TWI254353B - Solid-state of micro-light-emitting-device array - Google Patents

Abstract

A solid-state of micro-light-emitting-device array comprises a substrate, and a plurality of light emitting chips set on the substrate apart from each other. Each of the light emitting chips has a plurality of light emitting protrusions set on the substrate apart from each other and respectively having a surrounding surface. Each of the light emitting chips is defined a plurality of channels crossing each other by the light emitting protrusions and the substrate. Each of the light chips further has an insulator covered the substrate and the surrounding surfaces, and a current spreading layer formed on the insulator and the light emitting protrusions, so as to sandwich the light emitting protrusions and the insulator between the current spreading layer and the substrate.

Description

1254353 IX. Description of the Invention: [Technical Field] The present invention relates to a solid state light emitting device, and more particularly to an array of solid state light emitting elements. [Prior Art] Referring to Figure 1, HW Choi and C. W. Jeon et al., IEEE PHOTONIC TECHNOLOGY LETTERS, VOL. 15, NO. 4, APRIL 2003, disclose a side-by-side arrangement of indium gallium nitride (InGaN) micro-emitting dipoles. The method of micro-LED arrays 1 and its performance. First, an epitaxial crystal 11 is formed on a sapphire substrate. The epitaxial crystal n has a GaN buffer film 111 having a thickness of 〇·025 μm and a ytterbium doped GaN (ie, Si-doped GaN) film 112 having a thickness of 3.2 μm. A micro-titanium well (mui ti-quantum wal 1, referred to as MQW) film 113' and a magnesium-doped GaN film 114 having a thickness of 0.25 μm. The epitaxial germanium is subjected to a dry etching process by inductively c〇upled plas (simplified % ICP) dry etching. The dry etching condition of the dry etching enamel is that an air gas (Cl2) having a flow rate of 3 Torr and an argon gas (Ar) of 10 SCCffl are respectively used as an etching gas source, and an etching degree at 25 ° C and 20 mT 〇 Under the working pressure of rr, a 4 〇〇w IPC power and a 200 watt reactive ion etch (RIE) power are respectively provided, and the speed of the 姓·5 is 4 The dry etching is performed, and the 1254353 formed body 11 covered with a mask is subjected to the dry etching process to form a plurality of spaced-apart light-emitting posts U. It is worth mentioning that 'the sapphire substrate 1G is formed with a plurality of spaced-apart crystals (ehip) 1 , wherein mt has the above-mentioned inter-phase iw-shaped light-emitting studs (i ' (only one crystal is shown in FIG. Description of the grain r.

Using electron-beam evaporation, the light-emitting studs 11 of each of the crystal grains are formed, and a 40 nm-thickness yttrium (Si〇2) film 12 is formed as an isolation (is〇latic). ))), and in each of the crystal grains 1' bare exposed local shi-doped GaN film 112 for electrode contact, in each of the - luminescence & column 11, the uppermost magnesium-doped GaN film 1U is not covered by the "Hee Oxide Second Film" 12. Further, a read 贞 13 is continuously formed on the oxidized oxide film η of each of the crystal grains i, wherein each of the conductive films 13 is formed by - on the oxygen cut film 12 and has a thickness of 3 () A recording layer of (5) metal layers and a gold (Au) metal layer formed on the nickel metal layer and having a thickness of 3 Å (four).

