TWI474513B - Light emitting diode - Google Patents

Description

Light-emitting diode

The present invention relates to a light emitting diode.

With the advancement of technology, LEDs and their related applications have become more widely used, and they have become a new type of light source in the 21st century by virtue of their advantages of high efficiency, long life, and difficulty in damage. Improve the convenience of everyday life.

In the current process of light-emitting diodes, a dry etching machine is used to remove a portion of the surface of the P-type layer to expose the underlying N-type layer, and then a pad is formed on the P- and N-type layers, thereby electrically Connected to an external voltage source so that the current can conduct and illuminate.

Please refer to FIG. 1A and FIG. 1B simultaneously. FIG. 1A is a top view of a light-emitting diode in the prior art, and FIG. 1B is a view showing the light-emitting diode of FIG. 1A along the line 1-1′. Sectional view. As shown, the LED 100 includes a substrate 110, an N-type layer 120, a P-type layer 130, an N-type pad 140, and a P-type pad 150. The N-type layer 120 is on the substrate 110, and the P-type layer 130 is on the N-type layer 120. The N-type pad 140 and the P-type pad 150 are respectively disposed above the N-type layer 120 and the P-type layer 130 for performing a wire bonding process and electrically connecting to an external voltage source.

However, the above-mentioned prior art techniques often limit the PN junctions in contact with the P-type layer and the N-type layer in a small-scale process, so that the effective light-emitting area appears to be relatively insufficient, and under the influence of the light-shielding effect, it cannot provide an effective effect. brightness.

In view of the above, what is needed is a light-emitting diode that can increase the effective light-emitting area to improve the overall brightness, thereby improving the process yield and cost, and thus more appropriately integrating the light source of the current specification, which is increasingly reduced. Multimedia and display electronics.

Therefore, an object of the present invention is to provide a light-emitting diode for arranging an N-type pad and a P-type pad over a P-type layer, thereby increasing an effective light-emitting area, thereby reducing manufacturing cost and improving overall Luminous brightness.

One aspect of the present invention provides a light emitting diode comprising at least a substrate, an N-type layer, a P-type layer, an N-type pad, a P-type pad, and an insulating layer. The N-type layer is on the substrate and the P-type layer is on the N-type layer. The N-type pad includes a first portion and a second portion, wherein the first portion is on the N-type layer, the second portion is interconnected with the first portion, and the second portion extends above the P-type layer. The P-type pad is located on the P-type layer. The insulating layer is located between the N-type pad and the P-type layer.

In order to make the description of the present invention more complete and complete, reference is made to the accompanying drawings and the accompanying drawings. On the other hand, well-known elements and steps are not described in the embodiments to avoid unnecessarily limiting the invention.

Please refer to FIG. 2A and FIG. 2B simultaneously. FIG. 2A is a top view of a light-emitting diode according to an embodiment of the present invention, and FIG. 2B is a second light-emitting diode of FIG. 2A along line 2-2'. Sectional view of the line. As shown, the LED 200 includes at least a substrate 210, an N-type layer 220, a P-type layer 230, an N-type pad 240, a P-type pad 250, and an insulating layer 260. The N-type layer 220 is on the substrate 210, and the P-type layer 230 is on the N-type layer 220. The N-type pad 240 includes a first portion 242 and a second portion 244, wherein the first portion 242 is on the N-type layer 220, the second portion 244 is interconnected with the first portion 242, and the second portion 244 is extended to P. Above the layer 230. The P-type pad 250 is located on the P-type layer 230. The insulating layer 260 is between the N-type pad 240 and the P-type layer 230.

In one embodiment of the present invention, the area of the second portion 244 of the N-type pad 240 is relatively larger than the area of the first portion 242 of the N-type pad 240. In another embodiment of the present invention, the N-type pad 240 It has an L shape in appearance.

However, by the arrangement formed by the insulating layer 260, the N-type metal pad 240 can be effectively guided over the P-type layer 230, thereby expanding and increasing the area of the N-type layer 220 and the P-type layer 230 on the substrate 210. Therefore, the area of the PN junction at the junction of the N-type layer 220 and the P-type layer 230 is greatly increased, thereby increasing the voltage applied to the positive and negative terminals of the LED diode 200, generating a current and causing more electrons. Combined with the hole to increase the amount of light.

Furthermore, the insulating layer 260 includes a first segment 262 and a second segment 264. The first segment 262 is formed between the first portion 242 of the N-type pad 240 and the P-shaped layer 230. The second segment 264 is coupled to the first segment 262 and is formed between the second portion 244 of the N-type pad 240 and the P-shaped layer 230. In an embodiment of the invention, the second section 264 of the insulating layer 260 has an area that is relatively larger than the area of the first section 262 of the insulating layer 260. Moreover, in another embodiment of the present invention, the insulating layer 260 exhibits an L-shape in appearance.

