TWI657596B - Manufacturing method of light-emitting device - Google Patents

Abstract

A light emitting device includes: a light emitting layer comprising a first surface; a patterned dielectric layer formed on the first surface of the light emitting layer, comprising a first portion and a second portion substantially surrounding the first portion and The first portion has the same thickness; a first reflective electrode covers the first portion of the patterned dielectric layer; and a barrier layer covers the first reflective electrode and the second portion of the patterned dielectric layer.

Description

Method of manufacturing light emitting device

The present invention relates to a light-emitting device, and more particularly to a light-emitting device in which a light-emitting laminate is placed on a conductive substrate.

The principle of light emission of a light-emitting diode (LED) is due to electrons moving between an n-type semiconductor and a p-type semiconductor to release energy. Since the principle of illumination of a light-emitting diode is different from that of an incandescent lamp that heats a filament, the light-emitting diode is also referred to as a cold light source. Furthermore, the LED has better environmental tolerance, longer life, lighter and more portable, and lower power consumption making it an alternative to light sources in lighting applications. Light-emitting diodes have been used in various fields such as traffic signs, backlight modules, street lights, and medical equipment, and have gradually replaced traditional light sources.

The light emitting diode has a light emitting layer that is epitaxially grown on a conductive substrate or an insulating substrate. A light-emitting diode having a conductive substrate can form an electrode on top of the light-emitting layer, which is generally referred to as a vertical light-emitting diode. A light-emitting diode having an insulating substrate is required to expose two semiconductor layers of different polarities by an etching process, and to form electrodes on the two semiconductor layers, which are generally referred to as horizontal light-emitting diodes. The advantages of the vertical light-emitting diode are that the light-shielding area of the electrode is small, the heat-dissipating effect is good, and there is no additional etching and epitaxial process, but the conductive substrate used for growing epitaxial crystal has the problem of easily absorbing light, thus affecting the light-emitting diode. The luminous efficiency of the body. The advantage of the horizontal light-emitting diode is the insulating substrate Usually, it is also a transparent substrate, and light can be emitted from all directions of the light-emitting diode. However, there are disadvantages such as poor heat dissipation, a large amount of light-shielding area of the electrode, and loss of light-emitting area by the epitaxial etching process.

The above-described light emitting diodes may be further connected to other elements to form a light emitting device. The light emitting diode may be connected to the primary carrier by the side having the substrate, or formed between the secondary carrier and the light emitting diode by solder or glue to form a light emitting device. In addition, the secondary carrier may further include a circuit electrically connected to the electrode of the light emitting diode through a conductive structure such as a metal wire.

A light emitting device includes: a light emitting layer comprising a first surface; a patterned dielectric layer formed on the first surface of the light emitting layer, comprising a first portion and a second portion substantially surrounding the first portion and The first portion has the same thickness; a first reflective electrode covers the first portion of the patterned dielectric layer; and a barrier layer covers the first reflective electrode and the second portion of the patterned dielectric layer.

100, 200, 300‧‧‧ illuminating devices

102, 202, 302‧‧‧Lighting laminate

202a, 202a, 302a‧‧‧ first surface

102b, 202b, 302b‧‧‧ second surface

104, 204, 304‧‧‧ first semiconductor layer

106, 206, 306‧‧ ‧ luminescent layer

108, 208, 308‧‧‧ second semiconductor layer

110, 210, 310‧‧‧ patterned dielectric layer

110a, 210a, 310a‧‧‧ first part

110b, 210b, 310b‧‧‧ Part II

112, 212, 312‧‧‧ first reflective electrode

114, 214, 314‧‧ ‧ protective layer

214a, 314a‧‧‧ first protective layer

214b, 314b‧‧‧ second protective layer

116, 216, 316‧‧‧ second electrode structure

316a‧‧‧electrode pad

316b‧‧‧Extended branch electrode

118, 218, 318‧‧‧ first barrier layer

120, 220, 320‧‧‧ second barrier layer

122, 222, 322‧ ‧ barrier layer

124, 224, 324‧‧‧ connection layer

126, 226, 326‧‧‧ permanent substrate

Fig. 1 is a view showing a first embodiment of a light-emitting device of the present invention.

