CN118367420A

CN118367420A - VCSEL device and preparation method thereof

Info

Publication number: CN118367420A
Application number: CN202310116649.9A
Authority: CN
Inventors: 林珊珊; 王立; 汪辰杲; 刘赤宇; 李念宜
Original assignee: Zhejiang Ruixi Technology Co ltd
Current assignee: Zhejiang Ruixi Technology Co ltd
Priority date: 2023-01-17
Filing date: 2023-01-17
Publication date: 2024-07-19

Abstract

Disclosed are a VCSEL device and a method of fabricating the same, wherein the VCSEL device includes: a VCSEL body and a thermoelectric refrigeration structure molded to the VCSEL body at the wafer level, the thermoelectric refrigeration structure comprising a plurality of thermocouple pairs, each thermocouple pair comprising a P-type structure and an N-type structure electrically connected to each other. In this way, the VCSEL device provides a solution for reducing the operating temperature of the VCSEL, and allows for smaller bulk of the VCSEL device, for subsequent packaging, lower manufacturing costs, and higher bond strength between the thermal refrigeration structure and the VCSEL body than would be possible with a mounted to VCSEL body.

Description

VCSEL device and preparation method thereof

Technical Field

The present application relates to the field of semiconductor lasers, and more particularly to VCSEL devices and methods of fabricating the same.

Background

The VCSEL (Vertical-Cavity Surface-emitting laser) is a semiconductor laser which forms a resonant Cavity in the Vertical direction of a substrate and emits laser light along the Vertical direction, has the characteristics of small temperature drift, low threshold, easy optical fiber coupling, low power consumption, good dynamic single-mode property and the like, is widely applied to the fields of optical communication, optical storage, optical interconnection and the like, and is suitable for various application scenes such as vehicle-mounted laser radar, face recognition, 3D sensing and the like.

As VCSEL technology is gradually matured, more high power, high power density applications are also gradually developed, for example, multi-junction technology, which is gradually matured in recent years, can meet the application of vehicle-mounted lidar, however, the operating environment of the VCSEL in the vehicle-mounted lidar is more severe, the optical power of the VCSEL is rapidly reduced (as shown in fig. 1) when the operating environment temperature is 85 ℃ to 105 ℃, and the performance of the VCSEL is deteriorated with the increase of temperature based on the thermal sensitivity.

Currently, in order to reduce the operating temperature of a VCSEL to maintain its optimal performance, in existing VCSEL packaging products, it is mainly achieved by mounting a semiconductor refrigerator (TEC, thermo Electric Cooler) on the bottom of the chip. However, the requirement on mounting is high, so that the volume of the VCSEL packaging product is increased, the cost is greatly increased, and the VCSEL packaging product brings challenges to the market of VCSELs. And the semiconductor refrigerator is combined with the VCSEL in a mounting mode, so that the combination stability between the semiconductor refrigerator and the VCSEL is poor, and even if accidental collision does not occur, the combination degree between the VCSEL and the VCSEL can be gradually reduced along with the time.

Thus, a new VCSEL cooling scheme is needed.

Disclosure of Invention

An advantage of the present application is that a VCSEL device and a method of fabricating the same are provided, wherein the VCSEL device provides a solution for reducing an operating temperature of the VCSEL to improve an operating performance of the VCSEL device.

Another advantage of the present application is to provide a VCSEL device and a method of fabricating the same, wherein the VCSEL device is capable of achieving a reduction in an operating temperature of the VCSEL at a relatively low cost.

It is yet another advantage of the present application to provide a VCSEL device and method of fabricating the same in which the VCSEL device integrates a thermoelectric refrigeration structure into the VCSEL structure at the wafer level, which is less bulky and facilitates subsequent packaging processes than is possible with a die attach to a VCSEL.

It is yet another advantage of the present application to provide a VCSEL device and a method of fabricating the same, wherein the VCSEL device integrates a thermoelectric cooling structure into the VCSEL structure at the wafer level, which is relatively simple.

It is yet another advantage of the present application to provide a VCSEL device and a method of fabricating the same in which the VCSEL device integrates a thermoelectric refrigeration structure into the VCSEL structure at the wafer level such that the bonding strength between the thermoelectric refrigeration structure and the VCSEL structure is high.

Still another advantage of the present application is to provide a VCSEL device and a method for manufacturing the same, in which the prior art VCSEL manufacturing process can be used during the VCSEL device manufacturing process, so that the original VCSEL production line and production equipment can be maintained as much as possible, and the production line modification cost of the VCSEL device can be effectively reduced, thereby reducing the manufacturing cost of the VCSEL device.

To achieve at least one of the above or other advantages and objects, according to one aspect of the present application, there is provided a VCSEL device including:

a VCSEL body comprising an epitaxial structure and a first electrode and a second electrode electrically connected to the epitaxial structure; and

A thermoelectric refrigeration structure molded to the VCSEL body at the wafer level includes a plurality of thermocouple pairs, each thermocouple pair including a P-type structure and an N-type structure electrically connected to each other.

According to some embodiments, the thermoelectric refrigeration structure is molded to a surface of the VCSEL body.

According to some embodiments, the thermoelectric refrigeration structure is formed on a backlight side of the VCSEL device.

According to some embodiments, the thermoelectric cooling structure is formed on a bottom surface of the VCSEL body, the epitaxial structure comprising a substrate layer, a first reflective layer, an active region, a confinement layer having a confinement aperture, and a second reflective layer, the bottom surface of the substrate layer forming the bottom surface of the VCSEL body.

According to some embodiments, the thermoelectric refrigeration structure further comprises a thermoelectric positive electrode electrically connected to one of the thermocouple pairs and a thermoelectric negative electrode electrically connected to the other of the thermocouples, the thermoelectric positive electrode and the thermoelectric negative electrode configured to control a hot side of the thermoelectric refrigeration structure to form at a bottom of the thermoelectric refrigeration structure.

