WO2018153388A1

WO2018153388A1 - Hexagonally patterned substrate

Info

Publication number: WO2018153388A1
Application number: PCT/CN2018/084108
Authority: WO
Inventors: 孙智江; 梁宗文; 吴自力
Original assignee: 海迪科（南通）光电科技有限公司
Priority date: 2017-02-23
Filing date: 2018-04-23
Publication date: 2018-08-30
Also published as: CN107170868A; CN206584948U

Abstract

The present invention relates to a hexagonally patterned substrate, comprising a substrate, a surface of the substrate being provided with a periodic convex and concave pattern, a bottom edge of the convex and concave pattern being hexagonal and having a compact honeycomb arrangement, wherein a perpendicular bisector of any edge of each hexagon passes through the center of the hexagon and a corresponding adjacent hexagon, same or similar gaps are arranged between adjacent hexagons, and any edge of a hexagon and a corresponding edge of an adjacent hexagon are axisymmetric with respect to the gap. The advantages of the present invention are: any edge of a hexagon on the bottom edge of the periodic convex and concave pattern of the hexagonally patterned substrate is axisymmetric with a corresponding edge of an adjacent hexagon, and the compact arrangement is provided with larger pattern gaps while a duty ratio remains unchanged, thereby widening an epitaxial process window, and increasing product yield and reliability; the dislocation density of an epitaxial thin film grown on the substrate can be effectively reduced, and the light extraction efficiency of a chip can be increased.

Description

A positive hexagonal patterned substrate

Cross-reference to related applications

This application claims that the application number of the China Patent Office submitted on February 23, 2017 is 201720166354.2, the name is “a nano-patterned substrate” and the application number submitted to the China Patent Office on April 28, 2017 is 201710294891.X. The priority of the Chinese Patent Application entitled "A Orthogonal Hexagonal Patterned Substrate" is hereby incorporated by reference in its entirety.

Technical field

The present invention relates to the field of substrate preparation technology, and in particular, to a positive hexagonal patterned substrate and a nano patterned substrate.

Background technique

Compared with traditional light sources, GaN-based LEDs have the advantages of small size, long life, high efficiency, energy saving and environmental protection. They are widely used in displays, indicator lights, backlights, solid state lighting, traffic lights, short-range optical communications and biosensors. And so on. In general, the lattice constant mismatch and the thermal expansion coefficient mismatch of the GaN epitaxial film and the underlying substrate are large, resulting in a dislocation density of up to 10 ⁹ to 10 ¹⁰ cm ^-2 in the GaN epitaxial film. The high dislocation density will affect the optical and electrical properties of the epitaxial film, resulting in reduced device reliability and internal quantum efficiency. On the other hand, the refractive index of GaN is greater than the refractive index of air (n = 1) and the refractive index of the substrate, so the critical angle of the light escape pyramid is very small, causing only a small part of the photons generated by the active layer to overflow from the surface. Most of the photons gradually disappear from internal total reflection and are converted into heat.

Using a patterned substrate as a GaN-based light-emitting diode epitaxial substrate can promote lateral epitaxial growth, and the line dislocations in the GaN epitaxial layer above the substrate pattern are bent by 90°, so that the line dislocations cannot reach the surface of the film, which can greatly Reduce the line dislocation density of the GaN epitaxial film. At the same time, it can also increase the probability of light emission and improve the light extraction efficiency of the LED.

In order to improve the light extraction efficiency of the device, it is necessary to ensure a certain duty ratio. The ideal patterned substrate is to maintain the minimum c-plane area ratio while the c-plane width is required to meet the minimum size requirements for epitaxial initial growth. When the size of the image is reduced and the proportion of the c-plane area is kept constant, the conventional hemispherical patterned substrate gap is too small, and the epitaxial growth cannot be performed with high quality.

