LED chip

Abstract

The embodiment of the utility model provides an LED chip, which comprises a substrate, a first reflecting layer, a first electrode, an epitaxial structure layer, a second reflecting layer and a second electrode, and is characterized in that a first type of ohmic contact is arranged in the first reflecting layer; 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] This utility model relates to the field of semiconductor devices, and in particular to an LED chip. Background Technology

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

[0003] The main structure of current LED chips consists of a conductive substrate, a reflector, an epitaxial structure layer, and electrodes stacked sequentially. The light emission direction of this LED chip includes the top surface and sidewalls of the LED chip, meaning that this LED chip is a five-sided light-emitting chip, where the top surface is the surface away from the conductive substrate.

[0004] However, there is a current demand for LED chips that emit light at a small angle and with high power, and five-sided LED chips cannot meet this demand. Utility Model Content

[0005] In view of this, the purpose of this application is to provide an LED chip that achieves high power light emission at a small angle.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] This application provides an LED chip, including:

[0008] The 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 of ohmic contact is disposed in the first reflective layer and the first type of ohmic contact is electrically connected to the substrate;

[0009] An epitaxial structure layer is disposed on the 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 sequentially. The first type layer and the first type ohmic contact are in direct contact. The epitaxial structure layer has an inclined sidewall, and the angle between the inclined sidewall and the surface of the epitaxial structure layer near the substrate is an acute angle.

[0010] At least a second reflective layer covering the inclined sidewalls;

[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 region, and the orthographic projection of the first type of ohmic contact on the surface of the second electrode is located in the first hollow region, such that the electron-hole recombination region is located in the first hollow region.

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

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

[0014] Optionally, the second type of layer includes a robust layer;

[0015] The second electrode covers the solid layer.

[0016] Optionally, the bonding layer has a second hollowed-out area, and the orthographic projection of the first hollowed-out area onto the surface of the substrate includes the orthographic projection of the second hollowed-out area onto the surface of the substrate.

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

[0018] Optionally, the second reflective layer also covers the area of ​​the epitaxial structure layer on the side of the substrate away from the substrate that is not covered by the second electrode, except for the first hollowed-out area.

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

[0020] Optionally, the epitaxial structure layer has a first sidewall and a second sidewall disposed opposite to each other, and the distance between the first hollow area and the first sidewall is less than the distance between the first hollow area and the second sidewall.

[0021] Optionally, the shape of the first hollowed-out area is circular or polygonal.

[0022] Optionally, the angle between the inclined sidewall and the surface of the epitaxial structure layer near the substrate ranges from 5° to 85°.

[0023] This 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. A first type ohmic contact is disposed in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate. An epitaxial structure layer is disposed on the 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 sequentially. The first type layer and the first type ohmic contact are in direct contact; that is, the first type layer and the first electrode are electrically connected through the first type ohmic contact layer, realizing partial electrical lead-out of the LED chip. The epitaxial structure layer has inclined sidewalls, and the angle between the inclined sidewalls and the surface of the epitaxial structure layer near the substrate is an acute angle. The second reflective layer at least covers the inclined sidewalls; that is, the inclined sidewalls are combined with the first type ohmic contact layer covering the inclined sidewalls. The second reflective layer enables the LED to reflect light instead of emitting it from the sidewalls. A second electrode, located on the surface of the epitaxial layer away from the substrate, has a first hollowed-out area. This first hollowed-out area allows the light from the LED chip to be emitted only from this area, achieving small-angle light emission. The orthographic projection of a first-type ohmic contact on the surface of the second electrode lies within the first hollowed-out area, ensuring that the electron-hole recombination region is located within this area. In other words, by controlling the position of the first-type ohmic contact within the first hollowed-out area, the position of the electron-hole recombination region is controlled, achieving overlap between the electron-hole recombination region and the light-emitting first hollowed-out area. This increases the effective emitted light power from the first hollowed-out area, thereby achieving high power in the LED chip. Therefore, the LED chip of this application, by incorporating inclined sidewalls, a first reflective layer, and a first hollowed-out area, achieves high-power light emission at a small angle. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A cross-sectional structural diagram of an LED chip provided in an embodiment of this application is shown;

[0026] Figure 2 A cross-sectional structural diagram of another LED chip provided in an embodiment of this application is shown;

[0027] Figure 3 This illustration shows a top view of an LED chip according to an embodiment of this application.

