Light emitting diode suitable for low-brightness scene and preparation method thereof
By using SiOxN(1-x) layer or SiO2/Si3N4 stacked structure on the LED, the problem of excessive brightness of LEDs in low-brightness scenarios is solved, and the film layer structure and voltage conditions are realized The brightness is reduced and suitable for a variety of low-brightness scenes.
Patent Information
- Application Number
- CN202411171249.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2025-01-14
AI Technical Summary
Existing LEDs have too high brightness in low brightness scenarios, which limits their application, especially when the film layer structure and voltage conditions are difficult to reduce brightness.
Using SiOxN(1-x) layer or SiO2/Si3N4 stacked structure as passivation layer, adjusting the band gap width to improve light absorption capacity and reduce the brightness of the LED .
Without changing the film structure and voltage conditions of the LED, the brightness of the LED is effectively reduced, making it more suitable for low-brightness scenarios, and adapting to different low-brightness needs by controlling the light absorption capacity of the passivation layer.
Smart Images
Figure CN119317268A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a light emitting diode suitable for low-brightness scenes and a preparation method thereof. Background Art
[0002] Light Emitting Diode (LED) has been widely used in various light source fields such as backlight, lighting, and landscaping due to its small size, long service life, rich colors, and low energy consumption.
[0003] In the related art, an LED includes a light-emitting structure and a passivation layer, wherein the passivation layer is located on the surface of the light-emitting structure, wherein the passivation layer is a SiO2 layer.
[0004] However, due to the large bandgap width of the SiO2 layer, it has a high transmittance to the light emitted by the LED. Therefore, without changing the film structure and voltage conditions of the LED, the brightness of the LED is always high, resulting in limited use of LEDs in low-brightness scenarios such as computer indicator lights and car indicator lights. Summary of the invention
[0005] The embodiment of the present disclosure provides a light emitting diode suitable for low brightness scenes and a preparation method thereof, which can reduce the brightness of the LED without changing the film structure and voltage conditions of the LED, so that the LED can be better suitable for low brightness scenes. The technical solution is as follows:
[0006] In one aspect, a light emitting diode is provided, comprising a light emitting structure and a passivation layer, wherein the passivation layer is located on the surface of the light emitting structure, and the passivation layer comprises SiO x N (1-x) layer, 0.3≤x≤0.7, or includes at least one stacked structure, wherein the stacked structure includes a SiO2 layer and a Si3N4 layer stacked in sequence in a direction away from the light emitting structure.
[0007] Optionally, the passivation layer includes the SiO x N (1-x) layer, the SiO x N (1-x) The relationship between the O component content of the layer and the target brightness of the light-emitting diode satisfies the following formula:
[0008] y=85.975x+57.962;
[0009] Wherein, x is the SiO x N (1-x) The O component content of the layer, y is the target brightness of the light-emitting diode.
[0010] Optionally, the passivation layer includes a stacked structure, and the relationship between the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure and the target brightness of the light-emitting diode satisfies the following formula:
[0011] y = -98.496m + 141.03;
[0012] Wherein, m is the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure, and y is the target brightness of the light-emitting diode.
[0013] Optionally, the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure is 0.2 to 0.8.
[0014] Optionally, the passivation layer has a thickness of 2300 angstroms to 2500 angstroms.
[0015] Optionally, the passivation layer includes at least one stacked structure, the thickness of the SiO2 layer and the thickness of the Si3N4 layer in each stacked structure are the same, and the relationship between the number of the stacked structures and the target brightness of the light-emitting diode satisfies the following formula:
[0016] y = -1.6072n + 109.33;
[0017] Wherein, n is the number of the stacked structures, and y is the target brightness of the light emitting diode.
[0018] Optionally, the number of the stacked structures is 1 to 20.
[0019] Optionally, the thickness of each of the stacked structures is 150 angstroms to 250 angstroms.
[0020] On the other hand, a method for preparing a light emitting diode is provided, comprising: providing a light emitting structure; forming a passivation layer on the light emitting structure, wherein the passivation layer is located on the surface of the light emitting structure, and the passivation layer comprises SiO x N (1-x) layer, 0.3≤x≤0.7, or includes at least one stacked structure, the stacked structure including stacked SiO2 layers and Si3N4 layers.
[0021] Optionally, the passivation layer includes the SiO x N (1-x) The method of forming a passivation layer on the light emitting structure comprises: obtaining a target brightness of the light emitting diode; determining the SiO x N (1-x) The O component content of the layer is used to form the passivation layer on the light emitting structure, and the first formula includes:
[0022] y=85.975x+57.962;
[0023] Wherein, x is the SiO x N (1-x) The O component content of the layer, y is the target brightness of the light-emitting diode; or the passivation layer includes a stacked structure, and the forming of the passivation layer on the light-emitting structure includes: obtaining the target brightness of the light-emitting diode; determining the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure according to the target brightness of the light-emitting diode and a second formula, so as to form the passivation layer on the light-emitting structure, and the second formula includes:
[0024] y = -98.496m + 141.03;
[0025] Wherein, m is the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure, and y is the target brightness of the light-emitting diode; or, the passivation layer includes at least one of the stacked structures, and the thickness of the SiO2 layer in each of the stacked structures is the same as the thickness of the Si3N4 layer, and the forming of the passivation layer on the light-emitting structure comprises: obtaining the target brightness of the light-emitting diode; determining the number of the stacked structures according to the target brightness of the light-emitting diode and a third formula to form the passivation layer on the light-emitting structure, and the third formula comprises:
[0026] y = -1.6072n + 109.33;
[0027] Wherein, n is the number of the stacked structures, and y is the target brightness of the light emitting diode.