Summary of the invention

The technical problem to be solved by the present invention is to provide a positive hexagonal patterned substrate with a monolithic structure, which has a larger pattern gap while maintaining a constant duty ratio and tight alignment, ensuring high quality growth of epitaxial materials. .

In order to solve the above technical problems, a first aspect of the present invention provides a positive hexagonal patterned substrate, which is innovative in that it includes a substrate having a periodicized convex or concave pattern, the protrusion or The bottom edge of the concave pattern is a regular hexagon and arranged in a honeycomb shape, that is, a vertical bisector of any one of the arranged hexagons passes through the center of the regular hexagon and the corresponding adjacent hexagon, and a gap exists between the adjacent regular hexagons. The side of either side of the aligned hexagonal shape corresponding to the adjacent regular hexagon is axisymmetric with respect to the gap.

Further, the period of the periodic pattern is from 100 to 8000 nm.

Further, the base side of the periodic pattern has a length of 10 to 5000 nm.

Further, the height of the periodic pattern is 0.1 to 10 μm.

Further, the gap between adjacent regular hexagons is 10 to 1000 nm.

Further, the convex or concave pattern is a regular hexagonal shape.

Further, the convex or concave pattern is a regular hexagonal taper.

Further, the convex or concave pattern is a regular hexagonal column shape.

Further, the vertex of the regular hexagon has a curvature, and the length of the arc is 0 to 500 nm.

Further, the vertex of the regular hexagon is rounded.

Further, the side length of the regular hexagon is a straight line.

Further, the side of the regular hexagon is convex and convex.

Further, the side of the regular hexagon has a concave curve.

Further, the substrate is sapphire.

Further, the substrate is silicon carbide or silicon.

Further, the substrate is lithium aluminate.

In order to solve the above technical problems, a second aspect of the present invention provides a nano-patterned substrate including a base substrate and a honeycomb structure formed on the base substrate, a period of the honeycomb structure It is 100-5000 nm and has a height of 10-5000 nm.

Further, the nano-patterned substrate may be a honeycomb convex structure or a honeycomb structure.

Further, the nano-patterned substrate is one of sapphire, silicon carbide, and silicon of polar, semi- or non-polar orientation.

Advantages of the invention include:

(1) The positive hexagonal patterned substrate of the present invention, wherein either side of the regular hexagon of the bottom of the periodicized convex or concave pattern is symmetrical with the side axis corresponding to the adjacent regular hexagonal pattern, and the duty ratio is kept constant and tight In the case of alignment, there is a larger pattern gap, which widens the process window of the epitaxy, improves the yield and reliability of the product, and can effectively reduce the dislocation density of the epitaxial film grown thereon and improve the light extraction of the chip. effectiveness;

(2) The positive hexagonal patterned substrate of the present invention, wherein the vertex of the regular hexagon is a regular hexagon with rounded corners, or the regular hexagon of the convex curve or the regular hexagon of the concave curve, which is more capable of Effectively suppressing the dislocation density of the epitaxial layer on the patterned substrate and improving the crystal quality.

(3) Compared with the conventional nano-patterned substrate, the honeycomb structure is used, and when the duty ratio is kept constant and the period is decreased, the epitaxial growth on the nano-patterned substrate can still maintain a good crystal quality.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following drawings for the embodiments need to be briefly introduced. It is understood that the following drawings are merely illustrative of certain embodiments of the invention and are not intended to Other drawings can be obtained from those skilled in the art without departing from the drawings.

1 is a schematic view showing the structure of a regular hexagonal patterned substrate in the present invention.

2 is a schematic view showing the structure of a hexagonal hexagonal patterned substrate in the present invention.

3 is a schematic view showing the structure of a hexagonal hexagonal patterned substrate in the present invention.

Fig. 4 is a structural schematic view showing that the apex angle of the base hexagonal hexagonal corner is a circular arc curve in the present invention.

Fig. 5 is a structural schematic view showing the side of the base hexagonal hexagonal line being straight in the present invention.

