TW200913314A - White light emitting device and method for making same - Google Patents

Abstract

The present invention generally provides a white light emitting device and a method for making same. The white light emitting device includes a light emitting diode (LED) chip, a phosphor layer and a reflecting layer. The LED chip includes a substrate and a light emitting structure formed thereon. The light emitting structure includes a first-type semiconductor layer, an active layer and a second-type semiconductor layer arranged on the substrate in that order. The substrate has at least a cavity formed therein for partially exposing the first-type semiconductor layer. The LED chip has a plurality of sidewalls. The phosphor layer is formed in the at least a through hole and configured for wavelength conversion so as to produce a white light. The reflecting layer is formed on the sidewalls of the LED chip to surround the LED chip. The white light emitting device would produce a white light with an improved color uniformity via the use of the reflecting layer and the position configuration of the phosphor layer.

Description

200913314 .. IX. Description of the Invention: [Technical Field] The present invention relates to the field of semiconductor light-emitting, and more particularly to a white light-emitting device and a method of fabricating the same. [Prior Art] A white light emitting diode (Wh i te LED) is widely used as a white light emitting device because of its low power consumption, long life, small size, and high brightness. LCD display backlights, automotive light sources and general illumination sources, see Atsushi 〇kun〇 et al. 2003 IEEE Electronic Components and Technology

"uniqUe fhite LED Packaging Systems" published at the conference. As shown in FIG. 6, a typical white light emitting diode 6A includes a pedestal 62, a light emitting diode wafer 64, and a transparent package 66 doped with a phosphor. The LED wafer 64 is hermetically sealed by the pedestal 62 and the transparent package (10). Since the side surface of the light-emitting diode chip 64 and the front side (ie, the upper surface) have light emission, the light emitted from the side surface is different from the light intensity of the light emitted from the front side and penetrates the transparent package 66 of the doped phosphor material. The difference in optical path length is large, which will cause the white light color generated by the conversion of the fluorescent substance to be uneven, resulting in limited application of the white light emitting diode. SUMMARY OF THE INVENTION Hereinafter, a white color uniform color and a method of fabricating the same will be described by way of examples. Nine is equipped with a white light emitting device, which comprises: a light emitting diode chip, a camp 200913314 200913314 light material layer and a reflective layer. Luminescence - the light-emitting structure on the substrate, the external light I consists of - the substrate and the - and the --type semi-conducting =:: including: the first-type semiconductor layer, the second layer of the semiconductor layer And an active layer between the first-type semiconductor layer and the first-type abundance layer, the direction of the second layer: the semiconductor layer and the second-type semiconductor layer are separated from the substrate by the semiconductor sound, and at least one groove is formed on the surface To expose at least a portion of the substrate of the portion-type == body wafer, the side surface is light. A reflective layer is formed on a plurality of sides of the light emitting diode chip to surround the light emitting diode wafer. (10) _ shirt, (4) (4): (4) providing a substrate, a film comprising a substrate and a substrate formed on the substrate = 'I optical structure including - the first type semiconductor - =: = opposite type of the second type semiconductor layer and - an active layer between the two acoustic layers - a type semiconductor: a / θ and a second type of semiconductor layer arranged in a direction away from the substrate, a bamboo shooter = a polar body wafer having a plurality of sides; (8) a light emitting diode chip Base

Hi forming at least a recess to expose a portion of the first type semiconductor layer; (": forming a phosphor layer in the recess; and (4) forming a reflection on the plurality of sides of the dipole of the light emitting diode Compared with the prior art, the white light emitting device forms a reflective layer by a plurality of sides of the light emitting diode and a phosphor layer is disposed in at least a groove of the base of the light emitting chip; The light leakage phenomenon "17 system, on the other hand, the light emitted by the LED chip is concentrated 200913314. The optical path of the upper surface is emitted so that its light passage through the phosphor layer can be substantially the same 'so that the white light emitting device can be made The embodiment of the present invention will be further described in detail with reference to the accompanying drawings. FIG. 1 to FIG. 3 is a white light emitting device 100' provided by the embodiment of the present invention. The invention comprises a light emitting diode chip 12, a phosphor layer 140 and a reflective layer 160. The light emitting diode chip 120 comprises a substrate 122, an n-type semiconductor layer 124, and an n-type half. The bulk layer 124 has a p-type half V body layer 126 of opposite conductivity type and an active layer 125 between the n-type semiconductor layer 124 and the p-type semiconductor layer 126. The n-type semiconductor layer 124, the active layer 125 and the p-type semiconductor layer 126 A light-emitting structure is generally formed. The light-emitting body 120 has a plurality of side faces 127. The n-type semiconductor layer 124, the active layer 125, and the p-type semiconductor layer are disposed on the substrate 122 and arranged in a direction away from the substrate 122. The n-type semiconductor layer 124, the active layer 125, and the p-type semiconductor layer 126 may each be made of a nitride semiconductor material such as a binary, ternary or quaternary nitride semiconductor material. The active layer 125 is typically a multi-quantum well structure ( 1^丨衍?16