Finally, an n-contact electrode 4 and an H2 and a P-contact electrode 15 are respectively formed at each of the exposed germanium-doped GaN film-conducting films 13, thereby completing the parallel arrangement of indium gallium nitride. Micro-lighting diode array i. Wherein the 'per-n-type contact current 14 is a titanium (five) metal layer formed on the germanium-doped GaN film H2 and having a thickness of 20 nm, and an aluminum formed on the metal layer and having a thickness of 200 nm ( A1) is composed of a metal layer. Further, the structure of each P-contact electrode 15 is the same as that of the conductive film 13, except that the thickness of the metal layer is 2 Gnm' and the thickness of the gold metal layer is 200 nm. 〇” Although the external quantum effect of the nitrided gallium micro-light emitting diode array 1 of the parallel arrangement of 1,254,353 can be increased by the side portions of the light-emitting studs 11 ′, thereby avoiding the light source Problems such as absorption and attenuation caused by lateral transmission affect the external quantum efficiency of the LED as a whole. However, for the light-emitting diode, the excitation energy is high because the energy bandgap of the blue light is large, so The driving current value of the blue light emitting body is also relatively increased. When the length of the injection current (injecti〇n current) applied to the light-emitting diode is larger, the generated cumulative heat energy is generated. It also increased relatively. Therefore, the structure of the indium gallium nitride micro-light-emitting diode array 1 arranged in parallel is such that the thermal stress formed inside the element will follow the contact between the house crystal Π and the sapphire substrate 1 〇. The area is increased and the reliability of the entire component is reduced. It is known in the related art of the bonding technology of the chip bonding technology that the parallel arrangement of the indium gallium nitride micro-light emitting diode array 1 is A substrate with good heat dissipation can be provided by the wafer bonding technology, but the problem of unstable reliability due to the difference in thermal expansion coefficient (the ermal eXpansi〇n coefficient) is still exceeded. The gallium micro-light emitting diode array 1 is a horizontal feedthrough type solid-state light-emitting element. Once the single crystal chip 14 is damaged, the light-emitting studs 1 cannot be It emits light by itself, so the effective use rate of single crystal ruthenium is low. From the above, the external quantum efficiency of the solid-state light-emitting element is raised in consideration of 1,254,353 = the same day: 'the component also needs to be lowered @热应The problem that the overall component can meet the requirements of (4) and increase the effective use of the single-grain is a problem that must be overcome by the related fields in the development of solid-state light-emitting components. [Invention] Therefore, the object of the present invention That is, providing a solid-state micro-luminescence array' means, in particular, an external quantum efficiency is high, and the component thermal stress problem is small.

: A solid-state micro-emission device array that meets the reliability requirements and has a high effective use rate of a single die. The y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y Each of the illuminating dies defines a complex phase _ and a coarse day by the illuminating bumps and the substrate. a mother-emitting illuminating crystal - a ruthenium substrate and an insulating body surrounding the surface, and an electrical, 7-pack/guar fabric layer formed on the insulator and the illuminating bumps, thereby causing the illuminating bumps And the insulator is sandwiched between the current spreading layer and the substrate. [Embodiment] <Summary of Invention> * In general, the thermal stress formed inside two different materials can be pushed to two main reasons: one is that the difference in thermal expansion coefficient between two different materials is large, and the other is two different materials. The contact between the two is overpaid. When the difference in thermal expansion coefficient between two different materials is greater, then the thermal stress formed in the interior of the crease is also increased by the temperature applied by the tunneler. Furthermore, when the contact area between the two different materials is increased The bigger the time is. 8 1254353 = The problem that the 'Ml state light-emitting element has to solve for a long time is that the substrate is not easy to dissipate heat. Although the substrate heat-carrying substrate can be provided by the wafer bonding technology, the thermal expansion coefficient between the heat-transfer substrate and the stray crystal is greatly different due to the horizontal conductive design. The contact area is too large. Therefore, a large amount of thermal stress accumulated in the remote crystal will still affect the solid state light-emitting element due to cracking or separation of the substrate, and the present invention is bonded by using the wafer.

The substrate refers to the contact area between the steroids to reduce the influence of the accumulation of thermal energy generated by the stray crystal itself on the substrate, and thereby improve the solid-state luminescence. DETAILED DESCRIPTION OF THE INVENTION The foregoing and other objects, features, and advantages of the invention will be apparent from the Detailed Description Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals. Referring to FIG. 2 and FIG. 3, a first preferred embodiment of the solid-state micro-light-emitting device array of the present invention comprises: a substrate 2 and a plurality of light-emitting dies 3 disposed at intervals of the substrate 2 (FIG. 2 only A luminescent crystal is illustrated). Each of the illuminating crystal grains 3 has a plurality of illuminating bumps 31 which are disposed on the substrate 2 at intervals and have a surrounding surface 31 分别. Each of the light-emitting dies 3 and the light-emitting bumps 31 and the substrate 2 define a plurality of mutually interlaced channels 2, and the mother light-emitting die 3 further has an insulator 33 covering the substrate 2 and the surrounding faces 310, and a formation The insulator 33 and the light-emitting bumps 9 1254353 and the current spreading layer 34 on the insulator 31 cause the light-emitting bumps 31 33 to be sandwiched between the current spreading layer 34 and the substrate 2. Preferably, each of the light-emitting bumps 31 is one of a stud and a ring. In the specific embodiment, each of the light-emitting bumps 31 is a stud. Preferably, the substrate 2 has a plate body 21 and an electrically conductive bonding film 22 formed on the plate body 21 and sandwiched between the plate body 21 and the illuminating crystal grains 3.