Fig. 6 is a structural schematic view showing a side of a hexagonal positive hexagonal side having a convex curve in the present invention.

Fig. 7 is a structural schematic view showing the side of the hexagonal hexagonal side having a concave curve in the present invention.

Figure 8 is a schematic view showing the structure of a regular hexagonal columnar projection in the present invention.

Figure 9 is a schematic view showing the structure of a hexagonal tapered projection in the present invention.

Figure 10 is a schematic view showing the structure of a hexagonal hexagonal projection in the present invention.

Figure 11 is a schematic view showing the structure of a hexagonal column-shaped pit in the present invention.

Figure 12 is a schematic view showing the structure of a hexagonal tapered pit according to the present invention.

Figure 13 is a schematic view showing the structure of a regular hexagonal shaped pit according to the present invention.

Figure 14 is a top plan view of a patterned substrate in accordance with the present invention.

In the figure: 1-substrate; 2-negative hexagonal shape; 3-negative hexagonal cone; 4-negative hexagonal column; 5-rounded; 6-embossed structure.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is apparent that the described embodiments are part of the embodiments of the invention, and not all of the embodiments.

Therefore, the following detailed description of the embodiments of the invention is not intended to All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

It should be noted that the features and technical solutions in the embodiments and the embodiments of the present invention may be combined with each other without conflict.

It should be noted that similar reference numerals and letters indicate similar items in the following figures, and therefore, once an item is defined in a drawing, it is not necessary to further define and explain it in the subsequent drawings.

A positive hexagonal patterned substrate, which is innovative in that it comprises a substrate 1 having a periodicized convex or concave pattern on its surface, the bottom edge of the raised or concave pattern being a regular hexagon and presenting Honeycomb compact arrangement, that is, a vertical bisector of either side of a regular hexagonal shape passes through the center of the regular hexagon and the corresponding adjacent hexagonal shape, and a gap between adjacent positive hexagons, arranging either side of the positive hexagon and the adjacent positive six The sides corresponding to the corners are axisymmetric with respect to the gap.

GaN: gallium nitride; c-plane: control area.

The GaN epitaxial film lateral growth process consists of 2 steps:

In the first step, the GaN epitaxial film grows three-dimensionally around the periphery of the microstructure, and finally gradually closes each microstructure and covers the entire microstructure, and the lateral surface of the GaN epitaxial film is kept as flat as possible;

In the second step, the GaN epitaxial film is traversed on the flat GaN epitaxial film formed in the first step, and continues to grow in a two-dimensional mode, so that the quality of the epitaxial layer crystal is improved, the desired product is obtained, and finally the epitaxial layer, such as the light output of the LED chip, is improved. Efficiency and the crystal quality of the material.

Since the periodic distribution microstructure is added to the substrate 1, the dislocation extension can be effectively blocked, the dislocation density is reduced, the quality of the generated material is improved, and the crystal quality is improved.

The positive hexagonal patterned substrate 1 of the present invention has a regular hexagonal shape, and has a regular shape with a 360-degree rotating structure centered on the center of the regular hexagon; since the regular hexagon is periodically arranged and the hexagonal shape is The side corresponding to the adjacent regular hexagonal pattern is axisymmetric with respect to the central axis between the two, and therefore, when the duty ratio is kept constant and closely arranged, the order is more ordered, and the gap between the plurality of adjacent patterns is kept the largest. The process window of the epitaxy is broadened, and the yield and reliability of the product are improved; thereby, the dislocation density of the epitaxial film grown thereon can be effectively reduced and the light extraction efficiency of the chip can be improved.

The following is a detailed description of the above summary.

1 and FIG. 10, FIG. 1 is a schematic structural view of a hexagonal hexagonal patterned substrate according to the present invention; and FIG. 10 is a schematic structural view of a hexagonal hexagonal projection in the present invention.