Quantum Well Structures, MQWs). In one embodiment, the n-type semiconductor layer 124 and the p-type semiconductor layer 126 are respectively an n-type aluminum indium gallium nitride (n-type AlInGaN) semiconductor layer and a p-type aluminum indium gallium nitride (p-type A1 InGaN). ) a semiconductor layer. A recess 128 is formed on the substrate 122 to expose a portion of the n-type half 200913314. The n-type semiconductor layer 124 is located in the recess. The path/sigh is provided with a light-transmitting current diffusion layer (2) (6) Ting (5) = Τ: 2 Shown). The groove 128 is a tapered groove whose side wall is a sloped surface. The opening of the recess 128 is smaller than the opening of the conductor layer 124 of the n-type semiconductor layer 124. The area of the opening of the recess 128 adjacent to the n^ body layer 124 is smaller than the area of the surface of the n-type semiconductor layer i24 adjacent to the substrate 122. In addition, it can be understood that the groove (10) has a tapered groove as shown in Fig. 2, which may also be a rectangular groove having a side wall which is a vertical surface. The ice of the groove 128 is typically set to be less than or equal to 4 microns. =122 can be selected as metal and metal alloy, half =, its towel, semiconductor can be _ (Sl) or carbon cut (edge can be oxidized (10)), dioxide (10) 2), yttrium oxide magnesia (_ or blue Gemstone (Sapphire), etc. (4) When the base material is a metal or a metal alloy, the base (2) forms an ohmic contact with the n-type semiconductor sound 124 and can be used as a W (10), and the positive electrode (not shown) can be set. The two positive and negative electrodes are used to supply electric energy to the hair = 12 ;; and in this case, the side of the groove 128: the light W has a light reflection characteristic. (7) When the base a The material is transparent, because the negative electrode of the substrate 100 (not shown) usually needs a ^ " the light device is away from the side of the substrate 122, i is: the far conductor layer of the conductor layer 124 Then, it can be disposed on one side of the p-type semiconductor. (C) When the material 200913314 of the substrate 122 is a semiconductor, the negative electrode of the white light emitting device 100 can be a metal electrode that forms an ohmic contact with the substrate 122 (not shown). A positive electrode (not shown) may be disposed on one side of the P-type semiconductor layer away from the substrate 122. The phosphor layer 14 0 is filled in the recess 128 on the base 122 of the LED substrate 12 for wavelength conversion to form white light. Specifically, the phosphor layer 14 can be a solidified fill filled with the recess 128. The surface of the light substance colloid, which is away from the side of the n-type semiconductor layer 124, is preferably a plane 2 and the phosphor layer 140 is mainly composed of at least one kind of fluorescent substance capable of absorbing light emitted from the LED chip 120 and a transparent material. The light-transmissive resin may be selected from a viscous resin (S i 1丨cone ). For example, when the light emitted from the LED chip 120 is blue light, the phosphor layer 14 The invention may comprise a fluorescent substance which can absorb blue light and is excited by yellow light or two kinds of absorbable blue light and excites green light and red light respectively; when the light emitted by the light emitting diode chip 120 is ultraviolet (uv) light The phosphor layer 14 可 may include three kinds of phosphors that absorb ultraviolet light and are excited to emit red, green, and blue light respectively. · The reflective layer 160 is formed on the plurality of LEDs 12 The light-emitting one-pole wafer 120 is wound around the side 127 at % The reflective layer is disposed to prevent the light emitted by the LED chip 120 from exiting from the plurality of sides 127 thereof to prevent side leakage. The reflective layer 16 can be a metal or a dielectric material. The dielectric material may be tantalum nitride (SiNx) or cerium oxide. The white light emitting device 1 of the first embodiment of the present invention forms a reflective layer 160 by a plurality of side surfaces 127 of the light emitting diode chip 120. And the 200913314 camp light material layer 140 is placed in the groove m 竑 曰 曰 μ ι 〇 凹槽 m 凹槽 . . . 一方 一方 一方 凹槽 凹槽 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底 基底4 out of the light (4) to the above table, it passes through the fluorescent material, and the soil is π, ^, and the dreams are less than the same, so that the white light emitting device can make the light color uniform. Referring to Fig. 4, the groove m in the first embodiment of the present invention is not limited to one, and it may be provided in plural, for example, four. Fig. 4' is arranged in an array pattern, and the total area of the adjacent ports of the four grooves 128 is less than or equal to the area of the surface of the n-type semiconductor. The tenth embodiment of the second embodiment of the present invention provides a method for fabricating a pre-device 100, the method comprising