LED chip and manufacturing method thereof

Abstract

The embodiment of the invention provides an LED chip and a manufacturing method thereof, the LED chip comprises a substrate, a first reflecting layer, a first electrode, an epitaxial structure layer, a second reflecting layer and a second electrode, and the first reflecting layer is provided with a first type of ohmic contact; the epitaxial structure layer is provided with an inclined side wall; the second electrode is provided with a first hollow area, and the first hollow area can be used for enabling light rays of the LED chip to be emitted only from the first hollow area, so that small-angle light emitting of the LED chip is achieved. The orthographic projection of the first type of ohmic contact on the surface where the second electrode is located is located in the first hollowed-out area, so that the electron-hole recombination area is located in the first hollowed-out area. The position of the first type ohmic contact is controlled and the first type ohmic contact is arranged in the first hollow area, so that the position of the electron hole recombination area is controlled, the electron hole recombination area and the first hollow area for emitting light are overlapped, the effective emission light power of the light emitted from the first hollow area is improved, and the high power of the LED chip is further realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor devices, and in particular to an LED chip and a manufacturing method thereof. Background Art

[0002] With the rapid development of display-related technologies and semiconductor devices, display screens can use light-emitting diode (LED) chips to achieve color display.

[0003] The main structure of the current LED chip is a conductive substrate, a reflector, an epitaxial structure layer and an electrode stacked in sequence. The light-emitting direction of the LED chip of this structure includes the top surface and the side wall of the LED chip, that is, the LED chip of this structure is a five-sided light-emitting chip, wherein the top surface is the side surface away from the conductive substrate.

[0004] However, there is currently a demand for LED chips to emit light at a small angle and with high power, and LED chips that emit light from five sides cannot meet this demand. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide an LED chip and a method for manufacturing the same, so as to realize an LED chip that can emit light with high power at a small angle.

[0006] To achieve the above purpose, this application has the following technical solutions:

[0007] The present application provides an LED chip, comprising:

[0008] A substrate, a first reflective layer located on one side of the substrate, and a first electrode located on the other side of the substrate, wherein a first type ohmic contact is provided in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate;

[0009] An epitaxial structure layer is arranged on a surface of the first reflective layer away from the substrate, the epitaxial structure layer comprising a first type layer, an active layer and a second type layer stacked in sequence; the first type layer is in direct contact with the first type ohmic contact, the epitaxial structure layer has an inclined side wall, and an angle between the inclined side wall and a surface of the epitaxial structure layer close to the substrate is an acute angle;

[0010] a second reflective layer at least covering the inclined side wall;

[0011] A second electrode is located on the surface of the epitaxial structure layer away from the substrate; the second electrode has a first hollow area, and the positive projection of the first type ohmic contact on the surface where the second electrode is located is located in the first hollow area, so that the electron-hole recombination area is located in the first hollow area.

[0012] Optionally, it further includes a second type of ohmic contact located on a surface of the epitaxial structure layer away from the substrate, and the second electrode covers the second type of ohmic contact;

[0013] The second type ohmic contact surrounds the first hollow area.

[0014] Optionally, the second type of layer comprises a firm layer;

[0015] The second electrode covers the securing layer.

[0016] Optionally, the fixing layer has a second hollow area, and the orthographic projection of the first hollow area on the surface where the substrate is located includes the orthographic projection of the second hollow area on the surface where the substrate is located.

[0017] Optionally, an orthographic projection of the first type ohmic contact on the surface where the securing layer is located is located in the second hollow area.

[0018] Optionally, the second reflective layer also covers an area of ​​the surface of the epitaxial structure layer on one side away from the substrate but not covered by the second electrode except for the first hollow area.

[0019] Optionally, the epitaxial structure layer further has an extension plane connected to the inclined sidewall on a side thereof close to the substrate, and the second reflective layer further covers the extension plane.

[0020] Optionally, the epitaxial structure layer has a first side wall and a second side wall that are arranged opposite to each other, and a distance between the first hollow region and the first side wall is smaller than a distance between the first hollow region and the second side wall.

[0021] Optionally, the first hollow area is circular or polygonal in shape.

[0022] The present application provides a method for manufacturing an LED chip, comprising:

[0023] Forming an epitaxial structure layer on one side of the temporary substrate, wherein the epitaxial structure layer includes a second type layer, an active layer and a first type layer stacked in sequence;

[0024] forming a first reflective layer on the epitaxial structure layer, and forming a first type ohmic contact in the first reflective layer;

[0025] Bonding the substrate and the epitaxial structure layer in a direction where the first reflective layer faces the substrate, and removing the temporary substrate;

[0026] forming a second type ohmic contact;

[0027] Etching the epitaxial structure layer to form an inclined side wall, wherein an angle between the inclined side wall and a surface of the epitaxial structure layer close to the substrate is an acute angle;

[0028] forming a second reflective layer at least covering the inclined side wall;

[0029] A first electrode and a second electrode are formed, wherein the first electrode is located on a side of the substrate away from the epitaxial structure layer, and the second electrode has a first hollow region, and the orthographic projection of the first type ohmic contact on the surface where the second electrode is located is located in the first hollow region, so that the electron-hole recombination region is located in the first hollow region.