[0028] Figure 4 A flowchart illustrating a method for manufacturing an LED chip according to an embodiment of this application is shown;

[0029] Figures 5-10 A schematic diagram of the structure of an LED chip manufactured according to the LED chip manufacturing method provided in the embodiments of this application is shown. Detailed Implementation

[0030] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0032] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0033] The main structure of current LED chips consists of a conductive substrate, a reflector, an epitaxial structure layer, and electrodes stacked sequentially. The light emission direction of this LED chip includes the top surface and sidewalls of the LED chip, meaning that this LED chip is a five-sided light-emitting chip, where the top surface is the surface away from the conductive substrate.

[0034] However, there is a current demand for LED chips that emit light at a small angle and with high power, and five-sided LED chips cannot meet this demand.

[0035] Currently, an insulating layer can be placed on the sidewalls of LED chips to restrict light emission from the sides. However, this affects the effective emitted light power of the LED chip, resulting in a lower effective emitted light power. Furthermore, because the electron-hole recombination region cannot be controlled or restricted, the electro-optical conversion efficiency of the LED chip is also low.

[0036] Based on the above technical problems, this 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 ohmic contact is disposed in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate. An epitaxial structure layer is disposed on the 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 sequentially. The first type layer and the first type ohmic contact are in direct contact; that is, the first type layer and the first electrode are electrically connected through the first type ohmic contact layer, realizing partial electrical lead-out of the LED chip. The epitaxial structure layer has inclined sidewalls, and the angle between the inclined sidewalls and the surface of the epitaxial structure layer near the substrate is an acute angle, at least covering the second reflective layer of the inclined sidewalls. In other words, the inclined sidewalls combine with and cover the inclined reflective layer of the substrate. The second reflective layer on the sloping sidewall allows the LED to reflect light instead of emitting it from the sidewall. The second electrode, located on the surface of the epitaxial layer away from the substrate, has a first hollowed-out area. This first hollowed-out area allows the light from the LED chip to be emitted only from this area, achieving small-angle light emission. The orthographic projection of a first-type ohmic contact on the surface of the second electrode lies within the first hollowed-out area, ensuring that the electron-hole recombination region is located within this area. In other words, by controlling the position of the first-type ohmic contact within the first hollowed-out area, the position of the electron-hole recombination region is controlled, achieving overlap between the electron-hole recombination region and the light-emitting first hollowed-out area. This increases the effective emitted light power from the first hollowed-out area, thereby achieving high power in the LED chip. Therefore, the LED chip of this application, by incorporating the sloping sidewall, the first reflective layer, and the first hollowed-out area, achieves high-power light emission at a small angle.

[0037] To better understand the technical solution and effects of this application, the specific embodiments will be described in detail below with reference to the accompanying drawings.

[0038] refer to Figure 1 The diagram shown is a structural schematic of an LED chip provided in an embodiment of this application. The LED chip includes a substrate 110, a first reflective layer 120, a first electrode 130, a first type of ohmic contact 210, an epitaxial structure layer 140, a second reflective layer 150, and a second electrode 160.

[0039] In embodiments of this application, the substrate 110 can be a conductive semiconductor substrate. For example, the substrate 110 can be a P-type low-resistivity 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.

[0040] Specifically, the first reflective layer 120 includes a distributed Bragg (DBR) reflective layer 121 and a metallic reflective layer 122, as shown in the reference. Figure 2 As shown. The DBR reflective layer 121 is located on the surface of the metal reflective layer 122 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 a metallic material.

[0041] In practical applications, a metal bonding layer 170 is provided between the first reflective layer 120 and the substrate 110, and the metal bonding layer 170 is made of metal material.

