A brightness self-adaptive light-emitting diode and a preparation method thereof

Abstract

The present invention relates to a brightness self - adaptive light - emitting diode and a preparation method thereof. The diode comprises a substrate, a back gold electrode is arranged on the lower side of the substrate, an insulating layer and a bonding layer are arranged on one side of the substrate, a current spreading layer, a P - type ohmic contact layer, a multi - quantum well layer, an N - type ohmic contact layer and an N - type ohmic contact metal are arranged on one side of the bonding layer, and a P - type ohmic contact metal is arranged on the other side of the bonding layer; a P+ region is disposed inside the other side of the substrate, N+ regions are respectively arranged on both sides of the P+ region, a photosensitive diode anode and a photosensitive diode cathode are correspondingly arranged on the substrate, a DBR layer is arranged on the upper side of the device, electrode windows are formed in the DBR layer on the upper sides of the photosensitive diode anode, the N - type ohmic contact metal and the P - type ohmic contact metal, the photosensitive diode anode and the N - type ohmic contact metal are connected through a wire - bonding electrode, and the P - type ohmic contact metal is connected with a wire - bonding electrode through the electrode window. The present invention can automatically adjust the brightness of the light - emitting diode according to the change of the ambient brightness.

Description

Technical Field

[0001] The present invention relates to a brightness - adaptive light - emitting diode and a preparation method thereof, belonging to the field of optoelectronic technology. Background Art

[0002] As one of the most highly regarded light - source technologies, the LED has the characteristics of small size on the one hand; on the other hand, it has the power - saving characteristics of low - current and low - voltage driving; at the same time, it also has many advantages such as a firm structure, strong impact - resistance and earthquake - resistance capabilities, and an extremely long service life. Therefore, it has a wide range of applications in fields such as digital display and aiming. In actual use, some of these light sources have non - adjustable brightness, and some require complex circuit designs for manual adjustment, which brings inconvenience to users.

[0003] A photodiode is a semiconductor device that converts an optical signal into an electrical signal. When light irradiates the PN junction, electron - hole pairs can be generated in the PN junction, increasing the density of minority carriers. These carriers drift under a reverse voltage, increasing the reverse current. Therefore, the intensity of light irradiation can be used to change the current in the circuit. For this reason, the present invention is proposed to integrate an LED and a photodiode to achieve automatic adjustment of the brightness of the diode. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a brightness - adaptive light - emitting diode, which integrates an LED chip and a photodiode during the preparation process and can automatically adjust the brightness of the light - emitting diode according to the change in the surrounding ambient brightness.

[0005] The present invention also provides a preparation method for the above - mentioned brightness - adaptive light - emitting diode.

[0006] The technical solution of the present invention is as follows:

[0007] A brightness - adaptive light - emitting diode includes a substrate. A back - gold electrode is arranged on the lower side of the substrate. On one side of the substrate, an insulating layer, a bonding layer, and a current - spreading layer are sequentially arranged. On the upper side of the current - spreading layer, a P - type ohmic - contact layer, a multi - quantum - well layer, and an N - type ohmic - contact layer are sequentially arranged from bottom to top. The P - type ohmic - contact layer 7, the multi - quantum - well layer 8, and the N - type ohmic - contact layer 9 together form an LED epitaxial wafer. An N - type ohmic - contact metal is arranged on the N - type ohmic - contact layer, and a P - type ohmic - contact metal is arranged on the other side of the current - spreading layer. The insulating layer, the bonding layer, the current - spreading layer, the P - type ohmic - contact layer, the multi - quantum - well layer, the N - type ohmic - contact layer, the N - type ohmic - contact metal, and the P - type ohmic - contact metal form an LED chip;

[0008] On the other side of the substrate, a P + region is internally provided. On both sides of the P + region, N + regions are respectively arranged. A photodiode positive electrode and a photodiode negative electrode are correspondingly arranged on the substrate, and P+ Region, N + Region, the anode of the photosensitive diode and the cathode of the photosensitive diode form a photosensitive diode. DBR layers are provided on both the photosensitive diode and the LED chip. The anode of the photosensitive diode and the cathode of the photosensitive diode are separated by the DBR layer. The LED epitaxial wafer and the P-type ohmic contact metal are separated by the DBR layer. Electrode windows are opened in the DBR layers on the anode of the photosensitive diode, the N-type ohmic contact metal, and the P-type ohmic contact metal. The anode of the photosensitive diode and the N-type ohmic contact metal are connected by a wire bonding electrode, and the P-type ohmic contact metal is connected to a wire bonding electrode through the electrode window.

