TW437105B - Structure of vertical LED and its conductive circuit - Google Patents

Abstract

The present invention relates to the structure of vertical LED and its conductive circuit, especially to a blue light LED with a sapphire substrate, which is formed by etching at least one channel centered around the first electrode in a symmetric way on the sapphire substrate. A GaN thin film layer is formed with a similar thickness on the upper and lower layer of the substrate. Both layers of GaN material contact the inside of hollow channel, so that the conductive circuit of the LED can be formed naturally from the first electrode through the epitaxial layer, the buffered thin film layer, each channel in the substrate and the conductive layer, whereby a vertical LED with a sapphire substrate is formed. The absorption or blocking of the reflected light by the first electrode can be reduced since the path of the current conductive circuit is effectively guided. Therefore, the current density and the light-emitting efficiency in the effective light emitting region can be increased relatively.

Description

437U35 ^ Description of the invention (1) The present invention relates to an upright light-emitting diode and its conductive circuit 丨 structure 'especially a blue light-emitting diode with a basket gem (Sapph ire) as the substrate, and its main system The sapphire substrate is centered on the first electrode and at least one channel is etched in a symmetrical manner on the substrate, and a conductive material exists in the hollow channel, so that the conductive circuit of the light-emitting diode can be formed naturally. Effective planning and application 3 Light-Emitting Diode (LED; Light-Emitting Diode) has been in development since the 1960s, due to its long life, small size, low heat generation, low power consumption, fast response time, and The characteristics and advantages of unisex light emission, so in the past few decades, 'light-emitting diodes have been used in a variety of daily life: products and equipment, such as computer peripherals, clock displays, broadcast! Kanban, traffic Evidence of extensive use of light-emitting diodes can be found in signal lights, communications, or consumer electronics. The wide range of applications of this product has to be staggering. Especially when the blue light emitting diode is put on the market, the red, green, and blue colors have been developed and produced successively, so they can be combined into a complete basic structure of full color, which is not only more colorful. Transforming Ezli: Even if it is used to replace the traditional incandescent light source, it is also encouraging. Nowadays, the production of blue light-emitting diodes is mainly divided into silicon carbide (SiC) substrates or sapphire ( Sapphire) are the two main axes of the substrate. Please refer to FIG. 1A, which is a schematic cross-sectional view of a vertical light emitting diode structure conventionally used as a substrate of carbides. A doped with gallium, gallium, scale, and nitrogen is formed on the substrate 1 Q of carbides Wait for the buffer film layer 12 of the three or five groups to be sputtered or evaporated on the buffer film layer 12 to have a ρ-η interface.

