TW201403877A - Fabrication method of multiple light color LED - Google Patents

Abstract

A fabrication method of multiple light color LED includes a first semiconductor layer forming step, a light emitting unit forming step, and an electrode unit forming step. The fabrication method mainly uses multiple deposition and etching processes to form a first and a second epitaxial layers on a first semiconductor layer. The first and second epitaxial layers respectively defines a first and a second light sources with the first semiconductor layer, and the first and second light sources can emit different color lights outward when receiving electrical energy.

Description

Multi-light color LED manufacturing method

The invention relates to a method for fabricating a light-emitting diode, in particular to a method for manufacturing a multi-color light-emitting diode.

Light-emitting diodes (hereinafter referred to as LEDs) have the advantages of low power consumption, long component life, and fast response speed, and are small in size and easy to match the design of application components. Therefore, they have been widely used in communication, information, and consumerism. Electronic products, lighting and display devices have become increasingly popular electronic components. Among them, white LEDs have the advantages of power saving in lighting or display applications. Therefore, under the energy-saving issues in recent years, the development of white LEDs has become more and more important.

At present, there are three kinds of white LED manufacturing methods. The first one is to emit blue or ultraviolet light crystal grains and fluorescing powder, and the blue light or ultraviolet light is used to excite the fluorescent powder to illuminate and then mix colors to produce white light; the second is to The crystal grains respectively emitting red, green or blue light are packaged together to be mixed to produce white light; and the third is to form a light-emitting layer which can emit different light colors on a single crystal grain, and the difference emitted by the light-emitting layers is utilized. White light is produced after color mixing.

The first method described above is made by using a single wafer with different colors of phosphor powder. At present, most manufacturers mainly use blue light emitting LEDs to emit yellow phosphors, but this type of white LEDs is currently in use. There are still two problems with poor brightness and chromaticity that need to be broken. The second method is currently packaged with LED dies (eg, double, triple, or quad, etc.) that can emit different colors, however, in a dual-die package (eg, by blue light) LED+ yellow LED, blue LED+ yellow-green LED, or white LED made of blue-green LED+yellow LED, because it uses two colors of LED to form white light, therefore, the color rendering is poor, can only be applied in the display Where the color performance is not high; the white LEDs obtained by encapsulating three or four crystal grains have better working efficiency and color rendering, but LED crystals of different light colors may be driven. Differences in voltage, luminescence output, temperature characteristics, and lifetime are therefore not easy to control, and because they are packaged in multiple dies, the increase in assembly space and cost also limits their application; When the white light generated by the light mode is applied to the display, most of the light becomes unnecessary light when the light passes through the filter, which also reduces the light utilization efficiency. The third method is to form a light-emitting layer that can emit different light colors on a single crystal grain, although the color rendering property can be high, and the problem of large assembly space caused by the multi-die package method can be reduced. However, since this method is to form a luminescent material that emits different light colors on a single luminescent layer, multiple quantum wells are generated, which easily leads to an increase in the on-voltage (Vf) of the LED dies, and Reduce the luminous efficiency of LED dies.

Accordingly, it is an object of the present invention to provide a method of fabricating a multi-color light-emitting diode that can reduce the turn-on voltage and improve light utilization.

Thus, the method for fabricating the multi-color light-emitting diode of the present invention, A first semiconductor layer forming step, a light emitting unit forming step, and an electrode unit forming step are included.

The first semiconductor layer forming step is to prepare an epitaxial substrate having a surface, and a first semiconductor layer is formed on the surface.

The illuminating unit is formed by forming a first luminescent film on a surface of a portion of the first semiconductor layer, and a first semiconductor film electrically formed on the surface of the first luminescent film opposite to the first semiconductor layer. And then etching a portion of the surface of the first semiconductor film to expose the first semiconductor layer to form a first epitaxial layer, and then covering the surface of the first epitaxial layer with a protective layer, and a surface of the semiconductor layer spaced apart from the first epitaxial layer is formed with a second luminescent film, and a second semiconductor film electrically formed on the surface of the second luminescent film opposite to the first semiconductor layer, and then Part of the surface of the second semiconductor film is etched downward to expose the first semiconductor layer to form a second epitaxial layer, and the first and second epitaxial layers respectively define a first and second together with the first semiconductor layer The light source is emitted, and the first and second light sources emit different light colors when receiving the electrical energy.

The electrode unit is formed by removing the protective layer, depositing a bottom electrode on the surface of the first semiconductor layer, and forming a top electrode on the top surface of the first and second epitaxial layers, respectively, to provide a Electrical energy to the electrode units of the illumination sources.