The electrically conductive bonding film 22 suitable for use in the present invention has at least one metal layer selected from the group consisting of gold (Au), aluminum (A1), titanium (f) tin (Sn) platinum (Pt), Indium (In), silver (Ag), beryllium (Be) and alloys containing gold. In a specific embodiment, the electrical conductive bonding film 22 has an inscription layer, a titanium layer, and a gold layer (that is, the electrically conductive bonding film 22 has an Ai layer/Ti layer/Au layer). . The board body 21 suitable for use in the present invention is made of a material selected from the group consisting of copper (Cu), copper-containing alloy, copper-tungsten alloy, nickel (Ni). ), a nickel-containing alloy, a tungsten-molybdenum alloy, and doped (Si). In the first preferred embodiment, the board body 2 is made of copper, and each of the light-emitting crystals 3 has a plurality of contacts with the current spreading layer 34 and is respectively composed of a titanium layer and a platinum layer. a first contact electrode 35 composed of a gold layer (that is, a Ti layer, a seventh layer/Au layer), and the substrate 2 is further sandwiched between the electrically conductive bonding film 22 and the luminescent crystal grains 3 The reflective film 23 between. The reflective film 23 suitable for use in the present invention has at least one metal layer selected from the group consisting of platinum (pt), silver (Ag), titanium (Ti), gold (Au), and aluminum (A1). 10 1254353, indium (In) and palladium (Pd). In a specific embodiment, the reflective film 23 has a 'metal layer'. Preferably, each of the light-emitting bumps 31 of each of the light-emitting dies 3 has a first-type semiconductor layer 3H sandwiched between the substrate 2 and the current spreading layer 34, and is sandwiched between the first-type semiconductors. A light-emitting layer 312 between the layer 311 and the substrate 2, and a first-type semiconductor layer 313 sandwiched between the light-emitting layer 312 and the substrate 2. In a specific embodiment, the first type semiconductor layer 311 is an n-type semiconductor layer, and the second type semiconductor layer 313 is a -p type semi-conductor layer. Referring to FIG. 6, a second preferred embodiment of the solid-state micro-light-emitting device array of the present invention is substantially the same as the first preferred embodiment except that the plate body 21 is doped. The substrate 2 is further provided with a second contact electrode 24 contacting the plate body 21. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 2 and FIG. 3, in a specific embodiment of the solid-state micro-light-emitting element array of the present invention, the board body 21 is made of copper, and the electrically conductive bonding film 22 is formed. The structure is an A1 layer/Ti layer/Au layer, and the reflective film 23 is composed of a platinum layer. In addition, in the first embodiment, each of the light-emitting bumps 31 is a protrusion, and the first contact electrodes 35 are respectively formed by an outer layer of seven layers/Au layers, and the first type semiconductor layer 311 is An n-type semiconductor layer composed of n-GaN, the second type semiconductor layer 313 is a p-type semiconductor layer composed of jin, and the light-emitting layer 312 is connected to the first-type semiconductor layer (n-Gal) \i) 311 n-A1GaN film, one connected to the second type semiconductor layer (p-GaN) 313❸p-AlGalV film, and one is sandwiched between the n-11 1254353