Fig. 2 is a view showing a second embodiment of the light-emitting device of the present invention.

3A and 3B show a third embodiment of the light-emitting device of the present invention.

Referring to Fig. 1, there is shown a first embodiment of a light-emitting device of the present invention. The illuminating device 100 includes: a permanent substrate 126; a light emitting layer 102 is formed on the permanent substrate 126 and includes a first surface 102a facing the permanent substrate 126 and a second surface 102b opposite to the first surface 102a; a patterned dielectric The layer 110 is formed on the first surface 102a, and includes a first portion 110a and a second portion 110b substantially surrounding the first portion 110a. The first portion 110a includes a first thickness, and the second portion 110b includes a second thickness equal to a first thickness; a reflective first reflective electrode 112 covering the first portion 110a of the patterned dielectric layer 110, wherein the material of the first reflective electrode 112 may comprise silver (Ag), aluminum (Al) or other with high reflection a metal or a laminate or alloy of the foregoing metal; and a barrier layer 122 covering the first reflective electrode and the second portion 110a of the patterned dielectric layer 110. The second surface 102b of the light emitting layer 102 may include a second electrode structure 116 having a pattern corresponding to the first portion 110a of the patterned dielectric layer 110. The first reflective electrode 112 is ohmically contacted with the first surface 102a of the light emitting stack 102, the second electrode structure 116 is ohmically contacted with the second surface 102b of the light emitting stack 102, and the second electrode structure 116 and the first reflection are in a vertical direction. The regions where the electrodes 112 contact the light emitting stack 102 do not overlap each other. One of the barrier layers 122 may have a slightly wider cross-sectional width than the light-emitting layer 102. The outer edge of the second portion 110b of the patterned dielectric layer 110 may be substantially aligned with the sidewall of the barrier layer 122 and laterally protrude from the light-emitting layer. Side wall of 102. A protective layer 114 can cover the area of the second surface 102b of the light emitting layer 102 without the second electrode structure 116 in conformity with the shape of the light emitting layer 102, and cover the sidewall of the light emitting layer 102, and the lower end of the protective layer 114 is patterned. The second portion 110b of the dielectric layer 110 is connected. The material of the patterned dielectric layer 110 may comprise an insulating oxide, a nitride, a germanium oxide, titanium oxide, aluminum oxide, magnesium fluoride or tantalum nitride. The material of the protective layer 114 may comprise tantalum nitride or hafnium oxide. The material of the patterned dielectric layer 110 can be different than the material of the protective layer 114. In this embodiment, the material of the patterned dielectric layer 110 may be titanium dioxide (TiO ₂ ), and the material of the protective layer 114 may be cerium oxide (SiO ₂ ) or tantalum nitride (SiN _x or Si ₃ N ₄ ). If the second portion 110b of the dielectric layer 110 is not patterned, the barrier layer 122 is directly followed by the lower surface of the protective layer 114 and a portion of the first surface 102a. However, the material of the barrier layer 122 is usually metal, and the protective layer 114. The intervening force is not good, so that a gap may be formed between the lower end of the protective layer 114 and the barrier layer 122. At this time, moisture or other external disturbance may further affect the barrier by the gap between the protective layer 114 and the barrier layer 122. Following the layer 122 and the first surface 102a, once the barrier layer 122 is detached from the first surface 102a, the first reflective electrode 112 may overflow from the sidewall of the light emitting laminate 102, increasing the risk of electrical abnormality or failure of the light emitting device 100. In the present embodiment, the first reflective electrode 112 also covers a portion of the second portion 110b of the patterned dielectric layer 110 such that the barrier layer 122 does not contact the first surface 102a.