[0009] According to a preferred embodiment of the present invention, the substrate is an N-type single crystal silicon substrate with a thickness of 7000 Å and a resistivity of 150 - 450 Ω·cm;

[0010] N + Region has an implantation depth of 3000 - 5000 Å and a resistance of 10 - 20 Ω, P + Region has an implantation depth of 3500 - 5500 Å and a resistance of 40 - 60 Ω;

[0011] The electrode materials of the anode of the photosensitive diode and the anode and cathode of the photosensitive diode are Al, the electrode material of the wire bonding electrode is Al, and the back metal electrode material is TiAu.

[0012] According to a preferred embodiment of the present invention, the insulating layer material is SiO 2 , with a thickness of 1 μm. The current spreading layer is ITO, ZnO, GZO, etc., and the bonding layer uses SiO 2 or insulating materials such as polymer.

[0013] The preparation method of the above brightness adaptive light-emitting diode is as follows:

[0014] (1) Thermally grow an oxide layer on the surface of the substrate, and then form an N + isolation window through photolithography and etching;

[0015] (2) Form the N + region by diffusing and implanting a P source, and then remove the oxide layer;

[0016] (3) Continuously thermally grow an oxide layer with a thickness of 5000 Å on the surface of the substrate, and then form a P + isolation window through photolithography and etching;

[0017] (4) Form the P + region by diffusing and implanting a B source, and then remove the oxide layer;

[0018] (5) Evaporate an insulating layer on the surface of the substrate by PECVD;

[0019] (6) Evaporating a current spreading layer on the LED epitaxial wafer, and then bonding the LED epitaxial wafer to the insulating layer through a bonding process, and then removing the n-GaAs substrate of the LED epitaxial wafer;

[0020] (7) Etching the area outside the LED chip to the surface of the insulating layer through photolithography and ICP process;

[0021] (8) Etching the LED chip to the P-type ohmic contact layer again through photolithography and ICP process;

[0022] (9) Through photolithography, evaporation, and lift-off, the P-type ohmic contact metal and the N-type ohmic contact metal of the LED chip are formed respectively.

[0023] (10) removing the insulating layer in the photodiode region through photolithography, evaporation, and stripping processes, and manufacturing the photodiode anode and the photodiode cathode, which together constitute the photodiode electrode;

[0024] (11) growing a DBR layer on the surface of the wafer obtained in step (10) by optical coating equipment, wherein the DBR layer has a high reflectivity in the 580-680nm band to prevent the chip's own light emission from affecting the photodiode;

[0025] (12) forming an electrode window by photolithography and etching processes;

[0026] (13) Photolithography, evaporation, and stripping are performed again to form wire bonding electrodes between the photodiode chip and the LED chip, and the N-pole ohmic contact metal of the LED chip is connected to the positive electrode of the photodiode;

[0027] (14) The wafer obtained in step (13) is ground, and then a back gold electrode is deposited by electron beam evaporation, followed by laser scribing and diamond knife cutting to obtain a light-emitting diode.

[0028] Preferably, according to the present invention, in step (6), the LED epitaxial wafer includes an n-GaAs substrate and an N-type ohmic contact layer, a multi-quantum well layer and a P-type ohmic contact layer sequentially arranged on the n-GaAs substrate. The LED epitaxial wafer is an existing device and can be used directly without separately preparing structures such as the N-type ohmic contact layer, the multi-quantum well layer and the P-type ohmic contact layer, thereby speeding up the preparation process.

[0029] Preferably, according to the present invention, in step (6), the bonding conditions are a temperature of 380° C., a time of 50 minutes, and a pressure of 900 kg, and the n-GaAs substrate is removed by a mixed solution of ammonia water, hydrogen peroxide, and water, wherein the volume ratio of ammonia water, hydrogen peroxide, and water in the mixed solution is 1:6:8.

[0030] Preferably according to the present invention, in step (9), the P-type ohmic contact metal is an Au / AuZn / Au laminated metal, the alloying temperature is 500 °C, and the time is 10 min; the N-type ohmic contact is an Au / AuGeNi / Au laminated metal, the alloying temperature is 350 °C, and the time is 10 min.

[0031] Preferably according to the present invention, in step (14), the wafer is ground to 150 um.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. The present invention provides a brightness self-adaptive light-emitting diode, which integrates an LED chip and a photosensitive diode during the preparation process, and can automatically adjust the brightness of the light-emitting diode according to the change of the surrounding ambient brightness.