As shown in Fig. 1, due to the periodic distribution of a plurality of regular hexagonal shapes, the adjacent sides of the adjacent hexagonal hexagonal hexagons are axisymmetric, and when the duty ratio is constant, when compacted, The gap between adjacent regular hexagonal mesas is large, giving a space for lateral growth of the GaN epitaxial film, and the distance between adjacent sides of adjacent hexagons is the same from one end to the other end of the side, thus growing The possibility of dislocations occurring in the GaN epitaxial film is lowered, and the dislocation density of the GaN epitaxial film outside the side wall of the regular hexagonal column is more effectively reduced.

As shown in FIG. 10, the substrate 1 has a regular hexagonal shape, and a GaN epitaxial film is laterally epitaxially grown on the substrate. Since the dislocations of the laterally grown GaN film are bent by 90 degrees, the GaN epitaxial film is along the side wall of the truncated cone. Lateral growth. Since the truncated cone shape has a certain height, the GaN epitaxial film is laterally grown in the sidewall, so that part of the GaN epitaxial film is deposited at a certain height outside the domed-shaped sidewall, and the GaN epitaxially deposited on the upper surface of the truncated cone shape The film is almost flat and then covered with a hexagonal circular shaped micro-structure. Since the dislocation of the GaN epitaxial film grown below the height of the regular hexagonal truncated cone is reduced, the dislocation density of the regrown GaN epitaxial film is greatly reduced when the GaN epitaxial film covers the entire microstructure.

Further, since all the regular hexagonal patterns are in the shape of a regular hexagonal truncated cone, the gap between the adjacent regular hexagonal circular truncated cones is small in the lower part and large in the upper part. Therefore, in the process of lateral growth of the GaN epitaxial film, the upper and upper heights are increased. The slower the change, the certain adjustment time is given during the formation of the GaN epitaxial film to prevent the increase of the dislocation density.

Preferably, please refer to FIG. 13, which is a schematic structural view of a hexagonal hexagonal pit according to the present invention. As shown in Fig. 13, a part of the GaN epitaxial film is grown in a regular hexagonal pit, a part is grown outside the regular hexagonal pit, and the GaN epitaxial film in the hexagonal pit is laterally stacked inside, and the GaN epitaxial outside the hexagonal pit is extended. The film laterally accumulates in the lateral direction between the adjacent regular hexagonal pits, all reducing the dislocation density.

2 and FIG. 11, FIG. 2 is a schematic structural view of a hexagonal hexagonal patterned substrate according to the present invention; and FIG. 11 is a schematic structural view of a regular hexagonal tapered protrusion according to the present invention.

As shown in Fig. 2, due to the periodic distribution of a plurality of regular hexagonal tapers, the adjacent sides of the adjacent hexagonal hexagonal hexagonal hexagons are axisymmetric, and when the duty ratio is constant, when compacted When the gap between the adjacent regular hexagonal tapers is large, the space for lateral growth of the GaN epitaxial film is given, and the gap between the adjacent regular hexagonal tapers gradually increases from the bottom to the top. Therefore, the GaN epitaxial film is laterally oriented. The space for growth gradually becomes larger, the rate of high growth gradually becomes slower, and when the portion where the height is faster is extended toward the adjacent lower portion, the height difference of the adjusted GaN epitaxial film reduces the line dislocation density.

As shown in FIG. 11, the substrate 1 is a hexagonal pyramid, and the GaN epitaxial film is laterally epitaxially grown on the substrate. Since the line dislocations of the laterally grown GaN film are bent by 90 degrees, the GaN epitaxial film is tapered. The sidewalls grow laterally. Since the conical shape has a certain height, the GaN epitaxial film is deposited laterally in the sidewall, so that part of the GaN epitaxial film is deposited at a certain height outside the conical sidewall, giving the GaN epitaxial film a larger space for growth. The portion of the GaN epitaxial film is lowered to a normal height, and the line dislocation density is lowered.

