CN-115360278-B - Micro light-emitting device and preparation method thereof

CN115360278BCN 115360278 BCN115360278 BCN 115360278BCN-115360278-B

Abstract

The invention provides a miniature light-emitting device and a preparation method thereof, wherein a first metal reflecting layer is laminated on the surface of a transparent conducting layer with an island-shaped structure, so that light reflected downwards by the first metal reflecting layer forms a diffuse reflection effect at the island-shaped structure, and then the light is reflected by a second reflecting layer and a third reflecting layer to further enlarge a light-emitting angle; the first metal reflecting layer and the transparent conducting layer form ohmic contact with the second semiconductor layer through an alloy process, and meanwhile, the first metal reflecting layer has conductivity and a resistance value lower than that of the transparent conducting layer, so that the transverse conduction of current is facilitated, the voltage is reduced, and the photoelectric conversion efficiency of the miniature luminescent device is further improved.

Inventors

LIU WEI
LIU YINGCE
WU XINGEN
WANG RUI
CHEN XUANLIANG

Assignees

厦门乾照光电股份有限公司

Dates

Publication Date: 20260512
Application Date: 20220819

Claims (11)

1. The utility model provides a miniature light emitting device, includes the substrate and set up in the substrate surface and a plurality of LED array unit that keeps apart each other through the slot, its characterized in that, LED array unit includes: The epitaxial lamination comprises a first type semiconductor layer, an active region and a second type semiconductor layer which are sequentially stacked along a first direction, and a partial region of the epitaxial lamination is etched until a part of the first type semiconductor layer forms a groove and a table top; A transparent conductive layer provided on the mesa and having a plurality of island structures; the first metal reflecting layer is laminated on the surface of one side of the transparent conducting layer, which faces away from the table top; The passivation layer is formed on one side surface of the first metal reflecting layer, which is away from the transparent conducting layer, and is provided with a first electrode contact hole and a second electrode contact hole, wherein the second electrode contact hole is positioned above the table top, and the first electrode contact hole exposes part of the surface of the groove; a first electrode deposited in the first electrode contact hole and electrically connected with the first semiconductor layer; the second electrode is deposited in the second electrode contact hole and is electrically connected with the second type semiconductor layer, and the second electrode and the first electrode are arranged far away from each other; The passivation layer is provided with a graphical structure, and the projection of the graphical structure and the through hole on the surface of the substrate is not overlapped.
2. The micro light emitting device of claim 1, wherein the first metal reflective layer and the transparent conductive layer form an ohmic contact with the second type semiconductor layer through an alloying process.
3. The micro light emitting device of claim 1, further comprising a second metal reflective layer and an insulating reflective layer, wherein the second metal reflective layer is disposed on a surface of the patterned structure, and the insulating reflective layer covers the second metal reflective layer.
4. A micro light emitting device according to claim 3, wherein the insulating reflective layer covers the sidewalls of the epitaxial stack.
5. The micro light emitting device of claim 4, wherein the insulating reflective layer comprises a DBR mirror.
6. The micro light emitting device of claim 1, wherein the passivation layer has a tapered or bowl-shaped patterned structure.
7. The micro light emitting device of claim 1, wherein the passivation layer comprises one or more of SiO 2 、SiC、AlN、SiONx、SiN x .
8. The micro light-emitting device according to claim 1, wherein the passivation layer is stacked on the substrate so as to be held on the trench sidewall.
9. The micro light emitting device of claim 1, wherein the transparent conductive layer has a plurality of nano-island structures.
10. A method of fabricating a micro light emitting device, the method comprising: s01, providing a substrate; S02, growing an epitaxial lamination layer, wherein the epitaxial lamination layer comprises a first type semiconductor layer, an active layer and a second type semiconductor layer which are sequentially stacked on the surface of the substrate; S03, exposing part of the first semiconductor layer by etching the epitaxial lamination, so as to form a plurality of grooves and table tops, wherein the grooves are opposite to the table tops; S04, forming a plurality of epitaxial stacks which are mutually arranged at intervals through grooves by etching the epitaxial stacks back to expose the surface of the substrate; s05, depositing transparent conductive layers on the table tops of the epitaxial laminates which are arranged at intervals, wherein the transparent conductive layers comprise transparent conductive layers with a plurality of island structures; S06, forming a first metal reflecting layer on the surface of the transparent conductive layer, wherein the first metal reflecting layer is provided with at least one through hole; the first metal reflecting layer comprises a metal reflecting mirror and a metal blocking layer which are sequentially laminated; s07, manufacturing a first contact metal, which is formed on the bottom surface of the groove; S08, manufacturing a passivation layer, wherein the passivation layer is formed on the surface of the first metal reflecting layer in a mode of embedding the through hole, the passivation layer is provided with a graphical structure, and the projection of the graphical structure and the through hole on the surface of the substrate is not overlapped; S09, manufacturing a second metal reflecting layer on the surface of the patterned structure of the passivation layer; S10, manufacturing an insulating reflecting layer, wherein the insulating reflecting layer covers the second metal reflecting layer; S11, forming a first electrode contact hole and a second electrode contact hole through an etching process, wherein the second electrode contact hole is positioned above the table top and exposes the first metal reflecting layer, and the first electrode contact hole exposes the first contact metal; S12, manufacturing a first electrode and a second electrode, wherein the first electrode is deposited on the first electrode contact hole and extends to the surface of the insulating reflecting layer, the second electrode is deposited on the second electrode contact hole and extends to the surface of the insulating reflecting layer, and the first electrode and the second electrode are arranged far away.
11. The micro light emitting device of claim 1, wherein step S06 further comprises an alloying process to make ohmic contact between the first metal reflective layer and the transparent conductive layer and the second semiconductor layer through the alloying process.