4371 0 5 V. Description of the invention (2) Can emit blue light source silicon substrate 10 (series of substrates 10 of 10) and second electric light-emitting diode, and the above-mentioned implementation is made of transparent materials The emission caused by the emission does not help the whole | the body is the current in some limited 1 (M0VPE) process to emit light | some technologies are scattered in the United States 'LIGHT EMITTING with current blocking layer 丨 Although, carbon-based blue light emitting diode:' However, due to the inferiority of Carbide I or conductivity: the blue is still selected; please refer to the second diode structure profile I film (GaN) 2 2, the light emitting diode (LED ) The epitaxial layer 1 4 ′ is carbon as a conductive body, so only the first electrode (positive electrode (negative electrode) 18) is required to be separately plated on the surface of the epitaxial layer 14 and the carbon portion. The current conducting line is shown as a dashed line. In the example, since most of the first electrode 16 is not, the light of the current line under the first electrode 16 will be absorbed or blocked by the first electrode 16 , And the current of brightness increases, so 'some The organometallic vapor phase epitaxy is reused more than once on the photodiode layer. A current blocking layer 1 4 5 is also provided to increase the effective density and luminous efficiency, as shown in Figure 1B, and this country's patent No. 5, 1 53, 88 No. 9 "SEMICONDUCTOR DEVICE" or China Patent Bulletin No. 264573 "Light-Emitting Diode". Silicon-based substrate light-emitting diodes can be designed to be always three-dimensional, in order to meet the design goals of thin and light photovoltaic products. Light-emitting diodes are far better in brightness, contrast, and other electrical properties than sapphire-based luminescent diodes. Therefore, future development and high-brightness blue-emitting light-emitting diodes | gemstones are the mainstream. Figure 'Series is customary Sapphire is the blue light emission of the substrate. Figure; a thin gallium nitride I is formed on the sapphire substrate 20 and then sputtered or vapor-deposited on the thin gallium nitride layer 22 43 71 0 5 As amended on February 9 / Correct / Supplement V. Description of the invention (3) The light-emitting diode (LED) worm crystal layer 2 4 which has a P-η interface and can emit a blue light source. Since the sapphire substrate 20 is an insulator, it can only Select on top of LED worm crystal layer 2 4 Then, the first electrode C (front electrode) 2 and the second electrode (negative electrode) 2 8 which are in the same plane are individually plated, and can only be planar light-emitting diodes. The current conducting circuit is shown as a dotted line 200. . After that, it can be cut into diamonds of actual size by diamond cutting or laser cutting. Photodiodes also have problems and shortcomings that they have used to use sapphire as the substrate: (1) Due to the conductive properties of the sapphire substrate 20, the light-emitting diodes are on the same plane, so it is difficult to reduce the volume of the active surface. It is relatively impossible to have a mark; the body is an insulator material, without the body's positive and negative electrodes 2 6, 2 8 must be plated so that it cannot be made large enough to make its light-emitting diodes achieve the light and short design goals of the product (2) The sapphire substrate 20 itself is a great helmet ^ ^ ^ 4 is an insulator material, which is likely to cause static electricity in the production of%. Relative to tt # ή ^ j, it is easy to cause the unproductive rate of product production. (3) Because of the sapphire substrate GaN film layer 22 on 2 〇 \ 〇? Η? * Η υυ (thick skin A hi annealing temperature will easily cause its action f = H11) in the "π A 丞 pole uneven stress, sapphire substrate The rupture of 10, only increase the weight of the hair on Cheng Θ, so its A degree H1 must not be less than 2 80 microns (々m) 丨 Dantai plate thickness is generally in mass production, the substrate is centimeter H] Yushi SA _ double and degree H 1 since roughly 咼 3 0 0 micro, and Η 1 1 Then it is about 3 ~ 4 microns, so 1H 1 η ^ ^ ^ ^ ^ Α ^ ^ ', the thickness ratio of H1 and H11 is about 1 00: 1' So the thickness of the substrate is being cut 丨 乂, a μ & e j_ The knife will encounter a huge

Page 6

V. Description of the invention (4) d37! 05 Difficult; (4) In order to facilitate the feasibility of subsequent diamond cutting or laser cutting, after the production of the light emitting diode is completed, it is necessary to grind its sapphire with a high hardness material such as diamond The substrate 10 is about 200 microns or more, which not only causes an increase in cost, but also increases the trouble in the process; and the trouble in the process; and C 5) its current conducting circuit cannot be effectively planned, so its emission brightness will be the first The influence of the electrode is very large, and it is impossible to make the most effective arrangement of its brightness area. Therefore, 'how to propose a novel solution to the above problems, not only allows the sapphire-based light-emitting diode to have an upright state and reduce its planar area and product volume, but also can appropriately plan its The current flow circuit effectively improves the current density and luminous efficiency of its effective light-emitting area, and can accurately and facilitate the production process when cutting into crystal grains. It has been a user-like hope for a long time. Based on many years of experience in research, development, and sales of semiconductor device-related products, the inventor is thinking about and improving, and lacks his personal professional knowledge. After researching and designing in various ways, he has finally developed a special topic. An upright light-emitting diode and its conductive circuit structure are used to solve the above problems. Tritium is the main object of the present invention. In its conductive circuit structure, the current can only pass through the conductive flow circuit due to its stone substrate to effectively improve the light efficiency. In order to provide an upright light-emitting diode, the channel can pass through the sapphire with a very high hardness, and its channel ’so that the current can be appropriately planned |