[0042] A first type of ohmic contact 210 is provided in the first reflective layer 120, and the first type of ohmic contact 210 is electrically connected to the substrate 110.

[0043] As one possible implementation, the first type of ohmic contact 210 penetrates the DBR reflective layer 121, and the first type of ohmic contact 210 and the metal reflective layer 122 are in direct contact. The electrical connection between the first type of ohmic contact 210 and the substrate 110 is achieved through the metal reflective layer 122. (Refer to...) Figure 2 As shown.

[0044] In the embodiments of this application, an epitaxial structure layer 140 is disposed on the 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 sequentially. 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, realizing the electrical connection between the first type layer 141 and the first type ohmic contact 210.

[0045] In one possible implementation, the first type layer 141 includes a first type confinement layer 1412 and a first type window layer 1411. The first type confinement layer 1412 is located on the surface of the first type window layer 1411 away from the substrate 110. The second type layer 143 includes a second type confinement layer 1431, a second type current spreading layer 1432, a second type roughening layer 1433, and a reinforcement layer 1434, which are sequentially stacked. The second type current spreading layer 1432 covers the second type confinement layer 1431, the second type roughening layer 1433 covers the second type current spreading layer 1432, and the reinforcement layer 1434 covers the second type roughening layer 1433. (Refer to...) Figure 2 As shown.

[0046] The bonding layer 1434, as the top layer of the epitaxial structure layer 140, is covered by the second electrode 160. That is, the second electrode 160 is disposed on the bonding layer 1434. The second electrode 160 has strong adhesion to the bonding layer 1434, thereby avoiding the problem of poor adhesion caused by the second electrode 160 being disposed on the insulating material, and avoiding the problem of the second electrode 160 falling off during the formation process.

[0047] As an example, if 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, and the second type confinement layer 1431, the second type current spreading layer 1432, the second type roughening layer 1433, and the robust layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer, and an N-type robust 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 robust 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). In this case, the LED chip is an inverse polarity LED chip.

[0048] As another example, if 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, and 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 robust layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer, and an N-type robust 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 robust layer is GaInP, and the materials of the N-type roughening layer, the N-type current spreading layer, and the N-type confinement layer are AlGaAs. The active layer 142 is a multiple quantum well (MQW), and in this case, the LED chip is an anti-polarity LED chip.

[0049] The doping concentration of the first type window layer 1411 on the side closer to the first reflective layer 120 can be greater than the doping concentration on the side farther from the first reflective layer 120, thereby achieving a higher surface doping concentration of the first type window layer 1411 than the main body doping concentration, thus achieving a better electrical connection with the first type ohmic contact 210.

[0050] As an example, when the first type of 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 bulk portion is 1E18 / cm². 3 The surface doping concentration of the P-type window layer reaches 1E19 / cm².3 The above describes a method for controlling the electron-hole recombination region of an LED chip. A higher doping concentration can be applied only to a portion of the surface layer of the P-type window layer, while the doping concentration of the remaining surface layer can be the same as that of the main body. This portion corresponds to the light-emitting region of the LED chip and the first hollow region formed by the second electrode.

[0051] In the embodiments of this application, the epitaxial structure layer 140 has inclined sidewalls, and the angle between the inclined sidewalls and the surface of the epitaxial structure layer 140 near the substrate 110 is an acute angle. The second reflective layer 150 at least covers the inclined sidewalls. That is, by setting the inclined sidewalls, the second reflective layer 150 can be set on the inclined sidewalls. The combination of the inclined sidewalls and the second reflective layer 150 covering the inclined sidewalls enables the LED to reflect light instead of emitting light from the sidewalls. That is, the light that is incident on the sidewalls is reflected and finally emitted from the first hollow area formed by the second electrode, thereby facilitating the subsequent small-angle light emission of the LED chip.

[0052] The angle between the inclined sidewall and the surface of the epitaxial structure layer 140 near the substrate 110 can range from 5° to 85°, and further, the angle can range from 45° to 75°, which can achieve high-efficiency reflection of light to the light-emitting area of ​​the LED chip. (Refer to...) Figure 2 As shown. By setting inclined sidewalls, the integrity of the second reflective layer 150 covering the sidewalls of the epitaxial structure layer 140 can be improved, avoiding the problem of incomplete coverage of the second reflective layer 150 due to vertical sidewalls.