Further, since all the regular hexagonal patterns are hexagonal conical shapes, the gap between the adjacent regular hexagonal conical shapes is small in the lower part and large in the upper part. Therefore, in the process of lateral growth of the GaN epitaxial film, the upper and upper heights are increased. The slower the change, the certain adjustment time is given during the formation of the GaN epitaxial film, and the dislocation density is reduced.

Preferably, please refer to FIG. 12. FIG. 12 is a schematic structural view of a hexagonal hexagonal pit according to the present invention. As shown in FIG. 13, a part of the GaN epitaxial film is grown in a hexagonal hexagonal pit, a part is grown outside the hexagonal hexagonal pit, and a GaN epitaxial film in the hexagonal hexagonal pit is laterally stacked inside, and a hexagonal pyramid is pitted. The outer GaN epitaxial film laterally accumulates in the lateral direction between adjacent regular hexagonal pyramid pits, reducing the dislocation density.

Please refer to FIG. 3 and FIG. 8. FIG. 3 is a schematic structural view of a hexagonal hexagonal patterned substrate according to the present invention; and FIG. 11 is a schematic structural view of a regular hexagonal columnar protrusion according to the present invention.

As shown in Fig. 3, due to the periodic distribution of a plurality of regular hexagonal cylinders, the adjacent sides of the adjacent hexagonal hexagonal hexagons are axisymmetric, and when the duty ratio is constant, when compacted, The gap between the adjacent regular hexagonal columns is large, and the space for lateral growth of the GaN epitaxial film is given. The gap between the adjacent regular hexagonal columns is the same. Therefore, the space for lateral growth of the GaN epitaxial film is the same, and the bit is lowered. Wrong density.

As shown in FIG. 8, the substrate 1 has a regular hexagonal column shape, and a GaN epitaxial film is laterally epitaxially grown on the substrate. Since the line dislocation of the laterally grown GaN film is bent by 90 degrees, the GaN epitaxial film is along the cylindrical side. The wall grows laterally. Since the cylindrical shape has a certain height, the GaN epitaxial film is deposited laterally in the sidewall, so that part of the GaN epitaxial film is deposited at a certain height outside the cylindrical sidewall, giving the GaN epitaxial film a larger space for growth. Reduced dislocation density.

Further, since all the regular hexagonal patterns are regular hexagonal cylinders and the gaps between adjacent regular hexagonal cylinders are the same, the speed of the GaN epitaxial film is the same during the lateral growth of the GaN epitaxial film, and the speed is reduced. Dislocation density.

Preferably, please refer to FIG. 11. FIG. 11 is a schematic structural view of a hexagonal hexagonal pit according to the present invention. As shown in FIG. 11, a part of the GaN epitaxial film is grown in a regular hexagonal column pit, a part is grown outside the hexagonal hexagonal pit, and the GaN epitaxial film in the hexagonal columnar pit is laterally stacked inside, and the GaN epitaxial outside the hexagonal column pit is extended. The film laterally accumulates in the lateral direction between adjacent regular hexagonal pits, reducing the line dislocation density.

Preferably, the above various patterns are formed by a nano-printing method, and the pattern is not limited to a regular hexagonal shape, a regular hexagonal cone shape, a regular hexagonal column shape, a regular hexagonal column-shaped pit, a regular hexagonal pyramid pit, and a regular hexagonal column-shaped pit.

The positive hexagonal patterned substrate of the present invention, wherein the regular hexagon is a regular hexagon with a rounded corner, or a regular hexagon with a convex curve or a positive hexagon in a concave curve, so that the graphic can be effectively suppressed. The dislocation density of the epitaxial layer on the substrate is blocked, the dislocation extension is blocked, and the crystal quality is improved.

Preferably, as an embodiment, a more specific embodiment is that the period length of the periodic pattern is 100 to 8000 nm.

Preferably, the period of the bottom side of the periodic pattern is 10 to 5000 nm.