According to some embodiments, the thermoelectric refrigeration structure further comprises an insulating layer formed between the substrate layer and the thermocouple pair.

According to some embodiments, the thermoelectric cooling structure is formed on a top surface of the VCSEL body, the epitaxial structure comprising a substrate layer, a first reflective layer, an active region, a confinement layer having a confinement aperture, and a second reflective layer, the first electrode being formed over the second reflective layer, the top surface of the first electrode forming the top surface of the VCSEL body.

According to some embodiments, the thermoelectric refrigeration structure further comprises a thermoelectric positive electrode electrically connected to one of the thermocouple pairs and a thermoelectric negative electrode electrically connected to the other of the thermocouples, the thermoelectric positive electrode and the thermoelectric negative electrode configured to control a hot side of the thermoelectric refrigeration structure to form on top of the thermoelectric refrigeration structure.

According to some embodiments, the thermoelectric refrigeration structure further comprises an insulating layer formed between the first electrode and the thermocouple pair.

According to some embodiments, the first reflective layer is an N-DBR layer and the second reflective layer is a P-DBR layer.

According to some embodiments, the first reflective layer is a P-DBR layer and the second reflective layer is an N-DBR layer.

According to some embodiments, a plurality of said thermocouple pairs are connected in electrical series, thermal parallel.

According to some embodiments, the thermoelectric cooling structure comprises a plurality of first electrical connection lines and a plurality of second electrical connection lines, one P-type structure and one N-type structure of each thermocouple pair being formed in one first electrical connection line, and one P-type structure and one N-type structure of one thermocouple pair being formed in one second electrical connection line for every two adjacent thermocouple pairs.

The invention provides a preparation method of a VCSEL device, which comprises the following steps:

Forming a VCSEL body comprising an epitaxial structure and first and second electrodes electrically connected to the epitaxial structure;

Forming an insulating layer on a bottom surface of the VCSEL body;

forming a first electrical connection layer at the bottom of the insulating layer;

growing a thermocouple pair at the bottom of the first electric connection layer; and

And forming a second electric connection layer, a thermoelectric positive electrode and a thermoelectric negative electrode at the bottom of the thermocouple pair.

The invention also provides a preparation method of the VCSEL device, which comprises the following steps:

forming an insulating layer on a top surface of the VCSEL body;

Forming a second electrical connection layer, a thermoelectric positive electrode, and a thermoelectric negative electrode on the insulating layer;

Growing a thermocouple pair on the second electrical connection layer, the thermoelectric positive electrode and the thermoelectric negative electrode; and

Further objects and advantages of the present application will become fully apparent from the following description and the accompanying drawings, wherein a first electrical connection layer is formed over the thermocouple pair.

Drawings

These and/or other aspects and advantages of the present application will become more apparent and more readily appreciated from the following detailed description of the embodiments of the application, taken in conjunction with the accompanying drawings, wherein:

Fig. 1 illustrates a schematic diagram of the relationship between the operating temperature of a VCSEL chip and its optical power.

Fig. 2 illustrates a schematic diagram of one specific example of a VCSEL device according to an embodiment of the present application.

Fig. 3 illustrates a schematic diagram of another specific example of a VCSEL device according to an embodiment of the present application.

Fig. 4 illustrates a flow diagram of a method of fabricating a VCSEL device according to an embodiment of the present application.

Fig. 5 illustrates a schematic diagram of another flow of a method of fabricating a VCSEL device according to an embodiment of the present application.

Detailed Description

The terms and words used in the following description and claims are not limited to literal meanings, but are used only by the inventors to enable a clear and consistent understanding of the application. It will be apparent to those skilled in the art, therefore, that the following description of the various embodiments of the application is provided for illustration only and not for the purpose of limiting the application as defined by the appended claims and their equivalents.

It will be understood that the terms "a" and "an" should be interpreted as referring to "at least one" or "one or more," i.e., in one embodiment, the number of elements may be one, while in another embodiment, the number of elements may be plural, and the term "a" should not be interpreted as limiting the number.

Although ordinal numbers such as "first," "second," etc., will be used to describe various components, those components are not limited herein. The term is used merely to distinguish one component from another. For example, a first component may be referred to as a second component, and likewise, a second component may be referred to as a first component, without departing from the teachings of the present inventive concept. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting. As used herein, the singular is intended to include the plural unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or groups thereof.

Illustrative VCSEL device

As shown in fig. 2 and 3, a VCSEL device according to an embodiment of the present application is illustrated. In an embodiment of the present application, the VCSEL device comprises a VCSEL body 10 and a thermoelectric cooling structure 20 molded to the VCSEL body 10 at the wafer level. The thermoelectric refrigeration structure 20 utilizes the peltier effect of the material to reduce the operating temperature of the VCSEL body 10, thereby enhancing the operating performance of the VCSEL device. And through chip and process design, the thermoelectric refrigeration structure 20 is integrated in the VCSEL main body 10 in the preparation process of the traditional VCSEL chip, compared with the method of attaching the thermoelectric refrigeration structure to the VCSEL main body 10 in an attaching mode, the volume of the VCSEL device is smaller, the subsequent packaging is convenient, the manufacturing cost is lower, the bonding strength between the thermoelectric refrigeration structure 20 and the VCSEL main body 10 is higher, and the thermoelectric refrigeration structure has important significance for improving the market competitiveness.

Specifically, the VCSEL body 10 comprises an epitaxial structure 11 and a first electrode 12 and a second electrode 13 electrically connected to the epitaxial structure 11. The epitaxial structure 11 includes a substrate layer 111, a first reflective layer 112, an active region 113, a confinement layer 114 having a confinement aperture 103, and a second reflective layer 115 stacked one above the other. The first reflective layer 112 and the second reflective layer 115 are implemented as distributed bragg mirrors. The first reflection layer 112 is implemented as an N-DBR layer, the second reflection layer 115 is implemented as a P-DBR layer, or the first reflection layer 112 is implemented as a P-DBR layer, and the second reflection layer 115 is implemented as an N-DBR layer.