[0053] Specifically, the second reflective layer 150 can be a DBR reflective layer.

[0054] In the embodiments of this application, the second electrode 160 is located on the side surface of the epitaxial structure layer 140 away from the substrate 110. The second electrode 160 has a first hollow area 300. The first hollow area 300 can limit the light emission angle of the LED chip, so that the light is emitted only from the first hollow area 300, thereby realizing the small-angle light emission of the LED chip.

[0055] The orthographic projection of the first type of ohmic contact 210 onto the surface of the second electrode 160 lies within the first hollow region 300, such that the electron-hole recombination region is located within the first hollow region 300. In other words, by controlling the position of the first type of ohmic contact 210 within the first hollow region 300, the position of the electron-hole recombination region is controlled, achieving overlap between the electron-hole recombination region and the light-emitting first hollow region 300. This increases the effective emitted light power from the first hollow region 300, thereby achieving high power in the LED chip.

[0056] 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 the orthographic projection of the first type of ohmic contact 210.

[0057] As one possible implementation, the shape of the first hollow region 300 can be designed according to the actual light output requirements. The shape of the first hollow region 300 can be circular or polygonal. The orthographic projection of the first type of ohmic contact 210 on the surface where the second electrode 160 is located is circular.

[0058] In embodiments of this application, the LED chip further includes a second type of ohmic contact 220, which is disposed on the surface of the epitaxial structure layer 140 away from the substrate 110. The second electrode 160 covers the second type of ohmic contact 220. (Refer to...) Figure 2 As shown, this achieves electrical connection between the second type of ohmic contact 220 and the second electrode 160. The second type of ohmic contact 220 surrounds the first hollowed-out area 300, as shown in the reference diagram. Figure 3 As shown. By setting a second type of ohmic contact 220 around the first hollow area 300, and combining this with the orthographic projection of the first type of ohmic contact 210 located in the first hollow area 300, electrons and holes injected into the active layer 142 can be guided by the first type of ohmic contact 210 and the second type of ohmic contact 220. This further ensures that the electron-hole recombination region is located below the first hollow area 300, reducing recombination in areas outside the first hollow area 300, thereby improving the luminous efficiency of the LED.

[0059] The second type of ohmic contact 220 includes a second type of semiconductor ohmic contact 221 and a second type of metal ohmic contact 222. The second type of metal ohmic contact 222 is located on the side of the second type of semiconductor ohmic contact 221 away from the substrate 110, and the second electrode 160 covers the second type of metal ohmic contact 222.

[0060] Specifically, the second type of metal ohmic contact 222 is made of a metallic material, and the second type of semiconductor ohmic contact 221 is made of GaAs.

[0061] In embodiments of this application, the bonding layer 1434 has a second hollowed-out region 400, thereby enabling light emission from the LED chip. The orthographic projection of the first hollowed-out region 300 onto the surface of the substrate 110 includes the orthographic projection of the second hollowed-out region 400 onto the surface of the substrate 110. That is, the first hollowed-out region 300 includes the second hollowed-out region 400, as referenced. Figure 3As shown. The second cutout area 400 is smaller than the first cutout area 300, which allows the second electrode 160 to have sufficient area for wiring, thereby ensuring that the area where the second electrode 160 is set has sufficient adhesion.

[0062] In practical applications, the first cutout area 300 and the second cutout area 400 can completely overlap.

[0063] In the embodiments of this application, the orthographic projection of the first type of ohmic contact 210 onto the surface of the bonding layer 1434 is located in the second hollow region 400. By placing the first type of ohmic contact 210 in the second hollow region 400, it is possible to further control the location of the electron-hole recombination region in the second hollow region 400, thereby further limiting the light emission angle of the LED chip.

