TWI608633B - Light emitting diode device and method for manufacturing the same - Google Patents

Description

Light-emitting diode device and method of manufacturing same

The invention relates to a light-emitting diode device, in particular to a light-emitting diode device with easy process and improved heat dissipation, and a manufacturing method thereof.

In recent years, the application of the light-emitting diode device has become more and more widespread. In recent years, the LED filament lamp of the LED lamp with the transparent substrate can be illuminated on both sides. Because of its elegant appearance, it is very popular among consumers, and many manufacturers have invested in it. Production of LED filament lamps.

However, although the number of LED filament lamps continues to grow, there is still a considerable gap compared to the number of conventional tungsten filament lamps shipped. The main reason why LED filament lamps are not universal is that LED filament lamps have high requirements for packaging, are complicated in process technology, have low production yield, and are therefore expensive. Nowadays, LED filament lamps are mostly grown into LED units before the large substrate, and then the LED units are thinned and cut into individual LED dies, and then a plurality of individual LED dies are adhered or soldered to one carrier. Finally, the individual independent LED die wires on the carrier board are connected in series. Such a multi-step process, because at each step will result in a loss of yield reduction, so the yield is not high. For example, in the step of cutting into LED dies, the yield reduction is very obvious. In addition to the yield loss at the time of other steps, the improvement in production yield becomes an important issue in the manufacture of LED filament lamps.

Furthermore, the technical problem of cooling the LED filament lamp also needs to be overcome, especially when the large wattage LED filament lamp operates, a large amount of heat is generated, so how to effectively dissipate heat and improve the electro-optic efficiency, and also become an improvement of the LED filament lamp. important topic. In addition, some consumers believe that the problem of insufficient illumination and low light efficiency of LED filament lamps needs to be improved. As a result, the price and performance of LED filament lamps are still far from the market expectation, which has become an obstacle to the expansion of LED filament lamps.

However, LED lamps consume less power and have a longer lamp life, making them an efficient source of light. In order to achieve the goal of energy saving and energy saving, many manufacturers and research teams have invested in attempts to improve the process or structure. It is expected to improve the illumination of LED filament lamps, enhance heat dissipation and reduce costs, and then develop an existing LED. New lamps for the development of filament lamps.

The main object of the present invention is to provide a light-emitting diode device which is excellent in heat dissipation and has improved electro-optical conversion efficiency.

Another object of the present invention is to provide a method of manufacturing a light-emitting diode which has improved yield and simple steps.

In order to achieve the above object, the present invention particularly forms a plurality of epitaxial cells on a substrate, each epitaxial cell including an n-type semiconductor cell, a light-emitting layer, a p-type semiconductor cell, and a transparent electrode layer, and in the epitaxial The unit forms a plurality of pairs of Bragg mirror pairs, so that the pairs of Bragg mirror pairs cover the epitaxial units, and the reflected light is transmitted to enhance the light intensity. In other words, the illuminating diode device of the present invention has improved illuminance compared to conventional techniques in which more wafers are used simultaneously to achieve a sufficient amount of light output. In addition, the light-emitting diode device of the present invention has a structure in which the first metal layer and the second metal layer are provided, and has no disadvantage of poor heat dissipation, and has excellent heat dissipation properties.

Specifically, the LED device of the present invention comprises: a substrate; a plurality of epitaxial cells on a surface of the substrate; a first metal layer, the first metal layer is located on a part of the surface of the epitaxial cell Connecting the epitaxial unit to another adjacent epitaxial unit; n pairs of Bragg mirror pairs, covering the epitaxial cells and a portion of the surface of the first metal layer, wherein n is a greater than 6 And a second metal layer disposed on the surface of the pair of Bragg mirrors, and the second metal layer is connected to the first metal layer not covered by the Bragg mirror pair; wherein each epitaxial layer The unit includes: an n-type semiconductor unit on a surface of the substrate; an illuminating layer on the n-type semiconductor unit; a p-type semiconductor unit on the n-type semiconductor unit, and the luminescent layer is interposed on the substrate Between the p-type semiconductor unit and the n-type semiconductor unit, a portion of the n-type semiconductor unit is exposed and not covered by the p-type semiconductor unit; and a transparent electrode layer is located on the surface of the p-type semiconductor unit.