The N-DBR layer is formed of alternating layers of N-type doped high aluminum content Al _xGa_1-x As (x=1 to 0) and N-type doped low aluminum content Al _xGa_1-x As (x=1 to 0). The P-DBR layer is formed of alternating layers of P-doped high aluminum content Al _xGa_1-x As (x=1 to 0) and P-doped low aluminum content Al _xGa_1-x As (x=1 to 0). In some examples of the application, the N-DBR layer and the P-DBR layer may even be made of materials that do not include aluminum, i.e., aluminum.

The active region 113 is sandwiched between the first reflective layer 112 and the second reflective layer 115 to form a resonant cavity, in which photons are repeatedly amplified by back and forth reflection within the resonant cavity after being excited to form laser oscillation, thereby forming laser light.

The first and second reflective layers 112 and 115 are configured such that, after the VCSEL light emitting unit is turned on, laser light generated by the active region 113 is emitted from the first or second reflective layer 112 or 115 after being reflected multiple times within a resonant cavity formed between the first and second reflective layers 112 and 115.

Accordingly, the VCSEL body 10 includes a light emitting side and a backlight side, and the active region 113 is used as a boundary region, the same side as the laser light emitting direction is used as the light emitting side, and the opposite side to the laser light emitting direction is used as the backlight side.

The confinement layer 114 having the confinement holes 103 may be disposed between the active region 113 and the first reflective layer 112, between the active region 113 and the second reflective layer 115, between the active region 113 and the first reflective layer 112, and between the active region 113 and the second reflective layer 115.

When the confinement layer 114 is disposed between the active region 113 and the second reflective layer 115, the substrate layer 111, the first reflective layer 112, the active region 113, the confinement layer 114 having the confinement holes 103, and the second reflective layer 115 are arranged from bottom to top, and the light emitting direction of the VCSEL body 10 is directed from the active region 113 to the second reflective layer 115, the light emitting side of the VCSEL body 10 includes the confinement layer 114 and the second reflective layer 115, and the backlight side of the VCSEL body 10 includes the first reflective layer 112 and the substrate layer 111. When the first reflective layer 112 is the N-DBR layer and the second reflective layer 115 is the P-DBR layer, the light-emitting side of the VCSEL body 10 includes the confinement layer 114 and the P-DBR layer, and the backlight side of the VCSEL body 10 includes the N-DBR layer and the substrate layer 111. When the first reflective layer 112 is the P-DBR layer and the second reflective layer 115 is the N-DBR layer, the light-emitting side of the VCSEL body 10 includes the confinement layer 114 and the N-DBR layer, and the backlight side of the VCSEL body 10 includes the P-DBR layer and the substrate layer 111. When the first electrode 12 is formed on the second reflective layer 115 and the second electrode 13 is formed on the first reflective layer 112 or the substrate layer 111, the light-emitting side of the body further includes the first electrode 12, and the backlight side of the VCSEL body 10 further includes the second electrode 13. It should be understood that the first electrode 12 and the second electrode 13 may be distributed at other positions, for example, the first electrode 12 and the second electrode 13 are both formed on the light emitting side of the VCSEL body 10, or the first electrode 12 and the second electrode 13 are both formed on the backlight side of the VCSEL body 10.

When the confinement layer 114 is disposed between the active region 113 and the second reflective layer 115, the substrate layer 111, the first reflective layer 112, the active region 113, the confinement layer 114 having the confinement holes 103, and the second reflective layer 115 are arranged from bottom to top, and the light emitting direction of the VCSEL body 10 is directed from the active region 113 toward the first reflective layer 112, the light emitting side of the VCSEL body 10 includes the first reflective layer 112 and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the confinement layer 114 and the second reflective layer 115. When the first reflective layer 112 is the N-DBR layer and the second reflective layer 115 is the P-DBR layer, the light-emitting side of the VCSEL body 10 includes the N-DBR layer and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the confinement layer 114 and the P-DBR layer. When the first reflective layer 112 is the P-DBR layer and the second reflective layer 115 is the N-DBR layer, the light-emitting side of the VCSEL body 10 includes the P-DBR layer and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the confinement layer 114 and the N-DBR layer. When the first electrode 12 is formed on the second reflective layer 115 and the second electrode 13 is formed on the first reflective layer 112 or the substrate layer 111, the light-emitting side of the body further includes the second electrode 13, and the backlight side of the VCSEL body 10 further includes the first electrode 12.

When the confinement layer 114 is disposed between the active region 113 and the first reflective layer 112, the substrate layer 111, the first reflective layer 112, the confinement layer 114 having the confinement holes 103, the active region 113, and the second reflective layer 115 are arranged from bottom to top, and the light emitting direction of the VCSEL body 10 is directed from the active region 113 to the second reflective layer 115, the light emitting side of the VCSEL body 10 includes the second reflective layer 115, and the backlight side of the VCSEL body 10 includes the confinement layer 114, the first reflective layer 112, and the substrate layer 111. When the first reflective layer 112 is the N-DBR layer and the second reflective layer 115 is the P-DBR layer, the light-emitting side of the VCSEL body 10 includes the P-DBR layer, and the backlight side of the VCSEL body 10 includes the confinement layer 114, the N-DBR layer, and the substrate layer 111. When the first reflective layer 112 is the P-DBR layer and the second reflective layer 115 is the N-DBR layer, the light-emitting side of the VCSEL body 10 includes the N-DBR layer, and the backlight side of the VCSEL body 10 includes the confinement layer 114, the P-DBR layer, and the substrate layer 111.