The invention has the advantages of: simultaneously depositing a plurality of light-emitting layers capable of emitting different light colors on a single substrate, so that the light-emitting layers can be packaged at the same time, not only reducing the assembly space, but also reducing the multi-color light emission. The turn-on voltage of the diode further enhances its light utilization.

2‧‧‧ epitaxial substrate

21‧‧‧ surface

3‧‧‧Lighting unit

31‧‧‧First semiconductor layer

32‧‧‧First epitaxial layer

321‧‧‧First luminescent film

322‧‧‧First semiconductor film

33‧‧‧Second epilayer

331‧‧‧second luminescent film

332‧‧‧Second semiconductor film

34‧‧‧First light source

35‧‧‧second source of illumination

36‧‧‧Encapsulation layer

361‧‧‧Flame powder

37‧‧‧ Third epitaxial layer

371‧‧‧ Third luminescent film

372‧‧‧ Third semiconductor film

38‧‧‧the third source of illumination

4‧‧‧Electrode unit

41‧‧‧ bottom electrode

42‧‧‧ top electrode

51‧‧‧Steps

52‧‧‧Steps

53‧‧‧Steps

1 is a schematic view showing a multi-color light-emitting diode made by a preferred embodiment of the present invention; FIG. 2 is a flow chart showing a preferred embodiment of the method for fabricating a multi-color light-emitting diode of the present invention; 3 is a schematic view showing a multi-color light-emitting diode having an encapsulation layer; and FIG. 4 is a schematic view showing a multi-color light-emitting diode having three illumination sources.

The multi-color light-emitting diode of the present invention can be used to fabricate a multi-color light-emitting diode having a plurality of light-emitting sources. In the preferred embodiment, a multi-color light-emitting device having two light-emitting sources is used. The diode is taken as an example for illustration.

Referring to FIG. 1 , a preferred embodiment of the method for fabricating the multi-color light-emitting diode of the present invention can produce a multi-color light-emitting diode as shown in FIG. 1 , and the multi-color light-emitting diode includes a beam. The crystal substrate 2, a light emitting unit 3, and an electrode unit 4.

The epitaxial substrate 2 has a surface 21 which may be selected from materials such as tantalum, aluminum oxide, and tantalum carbide.

The light emitting unit 3 has a first semiconductor layer 31 connected to the surface 21 and two first and second epitaxial layers 32 and 33 disposed on the surface of the first semiconductor layer 31 and spaced apart from each other by a gap. One or two epitaxial layers 32, 33 together with the first semiconductor layer define a first and second illumination sources 34, 35. The first epitaxial layer 32 has a first luminescent film 321 formed in order from the surface of the first semiconductor layer 31, and a first semiconductor film 322 formed on the surface of the first luminescent film 321 . The crystal layer 33 has a second luminescent film 331 formed in this order from the surface of the first semiconductor layer 31, and a second semiconductor film 332 formed on the surface of the second luminescent film 331.

It is to be noted that the first semiconductor layer 31 may be selected from an n-type doped or a p-type doped semiconductor material, and the n-type doping or p-type doping is selected from the second and third semiconductor films. 322, 332 are corresponding, that is, when the first semiconductor layer 31 is composed of an n-type doped semiconductor material, the second and third semiconductor films 322, 332 are made of a p-type semiconductor material. The first and second luminescent films 321 and 331 are respectively selected from different luminescent materials. For example, the first luminescent film 321 may be selected from a luminescent material that emits blue light, such as InxGa1-xN; The second luminescent film 331 may be selected from a luminescent material that emits green light, such as InyGa1-yN, wherein the appropriate composition of In is adjusted so that x>y; in addition, the constituent materials of the second and third semiconductor films 322 and 332 may also be respectively Corresponding to the material selection of the first and second luminescent films 321, 331 are respectively made of the same or different semiconductor materials. In this way, the first and second illumination sources 34 and 35 emit two different color colors when receiving electric energy, and the illumination unit 3 can utilize different light colors emitted by the first and second illumination sources 34 and 35. After color mixing, the predetermined light color is emitted outward.