the steps of: ::220: providing a light-emitting diode wafer 'which includes- Substrate and shape = light-emitting structure on the substrate; the light-emitting diode wafer m includes a cured surface 127. Specifically, the light emitting structure generally includes an n-type semiconductor layer 124, a p-type semiconductor layer i26, and an active layer 125 between the n-type semiconductor layer 124 and the fish p-type conductor layer 126; an n-type semiconductor layer 124, an active layer 125, and a financial conductor layer 126 is formed on substrate 22 in a direction away from the substrate 122. The light-emitting structure may be epitaxially grown on the substrate 122 by chemical or physical means such as molecular beam growth (e.e., eamEpUaxy) or organometallic chemical vapor deposition. Step 240: Forming at least one recess on the base of the light emitting diode wafer = exposing a portion of the light emitting structure. Specifically, at least one groove 11 200913314 '.12 8 is formed on the base 122 by means of engraving, machining or laser processing to expose part of the n-type of the private & Semiconductor layer 124. a, - the silver engraving method can be selected by dry method, such as inductive light-converging plasma-reactive ion (IV) (iG Bu RiE), or wet silk engraving, such as photo-enhanced Chemical etching, etc. Step of the body = forming a layer of glory material in the at least one groove. Specifically, the method may include the steps of: filling and filling the at least one groove 128 with the phosphor of the phosphor; and removing the excess phosphor of the phosphor after filling to move the colloid of the camping material away from the n-type semiconductor layer 124. Surface = ruthenium; and the phosphor of the phosphor is cured to form a layer of phosphor material 140. Step 280: forming a reflective layer on the plurality of sides (8) of the LED substrate. Presented,·^土4<> Polar body crystal mx county rape cover protects the light two 127 wonderful"" (four) 丄 ^ a plurality of sides of the wafer 120, ..., and then use the Guangfeng coating technology on the light-emitting diode One side of the body wafer 1 is deposited on the side 127; 5 Hui + @ 1 ftn. & ^ device (10). Depositing the reflective layer to obtain a white light illuminating optional 'Before the step _ is performed, a step (not shown) may be included. The side of the light emitting diode wafer 12G opposite to the substrate 122 and the carrier plate Bonded or embossed (mc) unblocked to effectively prevent the light-emitting diode wafer 120 from being damaged due to possible stress during the formation of the at least one groove 128'. The yield of the device 100 is good. Optionally, before the step is performed, the step may further include: forming an electric portion of the exposed portion of the at least one groove 128 of the 12kn-type semiconductor layer 124 of the LED chip. 12 200913314 The flow diffusion layer 123. Further, it will be understood by those skilled in the art that the n-type semiconductor layer 124 and the p-type semiconductor layer 126 in the light-emitting diode wafer 12 of the first and second embodiments are not limited. In the foregoing positional arrangement, the n-type semiconductor layer and the method of fabricating the white light-emitting device 100 of the example of the present invention can also provide a plurality of light-emitting diodes formed on a single wafer at a time. The polar body wafer, and the step of forming the at least one recess and the phosphor layer is performed before the wafer is cut; and the step of forming the reflective layer is usually performed after the wafer is cut. The present invention has indeed met the requirements of the invention patent, and has been specifically requested by law. However, the above description is only a preferred embodiment of the present invention, and the scope of the patent application of the present invention cannot be limited thereby. The equivalent modifications or variations of the present invention in the spirit of the present invention are intended to be included in the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross section of a white light emitting device according to an embodiment of the present invention. Figure 2 is a top plan view of a white light emitting device shown in Figure 1. Figure 3 is a plan view of a white light emitting device according to another embodiment of the present invention. Figure 4 is a white light according to still another embodiment of the present invention. Fig. 5 is a block diagram showing the manufacturing process of a white light emitting device according to a second embodiment of the present invention. 'Yi 13 200913314 Fig. 6 is a schematic cross-sectional view of a typical white light emitting diode. Description] White light emitting device 100 Substrate 122 Current diffusion layer 123 η-type semiconductor layer 124 Active layer 125 Ρ-type semiconductor layer 126 Complex side 127 Groove 128 Fluorescent material layer 140 Reflective layer 160 White light emitting diode 60 pedestal 62 Light-emitting two Polar Wafer 64 Transparent Package · 66 14

