A kind of light-emitting diode chip for backlight unit and manufacture method thereof
Technical field
The present invention relates to a kind of light-emitting diode (LED) chip and manufacture method thereof.
Background technology
Along with the continuous development of semiconductor chip (chip) technology, traditional technology can not satisfy the requirement that increases day by day for the luminous efficiency of light-emitting diode and brightness.For traditional light-emitting diode, the ray structure that is formed by epitaxial growth is formed on the smooth substrate with particular crystal orientation usually, for example on the silicon chip.Between silicon chip and ray structure, form resilient coating then at low temperatures.Yet in traditional light-emitting diode, because smooth silicon chip and interfacial refraction between the resilient coating and absorbed inside, luminous efficiency is lowered.And the thermal conductivity of substrate in traditional light-emitting diode and resilient coating is low, and for example, the conductive coefficient of GaAs is 44-58W/mK, and sapphire conductive coefficient is 35-40W/mK.The heat that produces in the course of work of luminescence chip can't diffuse to the outside effectively like this, makes the life-span of luminescence chip reduce.Because be subjected to the influence of above-mentioned factor, the luminous efficiency of present traditional light-emitting diode chip for backlight unit can only can't satisfy the requirement of illumination for 40 to 50 lumens/watt, its life-span is also unstable.Therefore the luminous efficiency and the radiating efficiency that how to improve luminescence chip become one of important topic of the required solution in this area.
Summary of the invention
A kind of manufacture method of light-emitting diode chip for backlight unit is provided according to an aspect of the present invention.This method comprises: the preparation substrate forms a plurality of concave-convex micro-structures on the upper surface of this substrate; On the upper surface of this substrate, form the buffering patterned layer, this buffering patterned layer have a plurality of respectively with substrate on the opposite concave-convex micro-structure of the corresponding concave and convex direction of described concavo-convex little knot; On this buffering patterned layer, form the n type semiconductor layer; On the part of this n type semiconductor layer, form luminescent layer; On this luminescent layer, form the p type semiconductor layer; And on another part of this n N-type semiconductor N and this p type semiconductor layer, form n electrode and p electrode respectively.
According to one embodiment of the invention, have the micro-structural of a plurality of projectioies on the described substrate, described buffering patterned layer has the micro-structural of a plurality of corresponding depressions with it.
According to one embodiment of the invention, have the micro-structural of a plurality of depressions on the described substrate, described buffering patterned layer has the micro-structural of a plurality of corresponding projectioies with it.
The flat shape of described concave-convex micro-structure can be circle or regular hexagon.The maximum gauge of described circle can be 0.2 μ m to 10 μ m.Described orthohexagonal maximal side can be 0.15 μ m to 9 μ m.Wherein the distance between the central point of the described concave-convex micro-structure all around that is adjacent of the central point of each described concave-convex micro-structure is 0.3 μ m to 9 μ m.
Preferably, the sidewall of described concave-convex micro-structure can be more than or equal to 0 degree and less than 90 degree with respect to the angle of the normal of the upper surface of described substrate.The height of described concave-convex micro-structure can be 0.2 μ m to 1.5 μ m.
According to one embodiment of the invention, comprise in the method that forms a plurality of concave-convex micro-structures on the substrate: on this substrate, form photoresist; The pattern that adopts photoetching that this photoresist is graphically expected with formation; Adopt engraving method with the design transfer of this photoresist to this substrate.This engraving method can comprise coupled plasma reactive ion etching, chemical solution etching.
Preferably, the material of this substrate can be selected from silicon, sapphire, carborundum or zinc oxide.
According to one embodiment of the invention, the method that forms this buffering patterned layer can comprise: deposit resilient coating on this substrate; The pattern that adopts photoetching that this photoresist is graphically expected with formation; Adopt engraving method with the design transfer of this photoresist to this resilient coating to form this buffering patterned layer.The method of deposition resilient coating can comprise physical vapour deposition (PVD), Metalorganic chemical vapor deposition, molecular beam epitaxy, halogen vapour deposition.This engraving method can comprise coupled plasma reactive ion etching, chemical solution etching.
Preferably, the material of this buffering patterned layer can be selected from aluminium nitride, gallium nitride, InGaN or zinc oxide.