The electrode unit 4 has a first semiconductor layer 31 formed thereon a bottom electrode 41 having a surface adjacent to the gap between the first and second epitaxial layers 32, 33, and two top electrodes 42 respectively formed on the top surfaces of the first and second epitaxial layers 32, 33, and The bottom and top electrodes 41, 42 can be designed to be electrically connected in parallel or in series, and can be controlled to be separately illuminated or simultaneously illuminated when the first and second illumination sources 34, 35 receive electrical energy; for example, The top electrodes 42 are electrically connected to the outside by a wire bonding process, and the bottom electrodes 41 are separately supplied in series to the first and second light sources 34 and 35, or the top electrodes 42 are processed through a wire bonding process. After being connected to each other, the top electrode 42 is extended outwardly from the outside to be electrically connected to the outside, and the bottom electrode 41 is supplied in parallel to the first and second light sources 34, 35.

In addition, when the top electrodes 42 are connected in parallel, the first and second light sources 34, 35 and the surface of the first semiconductor layer 31 may further form an insulating protective layer to prevent short circuit. Since the manner in which the top electrode 42 and the bottom electrode 41 are electrically connected in parallel or in series to the outside is well known to those skilled in the art and is not the focus of the present technology, it will not be described in detail.

Referring to FIG. 2, a preferred embodiment of the method for fabricating the multi-color light-emitting diode of the present invention comprises a first semiconductor layer forming step 51, a light-emitting unit forming step 52, and an electrode unit forming step 53.

The first semiconductor layer forming step 51 is to prepare an epitaxial substrate 2 having a surface 21, and a first semiconductor layer 31 is formed on the surface 21.

In detail, the step 51 forms a first half of the n-type doped semiconductor material on the surface 21 by chemical vapor deposition. Conductor layer 31.

The light emitting unit forming step 52 is to form first and second light emitting layers 32, 33 spaced apart from each other on the surface of the first semiconductor layer 31.

In detail, the step 52 is to deposit a first luminescent film 321 on a portion of the surface of the first semiconductor layer 31, and a surface of the first luminescent film 321 is electrically formed on the first semiconductor layer 31. The first semiconductor film 322 is etched downward from a portion of the surface of the first semiconductor film 322 to expose the first semiconductor layer 31 to form a first epitaxial layer 32, and the first epitaxial layer 32 is formed. Forming a first light source 34 together with the first semiconductor layer 31; then, the surface of the first epitaxial layer 32 is covered with a protective layer made of cerium oxide, and then the first semiconductor layer 31 and the first A second luminescent film 331 is sequentially formed on the surface of the epitaxial layer 32, and a second semiconductor film 332 is formed on the surface of the second luminescent film 331 opposite to the first semiconductor layer 31, and then A portion of the surface of the second semiconductor film 332 is etched downward to expose the first semiconductor layer 31 to form a second epitaxial layer 33, and the second epitaxial layer 33 is defined together with the first semiconductor layer 31. The light-emitting unit 3 is obtained by a second light source 35.

It is to be noted that the first and second luminescent films 321 and 331 are respectively selected from luminescent materials that emit different light colors, and the second and third semiconductor films 322 and 332 may be selected from the same or different semiconductor materials. Since the process control parameters and related material selection of the light-emitting unit 3 are known to those skilled in the art, they are not described again.

The electrode unit forming step 53 is to remove the protective layer, and the first semiconductor layer 31 is interposed between the first and second light emitting layers 32 and 33. A bottom electrode 41 is formed on the surface, and a top electrode 42 is formed on the top surfaces of the first and second epitaxial layers 32, 33, respectively, to obtain an electrode for supplying electric energy to the first and second light sources 34, 35. In unit 4, a multi-color light-emitting diode as shown in Fig. 1 can be obtained.

Referring to FIG. 3, it is worth mentioning that the preferred embodiment of the present invention further includes an encapsulation layer forming step of covering the surface of the light emitting unit 3 with an encapsulation layer made of a light transmissive material such as epoxy resin. 36, can be used to protect the light-emitting unit 3, and the encapsulation layer 36 can also have a phosphor powder 361 that can be excited by the light emitted by the first and second illumination sources 33, 34 to emit different light colors, by using the package. The layer 36 is disposed not only to protect the multi-color light-emitting diode, but also to further adjust the light color emitted by the multi-color light-emitting diode via the phosphor powder 361. For example, when the first and second illuminating sources 33 and 34 emit blue light and yellow-green light, although the white light can be produced after being mixed, the emitted light has some green color and almost no red, so that the encapsulating layer can be Phosphor 361 which can be excited by any one of the first and second illuminating sources 33 and 34 to emit red light is added to 36, so that a warm white LED can be obtained by mixing light, which is more suitable for general living. Lighting source.