[0028] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:
[0029] In the embodiment of the present disclosure, the passivation layer includes SiO x N (1-x) layer, 0.3≤x≤0.7. SiO x N (1-x) The O component content in the layer is in the range of 0.3 to 0.7, which can make the bandgap width of the passivation layer smaller. Since the film layer is more likely to absorb light when the bandgap width is smaller than the photon energy, the smaller bandgap width of the passivation layer can increase the absorption of the light emitted by the LED by the passivation layer, thereby reducing the brightness of the LED without changing the film structure and voltage conditions of the LED, making the LED better suitable for low-brightness scenes. In addition, by controlling the SiO x N (1-x)The O component content in the layer adjusts the bandgap width of the passivation layer and the light absorption capacity of the passivation layer, thereby making the LED better suited for different low-brightness scenes.
[0030] Alternatively, the passivation layer includes at least one stacked structure, and the stacked structure includes a SiO2 layer and a Si3N4 layer stacked in sequence in a direction away from the light-emitting structure. Since the bandgap width of Si3N4 is smaller than that of SiO2, the bandgap width of the passivation layer can also be smaller, which is beneficial for reducing the brightness of the LED without changing the film structure and voltage conditions of the LED, so that the LED can be better applied to low-brightness scenes. In addition, the bandgap width of the passivation layer can be adjusted by controlling the thickness ratio of the Si3N4 layer in the stacked structure and controlling the number of stacked structures, and the light absorption capacity of the passivation layer can be adjusted, so that the LED can be better applied to different low-brightness scenes. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0032] Figure 1 is a schematic diagram of the structure of an LED provided by an embodiment of the present disclosure;
[0033] Figure 2 is a schematic structural diagram of a passivation layer provided in an embodiment of the present disclosure;
[0034] Figure 3 This is a SiO x N (1-x) Schematic diagram of the relationship between the O component content of the layer and the target brightness of the LED;
[0035] Figure 4 is a schematic diagram of the relationship between the thickness of the Si3N4 layer in a laminated structure provided by an embodiment of the present disclosure and the ratio of the thickness of the laminated structure and the target brightness of the LED;
[0036] Figure 5 is a schematic diagram of the relationship between the number of stacked structures and the target brightness of LEDs provided by an embodiment of the present disclosure;
[0037] Figure 6 is a flow chart of a method for preparing an LED provided by an embodiment of the present disclosure;
[0038] Figure 7 is a flow chart of another method for preparing an LED provided by an embodiment of the present disclosure;
[0039] Figure 8 It is a schematic diagram comparing the transmittance of different film layers provided in an embodiment of the present disclosure.
[0040] Reference numerals:
[0041] 10: light emitting structure; 11: first semiconductor layer; 12: light emitting layer; 13: second semiconductor layer; 14: table; 20: passivation layer; 201: SiO2 layer; 202: Si3N4 layer; 21: first through hole; 22: second through hole; 30: substrate; 40: transparent conductive layer; 50: current blocking layer; 60: first electrode; 61: second electrode. DETAILED DESCRIPTION
[0042] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.
[0043] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" and similar words mean that the elements or objects appearing before "include" include the elements or objects listed after "include" and their equivalents, and do not exclude other elements or objects. Words such as "connect" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0044] Figure 1 Schematic diagram of the structure of an LED provided by an embodiment of the present disclosure. Figure 1 As shown, the LED includes a light emitting structure 10 and a passivation layer 20, and the passivation layer 20 is located on the surface of the light emitting structure 10. The passivation layer 20 includes SiO x N (1-x) layer, 0.3≤x≤0.7.
[0045] In the disclosed embodiment, SiO x N (1-x)The O component content in the layer is in the range of 0.3 to 0.7, which can make the bandgap width of the passivation layer 20 smaller. Since the photon energy corresponding to the light in the visible light wavelength range is between 1.61eV and 3.54eV, the film layer is more likely to absorb light when the bandgap width is smaller than the photon energy. Therefore, the smaller bandgap width of the passivation layer 20 can increase the absorption of the light emitted by the LED by the passivation layer 20, thereby reducing the brightness of the LED without changing the film structure and voltage conditions of the LED, so that the LED can be better used in low-brightness scenes. In addition, by controlling the SiO x N (1-x) The O component content in the layer is adjusted, the band gap width of the passivation layer 20 is adjusted, and the light absorption ability of the passivation layer 20 is adjusted, so that the LED can be better applied to different low-brightness scenes.