The light-emitting layer 102 is epitaxially grown from a wafer-level growth substrate (not shown), and then the patterned dielectric layer 110, the first reflective electrode 112, and the barrier layer 122 are sequentially formed on the first surface 102a. Thereafter, the first portion 110a and the second portion 110b of the patterned dielectric layer 110 are simultaneously completed under the same process, and thus have the same thickness and material. The permanent substrate 126 can be followed by the light emitting layer 102 by a bonding layer 124. The barrier layer 122 can be interposed between the connecting layer 124 and the first reflective electrode 112, and the connecting layer 124 can be interposed between the barrier layer 122 and Between the permanent substrates 126. After the permanent substrate 126 is followed by the light emitting layer 102, the grown substrate can be removed to expose the second surface 102b, and the second surface 102b can be further roughened by, for example, dry etching. The plurality of light-emitting devices 100 can then be obtained by etching the light-emitting stack 102 to form trenches to form a plurality of cells insulated from each other, and then cutting the wafers along the trenches. The outer side of the second portion 110b may also be thinned by being cut together during the process of cutting the wafer, and the section of the second portion 110b in contact with the first surface 102a may substantially maintain the aforementioned second thickness.

The light emitting layer stack 102 can include a first semiconductor layer 104, a second semiconductor layer 108, and a light emitting layer 102 formed between the first semiconductor layer 104 and the second semiconductor layer 108, wherein the first semiconductor layer 104 can be p-type and There is a first surface 102a, and the second semiconductor layer 108 can be n-type and have a second surface 102b. The barrier layer 122 may include a two-layer structure of a first barrier layer 118 and a second barrier layer 120, and the material of the barrier layer 122 may include, for example, titanium (Ti), tungsten (W), and platinum (Pt). , titanium tungsten alloy (TiW) or a combination thereof. The structure of the light-emitting layer stack 102 may include a single heterostructure (SH), a double heterostructure (DH), a double-side double heterostructure (DDH), Or multiple quantum well structures (MQW). The light emitting layer stack 102 can be a nitride light emitting layer, and the material can be selected from the group consisting of aluminum (Al), indium (In), gallium (Ga), and nitrogen (N), and the growth substrate can be a transparent insulating layer. The substrate is, for example, a sapphire substrate, or a conductive substrate such as a bismuth (Si) or tantalum carbide (SiC) substrate. The material of the light-emitting layer 102 may also be selected from the group consisting of aluminum (Al), gallium (Ga), indium (In), phosphorus (P), and arsenic (As), and the growth substrate may be gallium arsenide ( GaAs).

Referring to Figure 2, there is shown a second embodiment of a light-emitting device of the present invention. The light-emitting device 200 includes: a permanent substrate 226; a light-emitting layer 202 is formed on the permanent substrate 226 and includes a first surface 202a facing the permanent substrate 226 and a second surface 202b opposite to the first surface 202a; a patterned dielectric The layer 210 is formed on the first surface 202a, and includes a first portion 210a and a second portion 210b substantially surrounding the first portion 210a. The first portion 210a includes a first thickness, and the second portion 210b includes a second thickness equal to a first thickness, and the first portion 210a is the same as the second portion 210b; a reflective first reflective electrode 212 covers the first portion 210a of the patterned dielectric layer 210, wherein the material of the first reflective electrode 212 may comprise silver (Ag), aluminum (Al), other highly reflective metal or a laminate or alloy of the foregoing metals; and a barrier layer 222 covering the first reflective electrode and the second portion 210b of the patterned dielectric layer 210. The second surface 202b of the light-emitting layer 202 may include a second electrode structure 216 having a pattern corresponding to the first portion 210a of the patterned dielectric layer 210. The second electrode structure 216 and the first reflective electrode 212 in a vertical direction. The areas in contact with the light-emitting stack 202 do not overlap each other. One of the barrier layers 222 may have a slightly wider cross-sectional width than the light-emitting layer 202. The outer edge of the second portion 210b of the patterned dielectric layer 210 may be substantially aligned with the sidewall of the barrier layer 222 and laterally protrude from the light-emitting layer. Side wall of 202. A protective layer 214 may cover the area of the second surface 202b of the light emitting layer 202 without the second electrode structure 216 in conformity with the shape of the light emitting layer 202, and cover the sidewall of the light emitting layer 202, and the lower end of the protective layer 214 is patterned. The second portion 210b of the dielectric layer 210 is connected. The material of the patterned dielectric layer 210 may comprise an insulating oxide, nitride, hafnium oxide, titanium oxide, aluminum oxide, magnesium fluoride or tantalum nitride. The protective layer 214 may have a first protective layer 214a followed by the second portion 210b of the patterned dielectric layer 210 and at least covering the sidewalls of the light emitting layer 202, and a second protective layer 214b covering the first protective layer 214a and covering the first layer Two surfaces 202b. The first protective layer 214a includes tantalum nitride (Si ₃ N ₄ or SiN _x ), and the second protective layer 214b contains hafnium oxide (SiO ₂ ). In this embodiment, the first reflective electrode 212 is spaced apart from the second portion 210b of the patterned dielectric layer 210 by an interval. The barrier layer 222 can include a first barrier layer 218 and a second barrier layer 220. A connection layer 224 may be formed between the barrier layer 222 and the permanent substrate 226.