[0030] The present application provides an LED chip, comprising: a substrate, a first reflective layer located on one side of the substrate, and a first electrode located on the other side of the substrate, wherein a first type ohmic contact is arranged in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate, and an epitaxial structure layer is arranged on a surface of the first reflective layer away from the substrate, wherein the epitaxial structure layer comprises a first type layer, an active layer, and a second type layer stacked in sequence, and the first type layer is in direct contact with the first type ohmic contact, that is, the first type layer and the first electrode are electrically connected through the first type ohmic contact layer, so that partial electrical extraction of the LED chip is realized; the epitaxial structure layer has an inclined side wall, and the angle between the inclined side wall and the surface of the epitaxial structure layer close to the substrate is an acute angle, and the second reflective layer at least covers the inclined side wall, that is, the inclined side wall is combined with the first active layer covering the inclined side wall. The second reflective layer can realize that the LED does not emit light from the side wall, but reflects the light; the second electrode is located on the surface of the epitaxial structure layer away from the side of the substrate, and the second electrode has a first hollow area. The first hollow area can be used to realize that the light of the LED chip is emitted only from the first hollow area, so as to realize the small-angle light emission of the LED chip; the positive projection of the first type of ohmic contact on the surface where the second electrode is located is located in the first hollow area, so that the electron-hole recombination area is located in the first hollow area, that is, by controlling the position of the first type of ohmic contact, it is set in the first hollow area, so as to control the position of the electron-hole recombination area, so as to realize the overlap of the electron-hole recombination area and the first hollow area where light is emitted, thereby increasing the effective emission light power of the light emitted from the first hollow area, and then realizing the high power of the LED chip. It can be seen that the LED chip of the present application realizes an LED chip that meets the requirements of small-angle high-power light emission by setting an inclined side wall, a first reflective layer and a first hollow area. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the cross-sectional structure of an LED chip provided in an embodiment of the present application is shown;

[0033] Figure 2 A schematic cross-sectional structure diagram of another LED chip provided in an embodiment of the present application is shown;

[0034] Figure 3 A schematic diagram of a top view of an LED chip provided in an embodiment of the present application is shown;

[0035] Figure 4 A flow chart showing a method for manufacturing an LED chip provided in an embodiment of the present application is shown;

[0036] Figure 5-Figure 10 A schematic diagram of the structure of manufacturing an LED chip according to the method for manufacturing an LED chip provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0039] Secondly, the present application is described in detail with reference to the schematic diagram. When describing the embodiments of the present application in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0040] The main structure of the current LED chip is a conductive substrate, a reflector, an epitaxial structure layer and an electrode stacked in sequence. The light-emitting direction of the LED chip of this structure includes the top surface and the side wall of the LED chip, that is, the LED chip of this structure is a five-sided light-emitting chip, wherein the top surface is the side surface away from the conductive substrate.

[0041] However, there is currently a demand for LED chips to emit light at a small angle and with high power, and LED chips that emit light from five sides cannot meet this demand.

[0042] Currently, an insulating layer can be set on the side wall of the LED chip to limit the side light emission of the LED chip, but this has an impact on the effective light emission power of the LED chip, resulting in a lower effective light emission power of the LED chip. In addition, since the electron-hole recombination area cannot be regulated and restricted, the electro-optical conversion efficiency of the LED chip is also low.

[0043] Based on the above technical problems, an embodiment of the present application provides an LED chip, comprising: a substrate, a first reflective layer located on one side of the substrate, and a first electrode located on the other side of the substrate, wherein a first type ohmic contact is arranged in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate, and an epitaxial structure layer is arranged on a surface of the first reflective layer away from the substrate, the epitaxial structure layer comprises a first type layer, an active layer, and a second type layer stacked in sequence, and the first type layer is in direct contact with the first type ohmic contact, that is, the first type layer and the first electrode are electrically connected through the first type ohmic contact layer, so as to realize partial electrical extraction of the LED chip; the epitaxial structure layer has an inclined side wall, and the angle between the inclined side wall and the surface of the side of the epitaxial structure layer close to the substrate is an acute angle, and the second reflective layer at least covers the inclined side wall, that is, the inclined side wall is combined with the second reflective layer covering the inclined side wall. The second reflective layer on the inclined side wall can realize that the LED does not emit light from the side wall, but reflects the light; the second electrode is located on the surface of the epitaxial structure layer away from the substrate, and the second electrode has a first hollow area. The first hollow area can be used to realize that the light of the LED chip is emitted only from the first hollow area, so as to realize the small-angle light emission of the LED chip; the positive projection of the first type of ohmic contact on the surface where the second electrode is located is located in the first hollow area, so that the electron-hole recombination area is located in the first hollow area, that is, by controlling the position of the first type of ohmic contact, it is set in the first hollow area, so as to control the position of the electron-hole recombination area, so as to realize the overlap of the electron-hole recombination area and the first hollow area for emitting light, thereby increasing the effective emission light power of the light emitted from the first hollow area, and then realizing the high power of the LED chip. It can be seen that the LED chip of the present application realizes an LED chip that meets the requirements of small-angle high-power light emission by setting the inclined side wall, the first reflective layer and the first hollow area.

