CN102184846A - Preparation method of patterned substrate - Google Patents

Abstract

The invention provides a preparation method of a heterogeneous material patterned substrate, which comprises the steps of preparing a periodic pattern by using a heterogeneous material, growing a single crystal heterogeneous material with a certain thickness on a sapphire substrate, uniformly coating photoresist on the sapphire substrate on which the single crystal heterogeneous material with a certain thickness is grown by adopting a photoresist throwing technology, exposing the periodic pattern on the photoresist by using an exposure technology, and displaying the periodic pattern on the photoresist by using a developing technology, thereby obtaining the patterned substrate of the periodic pattern on the surface of the sapphire, wherein the periodic pattern is formed by the heterogeneous material, or the periodic pattern is formed by layering the heterogeneous material and the sapphire according to a certain proportion. The invention breaks through the characteristic that the traditional patterned substrate only utilizes the sapphire substrate to form a periodic pattern, and achieves the purposes of improving the crystal growth quality and improving the light-emitting efficiency of the device.

Description

A method for preparing a patterned substrate

technical field

The invention belongs to the technical field of semiconductor optoelectronics and relates to a method for preparing a patterned substrate for growing GaN epitaxial wafers.

Background technique

GaN, InGaN, and AlGaN-based Ⅲ/Ⅴ nitrides are semiconductor materials that have attracted much attention in recent years. They have continuously variable direct band gaps of 1.9-6.2 eV, excellent physical and chemical stability, and high saturation electron mobility. And other characteristics, making it the most preferred material for optoelectronic devices such as lasers and light-emitting diodes.

Due to the difficulty in preparing GaN single crystals and finding materials that match the GaN lattice, nitride optoelectronic devices are usually fabricated on sapphire substrates. However, the lattice constants of sapphire and GaN differ by about 15%, and the coefficients of thermal expansion and chemical properties also differ greatly. The large mismatch makes the defect density of the nitride epitaxial layer grown on the sapphire substrate larger, and these defects will spread backward to the adjacent window, thereby increasing the defect density of the InGaN active region. It is reported that at 10 ⁹ cm ^{~ 2} ~ 10 ¹² cm ^{~ 2} orders of magnitude. The existence of line defects provides a path for the diffusion of Mg, and at the same time increases the probability of electron leakage from the MQW, thus affecting the lifetime and luminous efficiency of the device. When the emission wavelength is 410nm, the total reflection angle arctan (2154/ 1179) between GaN material and sapphire is 44.8°, which makes nearly 90% of the light generated in the active area confined in the device, and is reflected by multiple reflections. It is absorbed, which increases the heat generation of the LED and weakens its luminous brightness. Therefore, how to improve the growth quality of devices based on sapphire substrates has become a key issue restricting the development of LED devices.

In order to reduce defect density, increase light extraction efficiency, improve the brightness and reliability of light-emitting diodes, and prolong their life, researchers have adopted various methods. Among them, the lateral epitaxy technique is a relatively successful one, which is considered to be an effective means to reduce the dislocation density and improve the quality of growing GaN crystals.

Figure 1 shows the material structure required for lateral epitaxy. As shown in Figure 1, lateral epitaxy requires a substrate prepared as follows. A sapphire substrate, a 2-10 micron GaN layer on the sapphire substrate, and a 100-500nm thick, 5-10 micron-wide _SiO2 film strip grown on the GaN layer. MOCVD is used to grow thick-film GaN materials on such GaN\SiO ₂ alternate surfaces.

Using lateral epitaxy, the dislocations in the GaN layer under the _SiO2 strips will be blocked by the _SiO2 strips so as not to reach the sample surface, and only the dislocations between the _SiO2 strips have a chance to penetrate through the _SiO2 strips To the surface of the sample, as shown in Figure 2, Figure 2 is a schematic diagram of the growth of the lateral epitaxial dislocation reduction and a thick SEM picture of the growth. Therefore, its application reduces the dislocation density of epitaxially grown GaN materials, and effectively improves the crystal quality and device performance of GaN materials. However, the lateral epitaxy technology is mainly used for growing thick film GaN (more than 20 microns thick). In the application of blue-green LED epitaxy, because it requires a GaN layer of 2 to 10 microns, and the GaN layer in the LED epitaxial wafer The total thickness is only 3-5 microns, so it is not suitable for LED epitaxy.

In recent years, Patterned Structure Substrates technology has gradually become popular.