In the light-emitting diode device of the present invention, the sidewall of the p-type semiconductor unit and the sidewall of the light-emitting layer more selectively include an insulating layer. The material which can be used as the insulating layer is not particularly limited, and any of the insulating layer materials used in the light-emitting diode device can be used. For example, a nitride such as tantalum nitride; an oxide such as cerium oxide or aluminum oxide; or an oxynitride or the like may also be used. A person having ordinary skill in the art may select an appropriate material to form an insulating layer, and is not particularly limited to the above materials.

In an exemplary embodiment of the present invention, an epitaxial cell may be formed using any material used in the prior art to form an epitaxial cell. For example, the n-type semiconductor cell may be an n-type gallium nitride, the p The semiconductor unit is a p-type gallium nitride, the light-emitting layer is a plurality of layers of germanium-doped gallium indium nitride epitaxial (In _x Ga _y N/GaN multiple quantum well), and the transparent electrode layer can be ITO (oxidized) Indium Tin Oxide). In addition, other conventional auxiliary functional layers may be added in order to enhance the adhesion between the layers and the layers, or to provide other auxiliary or additional functions to the epitaxial unit. For example, a gallium nitride or aluminum nitride buffer layer may be further included between the substrate and the epitaxial unit to provide a better bond between the subsequently formed epitaxial unit and the substrate. However, the present invention There are no special restrictions.

The first metal layer and the second metal layer may be formed of any suitable metal material, for example, gold, silver, copper, titanium, aluminum, chromium, nickel, platinum, rhodium, magnesium, calcium, strontium or any of the above plural a combination of metallic materials. In the present invention, the first metal layer is connected to two adjacent epitaxial cells through the anode (or transparent electrode) connecting the epitaxial cells and the cathode of the other epitaxial cell.

In an exemplary embodiment of the invention, the second metal layer may be patterned to have a gap separating the second metal layer into at least two separate electrodes. The area covered by the second metal layer of the present invention is not limited, and preferably covers most of the substrate or n pairs of Bragg mirror pairs to improve light leakage, increase light recovery efficiency, and improve heat dissipation efficiency.

In the above n pairs of Bragg mirror pairs, wherein the Bragg mirror pair is formed by repeatedly stacking two different refractive index materials, and the thickness of the two different refractive index materials may be the same or different. In the present invention, the refractive index of the optical film of the Bragg mirror may be between 1.3 and 2.8, preferably between 1.45 and 2.3, more preferably between 1.3 and 2.8. Two different refractive index materials, which may be a combination of antimony pentoxide/aluminum oxide, a combination of antimony pentoxide/niobium nitride, a combination of antimony pentoxide/antimony oxide, titanium dioxide/cerium dioxide, titanium dioxide A combination of /aluminum trioxide, a combination of titanium oxide / cerium oxide, and a combination of titanium dioxide / cerium nitride, in a preferred embodiment of the invention, a pair of Bragg mirrors of a combination of titanium dioxide / ceria is used. The thickness of the two different refractive index materials of the Bragg mirror pair may be between 450 Å and 675 Å, and more preferably between 460 Å and 690 Å. For example, it can be a Bragg mirror pair consisting of 460Å titanium dioxide and 690Å cerium oxide, 450Å titanium dioxide and 675Å cerium oxide, or 400Å titanium dioxide and 770Å two. A Bragg mirror pair composed of cerium oxide, but the invention is not limited thereto.

The reflectance of the Bragg mirror pair varies with the number of layers of the material and the refractive index difference between the materials. In the present invention, the logarithm (n) of the Bragg mirror pair is preferably 6 pairs or more (n>6), Preferably, it is 20 or more; as for the refractive index difference between the materials, it is preferably in the range of 1.3 to 2.8, but the present invention is not limited thereto.

In an exemplary embodiment of the present invention, the substrate may be any translucent semiconductor material, or may be a sapphire substrate, a gallium nitride substrate, an aluminum nitride substrate, or preferably a sapphire substrate. The invention is not limited thereto, and those skilled in the art can select them according to requirements. The shape and size of the substrate used in the present invention are not limited and may be any conventional shape. It may preferably be rectangular, circular, polygonal, elliptical, semi-circular, or irregular.