[0044] In order to better understand the technical solution and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0045] refer to Figure 1, which is a schematic diagram of the structure of an LED chip provided in an embodiment of the present application, wherein the LED chip includes a substrate 110 , a first reflective layer 120 , a first electrode 130 , a first type ohmic contact 210 , an epitaxial structure layer 140 , a second reflective layer 150 and a second electrode 160 .

[0046] In an embodiment of the present application, the substrate 110 may be a conductive semiconductor substrate. For example, the substrate 110 may be a P-type low-resistance silicon substrate. The first reflective layer 120 is located on one side of the substrate 110, and the first electrode 130 is located on the other side of the substrate 110. The first electrode 130 is a conductive material, such as a metal material. The first reflective layer 120 is used to reflect light.

[0047] Specifically, the first reflective layer 120 includes a distributed Bragg (DBR) reflective layer 121 and a metal reflective layer 122. Figure 2 As shown, the DBR reflective layer 121 is located on the surface of the metal reflective layer 122 on one side away from the substrate 110. The DBR reflective layer 121 is formed by alternating growth of insulating oxide layers. The metal reflective layer 122 is made of metal material.

[0048] In practical applications, a metal bonding layer 170 is disposed between the first reflective layer 120 and the substrate 110 , and the metal bonding layer 170 is made of metal material.

[0049] A first type ohmic contact 210 is disposed in the first reflective layer 120 , and the first type ohmic contact 210 is electrically connected to the substrate 110 .

[0050] As a possible implementation, the first type ohmic contact 210 penetrates the DBR reflective layer 121, the first type ohmic contact 210 is in direct contact with the metal reflective layer 122, and the electrical connection between the first type ohmic contact 210 and the substrate 110 is achieved through the metal reflective layer 122. Figure 2 shown.

[0051] In the embodiment of the present application, an epitaxial structure layer 140 is disposed on a surface of the first reflective layer 120 away from the substrate 110, that is, the epitaxial structure layer 140 covers the first reflective layer 120. The epitaxial structure layer 140 includes a first type layer 141, an active layer 142, and a second type layer 143 stacked in sequence, the second type layer 143 covers the active layer 142, and the active layer 142 covers the first type layer 141. At this time, the first type layer 141 covers the DBR reflective layer 121 and is in direct contact with the first type ohmic contact 210, so that the first type layer 141 and the first type ohmic contact 210 are electrically connected.

[0052] As a possible implementation, the first type layer 141 includes a first type restriction layer 1412 and a first type window layer 1411. The first type restriction layer 1412 is located on a surface of the first type window layer 1411 away from the substrate 110. The second type layer 143 includes a second type restriction layer 1431, a second type current spreading layer 1432, a second type roughening layer 1433 and a fixing layer 1434 which are stacked in sequence, the second type current spreading layer 1432 covers the second type restriction layer 1431, the second type roughening layer 1433 covers the second type current spreading layer 1432, and the fixing layer 1434 covers the second type roughening layer 1433, refer to Figure 2 shown.

[0053] The firm layer 1434 serves as the top layer of the epitaxial structure layer 140 and is covered by the second electrode 160. That is, the second electrode 160 is arranged on the firm layer 1434. The second electrode 160 has a strong adhesion on the firm layer 1434, thereby avoiding the problem of poor adhesion caused by the second electrode 160 being arranged on the insulating material and avoiding the problem of the second electrode 160 falling off during the formation process.

[0054] As an example, the first type layer 141 is a P-type layer, and the second type layer 143 is an N-type layer, then the first type confinement layer 1412 is a P-type confinement layer, the first type window layer 1411 is a P-type window layer, the second type confinement layer 1431, the second type current spreading layer 1432, the second type roughening layer 1433 and the firm layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer and an N-type firm layer. The material of the P-type confinement layer is AlGaInP, the material of the P-type window layer is GaP, the material of the N-type firm layer is GaInP, the material of the N-type roughening layer and the N-type current spreading layer is AlGaInP, the material of the N-type confinement layer is AlGaInP, and the active layer 142 is a multiple quantum well (MQW). At this time, the LED chip is a reverse polarity LED chip.

[0055] As another example, the first type layer 141 is a P-type layer, and the second type layer 143 is an N-type layer, then the first type confinement layer 1412 is a P-type confinement layer, the first type window layer 1411 is a P-type window layer, the P-type window layer includes a P-type ohmic contact layer and a P-type current spreading layer, the second type confinement layer 1431, the second type current spreading layer 1432, the second type roughening layer 1433 and the firm layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer and an N-type firm layer. The material of the P-type confinement layer is AlGaAs, the material of the P-type ohmic contact layer is GaP, the material of the P-type current spreading layer is AlGaAs, the material of the N-type firm layer is GaInP, the materials of the N-type roughening layer, the N-type current spreading layer and the N-type confinement layer are AlGaAs, and the active layer 142 is a multiple quantum well (MQW), and in this case the LED chip is a reverse polarity LED chip.