Claims (1)

200913314, '10. Patent application scope: h A white light emitting device comprising: a two-emitting diode wafer comprising: a substrate and a substrate; the light emitting structure comprising a --type semiconductor layer, - and the * a second type semiconductor layer of opposite conductivity type of the bulk layer and a second type of semiconductor layer and the second type of semiconductor layer, the active layer and the layer, the first type, the layer and the second type semiconductor The layer is formed with at least one groove along the 2 away from the substrate to expose a portion of the first-whole material. The polar body wafer has a plurality of sides; in at least one of the concave samples, the first diode The substrate of the wafer is used for wavelength conversion to form a white light; and 22; the plurality of side tops of the light emitting diode chip are formed on the light emitting diode chip. 2. If the patent application is small, the groove is a concave concave shape, and the white light emitting device is described as being larger than the parallel groove, which is close to the opening of the first type semiconductor layer... the opening of the first type semiconductor layer . • The application of the patented model Jfl flute 1 κ 少—凹# The white light emitting device of item 1, wherein the to 4. For example: C: or equal to _ micron. The white light emitting device of the first aspect, wherein the area of the photodiode tr of the first type semiconductor layer (four) is smaller than the volume. a surface of the first-type semiconductor adjacent to the surface of the substrate 5. The photo-material layer fills the at least white light-emitting device, wherein the battalion groove 'and away from the first-type semiconductor layer 15 The surface of 200913314 is - plane. The white light emitting device of the above-mentioned item, wherein the firefly 'bean layer is a solidified colloidal phosphor. The white light emitting device of claim 1, wherein the material of the reverse and k is a metal or a dielectric material. The white light emitting device of claim 1, wherein the exposed portion of the first one-half body layer at the at least one groove position is provided with a light-transmissive current diffusion layer. 9. The white light emitting device of claim i, wherein the material of the substrate is a semiconductor or a light transmitting insulator. The self-light-emitting device of the above-mentioned item (4), wherein the material of the substrate is a metal or an alloy. (1) The white light emitting device of claim 4, wherein the light emitted from the light emitting diode chip has a wavelength of ultraviolet light to green light. 12. The white light emitting device of claim 2, wherein the first semiconductor layer, the active layer and the second semiconductor layer are respectively made of a nitride semiconductor material. 13. A method of fabricating a white light emitting device, comprising the steps of: providing a light emitting diode wafer comprising: a substrate and a light emitting structure formed on the substrate, the light emitting structure comprising a first type semiconductor layer, a second type semiconductor opposite to the conductivity type of the first type semiconductor layer; and an active layer between the first type semiconductor layer and the second type semiconductor layer, the first type semiconductor layer, the active layer and The second type semiconductor layer is arranged away from the substrate, and the light emitting diode chip has a plurality of: 16 200913314, a surface, and at least a groove is formed on the substrate of the diode wafer and the exposed portion is formed. a first semiconductor layer, a phosphor layer is formed in the at least one recess; and a reflective layer is formed on the plurality of sides of the LED wafer. 14. The method of fabricating a white light emitting device according to claim 13, wherein the step of forming the luminescent material layer in the at least one recess is as follows: filling at least one groove and filling a firefly a colloid of the light substance; removing the excess phosphor of the phosphor after filling to make the surface of the phosphor colloid away from the surface of the first type semiconductor; and curing the phosphor of the phosphor to form the layer of phosphor. 15. The method of fabricating a white light optical device according to claim 13, wherein the reflective layer is formed by optical means on the plurality of sides of the light emitting diode chip. The method of fabricating a white light device as described in claim 13, wherein the at least one time bucket is formed on the substrate. After the step, the method further includes the step of: attaching or bonding the side of the light-emitting diode chip to the substrate opposite to the base of the temple. Such as the scope of patent application! The method for fabricating a white light emitting device according to any of the preceding claims, wherein the step of forming the phosphor layer further comprises the step of: forming an opaque portion of the first type semiconductor layer at the exposed portion to the / w僧 position Current spreading layer. 18. The method of fabricating a white light emitting device according to claim 13, wherein the at least one recess is formed by a method of surname, machining or laser processing. 18