In addition, the present invention also provides a method for fabricating a light emitting diode device, comprising the steps of: (a) forming a plurality of independent epitaxial cells on a substrate, and each epitaxial cell comprises: an n-type a semiconductor unit is disposed on a surface of the substrate; at least one light emitting layer is disposed on the n-type semiconductor unit; a p-type semiconductor unit is disposed on the n-type semiconductor unit, and the light emitting layer is interposed on the p-type semiconductor unit Between the n-type semiconductor unit, a portion of the n-type semiconductor unit is exposed and not covered by the p-type semiconductor unit; and a transparent electrode layer is disposed on a surface of the p-type semiconductor unit; (b) Forming a first metal layer on the surface of the crystal unit such that the first metal layer covers a portion of the epitaxial unit surface to join the epitaxial unit and another adjacent epitaxial unit; (c) forming an n-pair Bragg mirror pair Having the Bragg mirror pairs enclose the epitaxial cells and a portion of the first metal layer, wherein n is an integer greater than 6; and (d) forming a second surface on one of the Bragg mirror pairs Metal layer, and the first Connected without a metal layer on the Bragg mirror covered of the first metal layer.

In the above manufacturing method, before the step (a), a buffer layer, such as an aluminum nitride buffer layer, may be selectively formed on the substrate to further improve the subsequent formation of the epitaxial unit and the substrate. Good combination.

In order to prevent the current from being short-circuited via the sidewall to the n-type layer or the metal electrode, in the step (a), an insulating layer is further formed on the sidewall of the p-type semiconductor unit and the sidewall of the light-emitting layer; further, the step (a) The n-type semiconductor unit described in the above may be an n-type gallium nitride, and the p-type semiconductor unit may be a p-type gallium nitride.

In addition, in the manufacturing method of the present invention, after the step (d), a step (e) is further included, and the second metal layer is patterned such that the second metal layer has a gap and is divided into at least two independent electrodes.

10‧‧‧Lighting diode device

110‧‧‧First metal layer

120‧‧‧ epitaxial unit

130‧‧‧Substrate

140‧‧‧Braph mirror pair

150‧‧‧Second metal layer

1 is a schematic structural view of a light emitting diode device according to an exemplary embodiment of the present invention.

2 is a top plan view showing the structure of a light emitting diode device according to an exemplary embodiment of the present invention.

The embodiments of the present invention are described in the following by means of specific embodiments, and those skilled in the art can readily understand the advantages and other effects of the present invention from the disclosure. The present invention may be embodied or applied in various other specific embodiments, and various modifications and changes may be made without departing from the spirit and scope of the invention.

Example 1

1 is a schematic structural view of a light emitting diode device 10 according to an exemplary embodiment of the present invention. The light emitting diode device 10 includes a first metal layer 110, an epitaxial unit 120, a substrate 130, a Bragg mirror pair 140, and a second metal layer 150.

More specifically, in the first embodiment, on the surface of one of the sapphire substrates 130, the gallium nitride intrinsic epitaxy is sequentially formed by the organometallic vapor deposition method under the operating conditions of 750 to 1200 ° C and 1 atm. The gallium nitride, the light-emitting layer, and the p-type gallium nitride; the epitaxial material is then fabricated into a device having a PN polarity by a semiconductor process such as a yellow light, a lithography, or an etching process. Then, a tantalum nitride insulating layer (not shown) is formed on the sidewalls of the p-type gallium nitride and the sidewalls of the light-emitting layer by chemical vapor deposition to prevent short-circuiting of current through the sidewalls via the n-type layer or the metal electrode.

Next, under vacuum conditions, the first metal layer 110 is formed of gold/nickel on the surface of the epitaxial cells 120 by electron beam evaporation, so that the first metal layer covers a portion of the epitaxial cell surface, so that The epitaxial cells and the adjacent epitaxial cells 120 can be connected in series with each other.

After the epitaxial cells are formed, a Bragg mirror pair 140 is formed on the surfaces of the epitaxial cells 120 and the first metal layer 110 by electron beam evaporation under vacuum conditions. The Bragg mirror pair 140 is composed of 460 Å TiO ₂ and 690 Å SiO ₂ , and has a total of 20 layers (pairs), and covers the epitaxial units 120 and a portion of the first metal layer 110, and the portion thereof A metal layer 110 is not covered by the Bragg reflector 140 (refer to FIG. 1).

Fig. 2 is a plan view showing the structure of a light-emitting diode device according to a first embodiment of the present invention. As can be clearly seen from FIG. 2, the first metal layer 110 is connected in series with the adjacent epitaxial cells 120 in a staggered manner. In other words, if viewed from above the light-emitting diode device, the first metal layer is located in the epitaxial layer. One side of one side of the unit connects the first epitaxial unit to the adjacent second epitaxial unit, and the other side opposite the opposite side causes the second epitaxial unit to be adjacent to the other Three epitaxial units are connected, and so on.