The main structure of the patterned substrate is shown in Figure 3. On the surface of the sapphire substrate, photolithography and dry etching techniques are used to form a patterned sapphire surface with conical sapphire protrusions. The base radius of the conical protrusions is between 3.0 microns and 5 microns, and the height is between 1.0 microns and 1.5 microns. The distance between the central axes of the cones is between 4 and 6 microns.

Then LED material epitaxy is carried out on the patterned substrate surface, and the patterned interface changes the growth process of the GaN material. The surface pattern provides a variety of growth crystal orientation options for GaN growth, and the growth rate of GaN along the pattern surface is different, so that the lattice mismatch dislocations are bent and closed in the substrate growth region, and the defect orientation is effectively suppressed. The extension of the epitaxial surface improves the internal quantum efficiency of the device; PSS substrate technology has become the preferred substrate material for major LED production and R&D companies to develop high-brightness and high-power LED devices due to its simple process.

Contents of the invention

The purpose of the present invention is to overcome the disadvantages of the prior art and provide a method for preparing a heterogeneous material patterned substrate. The patterned substrate of heterogeneous materials involved in the present invention refers to the use of heterogeneous materials (materials different from sapphire and GaN) to prepare periodic patterns to replace the sapphire patterns formed by etching on the surface of traditional patterned substrates; or the heterogeneous The sapphire material and sapphire are layered together in a certain proportion to form a periodic pattern on the sapphire surface; this material has the characteristics of high temperature resistance, can not decompose when grown at a high temperature above 800 degrees, and can exist in the form of a single crystal material. Compared with GaN, there is a big difference, such materials as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials and other materials.

In order to achieve the above object, a method for preparing a patterned substrate of the present invention adopts the following technical solutions:

A method for preparing a patterned substrate, a method for preparing a patterned substrate of a heterogeneous material, using a heterogeneous material to prepare a periodic pattern, the method includes the following steps:

①. Provide a sapphire substrate for use after cleaning;

②. Growing a single crystal heterogeneous material with a certain thickness on the sapphire substrate, and the thickness of the single crystal heterogeneous material is 100 nanometers to 3 microns;

③Using glue-spinning technology, evenly coat photolithography on the sapphire substrate grown with a certain thickness of single crystal heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials, etc.) (This photoresist can be positive or negative, as long as the corresponding photoresist plate can be used to get the same pattern), and the photoresist is thrown evenly by using the technology of throwing the photoresist, and the thickness of the photoresist is etched according to the required It depends on the depth of etching the heterogeneous material, preferably 1.0 micron to 3.0 micron;

④. Use exposure technology to expose periodic patterns on the photoresist, and use development technology to make the photoresist show periodic patterns;

⑤. Use dry etching technology, such as ICP, RIE, etc. to etch and develop single crystal heterogeneous materials with photoresist and a certain thickness (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series of materials) sapphire substrate, the photoresist pattern is etched to display a certain thickness of single crystal heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials and other materials )superior. Carry out dry etching until the surface of sapphire is etched, or continue to etch sapphire to a certain depth, and the etching depth is the same as that of single crystal heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials, etc. ) The remaining thickness ratio is optional from 0.001:0.999 to 0.95:0.05;

⑥. Use a solution such as acetone to remove the remaining photoresist, or the photoresist has been completely etched in dry etching without remaining. Thus, a patterned substrate is obtained in which a periodic pattern is formed by the heterogeneous material, or the heterogeneous material and sapphire are layered in a certain proportion to form a periodic pattern on the surface of the sapphire.

Further, in the step ②, PECVD, MOCVD, CVD or magnetron sputtering technology is used to grow a single crystal heterogeneous material with a certain thickness on the sapphire substrate, and the single crystal heterogeneous material is SiO ₂ , Si ₃ N ₄ , For SiC, Si, ZnO, GaAs series materials, the thickness of the single crystal heterogeneous material is preferably 500 nanometers to 1.8 microns.

Further, the periodic figure in the step ③ can also be concave (as shown in Figure 6a and Figure 6b), and the concave periodic figure is a conical pit, a columnar pit, a trapezoidal conical pit, a triangular conical pit, a triangular pit Table pit, square cone pit, square column pit, trapezoid square table pit and five-sided conical pit, five-sided cylindrical pit, trapezoidal five-sided trapezoidal pit, hexagonal conical pit, hexagonal cylindrical pit, trapezoidal Hexagonal pits, 12-sided conical pits, 12-sided columnar pits, trapezoidal 12-sided trapezoidal pits, and other polygonal conical pits, polygonal columnar pits, and trapezoidal polygonal pits.