When the confinement layer 114 is disposed between the active region 113 and the first reflective layer 112, the substrate layer 111, the first reflective layer 112, the confinement layer 114 having the confinement holes 103, the active region 113, and the second reflective layer 115 are arranged from bottom to top, and the light emitting direction of the VCSEL body 10 is directed from the active region 113 to the first reflective layer 112, the light emitting side of the VCSEL body 10 includes the confinement layer 114, the first reflective layer 112, and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the second reflective layer 115. When the first reflective layer 112 is the N-DBR layer and the second reflective layer 115 is the P-DBR layer, the light-emitting side of the VCSEL body 10 includes the confinement layer 114, the N-DBR layer, and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the P-DBR layer. When the first reflective layer 112 is the P-DBR layer and the second reflective layer 115 is the N-DBR layer, the light-emitting side of the VCSEL body 10 includes the confinement layer 114, the P-DBR layer, and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the N-DBR layer.

When the confinement layer 114 is disposed between the active region 113 and the first reflective layer 112, and between the active region 113 and the second reflective layer 115, the substrate layer 111, the first reflective layer 112, one of the confinement layers 114, the active region 113, the other of the confinement layers 114, and the second reflective layer 115 are arranged from bottom to top, and the light-emitting direction of the VCSEL body 10 is directed from the active region 113 toward the second reflective layer 115, the light-emitting side of the VCSEL body 10 includes one of the confinement layers 114 and the second reflective layer 115, and the backlight side of the VCSEL body 10 includes the other of the confinement layers 114, the first reflective layer 112, and the substrate layer 111. When the first reflective layer 112 is the N-DBR layer and the second reflective layer 115 is the P-DBR layer, the light-emitting side of the VCSEL body 10 includes one of the confinement layer 114 and the P-DBR layer, and the backlight side of the VCSEL body 10 includes the other of the confinement layer 114, the N-DBR layer, and the substrate layer 111. When the first reflective layer 112 is the P-DBR layer and the second reflective layer 115 is the N-DBR layer, the light-emitting side of the VCSEL body 10 includes one of the confinement layer 114 and the N-DBR layer, and the backlight side of the VCSEL body 10 includes the other of the confinement layer 114, the P-DBR layer, and the substrate layer 111.

When the confinement layer 114 is disposed between the active region 113 and the first reflective layer 112, and between the active region 113 and the second reflective layer 115, the substrate layer 111, the first reflective layer 112, one of the confinement layers 114, the active region 113, the other of the confinement layers 114, and the second reflective layer 115 are arranged from bottom to top, and the light-emitting direction of the VCSEL body 10 is directed from the active region 113 toward the first reflective layer 112, the light-emitting side of the VCSEL body 10 includes one of the confinement layers 114, the first reflective layer 112, and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the other of the confinement layers 114 and the second reflective layer 115. When the first reflective layer 112 is the N-DBR layer and the second reflective layer 115 is the P-DBR layer, the light-emitting side of the VCSEL body 10 includes one of the confinement layer 114, the N-DBR layer, and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the other of the confinement layer 114 and the P-DBR layer. When the first reflective layer 112 is the P-DBR layer and the second reflective layer 115 is the N-DBR layer, the light-emitting side of the VCSEL body 10 includes one of the confinement layer 114, the P-DBR layer, and the substrate layer 111, and the backlight side of the VCSEL body 10 includes the other of the confinement layer 114 and the N-DBR layer.

In an embodiment of the present application, the confinement layer 114 is implemented as an oxidation confinement layer 114 formed above and/or below the active region 113 by an oxidation process. In another embodiment of the present application, the confinement layer 114 may be implemented as another type, for example, implemented as an ion confinement layer 114 formed above or below the active region 113 by an ion implantation process, which is not limited to the present application.

As previously described, the thermoelectric refrigeration structure 20 utilizes the peltier effect of the material to reduce the operating temperature of the VCSEL body 10. The Peltier effect refers to that when current passes through loops formed by different conductors, irreversible Joule heat is generated, and heat absorption and heat release phenomena can respectively occur at joints of the different conductors along with different current directions. Accordingly, the thermoelectric refrigeration structure 20 includes a plurality of thermocouple pairs 21, wherein the thermocouple pairs 21 are alloys of Bi or Te doped with different materials (for example, bi2Te3 or BiSb), pbTe, siGe, mgSi, P-type doping elements Sb, B, etc., N-type doping elements Se, P, etc. That is, each thermocouple pair 21 includes a P-type structure 211 and an N-type structure 212 electrically connected to each other.

In an embodiment of the present application, the thermoelectric refrigeration structure 20 is formed on the surface of the VCSEL body 10. The thermoelectric cooling structure 20 is conveniently connected with a heat sink structure for radiating heat during packaging, wherein the heat sink structure is a structure with temperature not changing along with the change of the heat transferred to the heat sink structure. In the embodiment of the present application, the thermoelectric refrigeration structure 20 is formed on the backlight side of the VCSEL device, so as not to affect the light-emitting performance of the VCSEL device.

Accordingly, the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 or top surface of the VCSEL body 10. In a specific example of the present application, the light emitting direction of the VCSEL body 10 is directed from the active region 113 to the second reflective layer 115, and the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 of the VCSEL body 10, as shown in fig. 2. Specifically, the substrate layer 111, the first reflective layer 112, the active region 113, the confinement layer 114 having the confinement holes 103, and the second reflective layer 115 are arranged from bottom to top, the first reflective layer 112 being an N-DBR layer, and the second reflective layer 115 being a P-DBR layer. The first electrode 12 is disposed on top of the first reflective layer 112, the second electrode 13 is disposed on a surface of the second reflective layer 115, a bottom surface of the substrate layer 111 forms a bottom surface 102 of the VCSEL body 10, and a top surface of the first electrode 12 forms a top surface 101 of the VCSEL body 10. That is, the thermoelectric cooling structure 20 is formed on the bottom surface of the substrate layer 111 of the VCSEL body 10. It should be understood that the second electrode 13 may also be disposed on the bottom surface of the substrate layer 111, and the thermoelectric cooling structure 20 is formed on the bottom surface of the second electrode 13 of the VCSEL body 10.