[0064] In the embodiments of this application, the second reflective layer 150 not only covers the inclined sidewalls of the epitaxial structure layer 140, but also covers the area of ​​the epitaxial structure layer 140 on the side away from the substrate 110 that is not covered by the second electrode 160, except for the first hollow area 300. That is, the second electrode 160 and the second reflective layer 150 together cover the area of ​​the epitaxial structure layer 140 on the side away from the substrate 110, excluding the first hollow area 300. (Refer to...) Figure 2 As shown, this allows light to be emitted only through the first hollowed-out area 300.

[0065] Starting from the intersection line of the inclined sidewall away from the substrate 110 and the 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 surface of the epitaxial structure layer 140 away from the substrate 110, so as to ensure that the inclined sidewall is completely covered by the second reflective layer 150 and reduce the risk of leakage current.

[0066] As an example, the fixed distance is 1 micrometer.

[0067] In practical applications, the epitaxial structure layer 140 also has an extension plane connected to the inclined sidewall on the side near the substrate 110. That is, when the epitaxial structure layer 140 forms an inclined sidewall, the side of the inclined sidewall near the substrate 110 is connected to the extension plane, and the inclined sidewall extends away from the substrate 110 from the extension plane. The second reflective layer 150 not only covers the inclined sidewall of the epitaxial structure layer 140 but also covers a portion of the extension plane, as shown in the reference diagram. Figure 2 As shown, this is to ensure that the sloping sidewalls are fully covered by the second reflective layer 150, reducing the risk of leakage.

[0068] Specifically, the extension plane is a plane formed on the surface of the first type window layer 1411 away from the substrate 110. The extension plane is parallel to the plane containing the substrate 110. In the direction parallel to the plane containing the substrate 110, one side of the extension plane connects to the inclined sidewall, and the other side is a cut-out area. The second reflective layer 150 extends at least a fixed distance along the extension plane.

[0069] In embodiments of this application, the epitaxial structure layer 140 has a first sidewall and a second sidewall disposed opposite to each other, and the distance between the first hollow region 300 and the first sidewall is smaller than the distance between the first hollow region 300 and the second sidewall. (Refer to...) Figures 1-3 As shown. That is to say, the first hollow area 300 is not axially symmetrical with respect to the epitaxial structure layer 140. Instead, it is closer to the first sidewall and farther from the second sidewall than to the two sidewalls. This allows the surface of the epitaxial structure layer 140, which is farther away, to have sufficient area to accommodate the second electrode 160 and meet the wiring requirements of the second electrode 160.

[0070] Therefore, this 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 ohmic contact is disposed in the first reflective layer, and the first type ohmic contact is electrically connected to the substrate. An epitaxial structure layer is disposed on the 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 sequentially. The first type layer and the first type ohmic contact are in direct contact; that is, the first type layer and the first electrode are electrically connected through the first type ohmic contact layer, realizing partial electrical lead-out of the LED chip. The epitaxial structure layer has inclined sidewalls, and the angle between the inclined sidewalls and the surface of the epitaxial structure layer near the substrate is an acute angle. The second reflective layer at least covers the inclined sidewalls; that is, the inclined sidewalls are combined with and cover the inclined side... The second reflective layer on the sidewall allows the LED to reflect light instead of emitting it from the sidewall. The second electrode, located on the surface of the epitaxial layer away from the substrate, has a first hollowed-out area. This first hollowed-out area allows the light from the LED chip to be emitted only from this area, achieving small-angle light emission. The orthographic projection of a first-type ohmic contact on the surface of the second electrode lies within the first hollowed-out area, ensuring that the electron-hole recombination region is located within this area. In other words, by controlling the position of the first-type ohmic contact within the first hollowed-out area, the position of the electron-hole recombination region is controlled, achieving overlap between the electron-hole recombination region and the light-emitting first hollowed-out area. This increases the effective emitted light power from the first hollowed-out area, thereby achieving high power in the LED chip. Therefore, the LED chip of this application, by incorporating the inclined sidewall, the first reflective layer, and the first hollowed-out area, achieves high-power light emission at a small angle.