[0056] The doping concentration of the first type window layer 1411 on the side close to the first reflective layer 120 can be greater than the doping concentration on the side away from the first reflective layer 120, so that the surface doping concentration of the first type window layer 1411 is greater than the main doping concentration, thereby achieving better electrical connection with the first type ohmic contact 210.

[0057] As an example, when the first type window layer 1411 is a P-type window layer, the material of the P-type window layer is GaP, and the doping concentration of the main part is 1E18 / cm 3 Above, the surface doping concentration of the P-type window layer reaches 1E19 / cm 3 To achieve control of the electron-hole recombination area of ​​the LED chip, a higher doping concentration can be set only on the surface of a part of the P-type window layer, and the surface doping concentration of the remaining area can be the same as the doping concentration of the main part. This part of the area corresponds to the light-emitting area of ​​the LED chip and the first hollow area formed by the second electrode.

[0058] In the embodiment of the present application, the epitaxial structure layer 140 has an inclined side wall, and the angle between the inclined side wall and the surface of the side of the epitaxial structure layer 140 close to the substrate 110 is an acute angle. The second reflective layer 150 covers at least the inclined side wall. In other words, by setting the inclined side wall, it is possible to set the second reflective layer 150 on the inclined side wall, and the inclined side wall combined with the second reflective layer 150 covering the inclined side wall can realize that the LED does not emit light from the side wall, but reflects the light, that is, reflects the light directed to the side wall, and finally emits it from the first hollow area formed by the second electrode, thereby facilitating the subsequent small-angle light emission of the LED chip.

[0059] The angle between the inclined sidewall and the surface of the epitaxial structure layer 140 close to the substrate 110 can be in the range of 5°-85°. Further, the angle can be in the range of 45°-75°, which can achieve efficient reflection of light to the light emitting area of ​​the LED chip. Figure 2 By providing the inclined sidewalls, the integrity of the second reflective layer 150 covering the sidewalls of the epitaxial structure layer 140 can be improved, and the problem of incomplete coverage of the second reflective layer 150 due to the vertical sidewalls can be avoided.

[0060] Specifically, the second reflective layer 150 may be a DBR reflective layer.

[0061] In an embodiment of the present application, the second electrode 160 is located on a surface of the epitaxial structure layer 140 away from the substrate 110, and the second electrode 160 has a first hollow area 300. The first hollow area 300 can limit the light output angle of the LED chip so that light is only emitted from the first hollow area 300, thereby achieving small-angle light output of the LED chip.

[0062] The orthographic projection of the first type ohmic contact 210 on the surface where the second electrode 160 is located is located in the first hollow area 300, so that the electron-hole recombination area is located in the first hollow area 300. In other words, by controlling the position of the first type ohmic contact 210 and setting it in the first hollow area 300, the position of the electron-hole recombination area is controlled, and the electron-hole recombination area and the first hollow area 300 for emitting light overlap, thereby increasing the effective emission light power of the light emitted from the first hollow area 300, thereby achieving high power of the LED chip.

[0063] refer to Figure 1 and Figure 3 As shown, the second electrode 160 has a first hollow region 300 , that is, the second electrode 160 surrounds the first hollow region 300 , and the first hollow region 300 includes an orthographic projection of the first type ohmic contact 210 .

[0064] As a possible implementation, the shape of the first hollow area 300 can be designed according to actual light emission requirements, and the shape of the first hollow area 300 is circular or polygonal. The orthographic projection of the first type ohmic contact 210 on the surface where the second electrode 160 is located is circular.

[0065] In the embodiment of the present application, the LED chip further includes a second type ohmic contact 220, which is disposed on a surface of the epitaxial structure layer 140 away from the substrate 110, and the second electrode 160 covers the second type ohmic contact 220. Figure 2 As shown, the second type ohmic contact 220 is electrically connected to the second electrode 160. The second type ohmic contact 220 surrounds the first hollow area 300. Figure 3 By arranging the second type ohmic contact 220 surrounding the first hollow region 300 around the first hollow region 300, and combining the orthographic projection of the first type ohmic contact 210 being located in the first hollow region 300, the first type ohmic contact 210 and the second type ohmic contact 220 are used to guide the electrons and holes injected into the active layer 142, and further the electron-hole recombination zone is located below the first hollow region 300, reducing the recombination of the area outside the first hollow region 300, thereby improving the luminous efficiency of the LED.

[0066] The second type ohmic contact 220 includes a second type semiconductor ohmic contact 221 and a second type metal ohmic contact 222 . The second type metal ohmic contact 222 is located on a side of the second type semiconductor ohmic contact 221 away from the substrate 110 . The second electrode 160 covers the second type metal ohmic contact 222 .

[0067] Specifically, the second type metal ohmic contact 222 is made of metal material, and the second type semiconductor ohmic contact 221 is made of GaAs.