[0046] Figure 2 Schematic diagram of a passivation layer provided by an embodiment of the present disclosure. Figure 1 and Figure 2 As shown, the passivation layer 20 includes at least one stacked structure, and the stacked structure includes a SiO 2 layer 201 and a Si 3 N 4 layer 202 stacked in sequence in a direction away from the light emitting structure 10 .
[0047] In the disclosed embodiment, since the bandgap width of Si3N4 is about 2.2eV to 3.5eV, which is smaller than the bandgap width of SiO2 of 4.6eV, the bandgap width of the passivation layer 20 can also be made smaller, which is beneficial to reduce the brightness of the LED without changing the film structure and voltage conditions of the LED, so that the LED can be better applied to low-brightness scenes. In addition, the bandgap width of the passivation layer 20 can be adjusted by controlling the thickness ratio of the Si3N4 layer 202 in the stacked structure and controlling the number of stacked structures, and the light absorption capacity of the passivation layer 20 can be adjusted, so that the LED can be better applied to different low-brightness scenes.
[0048] Figure 3 This is a SiO x N (1-x) Schematic diagram of the relationship between the O component content of the layer and the target brightness of the LED. Figure 3 As shown, SiO x N (1-x) The higher the O component content in the layer, the higher the target brightness of the LED, and the target brightness can be a brightness value pre-set according to different low-brightness usage scenarios.
[0049] In the embodiment of the present disclosure, the passivation layer includes SiO x N (1-x) layer, can be controlled by SiO x N (1-x)The O component content in the layer can adjust the band gap width of the passivation layer and the light absorption capacity of the passivation layer, thereby adjusting the target brightness of the LED.
[0050] Optionally, SiO x N (1-x) The relationship between the O component content of the layer and the target brightness of the LED satisfies the following formula (1):
[0051] y=85.975x+57.962 (1);
[0052] Where x is SiO x N (1-x) The O component content of the layer, y is the target brightness of the LED.
[0053] In this way, the SiO x N (1-x) The O component content in the layer adjusts the bandgap width of the passivation layer and the light absorption capacity of the passivation layer, thereby making the LED better suited for different low-brightness scenes.
[0054] Exemplarily, the passivation layer includes SiO x N (1-x) When SiO x N (1-x) The band gap of the layer is 2.4 eV to 4.6 eV.
[0055] For example, SiO x N (1-x) When the O component content of the layer is 0.3 to 0.7, the target brightness of the LED is about 83.75 mcd to 118.14 mcd.
[0056] In a possible implementation, the passivation layer includes a stacked structure, that is, the passivation layer includes a SiO 2 layer and a Si 3 N 4 layer stacked in sequence in a direction away from the light emitting structure.
[0057] Figure 4 Schematic diagram of the relationship between the thickness of the Si3N4 layer in a laminated structure and the ratio of the thickness of the laminated structure and the target brightness of the LED provided by an embodiment of the present disclosure. Figure 4 As shown, the greater the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure, the lower the target brightness of the LED. The band gap width of the passivation layer can be adjusted by controlling the thickness ratio of the Si3N4 layer in the stacked structure, and the light absorption capacity of the passivation layer can be adjusted, thereby adjusting the target brightness of the LED.
[0058] Optionally, the relationship between the thickness of the Si3N4 layer in the stacked structure and the ratio of the thickness of the stacked structure and the target brightness of the LED satisfies the following formula (2):
[0059] y = -98.496m + 141.03 (2);
[0060] Wherein, m is the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure, and y is the target brightness of the LED.
[0061] In this way, according to different low-brightness usage scenarios and the required target brightness, the band gap width of the passivation layer and the light absorption capacity of the passivation layer can be adjusted by controlling the thickness of the Si3N4 layer in the stacked structure and the ratio of the thickness of the stacked structure, so that the LED can be better suited for different low-brightness scenarios.
[0062] Optionally, the passivation layer includes a stacked structure, and the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure is 0.2 to 0.8. In this way, since the thickness of the Si3N4 layer is relatively high, the bandgap width of the passivation layer can be effectively reduced, which is conducive to reducing the brightness of the LED without changing the film structure and voltage conditions of the LED.
[0063] Exemplarily, the passivation layer includes a stacked structure, and the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure can be 0.2, 0.5 or 0.8, etc.
[0064] Exemplarily, when the ratio of the thickness of the Si3N4 layer in the stacked structure to the thickness of the stacked structure is 0.2 to 0.8, the target brightness of the LED is approximately 62.23 mcd to 121.33 mcd.
[0065] Optionally, the passivation layer includes a laminated structure, and the thickness of the passivation layer is 2300 angstroms to 2500 angstroms. If the thickness of the passivation layer is too small, it cannot achieve a good passivation effect to protect the surfaces of the LED that may be exposed; if the thickness of the passivation layer is too large, it may cause waste of materials and increase production costs. The thickness of the passivation layer is within this range. The ratio of the thickness of the Si3N4 layer in the laminated structure to the thickness of the laminated structure can be used to better adjust the band gap width of the passivation layer and the light absorption capacity of the passivation layer, so that the LED can be better applied to different low-brightness scenes. In addition, the passivation layer has a good passivation ability, which can protect the surfaces of the LED that may be exposed, reduce the impact of mechanical damage or chemical corrosion on the LED, ensure the reliability of the LED, and will not increase additional production costs.