Further, the periodic figure in the step ③ can be a raised conical shape, a cylindrical shape, a trapezoidal truncated cone, a triangular cone, a square cone, a square column, a triangular square, a trapezoidal square and a pentagonal cone Shape, pentagonal column, trapezoidal pentagonal, hexagonal cone, hexagonal column, trapezoidal hexagonal, 12-sided cone, 12-sided column, trapezoidal 12-sided truncated polygonal cone, polygonal column and Trapezoidal polygonal frustum.

Further, the size range of the periodic figure in step ③ is shown in Figure 5, and the period of the periodic figure (the distance between the central axes of the two figures, represented by the letter A) is 0.2 to 50 microns, among which, preferably 1 to 10 microns micron; the diameter of the bottom surface of the periodic pattern (indicated by the letter W) is 0.1 to 50 microns, wherein, preferably 0.8 to 9 microns; the height of the periodic pattern (indicated by the letter d) is 0.1 to 3 microns, wherein, preferably 0.5 to 1.8 microns.

Further, the periodic pattern of the patterned substrate prepared in step ⑥ is completely composed of heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials), or is composed of heterogeneous materials and The sapphire is layered according to a certain proportion, the upper part of the figure is heterogeneous material, and the lower part of the figure is sapphire; the ratio of heterogeneous material to sapphire is from heterogeneous material layer thickness: sapphire graphic layer thickness = 0.05:0.95 to the figure is completely heterogeneous quality material.

Further, the concave periodic pattern can also be completely composed of heterogeneous materials, such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials, etc., as shown in Figure 6c; it can also be It is composed of layers of heterogeneous materials and sapphire in a certain ratio; the ratio of heterogeneous materials and sapphire varies from heterogeneous material layer thickness: sapphire graphic layer thickness = 0.05:0.95 to graphics are completely heterogeneous materials, as shown in Figure 6d.

Further, the size range of the concave periodic pattern is shown in Figure 6a and Figure 6b, and the period of the periodic pattern (the distance between the central axes of the two figures, represented by the letter A) is 0.2 to 50 microns, among which, preferably 1 ~10 microns; the diameter of the bottom surface of the periodic pattern (indicated by the letter W) is 0.1 to 50 microns, wherein, preferably 0.8 to 9 microns; the height of the periodic pattern (indicated by the letter d) is 0.1 to 3 microns, wherein , preferably 0.5 to 1.8 microns.

Advantages of the substrate:

Compared with ordinary sapphire substrates, growing gallium nitride epitaxial layers on PSS substrates has obvious advantages:

(1) Epitaxial defects can be reduced, the dislocation density can be reduced, and the crystal quality of the epitaxial layer can be significantly improved, thereby improving the internal quantum efficiency of the device.

(2) In addition, the refractive index of sapphire is 1.8, and that of gallium nitride is 2.4. Due to the difference in refractive index, when light enters the graphics substrate from the epitaxial layer, reflection will be formed, thereby improving the light output rate of GaN-based light-emitting diodes.

(iii) The GaN epitaxial wafer grown on the PSS substrate can significantly reduce the residual stress of the epitaxial wafer due to lattice mismatch and thermal mismatch.

Substrate application:

The parameters of LED devices made of epitaxial materials based on PSS substrates show that the optical power level at 20mA is about 30% higher than that of devices made of ordinary sapphire substrates. An effective measure of light extraction efficiency.

The reduction of stress in PSS growth is a necessary condition for HVPE thick film growth. When growing a thick film, the primary problem is that when the GaN grows thick, the crystal cracks due to the accumulation of residual stress. Therefore, the PSS substrate is also widely used in the manufacture of GaN substrates.

In summary, the current main applications of PSS substrates include,

First: Growth of high-power, high-brightness LED epitaxial wafers

Second: Growth of GaN single crystal substrate

Third: Growth of GaN composite substrate

The invention breaks the characteristic that the traditional patterned substrate only utilizes the sapphire substrate to form periodic patterns. Instead, a heterogeneous material different from sapphire or GaN is used to prepare periodic patterns on the surface of sapphire, which has achieved the purpose of improving the quality of crystal growth and improving the light extraction efficiency of the device. Therefore, the present invention is a significant improvement over conventional patterned substrate technology.

In addition, the present invention has two obvious advantages over the traditional sapphire patterned substrate.