In another specific example of the present application, the light emitting direction of the VCSEL body 10 is directed from the active region 113 to the second reflective layer 115, and the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 of the VCSEL body 10. Specifically, the substrate layer 111, the first reflective layer 112, the active region 113, the confinement layer 114 having the confinement holes 103, and the second reflective layer 115 are arranged from bottom to top, the first reflective layer 112 being a P-DBR layer, and the second reflective layer 115 being an N-DBR layer. The first electrode 12 is disposed on top of the first reflective layer 112, the second electrode 13 is disposed on a surface of the second reflective layer 115, a bottom surface of the substrate layer 111 forms a bottom surface 102 of the VCSEL body 10, and a top surface of the first electrode 12 forms a top surface 101 of the VCSEL body 10. That is, the thermoelectric cooling structure 20 is formed on the bottom surface of the substrate layer 111 of the VCSEL body 10.

In still another specific example of the present application, the light emitting direction of the VCSEL body 10 is directed from the active region 113 to the first reflective layer 112, and the thermoelectric cooling structure 20 is formed on the top surface 101 of the VCSEL body 10, as shown in fig. 3. Specifically, the substrate layer 111, the first reflective layer 112, the active region 113, the confinement layer 114 having the confinement holes 103, and the second reflective layer 115 are arranged from bottom to top, the first reflective layer 112 being an N-DBR layer, and the second reflective layer 115 being a P-DBR layer. The first electrode 12 is disposed on top of the second reflective layer 115, the second electrode 13 is disposed on a bottom surface of the substrate layer 111, the bottom surface of the second electrode 13 forms a bottom surface 102 of the VCSEL body 10, and a top surface of the first electrode 12 forms a top surface 101 of the VCSEL body 10. That is, the thermoelectric cooling structure 20 is formed on the top surface of the first electrode 12 of the VCSEL body 10.

In yet another specific example of the present application, the light exit direction of the VCSEL body 10 is directed from the active region 113 to the first reflective layer 112, and the thermoelectric cooling structure 20 is formed on the top surface 101 of the VCSEL body 10. Specifically, the substrate layer 111, the first reflective layer 112, the active region 113, the confinement layer 114 having the confinement holes 103, and the second reflective layer 115 are arranged from bottom to top, the first reflective layer 112 being a P-DBR layer, and the second reflective layer 115 being an N-DBR layer. The first electrode 12 is disposed on top of the second reflective layer 115, the second electrode 13 is disposed on the bottom surface of the substrate layer 111, the bottom surface of the second electrode 13 forms the bottom surface 102 of the VCSEL body 10, and the top surface of the first electrode 12 forms the top surface 101 of the VCSEL body 10. That is, the thermoelectric cooling structure 20 is formed on the top surface of the first electrode 12 of the VCSEL body 10.

It should be understood that the first electrode 12 and the second electrode 13 may be disposed in other manners, for example, the second electrode 13 is formed between the first reflective layer 112 and the substrate layer 111, which is not limited by the present application.

The thermoelectric refrigeration structure 20 further includes an insulating layer 26 formed between the VCSEL body 10 and the thermocouple pair 21. When the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 of the VCSEL body 10 and the bottom surface of the substrate layer 111 is the bottom surface 102 of the VCSEL body 10, the insulating layer 26 is formed between the substrate layer 111 and the thermocouple pair 21. When the thermoelectric refrigeration structure 20 is formed on the top surface 101 of the VCSEL body 10 and the top surface of the first electrode 12 is the top surface 101 of the VCSEL body 10, the insulating layer 26 is formed between the first electrode 12 and the thermocouple pair 21. The insulating layer 26 is not designed according to the present application, and may be made of a ceramic material, a high-resistance semiconductor material, or the like.

The hot side of the thermoelectric refrigeration structure 20, i.e., the heat release side, and the cold side of the thermoelectric refrigeration structure 20, i.e., the heat absorption side, may be controlled by designing the electrical connection of the thermoelectric refrigeration structure 20. Specifically, the thermoelectric refrigeration structure 20 further includes a thermoelectric positive electrode 24 electrically connected to one of the thermocouple pairs 21 and a thermoelectric negative electrode 25 electrically connected to the other thermocouple. The thermoelectric positive electrode 24 is formed on the N-type structure 212 of one thermocouple pair 21, and the thermoelectric negative electrode 25 is formed on the P-type structure 211 of the other thermocouple pair. When the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 of the VCSEL body 10, the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are configured to control the hot side of the thermoelectric refrigeration structure 20 to be formed on the bottom of the thermoelectric refrigeration structure 20. In this way, the top of the thermoelectric refrigeration structure 20 absorbs heat of the VCSEL body 10, and the bottom of the thermoelectric refrigeration structure 20 is connected to a heat sink structure for dissipating heat, so that the VCSEL body 10 operates at a lower temperature, ensuring its performance, for example, its optical power. When the thermoelectric refrigeration structure 20 is formed on the top surface 101 of the VCSEL body 10, the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are configured to control the hot side of the thermoelectric refrigeration structure 20 to be formed on top of the thermoelectric refrigeration structure 20. In this way, the bottom of the thermoelectric refrigeration structure 20 absorbs heat of the VCSEL body 10, and the top of the thermoelectric refrigeration structure 20 is connected to a heat sink structure for dissipating heat, so that the VCSEL body 10 operates at a lower temperature, ensuring its performance, for example, its optical power.