[0066] Exemplarily, the passivation layer includes a stacked structure, and the thickness of the passivation layer may be 2300 angstroms, 2400 angstroms, or 2500 angstroms.
[0067] like Figure 2As shown, the passivation layer includes at least one stacked structure, and the thickness of the SiO2 layer 201 and the thickness of the Si3N4 layer 202 in each stacked structure are the same. Figure 5 Schematic diagram of the relationship between the number of stacked structures and the target brightness of LEDs provided by the embodiment of the present disclosure. Figure 5 As shown, the more the number of stacked structures is, the lower the target brightness of the LED is. The bandgap width of the passivation layer and the light absorption capacity of the passivation layer can be adjusted by controlling the number of stacked structures, thereby adjusting the target brightness of the LED.
[0068] Optionally, the relationship between the number of stacked structures and the target brightness of the LED satisfies the following formula (3):
[0069] y=-1.6072n+109.33 (3);
[0070] Where n is the number of stacked structures and y is the target brightness of the LED.
[0071] In this way, according to different low-brightness usage scenarios and the required target brightness, the number of stacked structures can be controlled, the bandgap width of the passivation layer can be adjusted, and the light absorption capacity of the passivation layer can be adjusted, so that the LED can be better suited for different low-brightness scenarios.
[0072] Optionally, the thickness of the SiO2 layer and the thickness of the Si3N4 layer in each stacked structure are the same, and the number of stacked structures is 1 to 20. In this way, the proportion of Si3N4 material can be controlled by increasing the number of stacked structures, thereby effectively reducing the bandgap width of the passivation layer, which is beneficial to reducing the brightness of the LED without changing the film structure and voltage conditions of the LED.
[0073] Exemplarily, the thickness of the SiO2 layer and the thickness of the Si3N4 layer in each stacked structure are the same, and the number of stacked structures may be 6 to 15. For example, the number of stacked structures may be 6, 10, or 15, etc.
[0074] Exemplarily, when the number of stacked structures is 1 to 20, the target brightness of the LED is approximately 77.19 mcd to 107.72 mcd.
[0075] Optionally, the thickness of the SiO2 layer and the Si3N4 layer in each stacked structure are the same, and the thickness of each stacked structure is 150 angstroms to 250 angstroms. The thickness of each stacked structure is within this range, and the bandgap width of the passivation layer can be better adjusted by controlling the number of stacked structures, and the light absorption capacity of the passivation layer can be adjusted, so that the LED can be better applied to different low-brightness scenes.
[0076] Exemplarily, the thickness of the SiO2 layer and the thickness of the Si3N4 layer in each stacked structure are the same, and the thickness of each stacked structure may be 150 angstroms, 200 angstroms, or 250 angstroms, etc.
[0077] like Figure 1 As shown, the LED further includes a substrate 30, which is located on a surface of the light emitting structure 10 away from the passivation layer 20. The substrate 30 can provide support for the light emitting structure 10, thereby ensuring good reliability of the LED.
[0078] Optionally, the substrate 30 may be a sapphire substrate. The sapphire substrate is a transparent substrate with good light transmittance, and the sapphire substrate has high mechanical strength and is easy to handle and clean. In other embodiments, the substrate 30 may also be a Si substrate, a SiC substrate or a SiO2 substrate, which is not limited in the present disclosure.
[0079] Optionally, the LED may further include a buffer layer, which is located between the substrate 30 and the light emitting structure 10. The buffer layer may reduce the lattice mismatch and thermal mismatch between the substrate 30 and the semiconductor material, which is beneficial to improving the quality of the LED.
[0080] Optionally, the buffer layer may be a GaN buffer layer or an AlN buffer layer.
[0081] Optionally, the light emitting structure 10 includes a first semiconductor layer 11 , a light emitting layer 12 , and a second semiconductor layer 13 stacked in sequence, and the light emitting structure 10 has a mesa 14 extending from a surface of the second semiconductor layer 13 away from the light emitting layer 12 toward the first semiconductor layer 11 .
[0082] Optionally, the first semiconductor layer 11 may be an N-type GaN layer, and the second semiconductor layer 13 may be a P-type GaN layer.
[0083] Exemplarily, the first semiconductor layer 11 is a Si-doped GaN layer, and the second semiconductor layer 13 is a Mg-doped GaN layer.
[0084] Optionally, the light-emitting layer 12 is a multi-quantum well layer, including multiple pairs of InGaN layers and GaN layers stacked alternately. Different materials can be selected for the light-emitting layer 12 according to the different light-emitting wavelength ranges of the LED. For example, the light-emitting layer 12 of the blue-green LED can use multiple pairs of InGaN layers and GaN layers stacked alternately; the light-emitting layer 12 of the red LED can use multiple pairs of AlGaInP quantum barrier layers and AlGaInP quantum well layers stacked alternately, wherein the Al component content of the AlGaInP quantum barrier layer is greater than the Al component content of the AlGaInP quantum well layer.