Preferably, the height of the periodic pattern is 0.1 to 10 μm.

Preferably, the same gap is present within the error range, and the gap between adjacent regular hexagons is 10 to 1000 nm.

The above setting data is to make the microstructure distribution more scientific and reasonable, and it is convenient to form the GaN epitaxial film to grow into three-dimensional growth in the first step. And it is easier to achieve the filling of each microstructure after the end of the first step, and improve the crystal quality.

Referring to FIG. 4, FIG. 4 is a schematic structural view of a base hexagonal apex angle formed by a circular arc curve in the present invention. In order to effectively suppress the dislocation density of the epitaxial layer on the patterned substrate, the crystal quality is improved; as shown in FIG. 4, the vertex angle of the bottom hexagonal hexagon can be set as the rounded corner 5 with a curvature.

Preferably, the vertex of the regular hexagon is rounded.

Preferably, the above-mentioned curvature has a length of 0 to 500 nm.

Referring to FIG. 5, FIG. 5 is a schematic structural view showing a side of a hexagonal hexagonal side of a straight line in the present invention. Preferably, the side length of the regular hexagon is a straight line.

Please refer to FIG. 6. FIG. 6 is a schematic structural view showing a side of a hexagonal positive hexagonal side having a convex curve. Preferably, the side length of the regular hexagon is a convex curve.

Please refer to FIG. 7. FIG. 7 is a schematic structural view showing a side of a hexagonal hexagonal side having a concave curve. Preferably, the side length of the regular hexagon is a concave curve.

The above-mentioned regular pattern can reduce the dislocation density and improve the crystal quality in the first step of the GaN epitaxial film formation process.

As a person skilled in the art, it is to be understood that the substrate is not limited to the sapphire substrate 1, and any one of a silicon carbide substrate, a silicon substrate or a lithium aluminate substrate may also be selected.

Among them, the patterned sapphire substrate technology is a new technology without growth interruption, which can significantly reduce the dislocation density of the epitaxial layer, thereby reducing the non-radiative recombination of the LED active layer carriers and improving the internal quantum efficiency. At the same time, the pattern on the sapphire substrate can increase the scattering of the emitted light on the substrate, so that more light enters the escape region and emits the LED, thereby improving the light extraction rate, especially the nano-patterned sapphire substrate for the light extraction rate. The improvement effect is remarkable. Since the patterned sapphire substrate technology improves internal quantum efficiency and light extraction efficiency, the brightness of the LED is significantly improved. The patterned sapphire substrate is produced in two steps, including the preparation of the mask pattern and the transfer of the pattern. The shape and size of the mask pattern determines the shape and size of the substrate pattern.

Please refer to FIG. 14, which is a top view of a patterned substrate in the present invention. As shown in FIG. 1, the nanopatterned substrate comprises a substrate 1 and a honeycomb structure 6 on the base substrate. The period of the honeycomb structure 6 is 100-5000 nm and the height is 10-5000 nm. The period 6 has a period of 100 to 1000 nm and a height of 10 to 900 nm.

A more specific embodiment uses a nanoimprinting device for the nano-patterned substrate, that is, the base substrate 1 is surface-treated, then a photoresist is coated on the base substrate 1, and the photoresist is honeycombed. The patterning process, finally etching the substrate, forms a honeycomb-like convex structure on the base substrate 1; and in the present embodiment, the base substrate 1 is a polar-oriented sapphire substrate.

It should be understood by those skilled in the art that the base substrate 1 is not limited to a polar-oriented sapphire substrate, and a semi-oriented sapphire substrate may be used, and a polar, non-polar or non-polar orientation may also be employed. Silicon carbide and silicon. Further, a honeycomb structure is formed on the base substrate 1, and is not limited to the convex structure, and may be a concave structure.

Compared with the conventional nano-patterned substrate, the nano-patterned substrate of the embodiment adopts a honeycomb structure, and when the duty ratio is kept constant and the period is decreased, the epitaxial growth on the nano-patterned substrate can still be Maintain good crystal quality.