A multilayer quantum well (multi_Quantum wa 11, inter-called MQW) between the AlGaN film and the ρ-MGaN film is formed (not shown), wherein the structure of the multilayer quantum well is (InGaN/GaN)n. A method of fabricating the first embodiment of the solid-state micro-light-emitting device array of the present invention will be briefly described below. Referring to Figure 4, a component fabrication flow chart of the first embodiment is shown. First, a temporary sapphire substrate 4 is provided, and a GaN buffer layer 310, an n-GaN layer 311, an luminescent layer 312, and a P-GaN layer 313 are sequentially formed on the sapphire substrate 4, Thereby forming a crystal 33. Further, the epitaxial crystal 31' is subjected to dry etching so that the epitaxial crystal 31 forms a plurality of studs 31 projecting from the GaN buffer layer 310'. Forming a ruthenium oxide layer 33 on the epitaxial crystal 31' by high density plasma chemical vapor deposition (HDPCVD), covering the protrusions 31, and subsequently, and The ruthenium oxide layer 33 is subjected to chemical mechanical polishing (CMP) until the p-GaN layer 313' is exposed, and the insulator 33 is defined thereby. Forming a platinum layer on the insulator 33 and the studs 31 to define the reflective film 23, and subsequently bonding a copper substrate to the reflective film by using a bonding film and through a wafer bonding technique. At 23, the electrically conductive bonding film 22 and the plate body 21 are defined and a preliminary layered structure 5 is completed. Referring to FIG. 5, the preliminary layer structure 5 completed as described above is reversed, and the sapphire substrate 4 is irradiated with a laser to decompose the buffer layer 310', so that the sapphire substrate 4 and the GaN buffer layer 31 are folded. , separated from each other. 12 1254353 CMP until each of the defined illuminating bumps is exposed, and the n-GaN layer 311 of the GaN buffer layer 310 is applied to the GaN buffer layer 310, and further, 3, and No bumps υ丄 成 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 35, explain it). Finally, the ray and the cutting method are used to define the luminescent crystal grains 3, and each 定义 is defined.

The current spreading layer 34 of the particle 3 and the first contact electrode are as follows (ie, as shown in FIG. 2: Ο / <Specific Embodiment 2> Referring to FIG. 6, a specific implementation of the solid-state micro-light-emitting element array of the present invention is substantially The same as the first embodiment, the difference is only that the board body 21 is made of a modified and low resistance (four). In the second embodiment, the above 11 doped dopants (dopant) It is a deletion (B) having a concentration of 1〇16~1〇18 cm2. Further, the second contact electrode 24 of the substrate 2 is made of silver (Ag). Referring to Fig. 7, the solid-state micro-light-emitting element of the present invention The reliability analysis of the intensity of the optical fluorescence spectroscopy (electr〇l_inescence spectrum; referred to as the rainbow spectrum) of the array shows 'at room temperature environment and the injection current value is 2-4. Under the test conditions, the test time lasts 1〇〇. After 〇 hours, the 乩 light detail is less than 20%. In addition, referring to Fig. 8, the reliability analysis of the forward voltage value of the solid-state micro illuminating element array of the present invention shows that the room temperature environment and the injection current value are Under the test condition of 20 mA, the turbidity test time lasts 13

After the solid-state micro-luminous element of the present invention is 1,254,353 hours, the forward voltage values are stably maintained between 3·2 v and 3 3 V. In the solid-state micro-light-emitting device array of the present invention, since each of the optical crystal grains 3 has the light-emitting bumps 31 and is spaced apart by the channels &amp; The contact area between the contacts is reduced to reduce the thermal stress accumulated by the difference in thermal expansion coefficient of the component during operation, and to increase the lateral external quantum efficiency of the component. Therefore, the thermal stress at the light-emitting bumps 3K, that is, the aforementioned insect crystals 31, is reduced, and the problem that the light-emitting crystal grains 31 are cracked or the substrate is separated can be reduced, thereby improving the solid state of the present invention. The reliability of the micro-illuminated device array increases the effective utilization of the single-grain and the external quantum efficiency. In summary, the solid-state micro-light-emitting device array of the present invention has the characteristics of high external quantum efficiency, less thermal stress of components, compliance with reliability requirements, and high effective material of a single crystal grain, and indeed achieves the object of the present invention. The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, that is, the simple application of the patent application and the description of the invention according to the present invention. Both effect changes and modifications are still within the scope of the invention patent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view schematically showing an indium gallium nitride micro-rabbit photodiode array arranged in parallel; FIG. 2 is a first preferred embodiment of a partial stereoscopic image array; FIG. FIG. 4 is a flow chart showing the fabrication process of the first half of the first preferred embodiment. FIG. Figure 4 is a front view showing the second half of the embodiment of the solid-state micro-illuminator column of the present invention; Figure 7 is a second embodiment of the solid-state micro-illuminator column of the present invention; Time curve

Reliability analysis of the EL pre-spectral intensity of the F Μ卞I level of the solid-light micro-light element array of the present invention; and

FIG. 8 is a reliability analysis of the forward voltage of a micro-light-emitting element array with a forward voltage versus an aging time curve.