In the embodiment of the present application, a plurality of the thermocouple pairs 21 are connected in electrical series and thermal parallel. Accordingly, the thermoelectric cooling structure 20 includes a plurality of first electrical connection lines 221 and a plurality of second electrical connection lines 231, one P-type structure 211 and one N-type structure 212 of each thermocouple pair 21 are formed in one first electrical connection line 221, and each two adjacent thermocouple pairs 21, one P-type structure 211 of one thermocouple pair 21 and one N-type structure 212 of the other thermocouple pair 21 are formed in one second electrical connection line 231. Accordingly, each of the first electrical connection lines 221 is formed between the P-type structure 211 and the N-type structure 212 of each of the thermocouple pairs 21, and each of the second electrical connection lines 231 is formed between the P-type structure 211 of one of the thermocouple pairs 21 and the N-type structure 212 of the adjacent thermocouple pair 21. The plurality of first electrical connection lines 221 form a first electrical connection layer 22, and the plurality of second electrical connection lines 231 form a second electrical connection layer 23.

When the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 of the VCSEL body 10, the first electrical connection layer 22 is formed above the thermocouple pair 21, the second electrical connection layer 23, the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are formed below the thermocouple pair 21, the insulating layer 26 is formed above the first electrical connection layer 22, the top surface of the insulating layer 26 forms the top surface of the thermoelectric refrigeration structure 20, the second electrical connection layer 23, the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are formed below the thermocouple pair 21, the bottom surface of the thermoelectric positive electrode 24 and the bottom surface of the second electrical connection layer 23 form the bottom surface of the thermoelectric refrigeration structure 20, and the bottom surface of the second electrical connection layer 23 is connected to a heat sink structure.

When the thermoelectric refrigeration structure 20 is formed on the top surface 101 of the VCSEL body 10, the first electrical connection layer 22 is formed above the thermocouple pair 21, the second electrical connection layer 23, the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are formed below the thermocouple pair 21, the insulating layer 26 is formed below the second electrical connection layer 23, the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25, the top surface of the first electrical connection layer 22 forms the top surface of the thermoelectric refrigeration structure 20, the bottom surface of the insulating layer 26 forms the bottom surface of the thermoelectric refrigeration structure 20, and the top surface of the first electrical connection layer 22 is connected to a heat sink structure for dissipating heat.

It should be understood that a plurality of thermocouples may be wired in different circuit series arrangements, and this is not a limitation of the present application.

In an embodiment of the present application, the thermoelectric refrigeration structure 20 further includes an insulating filler 27 filled between the P-type structure 211 and the N-type structure 212. The insulating filler 27 formed between the P-type structure 211 and the N-type structure 212 of each adjacent two of the thermocouple pairs 21 is blocked between the adjacent two first electrical connection lines 221, and the insulating filler 27 formed between the P-type structure 211 and the N-type structure 212 of each of the thermocouple pairs 21 is blocked between the second electrical connection lines 231.

In summary, a VCSEL device according to an embodiment of the present application is illustrated, which provides a solution for reducing the operating temperature of the VCSEL to improve the operating performance of the VCSEL. The VCSEL device integrates the thermoelectric refrigeration structure 20 into the VCSEL body 10 during the fabrication of the conventional VCSEL chip through chip and process design, so that the volume of the VCSEL device is smaller, the subsequent packaging is facilitated, the fabrication cost is lower, and the bonding strength between the thermoelectric refrigeration structure 20 and the VCSEL body 10 is higher, compared with the case that the thermoelectric refrigeration structure is attached to the VCSEL body 10 in a mounting manner.

Method for preparing schematic VCSEL device

According to another aspect of the present application, there is also provided a method of manufacturing a VCSEL device for manufacturing a VCSEL device as described above. It should be noted that in the embodiment of the present application, in the process of manufacturing the VCSEL device, the process of manufacturing the VCSEL device in the prior art can be still used, so that the original VCSEL production line and production equipment can be maintained as much as possible, the production line modification cost of the VCSEL device is effectively reduced, and the manufacturing cost of the VCSEL device is further reduced.

The preparation method of the VCSEL device comprises the following steps: (a) Forming a VCSEL body 10, said VCSEL body 10 comprising an epitaxial structure 11 and a first electrode 12 and a second electrode 13 electrically connected to said epitaxial structure 11; and, (b) forming a thermoelectric cooling structure 20 molded to the VCSEL body 10 on a wafer level, the thermoelectric cooling structure 20 including a plurality of thermocouple pairs 21, each thermocouple pair 21 including a P-type structure 211 and an N-type structure 212 electrically connected to each other.

In the embodiment of the present application, the thermoelectric refrigeration structure 20 further includes an insulating layer 26 formed between the VCSEL body 10 and the thermocouple pair 21, a thermoelectric positive electrode 24 electrically connected to one of the thermocouple pairs 21, a thermoelectric negative electrode 25 electrically connected to the other thermocouple, a first electrical connection layer 22 electrically connected to the thermocouple pair 21, and a second electrical connection layer 23 electrically connected to the thermocouple pair 21.

In one embodiment of the present application, the thermoelectric refrigeration structure 20 is formed on the bottom surface 102 of the VCSEL body 10. As shown in fig. 4, the preparation method of the VCSEL device includes: S110A, forming a VCSEL body 10, the VCSEL body 10 comprising an epitaxial structure 11 and a first electrode 12 and a second electrode 13 electrically connected to the epitaxial structure 11; S120A, forming an insulating layer 26 on the bottom surface 102 of the VCSEL body 10; S130A, forming a first electric connection layer 22 at the bottom of the insulating layer 26; S140A growing a thermocouple pair 21 on the bottom of the first electrical connection layer 22; and S150A of forming a second electrical connection layer 23, a thermoelectric positive electrode 24, and a thermoelectric negative electrode 25 at the bottom of the thermocouple pair 21.

