrum and a radiation angle of a light beam is small, so that coupling efficiency (coupling efficiency) is high.
Recently, a technology of fabricating a light source matrix for patterning Vertical Cavity Surface Emitting Lasers (VCSELs) in a two-dimensional array form is actively studied. A three-dimensional image of an object can be constructed by illuminating the object with a light source matrix patterned in a two-dimensional array and analyzing the pattern of reflected light.
However, most vertical cavity surface emitting lasers are configured by a substrate, a lower reflective layer, a laser cavity, and an upper reflective layer structure, and emit light generated in the laser cavity to an upper portion, which is a direction opposite to the substrate.
That is, in the flip chip structure in which light generated in a laser cavity is emitted to the outside through a substrate, it is not practical to develop the flip chip structure.
Disclosure of Invention
Problems to be solved
The invention discloses a VCSEL laser device with a flip chip structure.
The invention discloses a VCSEL laser device with excellent light output.
The problem to be solved by the present invention is not limited to this, and may include an object or an effect that can be grasped from the means for solving the problem or the embodiments described below.
Means for solving the problems
The laser device according to an embodiment of the present invention includes: a substrate; a first reflective laminate disposed on the substrate; an active layer disposed on the first reflective stack; an oxide layer disposed on the active layer; a second reflective laminate disposed on the oxide layer; a plurality of grooves penetrating the second reflective laminate, the oxide layer, the active layer, and the first reflective laminate; a first electrode layer disposed on the second reflective laminate and electrically connected to the second reflective laminate; and a second electrode layer disposed on the second reflective laminate and extending into the plurality of grooves to be electrically connected to the first reflective laminate, wherein the second reflective laminate has a reflectance higher than that of the first reflective laminate.
The laser device may further include a conductive layer disposed between the substrate and the first reflective stack, wherein the substrate is not doped with a dopant, and the conductive layer is doped with a dopant.
The dopant doped in the conductive layer may be the same as the dopant doped in the first reflective stack, and the conductive layer may have a higher doping concentration than the first reflective stack.
The laser device may include a first insulating layer extending to an inside of the plurality of grooves, the plurality of grooves and the first insulating layer exposing a portion of an upper surface of the conductive layer.
The second electrode layer may include a contact portion extending into the plurality of grooves and electrically connected to the conductive layer.
The laser device may include a second insulating layer disposed between the first electrode layer and the second electrode layer.
The laser light generated in the active layer can be reflected by the second reflective laminate and emitted to the outside through the substrate.
The oxide layer may include a plurality of non-oxidized regions each surrounded on a plane by the plurality of grooves.
Each of the non-oxidized regions may be surrounded on a plane by the plurality of contact portions, and the plurality of contact portions may overlap the plurality of grooves on a plane.
A laser device according to another embodiment of the present invention includes: a substrate; a conductive layer disposed on the substrate; a first reflective laminate disposed on the conductive layer; an active layer disposed on the first reflective stack; an oxide layer disposed on the active layer; a second reflective laminate disposed on the oxide layer; a plurality of grooves that penetrate the second reflective laminate, the oxide layer, the active layer, and the first reflective laminate and expose the conductive layer; a first electrode layer disposed on the second reflective laminate; a first insulating layer which is disposed on the first electrode layer and the plurality of grooves and includes an opening portion exposing the conductive layer; a second electrode layer disposed on the first insulating layer, extending toward the opening, and contacting the conductive layer; a second insulating layer disposed on the second electrode layer; a first pad which penetrates the first insulating layer and the second insulating layer and is electrically connected to the first electrode layer; and a second pad electrically connected to the second electrode layer through the second insulating layer.
Effects of the invention
According to the embodiment, a laser device of a flip chip structure can be manufactured. Therefore, additional wire bonding operations can be omitted.
In addition, the light output can be improved.
In addition, the operating voltage can be reduced.
In addition, light uniformity can be improved.
In addition, the number of chips that can be produced in 1 wafer can be increased.
In addition, the manufacturing cost of the chip can be reduced.
Drawings
Fig. 1 is a top view of a laser device according to one embodiment of the present invention.