[0068] In the embodiment of the present application, the fixing layer 1434 has a second hollow region 400, so as to realize the light emission of the LED chip. The orthographic projection of the first hollow region 300 on the surface where the substrate 110 is located includes the orthographic projection of the second hollow region 400 on the surface where the substrate 110 is located. That is, the first hollow region 300 includes the second hollow region 400, and the reference Figure 3 The second hollow area 400 is smaller than the first hollow area 300, so that the second electrode 160 has a sufficient area for wiring arrangement, thereby achieving sufficient adhesion in the area where the second electrode 160 is arranged.

[0069] In practical applications, the first hollow area 300 and the second hollow area 400 may completely overlap.

[0070] In the embodiment of the present application, the orthographic projection of the first type ohmic contact 210 on the surface where the secure layer 1434 is located is located in the second hollow area 400. By arranging the first type ohmic contact 210 in the second hollow area 400, it is possible to further control the electron-hole recombination area to be located in the second hollow area 400, thereby further limiting the light emission angle of the LED chip.

[0071] In the embodiment of the present application, the second reflective layer 150 not only covers the inclined sidewall of the epitaxial structure layer 140, but also covers the area of ​​the surface of the epitaxial structure layer 140 on the side away from the substrate 110, except for the first hollow area 300, which is not covered by the second electrode 160. That is, the second electrode 160 and the second reflective layer 150 jointly cover the area of ​​the surface of the epitaxial structure layer 140 on the side away from the substrate 110, except for the first hollow area 300, Figure 2 As shown, the light can only be emitted through the first hollow area 300 .

[0072] Starting from the intersection line of the side of the inclined side wall away from the substrate 110 and the side surface of the epitaxial structure layer 140 away from the substrate 110, the second reflective layer 150 extends at least a fixed distance on the side surface of the epitaxial structure layer 140 away from the substrate 110 to ensure that the inclined side wall is completely covered by the second reflective layer 150 to reduce the risk of leakage.

[0073] As an example, the fixed distance is 1 micron.

[0074] In practical applications, the side of the epitaxial structure layer 140 close to the substrate 110 also has an extension plane connected to the inclined sidewall, that is, when the epitaxial structure layer 140 forms an inclined sidewall, the side of the inclined sidewall close to the substrate 110 is connected to the extension plane, and the inclined sidewall takes the extension plane as a starting point and extends in a direction away from the substrate 110. The second reflective layer 150 not only covers the inclined sidewall of the epitaxial structure layer 140, but also covers a part of the extension plane. Figure 2 As shown, in order to ensure that the inclined sidewall is completely covered by the second reflective layer 150, the risk of leakage is reduced.

[0075] Specifically, the extension plane is a plane formed by a surface of one side of the first type window layer 1411 away from the substrate 110. The extension plane is parallel to the plane where the substrate 110 is located. The extension plane is connected to the inclined side wall on one side in a direction parallel to the plane where the substrate 110 is located, and the other side is a cutting road area. The second reflective layer 150 extends at least a fixed distance on the extension plane.

[0076] In the embodiment of the present application, the epitaxial structure layer 140 has a first side wall and a second side wall that are arranged opposite to each other, and the distance between the first hollow region 300 and the first side wall is smaller than the distance between the first hollow region 300 and the second side wall. Figure 1-Figure 3 That is to say, the first hollow region 300 is not arranged axially symmetrically with respect to the epitaxial structure layer 140, but is closer to the first side wall and farther from the second side wall than the two oppositely arranged side walls, so that the surface of the epitaxial structure layer 140 at a farther distance has enough area to arrange the second electrode 160, meeting the wiring requirements of the second electrode 160.

[0077] It can be seen that the embodiment of the present application provides an LED chip, including: a substrate, a first reflective layer located on one side of the substrate, and a first electrode located on the other side of the substrate, a first type of ohmic contact is arranged in the first reflective layer, the first type of ohmic contact is electrically connected to the substrate, an epitaxial structure layer is arranged on a surface of the first reflective layer away from the substrate, the epitaxial structure layer includes a first type layer, an active layer and a second type layer stacked in sequence, the first type layer is in direct contact with the first type of ohmic contact, that is, the first type layer and the first electrode are electrically connected through the first type of ohmic contact layer, so as to realize partial electrical extraction of the LED chip; the epitaxial structure layer has an inclined side wall, the angle between the inclined side wall and the surface of the side of the epitaxial structure layer close to the substrate is an acute angle, and the second reflective layer at least covers the inclined side wall, that is, the inclined side wall is combined with the second reflective layer covering the inclined side wall. The second reflective layer on the wall can realize that the LED does not emit light from the side wall, but reflects the light; the second electrode is located on the surface of the epitaxial structure layer away from the substrate, and the second electrode has a first hollow area. The first hollow area can be used to realize that the light of the LED chip is emitted only from the first hollow area, so as to realize the small-angle light emission of the LED chip; the positive projection of the first type of ohmic contact on the surface where the second electrode is located is located in the first hollow area, so that the electron-hole recombination area is located in the first hollow area, that is, by controlling the position of the first type of ohmic contact, it is set in the first hollow area, so as to control the position of the electron-hole recombination area, so as to realize the overlap of the electron-hole recombination area and the first hollow area where light is emitted, thereby increasing the effective emission light power of the light emitted from the first hollow area, and then realizing the high power of the LED chip. It can be seen that the LED chip of the present application realizes an LED chip that meets the requirements of small-angle high-power light emission by setting an inclined side wall, a first reflective layer and a first hollow area.