[0085] Exemplarily, the light emitting layer 12 includes 3 to 8 pairs of InGaN layers and GaN layers stacked alternately, for example, 5 pairs of InGaN layers and GaN layers stacked alternately, and of course other pairs are also possible, which is not limited in the present disclosure.
[0086] Optionally, the LED further includes a transparent conductive layer 40, which is located on a surface of the second semiconductor layer 13 away from the substrate 30 and connected to the second semiconductor layer 13. The transparent conductive layer 40 may also be called a current spreading layer, which can make the current spread laterally to various regions of the second semiconductor layer 23, thereby ensuring a high internal quantum efficiency of the LED.
[0087] Optionally, the transparent conductive layer 40 may be an indium tin oxide (ITO) layer. ITO has good transmittance and low resistivity, so it can ensure the light emitting effect of the LED, and also facilitate carrier conduction and improve carrier injection efficiency.
[0088] Optionally, the LED further includes a current blocking layer 50, which is located between the second semiconductor layer 13 and the transparent conductive layer 40, and the transparent conductive layer 40 is located on the surface of the current blocking layer 50 away from the light emitting structure 10 and the sidewall of the current blocking layer 50. The current blocking layer 50 can cooperate with the transparent conductive layer 40 to prevent the current from gathering directly below the electrode, improve the current expansion capability, and enable the current to be better expanded laterally to various regions of the second semiconductor layer 13.
[0089] Optionally, the current blocking layer 50 may be a SiO 2 layer.
[0090] Exemplarily, the passivation layer 20 is also located on the side walls of the light emitting structure 10, the surface of the transparent conductive layer 40 away from the light emitting structure 10, and the side walls of the transparent conductive layer 40, and the passivation layer 20 has a first through hole 21 exposing the first semiconductor layer 11 at the table 14 and a second through hole 22 exposing the transparent conductive layer 40.
[0091] like Figure 1 As shown, the LED further includes an electrode layer, which includes a first electrode 60 and a second electrode 61 . The first electrode 60 is located in the first through hole 21 and connected to the first semiconductor layer 11 , and the second electrode 61 is located in the second through hole 22 and connected to the transparent conductive layer 40 .
[0092] Exemplarily, the material of the electrode layer includes at least one of a Cr layer, an Al layer, a Ti layer, a Pt layer, and an Au layer. For example, the electrode layer may include a Cr layer, an Al layer, a first Ti layer, a first Pt layer, a second Ti layer, a second Pt layer, and an Au layer stacked in sequence in a direction away from the light emitting structure 10.
[0093] It should be noted that Figure 1 The film layer structure of the LED shown and the material of the above film layer are only used as an example. In other embodiments, the LED may also include more or fewer film layer structures, and the materials of each film layer can be selected according to actual needs, etc., and there is no limitation on this publicly.
[0094] Figure 6 FIG. 1 is a flow chart of a method for preparing an LED provided by an embodiment of the present disclosure. Figure 6 As shown, the preparation method comprises:
[0095] In step S1001, a light-emitting structure is provided.
[0096] In step S1002 , a passivation layer is formed on the light emitting structure.
[0097] The passivation layer is located on the surface of the light-emitting structure, and the passivation layer includes SiO x N (1-x) layer, 0.3≤x≤0.7, or includes at least one stacked structure, the stacked structure includes stacked SiO2 layers and Si3N4 layers.
[0098] In the embodiment of the present disclosure, the passivation layer includes SiO x N (1-x) layer, 0.3≤x≤0.7. SiO x N (1-x) The O component content in the layer is in the range of 0.3 to 0.7, which can make the bandgap width of the passivation layer smaller. Since the film layer is more likely to absorb light when the bandgap width is smaller than the photon energy, the smaller bandgap width of the passivation layer can increase the absorption of the light emitted by the LED by the passivation layer, thereby reducing the brightness of the LED without changing the film structure and voltage conditions of the LED, making the LED better suitable for low-brightness scenes. In addition, by controlling the SiO x N (1-x) The O component content in the layer adjusts the bandgap width of the passivation layer and the light absorption capacity of the passivation layer, thereby making the LED better suited for different low-brightness scenes.
[0099] Alternatively, the passivation layer includes at least one stacked structure, and the stacked structure includes a SiO2 layer and a Si3N4 layer stacked in sequence in a direction away from the light-emitting structure. Since the bandgap width of Si3N4 is smaller than that of SiO2, the bandgap width of the passivation layer can also be smaller, which is beneficial for reducing the brightness of the LED without changing the film structure and voltage conditions of the LED, so that the LED can be better applied to low-brightness scenes. In addition, the bandgap width of the passivation layer can be adjusted by controlling the thickness ratio of the Si3N4 layer in the stacked structure and controlling the number of stacked structures, and the light absorption capacity of the passivation layer can be adjusted, so that the LED can be better applied to different low-brightness scenes.