Fig. 2a is a cross-sectional view a-a of fig. 1.
Fig. 2b is a partially enlarged view a of fig. 2 a.
Fig. 3 is a sectional view B-B of fig. 1.
Fig. 4 is a graph measuring relative light output according to doping concentration of a substrate.
Fig. 5 is a graph in which an I-V curve according to the thickness of a conductive layer is measured.
Fig. 6 to 25 are diagrams showing a laser device fabrication process.
Fig. 26 to 30 show various modifications of the arrangement of the recess and the non-oxidized region.
Detailed Description
Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described below. However, the present invention is not limited to the specific embodiments, and it should be understood that the present invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.
Terms including ordinal numbers such as first, second, and the like can be used to describe a plurality of types of components, but the components are not limited to the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, a second component can be named a first component without departing from the scope of the present invention, and similarly, a first component can also be named a second component. The term "and/or" includes a combination of a plurality of items described in association or one of a plurality of items described in association.
When a certain component is referred to as being "connected" or "in contact with" another component, it is to be understood that the component can be directly connected or in contact with the other component, but another component can also be present therebetween. On the contrary, in the case where a certain constituent element is referred to as being "directly connected" or "directly contacting" to another constituent element, it is to be understood that no other constituent element exists therebetween.
The terms used in the present application are used only for describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In the present application, the terms "including" or "having" are intended to specify the presence of the features, numerals, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not to preclude the presence or addition of one or more other features or numerals, steps, actions, components, parts, or combinations thereof.
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. Terms defined in dictionaries as generally used should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Hereinafter, the embodiments will be described in detail with reference to the drawings, and the same or corresponding constituent elements are denoted by the same reference numerals regardless of the reference numerals, and the repetitive description thereof will be omitted.
Fig. 1 is a top view of a laser device according to an embodiment of the present invention, fig. 2a is a sectional view a-a of fig. 1, fig. 2B is a partially enlarged view a of fig. 2a, and fig. 3 is a sectional view B-B of fig. 1.
Referring to fig. 1, the laser device according to the embodiment may be a flip chip type in which a
The
The laser device can include a plurality of grooves H1 and a plurality of
Each
At this time, the distance from the
The area ratio of the plurality of non-oxidized regions to the plurality of recesses may be 1: 0.03 to 1: 5. when the area ratio becomes more than 1: when the amount is small at 0.03 (for example, 1: 0.01), the area of the groove becomes too small, and the oxidation process becomes long. In addition, when the area ratio becomes larger than 1: in
The plurality of
Referring to fig. 2a and 2b, a laser device according to an embodiment can include a
The
In addition, the
The
The doping concentration of the
That is, the first
The thickness of the
The first
The first
Both the first
The first and second
The first and second
The reflectance of the first
The
The
The
The
The
In the case of the oxidized region of the
The second
The third
The second
The reflectance of the second
The number of layers of the first
The plurality of grooves H1 can penetrate the second
The
The
The first insulating
The
The second insulating
The first and second insulating
The
According to the embodiment, both the
Fig. 4 is a graph in which the relative light output according to the doping concentration of the substrate is measured, and fig. 5 is a graph in which the I-V curve according to the thickness of the conductive layer is measured.
Referring to fig. 4, it can be seen that the light output varies with the doping concentration of the substrate. Illustratively, the doping concentrations at the substrate are 2.0 × 10, respectively18cm-3、1.0×1018cm-3、5.0×1017cm-3、1.0×1017cm-3And 1.0X 1016cm-3In the case of (2), it is known that the light output varies depending on the thickness.
1.0X 10
Therefore, in the flip chip structure in which light is output through the substrate, it is found that the lower the doping concentration is, the more advantageous the light output is. Therefore, in one embodiment, the substrate is not doped but an additional thin conductive layer is formed, so that not only light output can be improved but also current spreading efficiency can be improved.