15 1254353 [Description of main component symbols] 2 *...substrate 21......board body 22.........electrically conductive bonding film 2 3.........reflecting film 24*...different contact electrode 3 * *..... ... illuminating crystal 31... illuminating bump 31' stupid crystal 31" ... ... stud 310. ..... ... surrounding surface 310' ... GaN buffer layer 311 ... ... ... first type semiconductor layer 311 , η-GaN layer 312 &quot;••... luminescent layer 312'... luminescent layer 313...* second type semiconductor layer 313, ... p-GaN layer 32... channel 33 ··•...·♦ • Insulator 33'...··...Oxide layer 34........♦ Current spreading layer 34'........Transparent conductive layer 35'... contact electrode 35......... A contact electrode 4 ........... supervised stone substrate 5 - ... · ... preliminary layered structure

16

Claims (1)

1254353 X. Patent Application Range: 1. An array of solid-state micro-light-emitting elements, comprising: a substrate; and a plurality of light-emitting crystal grains spaced apart from each other on the substrate, each of the light-emitting crystal grains having a plurality of spaced-apart intervals and disposed on the substrate Each of the illuminating dies has a plurality of light-emitting bumps surrounding the surface, and each of the illuminating dies defines a plurality of interdigitated channels through the illuminating bumps, and each of the illuminating dies further has a covering surface of the substrate and the surrounding surfaces. An insulator and a current spreading layer formed on the insulator and the light-emitting bumps cause the light-emitting bumps and the insulator to be sandwiched between the current spreading layer and the substrate. 2. The solid-state micro-light-emitting device array according to the invention of claim 2, wherein the mother-emitting bump is one of a pillar and a ring. 3. The solid-state micro-light-emitting element array according to claim 2, wherein each of the light-emitting bumps is a stud. 4. The solid-state micro-light-emitting device array according to the above application, wherein the substrate has a plate body and is formed on the plate body and sandwiched between the plate body and the light-emitting dies In the case of the solid-state micro-light-emitting element array according to the fourth aspect of the patent application, the medium-conducting conductive bonding film has at least one selected from the group consisting of Group of metal layers: gold, Ming, titanium, tin, turn, indium, silver, wrinkle and alloys containing gold. 6. The solid-state micro-light-emitting element array according to claim 4, wherein the plate body is made of a material 17 1254353 selected from the group consisting of copper, a steel containing alloy, Copper-tungsten alloy, nickel, nickel-containing alloy, tungsten-molybdenum alloy and doped shixi. The solid-state micro-light-emitting element array according to claim 6, wherein the plate body is made of copper. The solid-state micro-light-emitting device array of claim 7, wherein each of the light-emitting crystal grains further has at least one first contact electrode in contact with the current spreading layer, the substrate further having a clip Conductively bonding the film and a reflective film between the luminescent crystal grains. 9. The solid-state micro-light-emitting element array according to claim 8, wherein the reflective film has at least a metal layer selected from the group consisting of platinum, silver, !, gold, aluminum, Indium and palladium. The solid-state micro-light-emitting element array according to item 6, wherein the raft body is made of doped yttrium. 11. The solid-state micro-light-emitting element array/in the illuminating crystal grain of the invention, wherein each of the illuminating dies further has at least one first contact electrode in contact with the current spreading layer, the substrate further having a clip a conductive film between the conductive film, the oral film, and the illuminating crystal grains, and a second contact electrode contacting the body of the plate. The solid-state micro-emitters according to claim 11 have at least one selected from the group consisting of platinum, silver, titanium, gold, aluminum, indium and palladium. 13·^ According to the scope of the invention, each of the solid-state micro-light-emitting element arrays/, the mother-emitting light-emitting die, has a first type sandwiched between the plate and the current spreading layer. a semiconductor layer, a central portion; 18 1254353 a light-emitting layer between the first-type semiconductor layer and the substrate, and a second-type semiconductor layer sandwiched between the light-emitting layer and the substrate. The solid-state micro-light-emitting device array according to claim 13, wherein the first-type semiconductor layer is an n-type semiconductor layer, and the second-type semiconductor layer is a germanium-type semiconductor layer. 19