[0071] Based on the LED chip provided in the above embodiments, this application also provides a method for manufacturing an LED chip. (See reference...) Figure 4 The diagram shown is a flowchart of a method for manufacturing an LED chip according to an embodiment of this application. The method includes the following steps:

[0072] S101, an epitaxial structure layer is formed on one side of the temporary substrate. The epitaxial structure layer includes a second type layer, an active layer and a first type layer stacked sequentially.

[0073] In embodiments of this 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, with reference to... Figure 5 As shown, this allows the epitaxial structure layer 140 to be bonded to the substrate to ultimately manufacture the LED chip.

[0074] Specifically, the temporary substrate 201 can be made of GaAs, and an epitaxial structure layer 140 is formed on the temporary substrate 201 using a metal-organic chemical vapor deposition (MOCVD) process.

[0075] The epitaxial structure layer 140 includes a second type layer 143, an active layer 142 and a first type layer 141 stacked sequentially, with the active layer 142 covering the second type layer 143 and the first type layer 141 covering the active layer 142.

[0076] In one possible implementation, the first type layer 141 includes a first type confinement layer 1412 and a first type window layer 1411. The first type confinement layer 1412 is located on the surface of the first type window layer 1411 near the temporary substrate 201. The second type layer 143 includes a second type confinement layer 1431, a second type current spreading layer 1432, a second type roughening layer 1433, and a reinforcement layer 1434, which are sequentially stacked. The second type confinement layer 1431 covers the second type current spreading layer 1432, the second type current spreading layer 1432 covers the second type roughening layer 1433, and the second type roughening layer 1433 covers the reinforcement layer 1434. (Refer to...) Figure 5 As shown.

[0077] As an example, if 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, and the second type confinement layer 1431, the second type current spreading layer 1432, the second type roughening layer 1433, and the robust layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer, and an N-type robust 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 robust 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). In this case, the LED chip is an inverse polarity LED chip.

[0078] As another example, if 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, and 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 robust layer 1434 are respectively an N-type confinement layer, an N-type current spreading layer, an N-type roughening layer, and an N-type robust 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 robust layer is GaInP, and the materials of the N-type roughening layer, the N-type current spreading layer, and the N-type confinement layer are AlGaAs. The active layer 142 is a multiple quantum well (MQW), and in this case, the LED chip is an anti-polarity LED chip.

[0079] The doping concentration on the side of the first type window layer 1411 away from the temporary substrate 201 can be greater than the doping concentration on the side closer to the temporary substrate 201, thereby achieving a higher surface doping concentration on the first type window layer 1411 than the main body doping concentration, thus enabling better electrical extraction of the LED chip.

[0080] As an example, when the first type of 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 bulk portion is 1E18 / cm². 3 The surface doping concentration of the P-type window layer reaches 1E19 / cm². 3 The above describes a method to control the electron-hole recombination region of an LED chip. This involves etching a pre-defined region of the P-type window layer to create a higher doping concentration only on the surface of a portion of the P-type window layer. This ensures that the surface doping concentration of the pre-defined region is the same as the doping concentration of the main body. Since the pre-defined region corresponds to the non-light-emitting region of the LED chip, this limits current propagation.

[0081] In practical applications, before forming the epitaxial structure layer 140 on the temporary substrate 201, a buffer layer, an etch stop layer, and a second type semiconductor ohmic contact layer 200 can be formed in sequence. The second type semiconductor ohmic contact layer 200 covers the etch stop layer, and the etch stop layer covers the buffer layer. Specifically, the materials of the buffer layer and the second type semiconductor ohmic contact layer 200 can be GaAs, and the material of the etch stop layer can be GaInP.

[0082] S102, a first reflective layer is formed on the epitaxial structure layer, and a first type of ohmic contact is formed in the first reflective layer.

[0083] In the embodiments of this application, after the epitaxial structure layer 140 is formed on the temporary substrate 201, the first reflective layer 120 can be formed on the epitaxial structure layer 140.