Referring to fig. 5, it is understood that when the conductive layer has a thickness of 0.5 μm, 1.0 μm, 2.0 μm, 3.0 μm, or 6.0 μm, the voltage increase due to the increase in current is constant when the chip is driven. That is, it is found that the voltage rise due to the resistance of the conductive layer does not greatly affect the total operating voltage rise. However, it is known that the operating voltage is relatively large when the thickness of the conductive layer is 0.1 μm. Therefore, the thickness of the conductive layer is preferably 0.5 μm or more. In addition, when the thickness of the conductive layer is larger than 10 μm, there is a problem that the light absorption rate becomes large. Accordingly, the thickness of the conductive layer may be 0.5 μm to 10 μm.
Fig. 6 to 25 are diagrams showing a laser device fabrication process.
Referring to fig. 6, the
The substrate is GaAs substrate, and the doping concentration can be reduced to 1 × 1014cm-3To
Referring to fig. 7, a first photoresist R1 is formed on the second
The groove H1 can penetrate through the second
Referring to fig. 9, if the
Referring to fig. 10, when the oxidation is stopped, a
Referring to fig. 11, a second photoresist R2 can be filled in the plurality of grooves H1. Referring to fig. 12, the
Referring to fig. 14, the first insulating
Referring to fig. 18 and 19, it is possible to form a fourth photoresist R4 on the upper portion of the second groove H2 exposed by the
Referring to fig. 20 and 21, it is possible to selectively remove the fourth photoresist R4 and form the second insulating
Thereafter, as shown in fig. 24 and 25, the sixth photoresist R6 can be formed to form the
Fig. 26 to 30 show various modifications of the arrangement of the recess and the non-oxidized region.
The grooves H1 can be selectively formed in various shapes such as a cross shape, a polygon shape, a radial shape, and the like. However, since the uniform
Referring to fig. 26 and 27, the groove H1 can have a rectangular or square shape. In this case, the
Referring to fig. 28, the groove H1 can have a triangular shape. In this case, the
In addition, referring to fig. 29, the groove H1 can have a hexagonal shape. In this case, the
The laser device according to the present embodiment can be used as a light source for 3D face recognition and 3D imaging technology.
3D face recognition and 3D imaging techniques require a matrix of light sources patterned into a two-dimensional array configuration. Such a light source matrix patterned in a two-dimensional array form can be irradiated onto an object and the pattern of reflected light can be analyzed.
In this case, a three-dimensional image of the object can be formed by analyzing the state of distortion of each unit light reflected from the curved surface of each object in the light source matrix patterned in the two-dimensional array form.
When the VCSEL array according to the embodiment is fabricated using the light source (Structured light source) patterned in the two-dimensional array form, it is possible to provide a light source (Structured light source) matrix patterned in the two-dimensional array form in which the characteristics of each unit light source are uniform.
VCSELs required for 3D face recognition and 3D imaging technologies may require efficient optics capable of achieving light outputs of several to several tens of watts (watt) and short pulses of 1 to 10ns or light modulation above 100MHz with low power consumption.
The modulation equivalent circuit of the optical device can be represented by an RC circuit in which the characteristic time determining the modulation speed can be represented by the product of the resistance and the electrostatic capacitance. Therefore, it is important to ensure low resistance to realize a device capable of high-speed modulation and high photoelectric conversion efficiency. Therefore, the present invention can provide a solution that most suitably provides a light source for 3D face recognition and 3D imaging.
In addition, the laser device according to the present invention can be used as a low-priced VCSEL light source in various application fields such as an optical communication device, a Closed Circuit Television (CCTV), a night vision (night vision) for an automobile, motion recognition, medical treatment/therapy, a communication device for the internet of things (IoT), a thermal camera, a thermal imaging camera, a pump field of SOL (Solid state laser), a heating process for bonding a plastic film, and the like.
Although the above description has been mainly given with reference to the embodiments, the present invention is only illustrative and not limited thereto, and it will be apparent to those skilled in the art that various modifications and applications not illustrated above can be made within a scope not departing from the essential characteristics of the present embodiments. For example, each of the components specifically shown in the embodiments can be implemented by being modified. Also, various points of difference associated with such modifications and applications should be construed to include the scope of the present invention as defined in the appended claims.
- 上一篇:一种医用注射器针头装配设备
- 下一篇:火花塞