[0078] Based on the LED chip provided in the above embodiment, the present application embodiment also provides a method for manufacturing an LED chip. Figure 4 FIG. 1 is a flow chart of a method for manufacturing an LED chip provided in an embodiment of the present application, the method comprising the following steps:

[0079] S101, forming an epitaxial structure layer on one side of a temporary substrate, wherein the epitaxial structure layer includes a second type layer, an active layer, and a first type layer which are stacked in sequence.

[0080] In the embodiment of the present application, a temporary substrate 201 may be provided, and an epitaxial structure layer 140 may be formed on one side of the temporary substrate 201. Figure 5 As shown, the epitaxial structure layer 140 is subsequently bonded to the substrate to finally manufacture the LED chip.

[0081] Specifically, the material of the temporary substrate 201 may be GaAs, and the epitaxial structure layer 140 is formed on the temporary substrate 201 by using a Metal-organic Chemical Vapor Deposition (MOCVD) process.

[0082] The epitaxial structure layer 140 includes a second type layer 143 , an active layer 142 , and a first type layer 141 which are sequentially stacked. The active layer 142 covers the second type layer 143 , and the first type layer 141 covers the active layer 142 .

[0083] As a possible implementation, the first type layer 141 includes a first type restriction layer 1412 and a first type window layer 1411. The first type restriction layer 1412 is located on a surface of the first type window layer 1411 close to the temporary substrate 201. The second type layer 143 includes a second type restriction layer 1431, a second type current spreading layer 1432, a second type roughening layer 1433 and a fixing layer 1434 which are stacked in sequence, the second type restriction layer 1431 covers the second type current spreading layer 1432, the second type current spreading layer 1432 covers the second type roughening layer 1433, the second type roughening layer 1433 covers the fixing layer 1434, refer to Figure 5 shown.

[0084] As an example, the first type layer 141 is a P-type layer, and the second type layer 143 is an N-type layer, then the first type confinement layer 1412 is a P-type confinement layer, the first type window layer 1411 is a P-type window layer, the second type confinement layer 1431, the second type current spreading layer 1432, the second type roughening layer 1433 and the firm layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer and an N-type firm layer. The material of the P-type confinement layer is AlGaInP, the material of the P-type window layer is GaP, the material of the N-type firm layer is GaInP, the material of the N-type roughening layer and the N-type current spreading layer is AlGaInP, the material of the N-type confinement layer is AlGaInP, and the active layer 142 is a multiple quantum well (MQW). At this time, the LED chip is a reverse polarity LED chip.

[0085] As another example, the first type layer 141 is a P-type layer, and the second type layer 143 is an N-type layer, then the first type confinement layer 1412 is a P-type confinement layer, the first type window layer 1411 is a P-type window layer, the P-type window layer includes a P-type ohmic contact layer and a P-type current spreading layer, the second type confinement layer 1431, the second type current spreading layer 1432, the second type roughening layer 1433 and the firm layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer and an N-type firm layer. The material of the P-type confinement layer is AlGaAs, the material of the P-type ohmic contact layer is GaP, the material of the P-type current spreading layer is AlGaAs, the material of the N-type firm layer is GaInP, the materials of the N-type roughening layer, the N-type current spreading layer and the N-type confinement layer are AlGaAs, and the active layer 142 is a multiple quantum well (MQW), and in this case the LED chip is a reverse polarity LED chip.

[0086] The doping concentration of the first type window layer 1411 on the side away from the temporary substrate 201 can be greater than the doping concentration on the side close to the temporary substrate 201, so that the surface doping concentration of the first type window layer 1411 is greater than the main doping concentration, thereby achieving better electrical lead-out of the LED chip.

[0087] As an example, when the first type window layer 1411 is a P-type window layer, the material of the P-type window layer is GaP, and the doping concentration of the main part is 1E18 / cm 3 Above, the surface doping concentration of the P-type window layer reaches 1E19 / cm 3 In order to control the electron-hole recombination area of ​​the LED chip, a preset area of ​​the P-type window layer can be etched so that a higher doping concentration is set only on the surface of a part of the P-type window layer, so that the surface doping concentration of the preset area is the same as the doping concentration of the main part, and the preset area corresponds to the non-light-emitting area of ​​the LED chip, thereby limiting the current expansion.

[0088] In practical applications, before forming the epitaxial structure layer 140 on the temporary substrate 201, a buffer layer, an etching stop layer, and a second-type semiconductor ohmic contact layer 200 stacked in sequence may also be formed. The second-type semiconductor ohmic contact layer 200 covers the etching stop layer, and the etching stop layer covers the buffer layer. Specifically, the material of the buffer layer and the second-type semiconductor ohmic contact layer 200 may be GaAs, and the material of the etching stop layer may be GaInP.

[0089] S102, forming a first reflective layer on the epitaxial structure layer, and forming a first type ohmic contact in the first reflective layer.