^ 3 7] 05 V. Description of the invention (5) The secondary purpose of the present invention is to provide a vertical light-emitting diode and its conductive circuit structure 'no need to use complicated organic metal vapor phase epitaxy (MOVPE) process to set up A current blocking layer can effectively plan its current to flow in the effective light emitting area. : Another object of the present invention is to provide an upright light-emitting diode; and its conductive circuit structure, a plurality of channels are etched on the substrate, and a convenient process can be performed when cutting the wafer into a single die. The effect of implementation. Another object of the present invention is to provide an upright light-emitting diode. Its conductive circuit structure is provided with at least ~ channels on a sapphire substrate. The current between the two positive and negative electrodes under the I-Liquid passes through the pipeline, so Become—straight !, a geo-diode crystal grain, in order to reduce its active area and simplify its follow-up ’, Junga This is another aspect of the present invention.

丨 Mutual cancellation ”Therefore, it can not only prevent the resources of the blue substrate from being used. Stress phase

--- * Deduct %% to praise, also save and relatively simplify the process of polishing the substrate after the event. Hidden _ S 1 cn Ai ,, anti-blue source will _ use the sign and the β reached a further detailed explanation, said that in order to make the review committee to further understand and understand the structure of the present invention, I would like to add A better detailed description is as follows: I would like to refer to the preferred embodiment diagram and

In order to further enhance the effectiveness of the review, we have shared our own abilities. "W 4371 05 Five 'invention description (6) ~~ --- cross-sectional view of the process step structure and top view of part of the process structure; as shown in the figure, The main manufacturing steps include: ”Step 1: Select a sapphire substrate 30 (Sapphire) 'with a thickness of 100 μm or less and use chemical etching or mask printing to open at least one through substrate 30. And has a slope or straight channel! 31, as shown in Figure 3A. The arrangement of the channels 31 running through the sapphire substrate 30 is centered on a first electrode (as described later), and corresponding channels 3 1 are provided around it in a symmetrical manner, as shown in FIG. 4A; j Step 2: A buffer film layer 3 2 2, such as a gallium nitride film layer, is formed on the top layer of the sapphire substrate 30 by an epitaxial method such as an organic metal vapor phase crystal method (MOVPE). Part of the material of the thin film 3 2 2 exists in the space of the channel 31, as shown in FIG. 3B and FIG. 4B; | Step 3: Use the epitaxial method such as epitaxy or sputtering on the bottom layer of the sapphire substrate 30 to A conductive layer 3 2 6 is formed, which may be made of a non-metallic conductive material, and the conductive layer 3 2 6 material also exists in a part of the space of the channel 3 1 | and previously exists in the channel 3 The gallium nitride film | | 322 materials in 1 are in contact with each other. Since the gallium nitride film 322 itself is conductive | I electrical material, such contact will naturally form a complete current conducting path I | Shown in Figure C; i Step 4: Sputtering or vapor deposition on the top layer of the GaN thin film layer 3 2 2 to form a The LED epitaxial layer 3 i 4 that has a pn interface and can emit a blue light source, of course, it can also be an np interface, as shown by the scratch mark, as shown in Figure 3D; and 丨 1 Step 5: separately in the LED Top layer of crystal layer 34 and bottom of conductive layer 326 1

