Light emitting diode
By using a patterned heavily doped GaAs layer as the ohmic contact layer in the red light micro-light diode and layering it in aligned with the patterned second electrode, the problem of low brightness of the existing red light micro-light diode is solved, and higher brightness and photoelectric performance are achieved.
Patent Information
- Application Number
- CN202421143659.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-23
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2034-05-23
AI Technical Summary
The existing red light micro-light emitting diodes have low brightness and are difficult to meet certain application needs.
A patterned heavily doped GaAs layer was used as the ohmic contact layer, and it was layered in aligned with the patterned second electrode, and the thickness of the ohmic contact layer was controlled at 50 nm or less.
By improving the current expansion effect and reducing light absorption, the brightness and photoelectric performance of the light emitting diode are significantly improved.
Smart Images
Figure CN222840030U_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a light emitting diode. Background Art
[0002] Red light emitting diode (LED) is an AlGaInP-based LED device.
[0003] The red light emitting diode comprises a first semiconductor layer, a light emitting layer and a second semiconductor layer. However, how to improve the brightness of the red light micro light emitting diode is still the focus of current research. Utility Model Content
[0004] The embodiment of the present disclosure provides a light emitting diode, which can improve the brightness of a red light micro light emitting diode. The technical solution is as follows:
[0005] The present disclosure provides a light emitting diode, the light emitting diode comprising:
[0006] A first electrode, a first semiconductor layer, a light-emitting layer, a second semiconductor layer, an ohmic contact layer and a second electrode are stacked in sequence, wherein the ohmic contact layer is a patterned heavily doped GaAs layer, and the second electrode is a patterned electrode. The patterns of the ohmic contact layer and the second electrode are the same and they are aligned and stacked, and the thickness of the ohmic contact layer is not more than 50nm.
[0007] Optionally, the thickness of the ohmic contact layer is not greater than 50 nm and not less than 10 nm.
[0008] Optionally, the thickness of the ohmic contact layer is not greater than 30 nm and not less than 18 nm.
[0009] Optionally, the doping concentration of the ohmic contact layer is 1E18-1E19cm -3 .
[0010] Optionally, the second electrode includes a plurality of parallel finger portions and a connecting portion respectively connected to the plurality of finger portions, and the connecting portion includes a pad.
[0011] Optionally, the width of the finger portion is 2.5-3 μm.
[0012] Optionally, the light emitting diode further comprises: a current blocking layer, wherein the current blocking layer is located between the first electrode and the first semiconductor layer;
[0013] The current blocking layer has a plurality of through holes, and the first electrode is connected to the first semiconductor layer through the plurality of through holes.
[0014] Optionally, projections of the plurality of through holes on the first semiconductor layer are located in a region between projections of the plurality of finger portions on the first semiconductor layer.
[0015] Optionally, the second electrode is an AuGeNi electrode.
[0016] Optionally, the first semiconductor layer is a P-type AlGaInP layer, and the second semiconductor layer is an N-type AlGaInP layer.
[0017] The technical solution provided by the embodiments of the present disclosure brings the following beneficial effects:
[0018] In the light-emitting diode provided in the embodiment of the present disclosure, a patterned heavily doped GaAs layer is used as an ohmic contact layer. The ohmic contact layer can improve the current spreading effect and the electrical performance of the light-emitting diode. On the other hand, when the light of the light-emitting diode is emitted from one side of the ohmic contact layer, the patterned ohmic contact layer and the second electrode are aligned and stacked to ensure that the light is normally emitted from the light-emitting diode. In addition, the thickness of the ohmic contact layer is set to be 50nm or less, and the thickness is relatively thin, so that the ohmic contact layer absorbs less light, thereby improving the light output brightness of the light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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.
[0020] Figure 1 is a structural schematic diagram of a light emitting diode provided by an embodiment of the present disclosure;
[0021] Figure 2 It is a top view of a light emitting diode provided by an embodiment of the present disclosure.
[0022] The reference numerals are as follows:
[0023] 10: substrate; 11: first semiconductor layer; 12: light emitting layer; 13: second semiconductor layer; 14: ohmic contact layer; 15: second electrode; 16: first electrode; 17: current blocking layer; 171: through hole; 151: finger portion; 152: connection portion; 153: pad. DETAILED DESCRIPTION
[0024] 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.
[0025] Figure 1is a schematic diagram of the structure of a light emitting diode provided by an embodiment of the present disclosure. Figure 1 The light emitting diode includes: a first electrode 16, a first semiconductor layer 11, a light emitting layer 12, a second semiconductor layer 13, an ohmic contact layer 14 and a second electrode 15 which are stacked in sequence.
[0026] The ohmic contact layer 14 is a patterned heavily doped GaAs layer, and the second electrode 15 is a patterned electrode. The ohmic contact layer 14 and the second electrode 15 have the same pattern and are aligned and stacked. The thickness of the ohmic contact layer 14 is not greater than 50 nm.