[0090] In the embodiment of the present application, after the epitaxial structure layer 140 is formed on the temporary substrate 201 , the first reflective layer 120 may be further formed on the epitaxial structure layer 140 .

[0091] Specifically, the first reflective layer 120 can be formed by a deposition process. The first reflective layer 120 is used to reflect light. The first reflective layer 120 includes a distributed Bragg (DBR) reflective layer 121 and a metal reflective layer 122. Figure 6 As shown, the DBR reflective layer 121 is located on the surface of the metal reflective layer 122 on one side away from the substrate 110. The DBR reflective layer 121 is formed by alternating growth of insulating oxide layers. The metal reflective layer 122 is made of metal material.

[0092] In the embodiment of the present application, after the first reflective layer 120 is formed on the epitaxial structure layer 140 , a first type ohmic contact 210 is formed in the first reflective layer 120 .

[0093] Specifically, a DBR reflective layer 121 and a photoresist are deposited on the surface of the epitaxial structure layer 140. The DBR reflective layer 121 is photolithographically and etched to form a dielectric hole required for the first type ohmic contact 210 in the DBR reflective layer 121, the photoresist is removed, a metal material is evaporated on the surface of the DBR reflective layer 121, and a metal reflective layer 122 and a first type ohmic contact 210 filling the cut-off hole are formed after annealing. The metal reflective layer 122 is electrically connected to the first type ohmic contact 210 in the dielectric hole and the first type window layer 1411, and the first type ohmic contact 210 becomes a channel for current injection.

[0094] S103, bonding the substrate and the epitaxial structure layer with the first reflective layer facing the substrate, and removing the temporary substrate.

[0095] In the embodiment of the present application, after forming the first reflective layer 120 and the first type ohmic contact 210 , a substrate 110 is provided, and the substrate 110 and the epitaxial structure layer 140 are bonded in a direction where the first reflective layer 120 faces the substrate 110 .

[0096] Specifically, the substrate 110 may be a conductive semiconductor substrate. For example, the substrate 110 may be a P-type low-resistance silicon substrate. A metal bonding layer 170 is evaporated on the surface of the substrate 110, or the metal bonding layer 170 is evaporated on the metal reflective layer 122, and then the metal bonding layer 170 is used to achieve bonding between the substrate 110 and the epitaxial structure layer 140. During the bonding process of heating and pressurizing, the metal bonding layer 170 on the epitaxial structure layer 140 and the metal bonding layer 170 on the surface of the substrate 110 are combined together due to mutual diffusion, so that the epitaxial structure layer 140 is bonded to the substrate 110. Figure 7 shown.

[0097] In the embodiment of the present application, after bonding is completed, the temporary substrate 201 , the buffer layer and the etching stop layer are removed to expose the second type semiconductor ohmic contact layer 200 .

[0098] S104, forming a second type ohmic contact.

[0099] In the embodiment of the present application, after the bonding is completed and the temporary substrate 201 is removed, a second type ohmic contact 220 may be formed on the epitaxial structure layer 140, specifically, a second type ohmic contact 220 may be formed on the secure layer 1434, as shown in FIG. Figure 8 shown.

[0100] Specifically, the second type semiconductor ohmic contact 221 is made by photolithography and wet etching of the second type semiconductor ohmic contact layer 200, and then the second type metal ohmic contact 222 is made by photolithography, evaporation, stripping, and annealing processes, so that the second type metal ohmic contact 222 and the second type semiconductor ohmic contact 221 form a good ohmic contact, that is, a second type ohmic contact 220 is formed.

[0101] S105, etching the epitaxial structure layer to form an inclined side wall, wherein an angle between the inclined side wall and a surface of the epitaxial structure layer close to the substrate is an acute angle.

[0102] In the embodiment of the present application, after forming the second type ohmic contact 220, the epitaxial structure layer 140 can be etched to form an inclined sidewall, and the angle between the inclined sidewall and the surface of the epitaxial structure layer 140 close to the substrate 110 is an acute angle, referring to Fig. 9 Shown

[0103] Specifically, photoresist can be spin-coated on the surface of the epitaxial structure layer 140 away from the substrate 110, and a cutting path area is defined after exposure and development. The LED chip area is protected by photoresist, and the cutting path area is not protected by photoresist. The epitaxial structure layer 140 is etched in the cutting path area by dry etching until the first type window layer 1411 forms an inclined sidewall. For example, a partial thickness of the first type window layer 1411 can be etched to form an extended plane and an inclined sidewall.

[0104] As an example, the sidewalls of the epitaxial structure layer 140 may be etched into inclined sidewalls by adjusting parameters such as gas flow, chamber pressure, and radio frequency power in the dry etching process.

[0105] S106, forming a second reflective layer that at least covers the inclined side wall.

[0106] In the embodiment of the present application, after forming the inclined sidewall, a second reflective layer 150 at least covering the inclined sidewall may be formed. Fig.10 shown.