Referring to Figures 3A and 3B, a third embodiment of a light-emitting device of the present invention is shown. The illuminating device 300 includes: a permanent substrate 326; a light emitting layer 302 is formed on the permanent substrate 326 and includes a first surface 302a facing the permanent substrate 326 and a second surface 302b opposite to the first surface 302a; a patterned dielectric The layer 310 is formed on the first surface 302a, and includes a first portion 310a and a second portion 310b substantially surrounding the first portion 310a. The first portion 310a has a first thickness, and the second portion 310b has a second thickness equal to The first portion 310a is the same as the material of the second portion 310b; a reflective first reflective electrode 312 covers the first portion 310a of the patterned dielectric layer 310, wherein the material of the first reflective electrode 312 is A silver (Ag), aluminum (Al) or other metal having high reflectivity is included; and a barrier layer 322 covers the first reflective electrode and the second portion 310a of the patterned dielectric layer 310. The second surface 302b of the light emitting layer 302 may include a second electrode structure 316 having a pattern corresponding to the first portion 310a and the second portion 310b of the patterned dielectric layer 310. One of the barrier layers 322 may have a section width slightly wider than the light emitting layer 302. The outer edge of the second portion 310b of the patterned dielectric layer 310 may be substantially aligned with the sidewall of the barrier layer 322 and laterally protrude from the light emitting layer. Side wall of 302. A protective layer 314 may cover the area of the second surface 302b of the light emitting layer 302 that does not have the second electrode structure 316 in conformity with the shape of the light emitting layer 302, and cover the sidewall of the light emitting layer 302, and the lower end of the protective layer 314 is patterned. The second portion 310b of the dielectric layer 310 is connected. The material of the patterned dielectric layer 310 may comprise an insulating oxide, a nitride, a hafnium oxide, a titanium oxide compound or tantalum nitride. The protective layer 314 can have a first protective layer 314a followed by the second portion 310b of the patterned dielectric layer 310 and at least covering the sidewalls of the light emitting layer 302, and a second protective layer 314b covering the first protective layer 310a and the second Surface 302b. The first protective layer 314a includes a tantalum nitride (Si ₃ N ₄ or SiN _x ), and the second protective layer 314b contains an antimony compound such as hafnium oxide (SiO ₂ ). In this embodiment, the first reflective electrode 312 and the second portion 310b of the patterned dielectric layer 310 are spaced apart by a space. The barrier layer 322 can include a first barrier layer 318 and a second barrier layer 320. A connection layer 324 may be formed between the barrier layer 322 and the permanent substrate 326.

As shown in FIG. 3B, the second electrode structure 316 can include at least one electrode pad 316a and one of the extended strip electrodes 316b connected to the electrode pad 316a. The second portion 310b of the patterned dielectric layer 310 is from the top view. The electrode pad 316a and the extended branch electrode 316b are overlapped. The second portion 310b of the patterned dielectric layer 310 may include an outer boundary of the surrounding light emitting layer, and the width of the portion of the second portion 310b overlapping the extended branch electrode 316b is greater than the extended dendritic electrode 316b, and The section in which the two portions 310b overlap the electrode pads 316a corresponds to the pattern of the electrode pads 316a.