The reason why the traditional patterned sapphire substrate can improve the device efficiency is mainly due to two reasons. One is to improve the crystal quality of the epitaxial substrate. We have explained this in the background technology. The patterned substrate will make GaN dislocations in the GaN material grown at the windows between the patterns bend along the sides of the cone or other patterns, and the dislocations climb to the pattern. At the top, the dislocations grown from different windows will form a closure. Therefore, the dislocation density of the GaN material grown on the pattern substrate will be significantly reduced, the crystal quality will be improved, and the internal quantum efficiency of the GaN-based LED device will be improved. On the other hand, the light-emitting surface of the GaN-based LED epitaxial wafer grown on a sapphire substrate is mainly on the surface of the GaN material, and the light emitted from the GaN LED active layer to the sapphire substrate is basically encapsulated by the metal base, etc. Absorption by other materials does not contribute much to the overall luminous efficiency. Therefore, if the light emitted to the sapphire substrate can be reflected back to the top of the GaN and then emitted, the light extraction efficiency of the LED device will be greatly improved. The surface pattern of the patterned sapphire substrate happens to form a reflective grating, which can effectively reflect the light that hits the sapphire, thereby improving the efficiency of the LED device.

Compared with the traditional patterned sapphire substrate, the patterned substrate of heterogeneous material in the present invention has obvious improvements in these two aspects.

First of all, in the growth of the patterned substrate, in order to make the dislocations in the GaN material grown in the pattern window bend along the side of the pattern, and then close up on the top of the pattern, the key issue is to avoid the periodicity of the GaN material in the pattern substrate as much as possible. Lateral growth of sexual figures. However, the periodic pattern formed by the sapphire material makes it difficult for the pattern not to grow on the side. In this regard, the patterned substrate of heterogeneous materials has obvious advantages. Since the selected material itself is not suitable for GaN to grow on it, it is easy to prevent GaN from growing on the side of the pattern during growth, thereby promoting the growth of the position. The fault is bent along the side of the figure and then closed at the top of the figure, thereby further improving the crystal quality of the GaN material and improving device efficiency.

Secondly, in terms of improving the light extraction efficiency of LED devices by forming a reflective grating with periodic patterns on the patterned substrate, the large difference in the refractive index between GaN material and sapphire material is another very important factor besides the influence of pattern size on reflection formation. factor. The refractive index of GaN material is 2.5, while that of sapphire is 1.8. The difference between the two forms a larger total reflection angle, thereby improving the light extraction efficiency of LEDs. In this regard, periodic patterned substrates of heterogeneous materials will have greater advantages. The heterogeneous material we choose can have a larger refractive index difference with GaN, resulting in higher reflectivity. For example, SiO ₂ material has a reflectivity of 1.4, which is even more different from sapphire. By theoretically simulating the light extraction efficiency of the traditional patterned substrate and the SiO ₂ material patterned substrate, as shown in Figure 7, we can see that the patterned substrate of heterogeneous materials can improve the light extraction efficiency of LED devices. Figure 8 shows the optical power curves of LED devices prepared by using traditional patterned substrates and LED devices prepared by SiO ₂ patterned substrates. We can see that within the working current range of 0-50mA, SiO ₂ The optical power of the LED device prepared on the substrate is significantly higher than that of the LED device prepared on the traditional patterned substrate.

Compared with the lateral epitaxy technique, the present invention has obvious improvement and difference.

1. In the lateral epitaxy technique, a _SiO2 layer is first formed on a GaN layer with a thickness of 2-10 microns, while the present invention directly forms a periodic pattern of heterogeneous materials on a sapphire substrate.

2. The SiO ₂ thin film used in the lateral epitaxy technology is a SiO ₂ thin film strip structure, and the structure size is about 5-10 microns, and the thickness does not exceed 500nm. The heterogeneous material periodic structure used in the present invention is a periodic cone, column, or mesa. And its size range is obviously different from that of lateral epitaxy technology. The pattern height is preferably 0.5 to 1.8 microns.

Description of drawings

Figure 1 shows the material structure required for lateral epitaxy;

Figure 2 shows a schematic diagram of the growth of lateral epitaxial dislocation reduction and a thick SEM picture of growth;

Figure 3 shows a schematic structural diagram of a traditional patterned substrate, as well as an SEM photo and an interface SEM after GaN growth is applied;

Figure 4a shows a schematic diagram of a patterned substrate structure in which a complete heterogeneous material forms a periodic pattern;

Figure 4b shows a schematic diagram of a patterned substrate structure in which heterogeneous materials and sapphire are layered to form a periodic structure;

Figure 5 is a schematic diagram of the definition of critical dimensions of a heterogeneous material patterned substrate;