[0084] Specifically, a first reflective layer 120 can be formed using 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 metallic reflective layer 122, as shown in the reference. Figure 6 As shown. The DBR reflective layer 121 is located on the surface of the metal reflective layer 122 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 a metallic material.

[0085] In the embodiments of this application, after forming a first reflective layer 120 on the epitaxial structure layer 140, a first type of ohmic contact 210 is formed in the first reflective layer 120.

[0086] Specifically, a DBR reflective layer 121 and photoresist are deposited on the surface of the epitaxial structure layer 140. The DBR reflective layer 121 is photolithographically and etched to form the dielectric via required for the first type ohmic contact 210 in the DBR reflective layer 121. The photoresist is removed, and a metal material is deposited on the surface of the DBR reflective layer 121. After annealing, a metal reflective layer 122 and the first type ohmic contact 210 filling the stop hole are formed. The metal reflective layer 122 is electrically connected to the first type window layer 1411 through the first type ohmic contact 210 in the dielectric via. The first type ohmic contact 210 becomes a channel for current injection.

[0087] S103, the substrate and epitaxial structure layer are bonded with the first reflective layer facing the substrate, and the temporary substrate is removed.

[0088] In embodiments of this application, after forming the first reflective layer 120 and the first type of ohmic contact 210, a substrate 110 is provided, and the substrate 110 and the epitaxial structure layer 140 are bonded in the direction of the first reflective layer 120 toward the substrate 110.

[0089] Specifically, substrate 110 can be a conductive semiconductor substrate. For example, substrate 110 can be a P-type low-resistivity silicon substrate. A metal bonding layer 170 is deposited on the surface of substrate 110, or the metal bonding layer 170 can be deposited on the metal reflective layer 122. Then, the metal bonding layer 170 is used to bond substrate 110 and epitaxial structure layer 140. During the bonding process of heating and pressurizing, the metal bonding layer 170 on epitaxial structure layer 140 and the metal bonding layer 170 on the surface of substrate 110 are bonded together by interdiffusion, thus bonding epitaxial structure layer 140 to substrate 110. (Refer to...) Figure 7 As shown.

[0090] In the embodiments of this 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.

[0091] S104 forms a second type of ohmic contact.

[0092] In embodiments of this application, after bonding is completed and the temporary substrate 201 is removed, a second type of ohmic contact 220 can be formed on the epitaxial structure layer 140, specifically on the bonding layer 1434. (See reference...) Figure 8 As shown.

[0093] Specifically, a second type semiconductor ohmic contact 221 is fabricated by photolithography and wet etching of a second type semiconductor ohmic contact layer 200, and a second type metal ohmic contact 222 is fabricated by photolithography, vapor deposition, 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.

[0094] S105, etch the epitaxial structure layer to form a sloping sidewall. The angle between the sloping sidewall and the surface of the epitaxial structure layer closest to the substrate is an acute angle.

[0095] In embodiments of this application, after forming the second type of ohmic contact 220, the epitaxial structure layer 140 can be etched to form a sloping sidewall. The angle between the sloping sidewall and the surface of the epitaxial structure layer 140 near the substrate 110 is an acute angle. (Refer to...) Figure 9 As shown

[0096] Specifically, photoresist can be spin-coated on the side of the epitaxial structure layer 140 away from the substrate 110. After exposure and development, the dicing area is defined. The LED chip area is protected by photoresist, while the dicing area is not protected by photoresist. Dry etching is used to etch the epitaxial structure layer 140 in the dicing area, etching to the first type window layer 1411 to form a tilted sidewall. For example, a portion of the thickness of the first type window layer 1411 can be etched to form an extended plane and a tilted sidewall.

[0097] As an example, by adjusting parameters such as gas flow rate, chamber pressure, and radio frequency power in the dry etching process, the sidewalls of the epitaxial structure layer 140 can be etched into inclined sidewalls.

[0098] S106, forming a second reflective layer that at least covers the inclined sidewall.

[0099] In embodiments of this application, after forming the inclined sidewalls, a second reflective layer 150 can be formed to at least cover the inclined sidewalls, as shown in the reference. Figure 10 As shown.