[0100] Figure 7 FIG. 1 is a flow chart of another method for preparing an LED provided by an embodiment of the present disclosure. Figure 7 As shown, the preparation method comprises:
[0101] In step S2001, a light emitting structure is formed on a substrate.
[0102] Optionally, the substrate may be a sapphire substrate.
[0103] For example, the sapphire substrate may be pretreated first, the sapphire substrate may be placed in a metal-organic chemical vapor deposition (MOCVD) reaction chamber, and the sapphire substrate may be baked for 12 to 18 minutes to clean the sapphire substrate.
[0104] Exemplarily, the light-emitting structure includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked in sequence. A photoresist structure can be obtained on the surface of the second semiconductor layer away from the light-emitting layer by processes such as photoresist coating, exposure, and development, and the surface of the second semiconductor layer away from the light-emitting layer is etched using the photoresist structure as a mask by methods such as inductively coupled plasma (ICP) etching, and the etching depth extends from the surface of the second semiconductor layer away from the light-emitting layer to the first semiconductor layer, and after removing the photoresist structure, a table exposing the first semiconductor layer is formed.
[0105] Optionally, before forming the light emitting structure, a buffer layer may be formed on the substrate.
[0106] In step S2002, a current blocking layer is formed on the light emitting structure.
[0107] Exemplarily, a plasma enhanced chemical vapor deposition (PECVD) technique can be used to deposit an initial current blocking layer on the entire surface of the light-emitting structure, and a photoresist structure is obtained on the initial current blocking layer through photoresist coating, exposure, development and other processes. The initial current blocking layer is etched through a buffered oxide etch (BOE) process using the photoresist structure as a mask, and the current blocking layer is formed after removing the photoresist structure.
[0108] In other embodiments, the above steps S2001 to S2002 may also be to first form an initial first semiconductor layer, an initial light-emitting layer, an initial second semiconductor layer and an initial current blocking layer stacked in sequence on the substrate, and then etch out a table top and form a current blocking layer through two etching processes respectively. The present disclosure does not impose any restrictions on this.
[0109] Optionally, before forming the current blocking layer, deep etching (Isolation, ISO) photolithography may be performed on the light emitting structure to form a cutting path exposing the substrate.
[0110] In step S2003 , a transparent conductive layer is formed on the current blocking layer.
[0111] Exemplarily, an initial ITO layer can be deposited on the entire surface of the current blocking layer, and a photoresist structure can be obtained on the initial ITO layer through processes such as photoresist coating, exposure, and development. The initial ITO layer is etched using an ITO etching solution using the photoresist structure as a mask, and a transparent conductive layer is formed after the photoresist structure is removed. The transparent conductive layer is located on the surface of the current blocking layer away from the light-emitting structure and the side wall of the current blocking layer, and is connected to the second semiconductor layer.
[0112] In step S2004, a passivation layer is formed on the transparent conductive layer.
[0113] The passivation layer includes SiO x N (1-x) layer, 0.3≤x≤0.7, or includes at least one stacked structure, the stacked structure includes stacked SiO2 layers and Si3N4 layers.
[0114] Optionally, the passivation layer comprises SiO x N (1-x) The passivation layer formed in the above step S2004 may include the following steps:
[0115] The first step is to obtain the target brightness of the LED.
[0116] Here, the target brightness may be a brightness value preset according to different low-brightness usage scenarios.
[0117] The second step is to determine SiO based on the target brightness of the LED and the first formula. x N (1-x) The O component content of the layer is increased to form a passivation layer on the light emitting structure.
[0118] The first formula is the formula (1) above, including: y = 85.975x + 57.962, where x is SiO x N (1-x)The O component content of the layer is y, and the target brightness of the LED is y. In this way, according to different low-brightness usage scenarios and the required target brightness, the SiO x N (1-x) The O component content in the layer adjusts the bandgap width of the passivation layer and the light absorption capacity of the passivation layer, thereby making the LED better suited for different low-brightness scenes.
[0119] For example, PECVD technology can be used to simultaneously introduce N2, SiH4, NH3 and N2O into the reaction chamber, and the flow rates of NH3 and N2O can be controlled to control the SiO x N (1-x) The O component content of the layer, an initial passivation layer is deposited on the entire surface of the product obtained in step S2003, a photoresist structure is obtained on the initial passivation layer through photoresist coating, exposure, development and other processes, and the initial passivation layer is etched through the BOE process using the photoresist structure as a mask, and a passivation layer is formed after removing the photoresist structure, and the passivation layer is located on the surface of the transparent conductive layer away from the light-emitting structure, the side wall of the transparent conductive layer, the surface of the light-emitting structure and the side wall of the light-emitting structure, and the passivation layer has a first through hole exposing the first semiconductor layer at the table and a second through hole exposing the transparent conductive layer. When the transparent conductive layer and the current blocking layer are not provided, this step is to form a passivation layer on the light-emitting structure.