Description

Micro light-emitting device and preparation method thereof Technical Field The invention relates to the field of light emitting diodes, in particular to a miniature light emitting device and a preparation method thereof. Background With the continuous development of semiconductor light emitting technology, the application of LEDs is more and more varied, and particularly, the development of LEDs in display technology is advanced. Meanwhile, due to the high resolution requirement of the LED display screen, the distance between LED chips and the size of the chips are also smaller and smaller, such as micro-light emitting devices like Mini-LEDs. MiniLED is an LED chip with a size of 100 micrometers, and is mainly applied to backlight and direct display. From the dimension, the size of a single LED chip of MiniLED is between 50 and 200 mu m, and the pixel pitch is about 0.5 to 1 mm. Compared with the traditional LED chip backlight product, the LED chip backlight product has smaller dot spacing, so that more LED backlight beads can be integrated on the same display screen, the screen is divided into more fine backlight partitions, finer regional luminous adjustment is facilitated, and the contrast close to an OLED screen can be achieved. In addition, compared with an OLED screen, the Mini-LED backlight screen has the advantages of long service life, difficulty in screen burning and the like. However, the light emitting angle of the Mini-LED chip is 130-140 degrees, more backlight beads and backlight designs are integrated to achieve a good display effect, the thickness is not easy to thin, meanwhile, more heat is easily generated due to the fact that multiple backlight beads gather, the heat dissipation requirement on equipment is higher, and therefore the Mini-LED is difficult to apply to a screen with a larger specification. In view of this, the present inventors have specifically devised a micro light emitting device and a method for manufacturing the same, and the present disclosure is thereby generated. Disclosure of Invention The invention aims to provide a miniature light-emitting device and a preparation method thereof, which are used for solving the problems of high cost, large display screen thickness and heating of the miniature light-emitting device caused by small light-emitting angle. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the utility model provides a miniature light emitting device, includes the substrate and set up in the substrate surface and a plurality of LED array unit that keeps apart each other through the slot, LED array unit includes: The epitaxial lamination comprises a first type semiconductor layer, an active region and a second type semiconductor layer which are sequentially stacked along a first direction, and a partial region of the epitaxial lamination is etched until a part of the first type semiconductor layer forms a groove and a table top; a transparent conductive layer provided on the mesa and having an island-like structure; the first metal reflecting layer is laminated on the surface of one side of the transparent conducting layer, which faces away from the table top; The passivation layer is formed on one side surface of the first metal reflecting layer, which is away from the transparent conducting layer, and is provided with a first electrode contact hole and a second electrode contact hole, wherein the second electrode contact hole is positioned above the table top, and the first electrode contact hole exposes part of the surface of the groove; a first electrode deposited in the first electrode contact hole and electrically connected with the first semiconductor layer; And the second electrode is deposited in the second electrode contact hole and is electrically connected with the second type semiconductor layer, and the second electrode and the first electrode are arranged far away from each other. Preferably, the first metal reflective layer and the transparent conductive layer form ohmic contact with the second type semiconductor layer through an alloy process. Preferably, the first metal reflective layer has at least one via, and the passivation layer is embedded in the via. Further, the first metal reflecting layer comprises a metal reflecting mirror and a metal blocking layer which are sequentially stacked, wherein the reflecting metal comprises high-reflectivity metal such as Ag, al and the like, and the metal blocking layer comprises one or more overlapped TiW and Pt. Preferably, the passivation layer has a patterned structure, and the patterned structure and the projection of the through hole on the substrate surface do not overlap. Preferably, the patterning structure further comprises a second metal reflecting layer and an insulating reflecting layer, wherein the second metal reflecting layer is arranged on the surface of the patterning structure, and the insulating reflecting layer covers the second