[0027] In the light-emitting diode provided in the embodiment of the present disclosure, a patterned heavily doped GaAs layer is used as an ohmic contact layer. The ohmic contact layer can improve the current spreading effect and the electrical performance of the light-emitting diode. On the other hand, when the light of the light-emitting diode is emitted from one side of the ohmic contact layer, the patterned ohmic contact layer and the second electrode are aligned and stacked to ensure that the light is normally emitted from the light-emitting diode. In addition, the thickness of the ohmic contact layer is set to be 50nm or less, and the thickness is relatively thin, so that the ohmic contact layer absorbs less light, thereby improving the light output brightness of the light-emitting diode.
[0028] See again Figure 1 The light emitting diode may further include: a current blocking layer 17 , wherein the current blocking layer 17 is located between the first electrode 16 and the first semiconductor layer 11 .
[0029] The current blocking layer 17 has a plurality of through holes 171 , and the first electrode 16 is connected to the first semiconductor layer 11 through the plurality of through holes 171 .
[0030] In this implementation, a current blocking layer is provided to block the current from diffusing toward the first electrode, and a via hole is opened to electrically connect the first electrode and the first semiconductor layer.
[0031] See again Figure 1 The light emitting diode may further include: a substrate 10, and a first electrode 16 connected to the substrate 10 by bonding.
[0032] The semiconductor structure in the light-emitting diode can be first grown on a temporary substrate, and then transferred to the substrate 10 after the growth is completed, and connected through a bonding layer.
[0033] In the embodiment of the present disclosure, the substrate 10 may be a Si substrate, and the embodiment of the present disclosure does not limit the material of the substrate.
[0034] In the embodiment of the present disclosure, the first semiconductor layer 11 may be a P-type semiconductor layer, and the second semiconductor layer 13 may be an N-type semiconductor layer.
[0035] For example, the first semiconductor layer 11 may be a P-type AlGaInP layer, and the second semiconductor layer 13 may be an N-type AlGaInP layer. The AlGaInP material is used to form an epitaxial structure to realize a red light emitting diode, which can be applied in the fields of plant lighting and the like.
[0036] In the embodiment of the present disclosure, the light emitting layer 12 may be an AlGaInP-based material light emitting layer.
[0037] In the embodiment of the present disclosure, the thickness of the ohmic contact layer 14 may be no greater than 50 nm and no less than 10 nm.
[0038] In this implementation, the thickness of the ohmic contact layer is set within the above range, which can ensure that the thickness of the layer is small enough to avoid light absorption to the greatest extent; at the same time, the thickness is set at 10nm or above to ensure the current spreading effect.
[0039] In the embodiment of the present disclosure, the thickness of the ohmic contact layer 14 may be no greater than 30 nm and no less than 18 nm. The thickness of the ohmic contact layer is set within the above range to avoid light absorption to the greatest extent while ensuring a good current spreading effect, thereby achieving a balance between photoelectricity and light.
[0040] Exemplarily, the thickness of the ohmic contact layer 14 is 18 nm, 20 nm or 25 nm.
[0041] In the embodiment of the present disclosure, the ohmic contact layer 14 may be an N-type heavily doped GaAs layer.
[0042] For example, the doping concentration of the ohmic contact layer 14 may be 1E18-1E19 cm -3 For example, the doping concentration of the ohmic contact layer 14 is 5E18 cm -3 .
[0043] In this implementation, the ohmic contact layer 14 with the above doping concentration is used to ensure the ohmic contact effect of the ohmic contact layer 14 .
[0044] In the embodiment of the present disclosure, the second electrode 15 may be a metal electrode or a metal alloy electrode, such as an AuGeNi electrode.
[0045] In this implementation, the second electrode uses the above-mentioned material to ensure the electrical performance of the light-emitting diode.
[0046] In the embodiment of the present disclosure, the first electrode 16 may be a metal electrode or a metal alloy electrode, such as an AuZn electrode.
[0047] In this implementation, the first electrode uses the above material to ensure the electrical performance of the light-emitting diode. At the same time, the first electrode 16 uses the above material to ensure the reflection effect, so that the light emitted by the light-emitting layer is finally emitted from the second electrode side.
[0048] In the embodiment of the present disclosure, the first electrode 16 may be a surface electrode or a patterned electrode, and the pattern of the patterned electrode can ensure connection with the semiconductor layer through each through hole.
[0049] In the embodiment of the present disclosure, the current blocking layer 17 may be a silicon dioxide layer or a titanium oxide layer. The current blocking layer is combined with the first electrode 16 to realize light reflection.
[0050] Figure 2 It is a top view of a light emitting diode provided by an embodiment of the present disclosure. Figure 1 yes Figure 2 Schematic diagram of the cross section along the A-A' direction.
[0051] See also Figure 2 The second electrode 15 includes a plurality of parallel finger portions 151 and a connecting portion 152 respectively connected to the plurality of finger portions 151 , and the connecting portion 152 includes a pad 153 .
[0052] In this implementation, the second electrode adopts the above-mentioned pattern, which can ensure both the current spreading effect and the emission of light.
