US-12628474-B2 - Flip-chip light-emitting device having at least one stack unit that is free of gold

US12628474B2US 12628474 B2US12628474 B2US 12628474B2US-12628474-B2

Abstract

A flip-chip light-emitting device includes a light-emitting unit, a first electrode, and a second electrode. The light-emitting unit includes a first type semiconductor layer, an active layer, and a second type semiconductor layer. The first electrode is disposed on the light-emitting unit and electrically connected to the first type semiconductor layer. The second electrode is disposed on the light-emitting unit and electrically connected to the second type semiconductor layer. The first electrode or the second electrode is free of gold, and includes an aluminum layer and at least one platinum layer disposed on the aluminum layer opposite to the light-emitting unit.

Inventors

Min Huang
Yu ZHAN
ZHANGGEN XIA
Ling-yuan HONG
Su-Hui Lin
Chung-Ying Chang

Assignees

Quanzhou Sanan Semiconductor Technology Co., Ltd.

Dates

Publication Date: 20260512
Application Date: 20220907
Priority Date: 20210909

Claims (17)

1 . A flip-chip light-emitting device, comprising: a light-emitting unit including a first type semiconductor layer, an active layer, and a second type semiconductor layer that are disposed on one another in such order; a first electrode disposed on said light-emitting unit and electrically connected to said first type semiconductor layer; and a second electrode disposed on said light-emitting unit and electrically connected to said second type semiconductor layer, wherein at least one of said first electrode or said second electrode is free of gold, and includes an aluminum layer and a platinum layer disposed on said aluminum layer opposite to said light-emitting unit; wherein said at least one of said first electrode or said second electrode further includes a stress buffer layer disposed between said aluminum layer and said platinum layer; wherein said at least one of said first electrode or said second electrode includes at least one stack unit that is formed by said stress buffer layer and said platinum layer disposed on said stress buffer layer; wherein in said least one stack unit, a ratio of a thickness of said stress buffer layer to a thickness of said platinum layer is smaller than 1; wherein said flip-chip light-emitting device further includes an insulation layer, a first electrode pad, and a second electrode pad, said insulation layer covering said first and second electrodes and an upper surface and a side surface of said light-emitting unit, said insulation layer being formed with two through holes, each of said first electrode pad and said second electrode pad being disposed on said insulation layer and electrically connected to a respective one of said first and second electrodes through a respective one of said through holes; wherein said at least one of said first electrode or said second electrode further includes an adhesion layer disposed between said insulation layer and said platinum layer, said adhesion layer adhering to said insulation layer; and wherein said at least one of said first electrode or said second electrode is formed with a recess that penetrates through said adhesion layer and extends into said platinum layer.
2 . The flip-chip light-emitting device of claim 1 , wherein said at least one of said first electrode or said second electrode has a thickness of not greater than 800 nm.
3 . The flip-chip light-emitting device of claim 1 , wherein said aluminum layer has a thickness of not smaller than 80 nm.
4 . The flip-chip light-emitting device of claim 1 , wherein said aluminum layer has a thickness of not greater than 300 nm.
5 . The flip-chip light-emitting device of claim 1 , wherein said at least one stack unit includes a plurality of stack units.
6 . The flip-chip light-emitting device of claim 5 , wherein said platinum layer of a topmost one of said plurality of stack units distal from said aluminum layer has a thickness greater than that of said platinum layer of each of remaining ones of said plurality of stack units.
7 . The flip-chip light-emitting device of claim 6 , wherein said platinum layer of said topmost one of said plurality of stack units has a thickness ranging from 100 nm to 300 nm.
8 . The flip-chip light-emitting device of claim 6 , wherein said stress buffer layer of each of said plurality of stack units has a thickness ranging from 20 nm to 80 nm, and said thickness of said platinum layer of each of said remaining ones of said plurality of stack units is not greater than 100 nm.
9 . The flip-chip light-emitting device of claim 1 , wherein said stress buffer layer is made of titanium.
10 . The flip-chip light-emitting device of claim 1 , wherein the thickness of said platinum layer ranges from 100 nm to 300 nm.
11 . The flip-chip light-emitting device of claim 1 , wherein said at least one of said first electrode or said second electrode has a thickness not greater than 500 nm.
12 . The flip-chip light-emitting device of claim 1 , wherein a percentage of a depth of said recess extending downwardly from an upper surface of said platinum layer based on said thickness of said platinum layer ranges from 1% to 50%.
13 . The flip-chip light-emitting device of claim 12 , wherein said recess is spatially communicated with the respective one of said through holes.
14 . The flip-chip light-emitting device of claim 1 , wherein said adhesion layer is made of titanium.