The basic principles and main features of the invention and the advantages of the invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited by the foregoing embodiments, and that the present invention is only described in the foregoing description and the description of the present invention, without departing from the spirit and scope of the invention. Various changes and modifications are intended to be included within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and their equivalents.

Industrial applicability

The regular hexagonal patterned substrate 1 of the present application has the same hexagonal shape as the regular pattern, and has the same 360-degree rotating structure shape centered on the center of the regular hexagon; since the regular hexagon is periodically arranged and is hexagonal The side of either side that corresponds to the adjacent normal hexagonal pattern is axisymmetric with respect to the central axis between the two, so that it is more orderly while maintaining the duty cycle and closely aligned, and the gap between multiple adjacent patterns is kept the largest. The process window of the epitaxy is broadened, and the yield and reliability of the product are improved; thereby, the dislocation density of the epitaxial film grown thereon and the light extraction efficiency of the chip are improved. Since the periodic distribution microstructure is added to the substrate 1, the dislocation extension can be effectively blocked, the dislocation density is reduced, the quality of the generated material is improved, and the crystal quality is improved.

Claims

A positive hexagonal patterned substrate, comprising: a substrate having a periodicized convex or concave pattern, the bottom edge of the raised or concave pattern being a regular hexagon and being honeycomb tight Arrangement, that is, a vertical bisector of any one of the sides of the regular hexagon is passed through the center of the regular hexagon and the corresponding adjacent hexagon, and a gap exists between the adjacent regular hexagons, and any one of the sides of the regular hexagon is aligned with the adjacent regular hexagon. The side is axisymmetric with respect to the gap.
The regular hexagonal patterned substrate according to claim 1, wherein said periodic pattern has a length period of from 100 to 8000 nm.
The regular hexagonal patterned substrate according to claim 1, wherein said periodic pattern has a base side length of 10 to 5000 nm.
The regular hexagonal patterned substrate according to claim 1, wherein said periodically patterned pattern has a height of 0.1 to 10 μm.
The regular hexagonal patterned substrate according to claim 1, wherein a gap between adjacent regular hexagons is 10 to 1000 nm.
A regular hexagonal patterned substrate according to claim 1 wherein said raised or recessed pattern is a regular hexagonal shape.
The regular hexagonal patterned substrate of claim 1 wherein said raised or recessed pattern is a regular hexagonal taper.
The regular hexagonal patterned substrate of claim 1 wherein said raised or recessed pattern is a regular hexagonal prism.
The regular hexagonal patterned substrate according to claim 1, wherein the vertex of the regular hexagon has an arc having a length of 0 to 500 nm.
The regular hexagonal patterned substrate according to claim 1, wherein the vertex of the regular hexagon is rounded.
The regular hexagonal patterned substrate according to claim 1, wherein the side of the regular hexagon is a straight line.
The regular hexagonal patterned substrate according to claim 1, wherein said regular hexagon has a curved side curve.
A regular hexagonal patterned substrate according to claim 1 wherein the sides of said regular hexagons are concave curves.
The regular hexagonal patterned substrate of claim 1 wherein said substrate is sapphire.
The regular hexagonal patterned substrate of claim 1 wherein said substrate is silicon carbide or silicon.
The regular hexagonal patterned substrate of claim 1 wherein said substrate is lithium aluminate.
A nano-patterned substrate, characterized in that the nano-patterned substrate comprises a base substrate and a honeycomb structure formed on the base substrate, the honeycomb structure having a period of 100-5000 nm and a height of 10 -5000nm.
The nanopatterned substrate of claim 17 wherein said nanopatterned substrate is a honeycomb raised structure or a honeycomb structure.
The nanopatterned substrate of claim 17 wherein said nanopatterned substrate is one of polar, semi- or non-polar oriented sapphire, silicon carbide, and silicon.