Specifically, in step S110A, the VCSEL body 10 is formed, and the epitaxial structure 11 of the VCSEL body 10 includes a substrate layer 111, a first reflective layer 112, an active region 113, a confinement layer 114 having a confinement aperture 103, and a second reflective layer 115. The particular embodiment of forming the VCSEL body 10 is not limiting of the application. In one specific example of the present application, first, a substrate structure, a first reflective structure, an active structure, and a second reflective structure stacked on the substrate structure are formed by an epitaxial growth process to form an epitaxial body structure. Next, at least a portion of the semiconductor epitaxial structure 11 is removed by an etching process to form a cell structure, at least a portion of the second reflective structure is exposed, and the cell structure is subjected to an oxidation treatment to convert a portion of the second reflective structure into a confinement layer 114 having a confinement hole 103. At least a portion of the semiconductor epitaxial structure 11 may also be removed by an etching process to form a cell structure, at least a portion of the first reflective structure may be exposed, the cell structure may be subjected to an oxidation process to convert a portion of the first reflective structure into a confinement layer 114 having a confinement hole 103, and the confinement layer 114 may also be formed by other means, such as, for example, by an ion implantation process. Then, a portion of the first reflective structure is exposed to form the epitaxial structure 11, the first electrode 12 may be formed on the top surface of the second reflective layer 115 by electroplating, and the second electrode 13 may be formed on the exposed portion of the first reflective layer 112. The bottom surface of the substrate layer 111 forms the bottom surface 102 of the VCSEL body 10. The second electrode 13 may be formed at other positions, for example, between the substrate layer 111 and the first reflective layer 112; as another example, the bottom of the substrate layer 111, such that the bottom surface of the second electrode 13 will form the bottom surface 102 of the VCSEL body 10.

In step S120A, an insulating layer 26 is formed on the bottom surface 102 of the VCSEL body 10, and the insulating layer 26 is made of a material not designed in the present application, and may be a ceramic material, a high-resistance semiconductor material, or the like.

In step S130A, a first electrical connection layer 22 may be formed on the bottom of the insulating layer 26 through an electroplating process, and the first electrical connection layer 22 includes a plurality of (i.e., two or more) first electrical connection lines 221 spaced apart from each other.

In step S140A, a plurality of thermocouple pairs 21 may be grown on the bottom of the first electrical connection layer 22 through a semiconductor growth process, each thermocouple pair 21 including a P-type structure 211 and an N-type structure 212, and one P-type structure 211 and one N-type structure 212 of one thermocouple pair 21 being formed on one first electrical connection line 221.

In step S150A, a second electrical connection layer 23, a thermoelectric positive electrode 24, and a thermoelectric negative electrode 25 may be formed at the bottom of the thermocouple pair 21 through an electroplating process, wherein the second electrical connection layer 23 includes a plurality of second electrical connection lines 231, each second electrical connection line 231 is formed between a P-type structure 211 of one thermocouple pair 21 and an N-type structure 212 of an adjacent thermocouple pair 21, the thermoelectric positive electrode 24 is formed at the N-type structure 212 of one thermocouple pair 21, the thermoelectric negative electrode 25 is formed at the P-type structure 211 of the other thermocouple, and the thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are configured to control a hot end of the thermoelectric refrigeration structure 20 to be formed at the bottom of the thermoelectric refrigeration structure 20.

In another embodiment of the present application, the thermoelectric refrigeration structure 20 is formed on the top surface 101 of the VCSEL body 10. As shown in fig. 5, the preparation method of the VCSEL device includes: S110B forming a VCSEL body 10, the VCSEL body 10 comprising an epitaxial structure 11 and a first electrode 12 and a second electrode 13 electrically connected to the epitaxial structure 11; S120B, forming an insulating layer 26 on the top surface 101 of the VCSEL body 10; S130B, forming a second electrical connection layer 23, a thermoelectric positive electrode 24, and a thermoelectric negative electrode 25 on the insulating layer 26; S140B, growing a thermocouple pair 21 on the second electrical connection layer 23; and S150A of forming a first electrical connection layer 22 on the thermocouple pair 21.

Specifically, in step S110B, the VCSEL body 10 is formed, and the epitaxial structure 11 of the VCSEL body 10 includes a substrate layer 111, a first reflective layer 112, an active region 113, a confinement layer 114 having a confinement aperture 103, and a second reflective layer 115. The particular embodiment of forming the VCSEL body 10 is not limiting of the application. In one specific example of the present application, first, a substrate structure, a first reflective structure, an active structure, and a second reflective structure stacked on the substrate structure are formed by an epitaxial growth process to form an epitaxial body structure. Next, at least a portion of the semiconductor epitaxial structure 11 is removed by an etching process to form a cell structure, at least a portion of the second reflective structure is exposed, and the cell structure is subjected to an oxidation treatment to convert a portion of the second reflective structure into a confinement layer 114 having a confinement hole 103. At least a portion of the semiconductor epitaxial structure 11 may also be removed by an etching process to form a cell structure, at least a portion of the first reflective structure may be exposed, the cell structure may be subjected to an oxidation process to convert a portion of the first reflective structure into a confinement layer 114 having a confinement hole 103, and the confinement layer 114 may also be formed by other means, such as, for example, by an ion implantation process. Then, the substrate layer 111 is thinned to form the epitaxial structure 11, the first electrode 12 may be formed on the top surface of the second reflective layer 115 by electroplating, the top surface of the first electrode 12 forms the top surface 101 of the VCSEL body 10, and the second electrode 13 is formed on the bottom surface of the substrate layer 111. The second electrode 13 may be formed at other positions, for example, between the substrate layer 111 and the first reflective layer 112; as another example, the second reflective layer 115.

In step S120B, an insulating layer 26 is formed on the top surface 101 of the VCSEL body 10, and the insulating layer 26 is made of a material not designed in the present application, and may be a ceramic material, a high-resistance semiconductor material, or the like.