Page 9 A371 0 5 V. Description of the invention (7) A corresponding first electrode 36 and a second electrode 38 are plated, so that a vertical light-emitting diode chip can be formed, and its conductive circuit 300 can be sequentially passed from the first electrode 36 to the LED epitaxial layer 34, the gallium nitride thin I film layer 322, the channel 31 in each substrate, the conductive layer 326, and finally to the second electrode 38. Form a complete conductive line, as shown in Figure 3 E i. I Please refer to Figures 3E, 4C, and 5 again, which are the cross-sectional view, the top view, and the three-dimensional view of a single die when the invention is completed. The invention is based on the first electrode 36 as the center point, and a plurality of channels 31 passing through the sapphire! Stone substrate 30 are etched in the substrate 30 opposite to the surroundings. Therefore, the current conducting circuit 300 can follow the channel 3 The position of 1 is effectively planned to flow. Of course, it can be selected to cause the current flow to escape from the position below the first electrode 36, and increase its current density in the other effective light-emitting areas of the II and relatively increase its Luminous brightness, but these effects can be achieved without using a current blocking layer. In addition 1, the neatly designed channel 31 position can also be used as a single wafer to be cut into a single i; 1

I grain is effective, because in addition to the neat cutting line, the channel is easy to cut for the sapphire substrate is the main reason β i. Also, because the conductive material filled in the channel 31 is mainly used as conductive I For the purpose of i, in the above-mentioned preferred embodiment, the upper and lower layers of the gallium nitride 丨 material and the non-metal conductive material are contacted, but as long as the memory of the channel 31 丨 i has a conductive material (not shown) And the conductive material can be determined to be in good contact with the nitride gallium film layer 322 and the conductive layer 326. i

Finally, please refer to FIG. 6. Τ is a structure I i of another embodiment of the present invention.

Page 10 437? 05 leap year) March 3rd, supplementary supplementary 5, description of the invention (8) cross-sectional schematic diagram; as shown in this embodiment, in combination with the technology disclosed in Figure 3, the conductive layer 3 The non-metallic conductive material of 26 can also use the same material as the GaN thin film layer 3 2 2 and the thickness (H3, H4) of the upper and lower layers are similar or exactly the same, which can not only offset the gallium nitride. The stress generated during the annealing and cooling of the thin film layers 3 2 2 and 3 2 4 to maintain the sapphire substrate 30 is not damaged, and the use thickness of the sapphire substrate 30 can be greatly reduced, which is more convenient even in material management. Of course, the first electrode 36 located on the LED worm crystal layer 34 can also be made of a transparent material to form a transparent electrode in order to improve the luminous brightness. In addition, since the conductive layer 3 2 6 or the gallium nitride thin film layer 3 2 4 itself is made of a conductive material, the second electrode 38 can also be replaced by the conductive layer 3 2 6 or the gallium nitride thin film layer 3 2 4 Not established. In summary, it is known that the present invention relates to an upright light emitting diode and its conductive circuit structure, especially a blue light emitting diode with sapphire as the substrate, which is mainly based on the sapphire substrate. The first electrode is centered and at least one channel is etched in a symmetrical manner, and there is a conductive material in the hollow channel, so that the conductive circuit of the light emitting diode can be naturally formed into a vertical blue light emitting diode, not only Can effectively plan the current flowing conductive circuit, and increase the current density and luminous efficiency of its effective area. Therefore, the present invention is truly novel, progressive and available for industrial use. It should meet the patent application requirements stipulated by the Chinese Patent Law. No doubt, the invention patent application was submitted in accordance with the law. For prayer. However, the above is only one preferred embodiment of the present invention, and