15 . A flip-chip light-emitting device, comprising: a light-emitting unit including a first type semiconductor layer, an active layer, and a second type semiconductor layer that are disposed on one another in such order; a first electrode disposed on said light-emitting unit and electrically connected to said first type semiconductor layer; a second electrode disposed on said light-emitting unit and electrically connected to said second type semiconductor layer; an insulation layer; a first electrode pad; and a second electrode pad, said insulation layer covering said first and second electrodes and an upper surface and a side surface of said light-emitting unit, said insulation layer being formed with two through holes, each of said first electrode pad and said second electrode pad being disposed on said insulation layer and electrically connected to a respective one of said first and second electrodes through a respective one of said through holes, wherein at least one of said first electrode or said second electrode is free of gold, and includes an aluminum layer and a platinum layer disposed on said aluminum layer opposite to said light-emitting unit; wherein said at least one of said first electrode or said second electrode further includes an adhesion layer disposed between said insulation layer and said platinum layer, said adhesion layer adhering to said insulation layer; and wherein said at least one of said first electrode or said second electrode is formed with a recess that penetrates through said adhesion layer and extends into said platinum layer.
16 . The flip-chip light-emitting device of claim 15 , wherein a percentage of a depth of said recess extending downwardly from an upper surface of said platinum layer based on said thickness of said platinum layer ranges from 1% to 50%.
17 . The flip-chip light-emitting device of claim 16 , wherein said recess is spatially communicated with the respective one of said through holes.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority of Chinese Patent Application No. 202111057539.7, filed on Sep. 9, 2021. FIELD The disclosure relates to a light-emitting device, and more particularly to a flip-chip light-emitting device. BACKGROUND Flip-chip light-emitting diodes are widely applied in several fields, such as illumination, backlight, etc., for having advantageous characteristics, e.g., high efficiency in light emitting, energy saving, and long lifespan, etc. A conventional flip-chip light-emitting diode includes semiconductor layers, metal electrodes, a transparent conductive layer, an insulation layer, and solder pads. Each of the metal electrodes is used to transport current, and is electrically connected to the corresponding semiconductor layer or the transparent conductive layer. Each of the solder pads is disposed on the corresponding metal electrode, and is used to mount the flip-chip light-emitting diode on a substrate. Each of the metal electrodes includes an aluminum layer, and an aluminum-diffusion barrier layer that is disposed on the aluminum layer. The aluminum-diffusion barrier layer includes a gold layer that has a relatively large thickness, and that is used to enhance current spreading in a horizontal direction. In the conventional flip-chip light-emitting diode, each of the metal electrode has a thickness ranging from 1.5 μm to 2.5 μm, and the gold layer of the metal electrode has a thickness ranging from 0.6 μm to 1.2 μm. Since each of the metal electrodes has a relatively large thickness, the insulation layer on a side wall of each of the metal electrodes might be less compact. As the conventional flip-chip light-emitting diode ages, gold ions in the gold layer of each of the metal electrodes may migrate along the regions that are less compact, which might easily cause failures of the flip-chip light-emitting diode. In addition, since the gold layer might include undissolved gold particles, gold explosions might occur more easily. As a result, due to the aforesaid drawbacks, the conventional flip-chip light-emitting diode with such low reliability no longer meets the industry standards of applications such as backlight and display screen. SUMMARY Therefore, an object of the disclosure is to provide a flip-chip light-emitting device that can alleviate at least one of the drawbacks of the prior art. According to the disclosure, the flip-chip light-emitting device includes a light-emitting unit, a first electrode, and a second electrode. The light-emitting unit includes a first type semiconductor layer, an active layer, and a second type semiconductor layer that are disposed on one another in such order. The first electrode is disposed on the light-emitting unit, and is electrically connected to the first type semiconductor layer. The second electrode is disposed on the light-emitting unit, and is electrically connected to the second type semiconductor layer. At least one of the first electrode or the second electrode is free of gold, and includes an aluminum layer and a platinum layer that is disposed on the aluminum layer opposite to the light-emitting unit. BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiment(s) with reference to the accompanying drawings, of which: FIG. 1 is a schematic sectional view illustrating an embodiment of a flip-chip light-emitting device according to the present disclosure; FIG. 2 is schematic sectional view illustrating a structure of an electrode of the embodiment; and FIG. 3 is schematic sectional view illustrating another structure of the electrode of the embodiment. DETAILED DESCRIPTION Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics. It should be noted that, the formation of a first component over or on a second component in the description below may include embodiments in which the first and second components are formed in direct contact, and may also include embodiments in which additional components may be formed between the first and second components, such that the first and second components may not be in direct contact. A flip-chip light-emitting device according to the present disclosure may be configured as a small-sized flip-chip light-emitting device, such as a flip-chip mini light-emitting diode and a flip-chip micro light-emitting diode. In the flip-chip mini light-emitting diode, the flip-chip light-emitting device includes a transparent substrate, and has a size of not greater than 90000 μm2 (i.e., the flip-chip light-emitting device having a length and a width each ranging from 50 μm to 300 μm, and a height ranging from 40 μm to 150 μm). In the flip-chip micro light-emitting diode, th