[0120] Optionally, the flow rate of NH 3 is greater than 0 and less than or equal to 100 sccm.
[0121] Optionally, the flow rate of N2O is 100 sccm to 4000 sccm.
[0122] Optionally, the flow rate of N2 is 500 sccm to 1000 sccm.
[0123] Optionally, the flow rate of SiH4 is greater than 0 and less than or equal to 300 sccm.
[0124] Optionally, the pressure of the reaction chamber is 50Pa to 200Pa.
[0125] Optionally, the RF source power is 50W to 200W.
[0126] In a possible implementation manner, the passivation layer includes a stacked structure, and forming the passivation layer in the above step S2004 may include the following steps:
[0127] The first step is to obtain the target brightness of the LED.
[0128] In the second step, according to the target brightness of the LED and the second formula, the thickness of the Si3N4 layer in the stacked structure and the ratio of the thickness of the stacked structure are determined to form a passivation layer on the light-emitting structure.
[0129] The second formula is the formula (2) mentioned above, including: y = -98.496m + 141.03, where m is the ratio of the thickness of the Si3N4 layer in the laminated structure to the thickness of the laminated structure, and y is the target brightness of the LED. In this way, according to different low-brightness usage scenarios and the required target brightness, by controlling the ratio of the thickness of the Si3N4 layer in the laminated structure to the thickness of the laminated structure, the bandgap width of the passivation layer and the light absorption capacity of the passivation layer can be adjusted, so that the LED can be better applied to different low-brightness scenarios.
[0130] In another possible implementation, the passivation layer includes at least one stacked structure, and the thickness of the SiO2 layer and the thickness of the Si3N4 layer in each stacked structure are the same. The forming of the passivation layer in the above step S2004 may include the following steps:
[0131] The first step is to obtain the target brightness of the LED.
[0132] In the second step, according to the target brightness of the LED and the third formula, the number of stacked structures is determined to form a passivation layer on the light emitting structure.
[0133] The third formula is the formula (3) above, including: y = -1.6072n + 109.33, where n is the number of stacked structures and y is the target brightness of the LED. In this way, the number of stacked structures can be controlled according to different low-brightness usage scenarios and the required target brightness, and the bandgap width of the passivation layer and the light absorption capacity of the passivation layer can be adjusted, so that the LED can be better applied to different low-brightness scenarios.
[0134] In step S2005 , an electrode layer is formed.
[0135] For example, a photoresist structure can be obtained on the surface of the product obtained in step S2004 by photoresist coating, exposure, development and other processes, and the electrode layer is formed by electron beam evaporation and stripping processes using the photoresist structure as a mask. The electrode layer includes a first electrode and a second electrode, the first electrode is located in the first through hole and connected to the first semiconductor layer, and the second electrode is located in the second through hole and connected to the transparent conductive layer.
[0136] Optionally, after completing step S2005, the substrate may be scratched along the cutting path by a scratching process to obtain an LED.
[0137] Optionally, the structure, material, component content, thickness and quantity of each layer can be found in Figures 1 to 5 The detailed description of the related embodiments is omitted here.
[0138] Figure 8 It is a schematic diagram comparing the transmittance of different film layers provided in an embodiment of the present disclosure. Figure 8 In the experimental group, the film layer refers to the glass substrate, transparent conductive layer and passivation layer stacked in sequence, the transparent conductive layer is the ITO layer, and the passivation layer is the SiO x N (1-x) layer, and SiO x N (1-x) The O component content of the layer is 0.5; the control group film layer refers to the glass substrate, transparent conductive layer and passivation layer stacked in sequence, the transparent conductive layer is the ITO layer, and the passivation layer is the SiO2 layer. The experimental group film layer and the control group film layer were irradiated with light of different wavelengths, and their transmittance was tested. Figure 8 As shown in the figure, at a wavelength of 450nm, the transmittance of the experimental group film layer is about 81.9%, and the transmittance of the control group film layer is about 96.7%. The transmittance of the experimental group film layer is about 14.8% lower than that of the control group film layer. Therefore, the passivation layer in the embodiment of the present disclosure is SiO x N (1-x) The layer can have the effect of reducing the brightness of the LED.
[0139] The brightness of the LED provided in the embodiment of the present disclosure is exemplarily described below. Figure 1 In the LED of the related embodiment, the passivation layer of the LED is SiO x N (1-x) layer, and SiO x N (1-x) The O component content of the layer is 0.5. The control group LED refers to the LED in the relevant technology. The difference between the control group LED and the experimental group LED is only the material of the passivation layer. The passivation layer of the control group LED is a SiO2 layer.
[0140] The brightness of multiple control group LEDs and multiple experimental group LEDs were tested under the condition of 60 mA current. Table 1 shows the brightness test results of the control group LEDs and the experimental group LEDs.
[0141] Table 1 Brightness test results
[0142]
[0143] After testing, it was found that under the condition of 60mA current, there was no significant difference in the emission wavelength and driving voltage between the experimental group LED and the control group LED, and the brightness of the experimental group LED was lower than that of the control group LED. The brightness of the experimental group LED was reduced by about 17.76% on average relative to the brightness of the control group LED. Therefore, the LED provided in the embodiment of the present disclosure can reduce the brightness of the LED without changing the film structure and voltage conditions of the LED, so that the LED can be better applied to low-brightness scenes.