[0053] In the embodiment of the present disclosure, the finger portion 151 of the second electrode 15 is in a long strip shape, and the width W of the finger portion 151 may be 2.5-3 μm.
[0054] In the embodiment of the present disclosure, the second electrode 15 and the ohmic contact layer 14 are formed by one etching process, so the finger portion of the second electrode 15 does not cover the ohmic contact layer 14, so that the width of the finger portion can be thinner.
[0055] In this implementation, since the width of the finger portion 151 is 2.5-3 μm and the finger portion is thin, the light absorption of the ohmic contact layer and the light shielding of the second electrode can be reduced, thereby ensuring the light extraction effect.
[0056] Exemplarily, the width W of the finger portion 151 is 2.8 μm.
[0057] In the embodiment of the present disclosure, the interval D between adjacent finger portions 151 of the second electrode 15 is 80-140 μm.
[0058] Exemplarily, the interval D between adjacent finger portions 151 of the second electrode 15 is 100 μm.
[0059] The interval between adjacent finger portions 151 is related to the size of the light emitting diode, but setting the interval within the above range can ensure that the light emitting diode has better photoelectric performance.
[0060] See again Figure 2 , projections of the plurality of through holes 171 on the first semiconductor layer 11 are located in a region between projections of the plurality of finger portions 151 on the first semiconductor layer 11 .
[0061] In this implementation, by disposing the through holes 171 between the finger portions 151 , current spreading and light reflection can be better ensured, thereby ensuring the photoelectric effect.
[0062] like Figure 2 As shown, a plurality of through holes 171 are arranged in an array, and no through hole 171 is provided at a position corresponding to the pad 153 .
[0063] like Figure 2 As shown, the projections of the two pads 153 are respectively located in the rows where the projections of the two adjacent rows of through holes 171 are located.
[0064] like Figure 2 As shown, the shape of the through hole 171 can be circular. In other examples, the through hole 171 can also be other shapes, such as rectangular.
[0065] Optionally, a metal layer may be provided on the surface of the substrate 10 facing away from the first semiconductor layer to achieve connection between the light emitting diode and other structures. The metal layer may be a Ti or Au layer.
[0066] In the experimental stage, light-emitting diodes with ohmic contact layers of different thicknesses were selected for the experiment. The experimental results are shown in Table 1 below, where VF1_avg represents voltage, in V; LOP_avg represents average brightness, in mW; and WLP_avg represents average peak wavelength, in nm.
[0067] Table 1
[0068]
[0069] As can be seen from Table 1, when the thickness of the ohmic contact layer is 50 nm or less, the brightness is sufficiently improved compared with the ohmic contact layer of 85 nm, while the electrical performance is not deteriorated, and the photoelectric performance of the light-emitting diode is guaranteed.
[0070] The above descriptions are merely embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.
Claims
1. A light emitting diode, characterized in that: The light emitting diode comprises: A first electrode (16), a first semiconductor layer (11), a light-emitting layer (12), a second semiconductor layer (13), an ohmic contact layer (14) and a second electrode (15) are sequentially stacked, wherein the ohmic contact layer (14) is a patterned heavily doped GaAs layer, and the second electrode (15) is a patterned electrode. The ohmic contact layer (14) and the second electrode (15) have the same pattern and are aligned and stacked, and the thickness of the ohmic contact layer (14) is not greater than 50 nm.
2. The light emitting diode according to claim 1, characterized in that: The thickness of the ohmic contact layer (14) is not greater than 50 nm and not less than 10 nm.
3. The light emitting diode according to claim 2, characterized in that: The thickness of the ohmic contact layer (14) is not greater than 30 nm and not less than 18 nm.
4. The light emitting diode according to any one of claims 1 to 3, characterized in that: The second electrode (15) includes a plurality of parallel finger portions (151) and a connection portion (152) respectively connected to the plurality of finger portions (151), and the connection portion (152) includes a pad (153).
5. The light emitting diode according to claim 4, characterized in that: The width of the finger portion (151) is 2.5 to 3 μm.
6. The light emitting diode according to claim 4, characterized in that: The light emitting diode further comprises: a current blocking layer (17), wherein the current blocking layer (17) is located between the first electrode (16) and the first semiconductor layer (11); The current blocking layer (17) has a plurality of through holes (171), and the first electrode (16) is connected to the first semiconductor layer (11) through the plurality of through holes (171).
7. The light emitting diode according to claim 6, characterized in that: Projections of the plurality of through holes (171) on the first semiconductor layer (11) are located in a region between projections of the plurality of finger portions (151) on the first semiconductor layer (11).
8. The light emitting diode according to any one of claims 1 to 3, characterized in that: The second electrode (15) is an AuGeNi electrode.
9. The light emitting diode according to any one of claims 1 to 3, characterized in that: The first semiconductor layer (11) is a P-type AlGaInP layer, and the second semiconductor layer (13) is an N-type AlGaInP layer.