Alternatively, according to one embodiment of the invention, described method can also be included in and form before this p electrode, forms transparent electrode layer on the p type semiconductor layer.
According to a further aspect in the invention, provide a kind of light-emitting diode.This light-emitting diode comprises: substrate has the concave-convex micro-structure on a plurality of upper surfaces that are formed at this substrate; The buffering patterned layer is formed on the upper surface of this substrate, and this buffering patterned layer has a plurality of corresponding with the described concave-convex micro-structure position on the substrate respectively, the concave-convex micro-structure that concave and convex direction is opposite; The n type semiconductor layer is formed on this buffering patterned layer; Luminescent layer is formed on the part of this n type semiconductor layer; The p type semiconductor layer is formed on this luminescent layer; And n electrode and p electrode, be formed at respectively on another part and this p type semiconductor layer of this n N-type semiconductor N.
According to embodiments of the invention,, can reduce boundary reflection and reduce absorbed inside, thereby improve luminous efficiency owing on substrate, formed a plurality of concave-convex micro-structures.And compare with the thin resilient coating that forms on the traditional handicraft, resilient coating has bigger thickness according to an embodiment of the invention, thus the crystal defect of the resilient coating that forms reduces, and has improved the yield of light-emitting diode chip for backlight unit.And resilient coating is formed by the high material of thermal conductivity, has improved the luminous efficiency of light-emitting diode chip for backlight unit.And form on the resilient coating with substrate on the opposite pattern of corresponding direction can change the propagation path of light, thereby further reduced the reflection and the absorption at interface, improved the luminous efficiency of light-emitting diode chip for backlight unit.
Description of drawings
Figure 1A-1C is the structural profile schematic diagram according to the manufacture method of the light-emitting diode chip for backlight unit of the first embodiment of the present invention;
Fig. 2 A-2C is the structural profile schematic diagram of the manufacture method of light-emitting diode chip for backlight unit according to a second embodiment of the present invention;
Fig. 3 A-3C is the structural profile schematic diagram of manufacture method of the light-emitting diode chip for backlight unit of a third embodiment in accordance with the invention;
Fig. 4 A-4C is the structural profile schematic diagram of manufacture method of the light-emitting diode chip for backlight unit of a fourth embodiment in accordance with the invention;
Fig. 5 is the structural plan schematic diagram of light-emitting diode chip for backlight unit according to an embodiment of the invention;
Fig. 6 is the amplification floor map of concave-convex micro-structure according to an embodiment of the invention; And
Fig. 7 is the amplification profile schematic diagram of concave-convex micro-structure according to an embodiment of the invention.
Embodiment
Describe embodiments of the invention with reference to accompanying drawing in detail by embodiment.For the convenience that illustrates, accompanying drawing is not proportionally drawn.
First embodiment
At first with reference to the manufacture method of figure 1A-1C description according to the light-emitting diode chip for backlight unit of the first embodiment of the present invention.Shown in Figure 1A, preparation substrate 1.The material of this substrate 1 for example can be selected from silicon, sapphire, carborundum or zinc oxide etc.On the upper surface of this substrate 1, form a plurality of protruding 2 then.A plurality of protruding 2 can arrange on the upper surface of substrate 1 regularly, as shown in Figure 5.The flat shape of this projection 2 can for example be circle or regular hexagon, as shown in Figure 6.Yet the present invention is not limited to the above embodiments.Projection 2 also can be other shape, perhaps arranges brokenly on the upper surface of substrate 1.The sidewall of this projection 2 with respect to the scope of the angle θ of the normal on the plane of substrate for greater than 0 degree smaller or equal to 90 degree, as shown in Figure 7.Promptly should projection 2 can be column or frustum.And should projection 2 can adopt the whole bag of tricks to form.For example, painting photoresist on substrate 1, the pattern that utilizes photoetching method that this photoresist is graphically expected with formation then.Next, adopt engraving method with the design transfer of this photoresist to this substrate 1.This engraving method comprises coupled plasma reactive ion etching, chemical solution etching etc.The sidewall of projection 2 can be more than or equal to 0 degree and less than 90 degree with respect to the angle of the normal of the upper surface of described substrate 1, and promptly this projection can be cylindricality or taper.The height of projection 2 for example is 0.2 μ m to 1.5 μ m.And when this protruding cross section was circle, this circular maximum gauge was 0.2 μ m to 10 μ m.And when this protruding cross section was regular hexagon, this orthohexagonal maximal side was 0.15 μ m to 9 μ m.Distance between the central point of the described concave-convex micro-structure all around that the central point of each described concave-convex micro-structure is adjacent is 0.3 μ m to 9 μ m.