[0107] Specifically, the second reflective layer 150 may be a DBR reflective layer. A DBR reflective material is deposited on a surface of the side of the epitaxial structure layer 140 away from the substrate 110, an inclined side wall, and an extended surface, and the DBR reflective material in a preset area is etched to form a second reflective layer 150 covering the inclined side wall, the extended surface, and a portion of the surface of the side of the epitaxial structure layer 140 away from the substrate 110. The preset area is an area where the second electrode 160 is subsequently set, and the preset area includes an area where the second type ohmic contact 220 is set.

[0108] S107, forming a first electrode and a second electrode, the first electrode is located on a side of the substrate away from the epitaxial structure layer, the second electrode has a first hollow area, and the orthographic projection of the first type ohmic contact on the surface where the second electrode is located is located in the first hollow area, so that the electron-hole recombination area is located in the first hollow area.

[0109] In the embodiment of the present application, after forming the second reflective layer 150, the first electrode 130 and the second electrode 160 are formed respectively. Figure 1 shown.

[0110] Specifically, electrode materials are deposited on the surface of the firm layer 1434, and then the second electrode 160 is manufactured by photolithography, evaporation, stripping, and annealing processes. The second electrode 160 has a first hollow region 300, and the orthographic projection of the first type ohmic contact 210 on the surface where the second electrode 160 is located is located in the first hollow region 300, so that the electron-hole recombination region is located in the first hollow region 300.

[0111] The side of the substrate 110 away from the epitaxial structure layer 140 is thinned, and then an electrode material is evaporated to form the first electrode 130 .

[0112] The fixing layer 1434 in the first hollow region 300 may also be removed to form the second hollow region 400 , and the surface of the second type roughening layer 1433 of the second hollow region 400 may be roughened.

[0113] In practical applications, after the first electrode 130 and the second electrode 160 are formed, the substrate 110 may be cut, for example, through processes such as front cutting, back cutting and splitting, to obtain independent LED chips.

[0114] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiment, since it is basically similar to the structural embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the structural embodiment.

[0115] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. An LED chip, characterized in that: include: A substrate, a first reflective layer located on one side of the substrate, and a first electrode located on the other side of the substrate, wherein a first type ohmic contact is provided in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate; An epitaxial structure layer is arranged on a surface of the first reflective layer away from the substrate, the epitaxial structure layer comprising a first type layer, an active layer and a second type layer stacked in sequence; the first type layer is in direct contact with the first type ohmic contact, the epitaxial structure layer has an inclined side wall, and an angle between the inclined side wall and a surface of the epitaxial structure layer close to the substrate is an acute angle; a second reflective layer at least covering the inclined side wall; A second electrode is located on the surface of the epitaxial structure layer away from the substrate; the second electrode has a first hollow area, and the positive projection of the first type ohmic contact on the surface where the second electrode is located is located in the first hollow area, so that the electron-hole recombination area is located in the first hollow area.

2. The LED chip according to claim 1, characterized in that: It also includes a second type of ohmic contact located on a surface of the epitaxial structure layer away from the substrate, and the second electrode covers the second type of ohmic contact; The second type ohmic contact surrounds the first hollow area.

3. The LED chip according to claim 1, characterized in that: The second type of layer comprises a firm layer; The second electrode covers the securing layer.

4. The LED chip according to claim 3, characterized in that: The fixing layer has a second hollow area, and the orthographic projection of the first hollow area on the surface where the substrate is located includes the orthographic projection of the second hollow area on the surface where the substrate is located.

5. The LED chip according to claim 4, characterized in that: The orthographic projection of the first type ohmic contact on the surface where the secure layer is located is located in the second hollow area.

6. The LED chip according to claim 1, characterized in that: The second reflective layer also covers an area of ​​the surface of the epitaxial structure layer on one side away from the substrate but not covered by the second electrode except for the first hollow area.

7. The LED chip according to claim 1, characterized in that: The epitaxial structure layer also has an extension plane connected to the inclined side wall on a side close to the substrate, and the second reflective layer also covers the extension plane.

8. The LED chip according to claim 1, characterized in that: The epitaxial structure layer has a first side wall and a second side wall that are oppositely disposed, and a distance between the first hollow region and the first side wall is smaller than a distance between the first hollow region and the second side wall.

9. The LED chip according to claim 1, characterized in that: The first hollow area is in a circular or polygonal shape.

10. A method for manufacturing an LED chip, characterized in that: include: Forming an epitaxial structure layer on one side of the temporary substrate, wherein the epitaxial structure layer includes a second type layer, an active layer and a first type layer stacked in sequence; forming a first reflective layer on the epitaxial structure layer, and forming a first type ohmic contact in the first reflective layer; Bonding the substrate and the epitaxial structure layer in a direction where the first reflective layer faces the substrate, and removing the temporary substrate; forming a second type ohmic contact; Etching the epitaxial structure layer to form an inclined side wall, wherein an angle between the inclined side wall and a surface of the epitaxial structure layer close to the substrate is an acute angle; forming a second reflective layer at least covering the inclined side wall; A first electrode and a second electrode are formed, wherein the first electrode is located on a side of the substrate away from the epitaxial structure layer, and the second electrode has a first hollow region, and the orthographic projection of the first type ohmic contact on the surface where the second electrode is located is located in the first hollow region, so that the electron-hole recombination region is located in the first hollow region.

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