[0144] The above description does not limit the present disclosure in any form. Although the present disclosure has been disclosed as above through the embodiments, it is not used to limit the present disclosure. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present disclosure. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present disclosure without departing from the content of the technical solution of the present disclosure still falls within the scope of the technical solution of the present disclosure.
Claims
1. A light emitting diode, characterized in that: It comprises a light emitting structure (10) and a passivation layer (20), The passivation layer (20) is located on the surface of the light emitting structure (10), and the passivation layer (20) comprises SiO x N (1-x) layer, 0.3≤x≤0.7, or includes at least one stacked structure, wherein the stacked structure includes a SiO2 layer (201) and a Si3N4 layer (202) stacked in sequence in a direction away from the light emitting structure (10).
2. The light emitting diode according to claim 1, characterized in that: The passivation layer (20) includes the SiO x N (1-x) layer, the SiO x N (1-x) The relationship between the O component content of the layer and the target brightness of the light-emitting diode satisfies the following formula: y=85.975x+57.962; Wherein, x is the SiO x N (1-x) The O component content of the layer, y is the target brightness of the light-emitting diode.
3. The light emitting diode according to claim 1, characterized in that: The passivation layer (20) comprises a stacked structure, and the relationship between the ratio of the thickness of the Si3N4 layer (202) in the stacked structure to the thickness of the stacked structure and the target brightness of the light-emitting diode satisfies the following formula: y = -98.496m + 141.03; Wherein, m is the ratio of the thickness of the Si3N4 layer (202) in the stacked structure to the thickness of the stacked structure, and y is the target brightness of the light-emitting diode.
4. The light emitting diode according to claim 3, characterized in that: The ratio of the thickness of the Si3N4 layer (202) in the stacked structure to the thickness of the stacked structure is 0.2 to 0.
8.
5. The light emitting diode according to claim 3 or 4, characterized in that: The thickness of the passivation layer (20) is 2300 angstroms to 2500 angstroms.
6. The light emitting diode according to claim 1, characterized in that: The passivation layer comprises at least one stacked structure, the thickness of the SiO2 layer (201) and the thickness of the Si3N4 layer (202) in each stacked structure are the same, and the relationship between the number of stacked structures and the target brightness of the light-emitting diode satisfies the following formula: y = -1.6072n + 109.33; Wherein, n is the number of the stacked structures, and y is the target brightness of the light emitting diode.
7. The light emitting diode according to claim 6, characterized in that: The number of the stacked structures is 1 to 20.
8. The light emitting diode according to claim 6 or 7, characterized in that: The thickness of each of the stacked structures is 150 angstroms to 250 angstroms.
9. A method for preparing a light emitting diode, characterized in that: include: Providing a light-emitting structure (10); A passivation layer (20) is formed on the light emitting structure (10), wherein the passivation layer (20) is located on the surface of the light emitting structure (10), and the passivation layer (20) comprises SiO x N (1-x) layer, 0.3≤x≤0.7, or includes at least one stacked structure, wherein the stacked structure includes a stacked SiO2 layer (201) and a Si3N4 layer (202).
10. The preparation method according to claim 9, characterized in that: The passivation layer (20) includes the SiO x N (1-x) The passivation layer (20) is formed on the light emitting structure (10), comprising: Obtain the target brightness of the light-emitting diode; determine the SiO x N (1-x) The O component content of the layer is used to form the passivation layer (20) on the light emitting structure (10), and the first formula includes: y=85.975x+57.962; Wherein, x is the SiO x N (1-x) The O component content of the layer, y is the target brightness of the light-emitting diode; Alternatively, the passivation layer comprises a stacked structure, and the passivation layer (20) is formed on the light emitting structure (10), comprising: Acquiring a target brightness of the light-emitting diode; determining the ratio of the thickness of the Si3N4 layer (202) in the stacked structure to the thickness of the stacked structure according to the target brightness of the light-emitting diode and a second formula, so as to form the passivation layer (20) on the light-emitting structure (10), wherein the second formula includes: y = -98.496m + 141.03; Wherein, m is the ratio of the thickness of the Si3N4 layer (202) in the stacked structure to the thickness of the stacked structure, and y is the target brightness of the light-emitting diode; Alternatively, the passivation layer comprises at least one of the stacked structures, the thickness of the SiO2 layer (201) and the thickness of the Si3N4 layer (202) in each of the stacked structures are the same, and the passivation layer (20) is formed on the light emitting structure (10), comprising: Obtaining a target brightness of the light-emitting diode; determining the number of the stacked structures according to the target brightness of the light-emitting diode and a third formula to form the passivation layer (20) on the light-emitting structure (10), wherein the third formula includes: y = -1.6072n + 109.33; Wherein, n is the number of the stacked structures, and y is the target brightness of the light emitting diode.