[0034] 2. The DBR layer of the present invention has a high reflectivity in the wavelength range of 580 - 680 nm, preventing the light emitted by the chip itself from affecting the photosensitive diode.

[0035] 3. During the preparation process of the present invention, the existing LED epitaxial wafers are directly used, and there is no need to separately prepare structures such as an N-type ohmic contact layer, a multi-quantum well layer, and a P-type ohmic contact layer, which speeds up the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic structural diagram of the present invention.

[0037] Figure 2 is the present invention after completing the P + region and N + region.

[0038] Figure 3 is a schematic structural diagram of the present invention after completing the bonding process.

[0039] Figure 4 is a schematic structural diagram of the present invention after completing the production of the P-type ohmic contact metal and the N-type ohmic contact metal.

[0040] Figure 5 is a schematic structural diagram of the present invention after completing the production of the photosensitive diode electrodes.

[0041] Figure 6 is a schematic structural diagram of the present invention after completing the production of the wire bonding electrodes.

[0042] Among them, 1. Substrate, 2. N + region, 3. P +Region, 4. Insulating layer, 5. Bonding layer, 6. Current spreading layer, 7. P-type ohmic contact layer, 8. Multi-quantum well layer, 9. N-type ohmic contact layer, 10. N-type ohmic contact metal, 11. Photosensitive diode electrode, 12. DBR layer, 13. Bonding wire electrode, 14. Back gold electrode, 15. P-type ohmic contact metal. Detailed implementation mode

[0043] The present invention will be further described below by way of examples in conjunction with the accompanying drawings, but not limited thereto.

[0044] Example 1:

[0045] As Figures 1-6 shown, this embodiment provides a brightness self-adaptive light-emitting diode, including a substrate 1, a back gold electrode 14 is arranged on the lower side of the substrate 1, an insulating layer 4, a bonding layer 5 and a current spreading layer 6 are sequentially arranged on one side of the substrate 1, a P-type ohmic contact layer 7, a multi-quantum well layer 8 and an N-type ohmic contact layer 9 are sequentially arranged on the upper side of the current spreading layer 6 from bottom to top. The P-type ohmic contact layer 7, the multi-quantum well layer 8 and the N-type ohmic contact layer 9 together form an LED epitaxial wafer. An N-type ohmic contact metal 10 is arranged on the N-type ohmic contact layer 9, and a P-type ohmic contact metal 15 is arranged on the other side of the current spreading layer 6. The insulating layer 4, the bonding layer 5, the current spreading layer 6, the P-type ohmic contact layer 7, the multi-quantum well layer 8, the N-type ohmic contact layer 9, the N-type ohmic contact metal 10 and the P-type ohmic contact metal 15 form an LED chip;

[0046] On the other side of the substrate 1, a P + region 3 is internally provided, and N + regions 2 are respectively arranged on both sides of the P + region 3. A photosensitive diode positive electrode and a photosensitive diode negative electrode are correspondingly arranged on the substrate 1. The P + region 3, the N + region 2, the photosensitive diode positive electrode and the photosensitive diode negative electrode form a photosensitive diode. DBR layers 12 are arranged on both the photosensitive diode and the LED chip. The photosensitive diode positive electrode and the photosensitive diode negative electrode are separated by the DBR layer. The LED epitaxial wafer and the P-type ohmic contact metal 15 are separated by the DBR layer. Electrode windows are opened in the DBR layers 12 on the upper sides of the photosensitive diode positive electrode, the N-type ohmic contact metal 10 and the P-type ohmic contact metal 15. The photosensitive diode positive electrode and the N-type ohmic contact metal 10 are connected by a bonding wire electrode 13, and the P-type ohmic contact metal 15 is connected to a bonding wire electrode 13 through the electrode window.

[0047] The substrate 1 is an N-type single-crystalline silicon substrate with a thickness of 7000 angstroms and a resistivity of 150 - 450 Ω·cm;

[0048] N +The implantation depth of zone 2 is 3000-5000 angstroms, the resistance is 10-20Ω, and the P + Zone 3 has an implant depth of 3500-5500 angstroms and a resistance of 40-60Ω;

[0049] The electrode material of the anode of the photodiode and the cathode of the photodiode is Al, the electrode material of the bonding wire electrode 13 is Al, and the material of the back gold electrode 14 is TiAu.

[0050] The insulating layer 4 is made of SiO 2 , thickness is 1um, the current spreading layer 6 is ITO, and the bonding layer is SiO 2 .