Page 11 4 ^ ^ / 1 0 5 Included 2 Q. 5 '4-3 T ^ 0 5 V. Description of the invention (9) It is not used to limit the scope of the invention, for example, it can be used in the LED epitaxial layer and Add some impurity layers between gallium nitride thin film layers, such as indium aluminum gallium phosphide layer, or add other layers such as SiC, A1N, Si02, InGaN, Sn02, A 1 I nGaP, etc. on the other thin film layers. The equal changes and modifications of the shape, structure, features and spirit described in the patent scope shall all be included in the scope of patent application of the present invention. Brief description of drawing number • 1 0 SiC substrate 1 4 LED crystal layer 1 8 second electrode 2 0 sapphire substrate 2 4 LED epitaxial layer 2 8 second electrode 3 0 sapphire substrate 3 2 2 GaN thin film layer 3 2 6 conductive layer 3 6 First electrode 3 0 0 Current flow line ο ο 5 2 6 0 2 6 0 1 4 8 4 1 — 1x 1 ± oo QU 0〇τt Buffer film layer first electrode Current flow line GaN thin film layer first electrode Current flow line channel LED epitaxial layer Second electrode current blocking layer

D371 0 5 on page 12 Brief description of the drawing Figure 1 A: A sectional view of the structure of a conventional vertical light-emitting diode; Figure 1 B: A sectional view of the structure of a conventional vertical light-emitting diode including a current blocking layer; Fig. 2 is a cross-sectional view of the structure of a blue light-emitting diode used as a sapphire substrate. Figs. 3A to 3E are cross-sectional views of the production steps of a light-emitting diode with a sapphire as a substrate according to the present invention. Figure: Top view of a single wafer structured as shown in Figure 3A; Figure 4B: Top view of a single wafer structured as shown in Figure 3B; Figure 4C: shown in Figure 3E Top view of a structured single wafer; FIG. 5 is a schematic perspective view of a single crystal of a vertical light emitting diode of the present invention; and FIG. 6 is a cross-sectional view of a structure of another embodiment of the present invention.

Page 13

Claims (1)

4371 05 VI. Scope of patent application 1 · An upright light-emitting diode, the main structure of which includes: a substrate, the substrate is etched with at least one channel that can pass through the substrate, and there is at least one channel in the hollow channel. A conductive material; a buffer film layer formed on the top layer of the substrate; a light-emitting diode epitaxial layer with a P-η interface, grown on the buffer film layer, and on a part of the surface of the remote crystal layer A first electrode is formed; and a conductive layer is formed on the bottom layer of the substrate, so that the current-conducting circuit of the light-emitting diode is formed naturally, and can be sequentially passed from the first electrode through the insect crystal layer, the buffer film, and the substrate. Each channel ends in the conductive layer. 2 * The light-emitting diode described in item 1 of the scope of the patent application, wherein the base I.i plate is centered on the first electrode and at least one channel is provided in a symmetrical manner around the first electrode. 3 · The light-emitting diode according to item 1 of the scope of patent application, wherein the conductive material in the base I-plate channel is made of the same material as the buffer film layer and the conductive layer | .丨 4 _ The light-emitting diode according to item 1 of the patent application scope, wherein the substrate is a sapphire substrate. I 5 · The light emitting diode as described in item 4 of the scope of patent application, wherein the buffer film layer is a gallium nitride film layer made of a gallium nitride material 6 · The light-emitting diode according to item 1, wherein the conductive layer is made of a non-metallic conductive material. Page 14 43/1 〇5. Patent application scope 7 · The light-emitting diode described in item 5 of the patent application scope, wherein the conductive layer is a gallium nitride thin film layer made of a gallium nitride material By. 8 · The light-emitting diode described in item 7 of the scope of the patent application, wherein the upper and lower gallium nitride thin film layers have the same thickness. 9 · The light-emitting diode according to item 1 of the scope of patent application, wherein the thickness of the buffer film layer and the conductive layer are similar. 10 · The light-emitting diode according to item 1 of the scope of patent application, wherein the first electrode is made of a transparent conductive material. 1 1 · The light-emitting diode according to item 1 of the scope of the patent application, wherein a portion of the surface of the conductive layer that is not connected to the substrate may also be provided with a second electrode, so that its conductive circuit can be sequentially from the first electrode Via the epitaxial layer, the buffer film layer, the channel in each substrate, the conductive layer, and finally the second electrode. Page 15