Although the invention has been described above, it is not intended to limit the scope of the invention, the order of implementation, or the materials and process methods used. Various modifications and variations of the present invention are possible without departing from the spirit and scope of the invention.

Claims (10)

A method of manufacturing a light-emitting device, comprising: providing a growth substrate; epitaxially growing a light-emitting layer on the growth substrate, the light-emitting layer stack comprising a first surface and a second surface; forming a patterned dielectric layer On the first surface of the light emitting layer, the patterned dielectric layer comprises a first portion and a second portion, and the second portion substantially surrounds the first portion; forming a silver (Ag) or a first reflective electrode of aluminum (Al) on the first surface of the light emitting stack; a barrier layer is formed to cover the first reflective electrode and the patterned dielectric layer, wherein the barrier layer does not contact the first layer a surface; a permanent substrate on the first surface of the light emitting stack; removing the growth substrate to expose the second surface of the light emitting layer; etching the light emitting layer to form a trench, and forming a plurality a unit insulated from each other; forming a protective layer on the light emitting laminate; and cutting along the trench to form the light emitting device, wherein one of the outer sides of the second portion is thinned during the cutting process. The method of manufacturing a light-emitting device according to claim 1, wherein the barrier layer comprises titanium (Ti), tungsten (W), platinum (Pt), titanium tungsten alloy (TiW), or a combination thereof. A method for manufacturing a light-emitting device, comprising: providing a growth substrate; epitaxially growing a light-emitting layer on the growth substrate, the light-emitting layer comprising a first surface and a second surface; Forming a patterned dielectric layer on the first surface of the light emitting stack, the patterned dielectric layer includes a first portion and a second portion, and the second portion substantially surrounds the first portion; Forming a first reflective electrode comprising silver (Ag) or aluminum (Al) on the first surface of the light emitting stack; wherein the first reflective electrode directly contacts the first portion of the patterned dielectric layer, and The first reflective electrode is spaced apart from the second portion of the patterned dielectric layer; a barrier layer is formed to cover the first reflective electrode and the patterned dielectric layer; and then a permanent substrate is disposed on the light-emitting stack a first surface of the layer; removing the growth substrate to expose the second surface of the light-emitting layer; etching the light-emitting layer to form a trench, and forming a plurality of cells insulated from each other; forming a protective layer thereon And illuminating along the trench to form the illuminating device, wherein one of the outer sides of the second portion is thinned during the cutting process. The method of manufacturing a light-emitting device according to claim 1 or 3, further comprising etching the second surface to form a roughened surface, and the protective layer conforms to the roughened surface. The method for manufacturing a light-emitting device according to claim 4, wherein the protective layer comprises a first protective layer directly covering one side of the light-emitting device and a second protective layer covering the first protective layer, wherein the first protective layer A protective layer is tantalum nitride and the second protective layer is tantalum oxide. The method of manufacturing a light-emitting device according to claim 5, wherein the second protective layer directly covers the second surface. The method for manufacturing a light-emitting device according to claim 6, further comprising Forming an electrode structure on the second surface of the light emitting stack, the electrode structure comprising an electrode pad and a plurality of extended dendritic electrodes, wherein the light emitting layer comprises a portion located from a view of the light emitting device One of the electrode structures is outside and surrounding the electrode structure; wherein the patterned dielectric layer comprises a pattern to correspond to a pattern of one of the electrode structures. The method of manufacturing a light-emitting device according to claim 4, wherein the material of the patterned dielectric layer is different from the material of the protective layer. The method of manufacturing a light-emitting device according to claim 8, wherein the patterned dielectric layer is titanium dioxide. The method of manufacturing a light-emitting device according to claim 7, wherein the protective layer forms all of the second surface except a region of the electrode structure, and the first reflective electrode covers the first portion and the second portion section.