Referring to FIG. 4, it is to be noted that the light emitting unit 3 can further form a third epitaxial layer 37 having a third luminescent film 371 and a third semiconductor film 372, and the third epitaxial layer 37 and the first A semiconductor layer 31 further defines a third illumination source 38, and a multi-color LED having three illumination sources 33, 34, 38 is obtained, and the third epitaxial layer 37 is fabricated and The two epitaxial layers 33 are substantially identical and therefore will not be described in detail.

Since the first, second, and third light sources 34, 35, and 38 are formed separately, the light color of the light emitting unit 3 can be selected by materials of the first, second, and third light emitting films 321, 331 and 371. In addition, the intensity ratio of the first, second, and third light-emitting sources 34, 35, and 38 can be controlled by the area adjustment of the first, second, and third epitaxial layers 32, 33, and 37. The light color emitted by the light emitting unit 3 is regulated.

In summary, the present invention forms a first, second, and third illumination sources 34, 35, 38 on the same epitaxial substrate 2 that can independently emit different light colors in a plurality of deposition manners. The diode and the obtained multi-color light-emitting diode can effectively reduce the problem of large assembly space in the conventional multi-die package; in addition, because each of the multi-color light-emitting diodes 34, 35, 38 are independent light-emitting, do not affect each other, have a low on-voltage (Vf), can be solved in order to make the light-emitting layer emit white light when receiving electric energy, but need to form on the same light-emitting layer Multiple quantum wells, which have the disadvantage that the light-emitting diode has a high on-voltage (Vf); in addition, the brightness can be controlled by the area modulation of the first, second and third illumination sources 34, 35, 38, and The light intensity ratio emitted by the light-emitting unit 3 makes the light color emitted by the light-emitting unit 3 more suitable for the light color requirement of different illumination purposes, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

51‧‧‧First semiconductor layer formation step

52‧‧‧Lighting unit formation steps

53‧‧‧Electrode unit formation steps

Claims (6)

A method for fabricating a multi-color light-emitting diode, comprising: a first semiconductor layer forming step, preparing an epitaxial substrate having a surface, and forming a first semiconductor layer on the surface; and forming a light-emitting unit a portion of the surface of the first semiconductor layer forms a first luminescent film, and a first semiconductor film formed on the surface of the first luminescent film opposite to the first semiconductor layer, and then from the first semiconductor film Part of the surface is etched downward to expose the first semiconductor layer to form a first epitaxial layer, and then the first epitaxial layer surface is covered with a protective layer, and the first semiconductor layer and the first epitaxial layer a second luminescent film is sequentially formed on the surface of the layer, and a second semiconductor film is formed on the surface of the second luminescent film opposite to the first semiconductor layer, and then a part of the surface of the second semiconductor film Etching down to expose the first semiconductor layer to form a second epitaxial layer, wherein the first and second epitaxial layers respectively define a first and second light source together with the first semiconductor layer, and the first Second light source When the electric energy is generated, different light colors are emitted outward; and an electrode unit is formed, the protective layer is removed, and a bottom electrode is deposited on the surface of the first semiconductor layer, and is respectively disposed on the top surface of the first and second epitaxial layers. A top electrode is formed to produce an electrode unit for supplying electrical energy to the first and second light sources. The method for fabricating a multi-color light-emitting diode according to the first aspect of the invention, wherein the step of forming the light-emitting unit further comprises forming a third epitaxial layer, the surface of the second epitaxial layer being covered and protected. Layer and Forming a third luminescent film on the surface of the first semiconductor layer and the first and second epitaxial layers, and forming a third luminescent film on the surface of the third luminescent film, electrically opposite to the first semiconductor layer The semiconductor film is then etched downward from a portion of the surface of the third semiconductor film to expose the first semiconductor layer to form a third epitaxial layer, the third epitaxial layer and the first semiconductor layer together defining a The third light source is configured to remove the protective layer formed on the second and third epitaxial layers, and form a top electrode on the top surfaces of the first, second and third epitaxial layers respectively. The method for fabricating a multi-color light-emitting diode according to claim 1, wherein the top electrodes are electrically connected to the bottom electrode in a series connection. The method for fabricating a multi-color light-emitting diode according to claim 1, wherein the top electrodes are electrically connected to the bottom electrode in parallel. The method for fabricating a multi-color light-emitting diode according to claim 1, further comprising an encapsulating layer forming step, wherein the surface of the light-emitting unit is covered with an encapsulating layer made of a light-permeable material. The method for fabricating a multi-color light-emitting diode according to claim 5, wherein the encapsulating layer has a phosphor powder that is excited by light emitted by at least one of the light-emitting sources to emit different light colors.