Next, shown in Figure 1B, on the upper surface of substrate 1, form buffering patterned layer 3.This buffering patterned layer 3 have a plurality of respectively with substrate on described protruding 2 corresponding protruding 4.For example shape, the size with projection 2 is suitable for the shape of projection 4, size.Promptly projection 4 can be circular or orthohexagonal column or frustum for cross section.The formation that can in all sorts of ways of this buffering patterned layer 3.For example, can be at first by for example methods such as physical vapour deposition (PVD), Metalorganic chemical vapor deposition, molecular beam epitaxy, halogen vapour deposition, the resilient coating of the above thickness of deposition 0.5 μ m on substrate 1.The material of this resilient coating is selected from aluminium nitride, gallium nitride, InGaN or zinc oxide etc., so this resilient coating has high thermal.Compare with the thin resilient coating that forms on the traditional handicraft, because resilient coating has bigger thickness according to an embodiment of the invention, thereby the crystal defect of the resilient coating that forms reduces, and has improved the yield of light-emitting diode chip for backlight unit.Next, for example adopt above-mentioned photoetching and engraving method on the upper surface of this resilient coating, to form a plurality of corresponding with protruding 2 respectively projectioies 4, thereby form buffering patterned layer 3.
Next, on this buffering patterned layer 3, form n type semiconductor layer 5.On the part of n type semiconductor layer 5, form luminescent layer 6.On this luminescent layer 6, form p type semiconductor layer 7.Alternatively, can also on the surface of p type semiconductor layer 7, form transparency conducting layer 8.Then, on another part of transparency conducting layer 8 and this n N-type semiconductor N 5, utilize methods such as evaporation, sputter to form p electrode 9 and n electrode 10 respectively.Resulting structure has formed the light-emitting diode chip for backlight unit of high brightness through subsequent techniques such as grinding, polishing and cuttings.
According to the first embodiment of the present invention,, can reduce boundary reflection and reduce absorbed inside, thereby improve luminous efficiency owing on substrate, formed a plurality of concave-convex micro-structures.And compare with the thin resilient coating that forms on the traditional handicraft, resilient coating has bigger thickness according to an embodiment of the invention, thus the crystal defect of the resilient coating that forms reduces, and has improved the yield of light-emitting diode chip for backlight unit.And resilient coating is formed by the high material of thermal conductivity, has improved the luminous efficiency of light-emitting diode chip for backlight unit.And the pattern that forms on the resilient coating further reduced the reflection and the absorption at interface, improved the luminous efficiency of light-emitting diode chip for backlight unit.
Second embodiment
Fig. 2 A-2C is the structural profile schematic diagram of the manufacture method of light-emitting diode chip for backlight unit according to a second embodiment of the present invention.The structure of light-emitting diode chip for backlight unit according to a second embodiment of the present invention and manufacture method thereof are similar substantially to the light-emitting diode chip for backlight unit of first embodiment, and its difference is to have formed a plurality of depressions 2 ' and replaces a plurality of protruding 2 among first embodiment on the upper surface of Semiconductor substrate 1.Shape, size and the distribution of depression 2 ' are similar to the projection 2 among first embodiment.That is to say that a plurality of depressions 2 ' can be arranged regularly, as shown in Figure 5 on the upper surface of substrate 1.The flat shape of this depression 2 ' can for example be circle or regular hexagon, as shown in Figure 6.Yet the present invention is not limited to the above embodiments.Depression 2 ' also can be other shape, perhaps arranges brokenly on the upper surface of substrate 1.This depression sidewall of 2 ' with respect to the scope of the angle θ of the normal on the plane of substrate for greater than 0 degree smaller or equal to 90 degree, as shown in Figure 7.For fear of repetition, omitted description for other similar characteristics.