On the other hand, in an embodiment of the invention, the insulating layer 260 is made of a transparent material of ceria, titanium dioxide or aluminum oxide. This can not only electrically isolate the N-type pad 240 and the P-type layer 230, thereby avoiding malfunction, causing damage to the LED 201, and also enabling the PN junction to be turned on by the material having light transmissivity. The light generated thereafter is respectively emitted through the first segment 262 of the insulating layer 260 and a second segment 264, thereby increasing the overall luminance of the light.

In another embodiment of the present invention, the insulating layer 260 is made of a multilayer film reflective layer or a composite material having a transparent layer and a metal reflective layer, which is caused by a multi-layer coating technique and an optical interference principle. With a higher reflectance, the light generated by the PN junction can be led out from the side of the LED 200, which improves the overall luminance. In addition, the metal material used in the composite material may be aluminum or silver.

In addition, in an embodiment of the invention, the N-type pad and the P-type pad are made of a metal material, which has better conductivity for connection to an external voltage source. Moreover, in another embodiment of the present invention, the area of the second portion 244 of the N-type pad 240 is relatively larger than the area of the first portion 242 of the N-type pad 240, providing a sufficient area to facilitate wire bonding.

In this way, the overall design of the light-emitting diode 200 can be effectively improved by the structural design of the present invention, and the effect is most remarkable. For example, in the fabrication of 150×240 ( um ² ) small-sized blue LED dies, it is generally required to make a 90 ( um ) diameter wiring region on the P-type layer and the N-type layer. The dry etching machine must be used to remove the P-type layer portion of the surface to expose the underlying N-type layer, and then make solder pads on the P and N-type layers respectively to provide sufficient area for wire bonding, such as Figure 1A and Figure 1B show. This tends to limit the area of the effective illuminating area of the small-sized blue LED to have an area of only about 23,000 ( um ² ) of effective illuminating area, often resulting in an inability to provide effective brightness. However, with the above-mentioned design structure of the light-emitting diode of the present invention, not only the PN junction can be effectively increased, but the area of the effective light-emitting area is increased by 20% to 29,000 ( um ² ), and at the same time, the side light can be improved. Output. Therefore, compared with the previous general production method, the overall brightness of the light-emitting diode in the small-size process can be improved, and thus can be integrated into the light source or display product which is now downsized.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100. . . Light-emitting diode

110. . . Substrate

120. . . N-type layer

130. . . P-type layer

140. . . N type pad

150. . . P type pad

200. . . Light-emitting diode

210. . . Substrate

220. . . N-type layer

230. . . P-type layer

240. . . N type pad

242. . . First

244. . . Second part

250. . . P type pad

260. . . Insulation

262. . . First paragraph

264. . . Second paragraph

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

FIG. 1A is a top view showing a light-emitting diode of the prior art.

Fig. 1B is a cross-sectional view showing the light-emitting diode of Fig. 1A taken along line 1-1'.

2A is a top view of a light emitting diode in accordance with an embodiment of the present invention.

Fig. 2B is a cross-sectional view of the light-emitting diode of Fig. 2A taken along line 2-2'.

200. . . Light-emitting diode

210. . . Substrate

220. . . N-type layer

230. . . P-type layer

240. . . N type pad

242. . . First

244. . . Second part

250. . . P type pad

260. . . Insulation

262. . . First paragraph

264. . . Second paragraph

Claims (9)

A light-emitting diode comprising at least: a substrate; an N-type layer on the substrate; a P-type layer on the N-type layer; and an N-type pad comprising: a first portion located at the N And a second portion interconnected with the first portion, and the second portion extends above the P-type layer, the second portion of the N-type pad is relatively larger than the N-type pad The area of the first portion; a P-type pad on the P-type layer; and an insulating layer between the N-type pad and the P-type layer. The light-emitting diode of claim 1, wherein the N-type pad has an L-shaped appearance. The light-emitting diode of claim 1, wherein the insulating layer comprises: a first segment formed between the first portion of the N-type pad and the P-shaped layer; and a second a segment connecting the first segment and formed between the second portion of the N-type pad and the P-shaped layer. The light-emitting diode according to claim 3, wherein The area of the second segment of the insulating layer is relatively larger than the area of the first segment of the insulating layer. The light-emitting diode of claim 3, wherein the insulating layer has an L-shaped appearance. The light-emitting diode according to claim 1, wherein the insulating layer is made of a transparent material of cerium oxide, titanium dioxide or aluminum oxide. The light-emitting diode according to claim 1, wherein the insulating layer is made of a multilayer film reflective layer. The light-emitting diode according to claim 1, wherein the insulating layer is made of a composite material having a transparent layer and a metal reflective layer. The light-emitting diode according to claim 1, wherein the N-type pad and the P-type pad are made of a metal material.