In step S130B, a second electrical connection layer 23 may be formed on top of the insulating layer 26 through an electroplating process, and the second electrical connection layer 23 includes a plurality of (i.e., two or more) second electrical connection lines 231 spaced apart from each other.

In step S140B, a plurality of thermocouple pairs 21 may be grown on top of the second electrical connection layer 23, the thermoelectric positive electrode 24, and the thermoelectric negative electrode 25 through a semiconductor growth process, and in each two adjacent thermocouple pairs 21, a P-type structure 211 of one thermocouple pair 21 and an N-type structure 212 of the other thermocouple pair 21 are formed on one second electrical connection line 231. Of all the thermocouple pairs 21, the P-type structure 211 of one of the thermocouple pairs 21 is formed on the thermoelectric negative electrode 25, and the N-type structure 212 of the other thermocouple pair 21 is formed on the thermoelectric negative electrode 25. The thermoelectric positive electrode 24 and the thermoelectric negative electrode 25 are configured to control a hot side of the thermoelectric refrigeration structure 20 to form on top of the thermoelectric refrigeration structure 20.

In step S150B, a first electrical connection layer 22 may be formed on the thermocouple pair 21 through an electroplating process, wherein the first electrical connection layer 22 includes a plurality of first electrical connection lines 221, and each first electrical connection line 221 is formed between the P-type structure 211 and the N-type structure 212 of one of the thermocouple pairs 21.

In summary, the method for manufacturing the VCSEL device according to the embodiments of the present application is explained, by which the thermoelectric refrigeration structure 20 can be integrated on the wafer level into the VCSEL main body 10, the operating temperature of the VCSEL can be reduced, and the operating performance of the VCSEL can be improved, compared with the method in which the VCSEL device is mounted on the VCSEL main body 10 in a mounting manner, the volume of the VCSEL device is smaller, the subsequent packaging is facilitated, the manufacturing cost is lower, and the bonding strength between the thermoelectric refrigeration structure 20 and the VCSEL main body 10 is higher.

It is noted that in the apparatus and method of the present application, the components or steps of the different embodiments may be disassembled and/or assembled without departing from the principles of the present application. Such decomposition and/or recombination should be considered to be included within the inventive concept of the present application.

The basic principles of the present application have been described above in connection with specific embodiments, but it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are merely examples and not intended to be limiting, and these advantages, benefits, effects, etc. are not to be construed as necessarily possessed by the various embodiments of the application. Furthermore, the specific details disclosed herein are for purposes of illustration and understanding only, and are not intended to be limiting, as the application is not necessarily limited to practice with the above described specific details.

Claims

1. A VCSEL device, comprising:

a VCSEL body comprising an epitaxial structure and a first electrode and a second electrode electrically connected to the epitaxial structure;

2. The VCSEL device of claim 1, wherein the thermoelectric refrigeration structure is molded to a surface of the VCSEL body.

3. The VCSEL device of claim 2, wherein the thermoelectric refrigeration structure is formed on a backlight side of the VCSEL device.

4. The VCSEL device of claim 2, wherein the thermoelectric cooling structure is formed on a bottom surface of the VCSEL body, the epitaxial structure comprising a substrate layer, a first reflective layer, an active region, a confinement layer having a confinement aperture, and a second reflective layer, the bottom surface of the substrate layer forming the bottom surface of the VCSEL body.

5. The VCSEL device of claim 4, wherein the thermoelectric refrigeration structure further comprises a thermoelectric positive electrode electrically connected to one of the thermocouple pairs and a thermoelectric negative electrode electrically connected to the other thermocouple, the thermoelectric positive electrode and the thermoelectric negative electrode being configured to control a hot side of the thermoelectric refrigeration structure to form at a bottom of the thermoelectric refrigeration structure.

6. The VCSEL device of claim 4, wherein the thermoelectric refrigeration structure further comprises an insulating layer formed between the substrate layer and the thermocouple pair.

7. The VCSEL device of claim 2, wherein the thermoelectric refrigeration structure is formed on a top surface of the VCSEL body, the epitaxial structure comprising a substrate layer, a first reflective layer, an active region, a confinement layer having a confinement aperture, and a second reflective layer, the first electrode being formed over the second reflective layer, the top surface of the first electrode forming the top surface of the VCSEL body.

8. The VCSEL device of claim 7, wherein the thermoelectric refrigeration structure further comprises a thermoelectric positive electrode electrically connected to one of the thermocouple pairs and a thermoelectric negative electrode electrically connected to the other thermocouple, the thermoelectric positive electrode and the thermoelectric negative electrode being configured to control a hot side of the thermoelectric refrigeration structure to form on top of the thermoelectric refrigeration structure.

9. The VCSEL device of claim 7, wherein the thermoelectric refrigeration structure further comprises an insulating layer formed between the first electrode and the thermocouple pair.

10. A VCSEL device as claimed in claim 4 or 8, wherein the first reflective layer is an N-DBR layer and the second reflective layer is a P-DBR layer.

11. The VCSEL device of claim 1, wherein a plurality of the thermocouple pairs are electrically connected in series, thermally connected in parallel.

12. The VCSEL device as claimed in claim 11, wherein the thermoelectric cooling structure comprises a plurality of first electrical connection lines and a plurality of second electrical connection lines, one P-type structure and one N-type structure of each thermocouple pair being formed in one first electrical connection line, and one P-type structure and one N-type structure of one thermocouple pair being formed in one second electrical connection line for each two adjacent thermocouple pairs.

13. A method of fabricating a VCSEL device, comprising:

Forming an insulating layer on a bottom surface of the VCSEL body;

14. A method of fabricating a VCSEL device, comprising:

forming an insulating layer on a top surface of the VCSEL body;

A first electrical connection layer is formed over the thermocouple pair.