[0051] The method for preparing the brightness adaptive light emitting diode comprises the following steps:

[0052] (1) Thermally grow an oxide layer on the surface of substrate 1, and then form N + Isolation window;

[0053] (2) Forming N by diffusing P source + Zone 2, then remove the oxide layer;

[0054] (3) Continue to thermally grow a 5000 angstrom oxide layer on the substrate surface, and then form a P + Isolation window;

[0055] (4) Forming P by diffusing B source + Zone 3, then remove the oxide layer;

[0056] (5) depositing an insulating layer 4 on the substrate surface by PECVD;

[0057] (6) vapor-depositing a current spreading layer 6 on the LED epitaxial wafer, and then bonding the LED epitaxial wafer to the insulating layer through a bonding process under the bonding conditions of a temperature of 380° C., a time of 50 minutes, and a pressure of 900 kg, and then removing the n-GaAs substrate of the LED epitaxial wafer through a mixed solution of ammonia water, hydrogen peroxide, and water, wherein the volume ratio of ammonia water, hydrogen peroxide, and water in the mixed solution is 1:6:8;

[0058] (7) Etching the area outside the LED chip to the surface of the insulating layer 4 through photolithography and ICP process;

[0059] (8) Etching the LED chip to the P-type GaP ohmic contact layer again through photolithography and ICP process;

[0060] (9) Through photolithography, evaporation, and lift-off, the P-type ohmic contact metal 15 and the N-type ohmic contact metal 10 of the LED chip are respectively formed. The P-type ohmic contact metal is an Au / AuZn / Au laminated metal, with an alloying temperature of 500 °C and a time of 10 min; the N-type ohmic contact is an Au / AuGeNi / Au laminated metal, with an alloying temperature of 350 °C and a time of 10 min;

[0061] (10) Through photolithography, evaporation, and lift-off processes, the insulating layer in the photosensitive diode region is removed, and the positive electrode and the positive and negative electrodes of the photosensitive diode are fabricated. The positive electrode and the positive and negative electrodes of the photosensitive diode together constitute the photosensitive diode electrode 11;

[0062] (11) On the surface of the wafer obtained in step (10), a DBR layer 12 is grown through an optical coating device. The DBR layer has a high reflectivity in the wavelength band of 580 - 680 nm to prevent the light emitted by the chip itself from affecting the photosensitive diode;

[0063] (12) An electrode window is formed through photolithography and etching processes;

[0064] (13) Again through photolithography, evaporation, and lift-off, the bonding wire electrodes 13 of the photosensitive diode chip and the LED chip are formed. The N-type ohmic contact metal 10 of the LED chip is connected to the positive electrode of the photosensitive diode;

[0065] (14) The wafer obtained in step (13) is polished to 150 um, then a back gold electrode is deposited by electron beam evaporation, and then laser scribing and diamond knife cutting are used to obtain the light-emitting diode.

[0066] Example 2:

[0067] A method for preparing a brightness self-adaptive light-emitting diode, the steps are as described in Example 1, the difference is that in step (6), the LED epitaxial wafer includes an n-GaAs substrate and an N-type ohmic contact layer 9, a multi-quantum well layer 8, and a P-type ohmic contact layer 7 sequentially arranged on the n-GaAs substrate. The LED epitaxial wafer is an existing device and can be directly used without separately preparing structures such as an N-type ohmic contact layer, a multi-quantum well layer, and a P-type ohmic contact layer, which speeds up the preparation process.

[0068] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A brightness adaptive light emitting diode, It is characterized in that The invention comprises a substrate, a back-gold electrode is arranged on the lower side of the substrate, an insulating layer, a bonding layer and a current expansion layer are arranged in sequence on one side of the substrate, a P-type ohmic contact layer, a multi-quantum well layer and an N-type ohmic contact layer are arranged in sequence on one side of the current expansion layer, the P-type ohmic contact layer, the multi-quantum well layer and the N-type ohmic contact layer together constitute an LED epitaxial wafer, an N-type ohmic contact metal is arranged on the N-type ohmic contact layer, a P-type ohmic contact metal is arranged on the other side of the current expansion layer, and the insulating layer, the bonding layer, the current expansion layer, the P-type ohmic contact layer, the multi-quantum well layer, the N-type ohmic contact layer, the N-type ohmic contact metal and the P-type ohmic contact metal constitute an LED chip; On the other side of the substrate, P is built-in. + region, P + regions are respectively arranged on both sides of the P + region. A positive photodiode electrode and a negative photodiode electrode are correspondingly arranged on the substrate. The P + region, N + region, the positive photodiode electrode and the negative photodiode electrode form a photodiode. DBR layers are arranged on both the photodiode and the LED chip. The positive photodiode electrode and the negative photodiode electrode are separated by the DBR layer. The LED epitaxial wafer and the P-type ohmic contact metal are separated by the DBR layer. Electrode windows are opened in the DBR layers on the upper sides of the positive photodiode electrode, the N-type ohmic contact metal and the P-type ohmic contact metal. The positive photodiode electrode and the N-type ohmic contact metal are connected by a wire bond electrode. The P-type ohmic contact metal is connected with a wire bond electrode through the electrode window.