[0100] Specifically, the second reflective layer 150 can be a DBR reflective layer. DBR reflective material is deposited on the surface of the epitaxial structure layer 140 away from the substrate 110, the inclined sidewalls, and the extended surface. The DBR reflective material in a predetermined area is etched to form the second reflective layer 150 covering the inclined sidewalls, the extended surface, and a portion of the surface of the epitaxial structure layer 140 away from the substrate 110. The predetermined area is the region where the second electrode 160 is subsequently disposed, and the predetermined area includes the region where the second type of ohmic contact 220 is disposed.

[0101] S107, forming a first electrode and a second electrode, the first electrode being located on the side of the substrate away from the epitaxial structure layer, the second electrode having a first hollow region, the orthogonal projection of a first type of ohmic contact on the surface of the second electrode being located in the first hollow region, such that the electron-hole recombination region is located in the first hollow region.

[0102] In the embodiments of this application, after the second reflective layer 150 is formed, the first electrode 130 and the second electrode 160 are formed respectively, with reference to... Figure 1 As shown.

[0103] Specifically, electrode material is deposited on the surface of the bonding layer 1434, and then the second electrode 160 is fabricated by photolithography, vapor deposition, lift-off, 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 of the second electrode 160 is located in the first hollow region 300, so that the electron-hole recombination region is located in the first hollow region 300.

[0104] The side of the substrate 110 away from the epitaxial structure layer 140 is thinned, and then electrode material is deposited by vapor deposition to form the first electrode 130.

[0105] Alternatively, the solid layer 1434 within the first hollow area 300 can be removed to form the second hollow area 400, and the surface of the second type roughening layer 1433 of the second hollow area 400 can be roughened.

[0106] In practical applications, after the first electrode 130 and the second electrode 160 are formed, the substrate 110 can be cut, for example, by processes such as orthogonal cutting, back cutting and dicing, to obtain independent LED chips.

[0107] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the method embodiments are basically similar to the structural embodiments, so they are described more simply; relevant parts can be referred to the descriptions of the structural embodiments.

[0108] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. An LED chip, characterized in that, include: The 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 of ohmic contact is disposed in the first reflective layer and the first type of ohmic contact is electrically connected to the substrate; An epitaxial structure layer is disposed on the 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 sequentially. The first type layer and the first type ohmic contact are in direct contact. The epitaxial structure layer has an inclined sidewall, and the angle between the inclined sidewall and the surface of the epitaxial structure layer near the substrate is an acute angle. At least a second reflective layer covering the inclined sidewalls; A second electrode is located on the surface of the epitaxial structure layer away from the substrate; the second electrode has a first hollow region, and the orthographic projection of the first type of ohmic contact on the surface of the second electrode is located in the first hollow region, such that the electron-hole recombination region is located in the first hollow region.

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

3. The LED chip according to claim 1, characterized in that, The second type of layer includes a robust layer; The second electrode covers the solid layer.

4. The LED chip according to claim 3, characterized in that, The bonding layer has a second hollow area, and the orthographic projection of the first hollow area onto the surface of the substrate includes the orthographic projection of the second hollow area onto the surface of the substrate.

5. The LED chip according to claim 4, characterized in that, The orthographic projection of the first type of ohmic contact onto the surface of the solid layer is located in the second cutout region.

6. The LED chip according to claim 1, characterized in that, The second reflective layer also covers the area of ​​the epitaxial structure layer on the side away from the substrate that is 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 extended plane connected to the inclined sidewall on the side near the substrate, and the second reflective layer also covers the extended plane.

8. The LED chip according to claim 1, characterized in that, The epitaxial structure layer has a first sidewall and a second sidewall disposed opposite to each other, and the distance between the first hollow area and the first sidewall is less than the distance between the first hollow area and the second sidewall.

9. The LED chip according to claim 1, characterized in that, The first hollowed-out area is circular or polygonal in shape.

10. The LED chip according to claim 1, characterized in that, The angle between the inclined sidewall and the surface of the epitaxial structure layer closest to the substrate ranges from 5° to 85°.

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