The 3rd embodiment
Fig. 3 A-3C is the structural profile schematic diagram of manufacture method of the light-emitting diode chip for backlight unit of a third embodiment in accordance with the invention.The structure of the light-emitting diode chip for backlight unit of a third embodiment in accordance with the invention and manufacture method thereof are similar substantially to the light-emitting diode chip for backlight unit of first embodiment, and its difference is that having formed a plurality of depressions 4 ' on the upper surface of buffering patterned layer 3 replaces a plurality of protruding 4 among first embodiment.Shape, size and the distribution of depression 4 ' are similar to the projection 4 among first embodiment.That is to say that a plurality of depressions 4 ' can be arranged regularly, as shown in Figure 5 on the upper surface of substrate 1.The flat shape of this depression 4 ' can for example be circle or regular hexagon, as shown in Figure 6.Yet the present invention is not limited to the above embodiments.Depression 4 ' also can be other shape, perhaps arranges brokenly on the upper surface of substrate 1.This depression sidewall of 4 ' with respect to the scope of the angle θ of the normal on the plane of substrate for greater than 0 degree smaller or equal to 90 degree, as shown in Figure 7.For fear of repetition, omitted description for other similar characteristics.
The 4th embodiment
Fig. 4 A-4C is the structural profile schematic diagram of manufacture method of the light-emitting diode chip for backlight unit of a fourth embodiment in accordance with the invention.The structure of the light-emitting diode chip for backlight unit of a fourth embodiment in accordance with the invention and manufacture method thereof are similar substantially to the light-emitting diode chip for backlight unit of second embodiment, and its difference is that having formed a plurality of depressions 4 ' on the upper surface of buffering patterned layer 3 replaces a plurality of protruding 4 among second embodiment.Shape, size and the distribution of depression 4 ' are similar to the projection 4 among second embodiment.That is to say that a plurality of depressions 4 ' can be arranged regularly, as shown in Figure 5 on the upper surface of substrate 1.The flat shape of this depression 4 ' can for example be circle or regular hexagon, as shown in Figure 6.Yet the present invention is not limited to the above embodiments.Depression 4 ' also can be other shape, perhaps arranges brokenly on the upper surface of substrate 1.This depression sidewall of 4 ' with respect to the scope of the angle θ of the normal on the plane of substrate for greater than 0 degree smaller or equal to 90 degree, as shown in Figure 7.For fear of repetition, omitted description for other similar characteristics.
In sum, embodiments of the invention provide a kind of light-emitting diode chip for backlight unit, and this light-emitting diode chip for backlight unit comprises: substrate has the concave-convex micro-structure on a plurality of upper surfaces that are formed at this substrate; The buffering patterned layer is formed on the upper surface of this substrate, and this buffering patterned layer has a plurality of corresponding with the described concave-convex micro-structure position on the substrate respectively, the concave-convex micro-structure that concave and convex direction is opposite; The n type semiconductor layer is formed on this buffering patterned layer; Luminescent layer is formed on the part of this n type semiconductor layer; The p type semiconductor layer is formed on this luminescent layer; And n electrode and p electrode, be formed at respectively on another part and this p type semiconductor layer of this n N-type semiconductor N.
According to embodiments of the invention, because corresponding in the concave-convex micro-structure position that has formed on the resilient coating with on the substrate, the opposite concave-convex micro-structure of concave and convex direction has changed the propagation path of light, can farthest reduce boundary reflection and reduce absorbed inside, thereby improve luminous efficiency.And compare with the thin resilient coating that forms on the traditional handicraft, resilient coating has bigger thickness according to an embodiment of the invention, thus the crystal defect of the resilient coating that forms reduces, and has improved the yield of light-emitting diode chip for backlight unit.And resilient coating is formed by the high material of thermal conductivity, has improved the luminous efficiency of light-emitting diode chip for backlight unit.
Though specifically show and described the present invention with reference to embodiment; yet those having ordinary skill in the art will appreciate that; do not breaking away under the situation of the spirit and scope of the present invention that define by claim; can make the different variations on form and the details, and these variations will drop within protection scope of the present invention.