2. The brightness adaptive light emitting diode according to claim 1, It is characterized in that The substrate is an N-type single crystal silicon substrate with a thickness of 7000 angstroms and a resistivity of 150-450Ω·cm; N + The implantation depth of the N region is 3000 - 5000 Å, and the resistance is 10 - 20 Ω, P + The implantation depth of the P region is 3500 - 5500 Å, and the resistance is 40 - 60 Ω; The electrode material of the positive electrode of the photosensitive diode and the negative electrode of the photosensitive diode is Al, the electrode material of the bonding wire electrode is Al, and the back gold electrode material is TiAu.

3. The brightness adaptive light emitting diode according to claim 2, It is characterized in that The insulating layer is made of SiO 2 , with a thickness of 1 um. The current spreading layer is ITO, ZnO or GZO, and the bonding layer is made of SiO 2 or a polymer.

4. The method for preparing a brightness adaptive light emitting diode according to any one of claims 1 to 3, It is characterized in that Here are the steps: (1) Thermally grow an oxide layer on the substrate surface, and then form an N + isolation window through photolithography and etching; (2) Form an N region by diffusing and injecting a P source, and then remove the oxide layer; + ​ (3) Continuously grow a 5000-angstrom oxide layer on the substrate surface, and then form a P + isolation window through photolithography and etching; (4) Form a P region by diffusing and injecting B source, and then remove the oxide layer; + ​ (5) depositing an insulating layer on the substrate surface by PECVD; (6) Evaporating a current spreading layer on the LED epitaxial wafer, and then bonding the LED epitaxial wafer to the insulating layer through a bonding process, and then removing the n-GaAs substrate of the LED epitaxial wafer; (7) Etching the area outside the LED chip to the surface of the insulating layer through photolithography and ICP process; (8) Etching the LED chip to the P-type ohmic contact layer again through photolithography and ICP process; (9) forming a P-type ohmic contact metal and an N-type ohmic contact metal of the LED chip respectively by photolithography, evaporation, and stripping; (10) removing the insulating layer in the photodiode region through photolithography, evaporation, and stripping processes to produce a positive electrode of the photodiode and a negative electrode of the photodiode; (11) growing a DBR layer on the surface of the wafer obtained in step (10) by an optical coating device; (12) forming an electrode window by photolithography and etching processes; (13) Photolithography, evaporation, and stripping are performed again to form wire bonding electrodes between the photodiode chip and the LED chip, and the N-pole ohmic contact metal of the LED chip is connected to the positive electrode of the photodiode; (14) The wafer obtained in step (13) is ground, and then a back gold electrode is deposited by electron beam evaporation, followed by laser scribing and diamond knife cutting to obtain a light-emitting diode.

5. The method for preparing a brightness adaptive light emitting diode according to claim 4, It is characterized in that In step (6), the LED epitaxial wafer includes an n-GaAs substrate and an N-type ohmic contact layer, a multi-quantum well layer and a P-type ohmic contact layer sequentially arranged on the n-GaAs substrate.

6. The method for preparing a brightness adaptive light emitting diode according to claim 4, It is characterized in that In step (6), the bonding conditions are a temperature of 380 °C, a time of 50 minutes, and a pressure of 900 kg. The n-GaAs substrate is removed by a mixed solution of ammonia water, hydrogen peroxide, and water, and the volume ratio of ammonia water, hydrogen peroxide, and water in the mixed solution is 1:6:

8.

7. The method for preparing a brightness adaptive light-emitting diode according to claim 4, wherein, in step (9), the P-type ohmic contact metal is an Au / AuZn / Au laminated metal, the alloying temperature is 500 °C, and the time is 10 min; the N-type ohmic contact metal is an Au / AuGeNi / Au laminated metal, the alloying temperature is 350 °C, and the time is 10 min.

8. The method for preparing a brightness adaptive light-emitting diode according to claim 4, wherein, in step (14), the wafer is ground to 150 um.

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