Finally, under vacuum conditions, a second metal layer 150 is formed on one surface of the Bragg mirror pair 140 by electron beam evaporation, and the second metal layer 150 is not covered by the pair of Bragg mirrors 140. The first metal layer 110 is connected. And further patterning the second metal layer 150 such that the second metal 150 layer has a gap and is divided into at least two independent electrodes.

Under the operating conditions of 80V and 15mA of the integrating sphere, the light intensity of the light-emitting diode device obtained by actual measurement is 750 to 850 mW, and the electro-optic conversion efficiency is about 60%, which proves that the light-emitting diode device of the present invention is excellent. Performance.

10‧‧‧Lighting diode device

110‧‧‧First metal layer

120‧‧‧ epitaxial unit

130‧‧‧Substrate

140‧‧‧Braph mirror pair

150‧‧‧Second metal layer

Claims (14)

A light emitting diode device comprising: a substrate; a plurality of epitaxial cells on a surface of the substrate, each epitaxial unit comprising: an n-type semiconductor unit on a surface of the substrate; at least one light emitting layer, Located on the n-type semiconductor unit; a p-type semiconductor unit is disposed on the n-type semiconductor unit, and the light-emitting layer is interposed between the p-type semiconductor unit and the n-type semiconductor unit, and part of the n-type semiconductor The unit is exposed and not covered by the p-type semiconductor unit; and a transparent electrode layer is located on the surface of the p-type semiconductor unit; a first metal layer, the first metal layer is located on a part of the surface of the epitaxial unit to be connected The epitaxial unit and another adjacent epitaxial unit; n pairs of Bragg mirror pairs, the epitaxial unit and a part of the surface of the first metal layer, wherein n is an integer greater than 6; And a second metal layer is disposed on the surface of the pair of Bragg mirrors, and the second metal layer is connected to the first metal layer not covered by the Bragg mirror pair, and the second metal layer is patterned And There is a gap, so that the second metal layer is divided into at least two of the electrodes independently. The illuminating diode device of claim 1, further comprising an insulating layer disposed on a sidewall of the p-type semiconductor unit and a sidewall of the luminescent layer. The light emitting diode device of claim 1, further comprising a buffer layer located on the substrate and the epitaxial unit. The light-emitting diode device according to claim 1, wherein the n-type semiconductor unit is an n-type gallium nitride, and the p-type semiconductor unit is a p-type gallium nitride. The light-emitting diode device of claim 1, wherein n is an integer greater than 6. The light-emitting diode device according to claim 1, wherein the optical film layer of the Bragg mirror has a refractive index of between 1.3 and 2.8. The light-emitting diode device according to claim 1, wherein the substrate is a sapphire substrate. A method for fabricating a light-emitting diode device includes the steps of: (a) forming a plurality of independent epitaxial cells on a substrate, and each epitaxial cell comprises: an n-type semiconductor cell disposed on the substrate a surface; at least one light emitting layer is disposed on the n-type semiconductor unit; a p-type semiconductor unit is disposed on the n-type semiconductor unit, and the light emitting layer is interposed between the p-type semiconductor unit and the n-type semiconductor unit a portion of the n-type semiconductor unit is exposed and not covered by the p-type semiconductor unit; and a transparent electrode layer is disposed on the surface of the p-type semiconductor unit; (b) forming a first surface on the surface of the epitaxial unit a metal layer such that the first metal layer covers a portion of the epitaxial cell surface to join the epitaxial cell to another adjacent epitaxial cell; (c) forming an n-pair Bragg mirror pair, such Bragg mirrors And coating a portion of the epitaxial unit and a portion of the first metal layer, wherein n is an integer greater than 6; (d) forming a second metal layer on one surface of the Bragg mirror pair, and the second metal Layer connection without the Bra Mirror pairs of the first layer is covered with the metal; and (e) patterning the second metal layer such that the second metal layer has a gap of the partition into at least two separate electrodes. The manufacturing method of claim 8, further comprising forming a buffer layer on the substrate before the step (a). The manufacturing method according to claim 8, wherein in the step (a), the insulating layer is formed on the sidewall of the p-type semiconductor unit and the sidewall of the light-emitting layer. The manufacturing method according to claim 8, wherein in the step (a), the n-type semiconductor unit is an n-type gallium nitride, and the p-type semiconductor unit is a p-type gallium nitride. The method of claim 8, wherein in the step (c), n is an integer greater than 6. The method of claim 8, wherein in the step (c), the refractive index of the optical film of the Bragg mirror pair is between 1.3 and 2.8. The method of claim 8, wherein the substrate is a sapphire substrate.