Figure 6a and Figure 6b show a schematic diagram of the structure of a concave patterned substrate of heterogeneous materials and a schematic diagram of the definition of several key dimensions;

Figure 6c shows a schematic diagram of the structure of a periodic concave pattern substrate of a complete heterogeneous material;

Figure 6d shows a schematic diagram of the structure of heterogeneous material and sapphire layered concave pattern substrate;

Figure 7 shows the total light output power spectrum lines of LED devices prepared from a pattern height of 0.8 microns to 1.8 microns using simulated traditional conical patterned substrates and _SiO2 conical patterned substrates;

Figure 8 shows the optical power curves of LED devices prepared using traditional conical patterned substrates and SiO ₂ conical patterned substrates;

Figure 9 shows a process flow diagram of Embodiment 1 of the present invention;

Fig. 10 shows the schematic diagram of the patterned substrate of the complete SiO obtained in Example ₁ of the present invention to prepare periodic patterns;

FIG. 11 shows a schematic diagram of a complete _SiO2 patterned substrate of a second _SiO2 periodic pattern of the present invention;

Figure 12 shows the process flow chart of the third embodiment of the present invention;

FIG. 13 is a schematic diagram of a complete Si3N4 patterned substrate of a third Si3N4 periodic pattern in the embodiment of the present invention;

The relevant structure in the figure mainly includes the following components: photoresist 1, SiO ₂ thin film 2, sapphire substrate 3, Si ₃ N ₄ thin film 4.

Detailed ways

In order to further understand the features, technical means, specific objectives and functions achieved by the present invention, and to analyze the advantages and spirit of the present invention, a further understanding of the present invention can be obtained through the following detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments.

The preparation method involved in the present invention is as follows:

First, grow a certain thickness of single crystal heterogeneous materials on a sapphire substrate, such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials and other materials. Its thickness can be from 100 nm to 3 microns, wherein 500 nm to 1.8 microns is preferred.

Secondly, using the glue-spinning technology well known to those skilled in the art, the sapphire lining grown with a certain thickness of single crystal heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials, etc.) Evenly coat the photoresist on the bottom (this photoresist can be positive or negative, as long as the corresponding photolithography plate can be used to get the same pattern), and use the technology of spraying the photoresist to throw the photoresist evenly, and the photoresist The thickness of the resist depends on the desired etching depth of the heterogeneous material, preferably 1.0 micron to 3.0 micron.

In the third step, a periodic pattern is exposed on the photoresist by using an exposure technique well known to those skilled in the art, and a periodic pattern is displayed on the photoresist by using a development technique well known to those skilled in the art.

The fourth step is to use dry etching technology, such as ICP, RIE, etc. to etch and develop the single crystal heterogeneous material with photoresist and a certain thickness (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO , GaAs series materials and other materials) sapphire substrate, the photoresist pattern is etched to display a certain thickness of single crystal heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials and other materials). Carry out dry etching until the surface of sapphire is etched, or continue to etch sapphire to a certain depth, and the etching depth is the same as that of single crystal heterogeneous materials (such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials, etc. ) The remaining thickness ratio is optional from 0.001:0.999 to 0.95:0.05.

In the fifth step, use a solution such as acetone to remove the remaining photoresist, or the photoresist has been completely etched in the dry etching process and there is no remaining photoresist. Thus, a patterned substrate is obtained in which a periodic pattern is formed by the heterogeneous material, or the heterogeneous material and sapphire are layered in a certain proportion to form a periodic pattern on the surface of the sapphire.

The patterned substrate finally prepared by the method described in the present invention is characterized in that its periodic pattern can be completely composed of heterogeneous materials, such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials and other materials, As shown in Figure 4a, it can also be composed of heterogeneous materials and sapphire in a certain proportion. As shown in Figure 4b, the upper part of the pattern is heterogeneous material, and the lower part of the pattern is sapphire. The ratio of heterogeneous material to sapphire ranges from heterogeneous material layer thickness: sapphire graphic layer thickness = 0.05:0.95 to graphic is completely heterogeneous material.

The periodic figure in the present invention can be a raised conical shape, a cylindrical shape, a trapezoidal truncated cone, a triangular cone, a square cone, a square column, a triangular square, a trapezoidal square and a pentagonal cone, Pentagonal, trapezoidal, hexagonal, hexagonal, trapezoidal, hexagonal, 12-sided, 12-sided, trapezoidal, 12-sided Table shape.

The size range of the periodic pattern is shown in Figure 5, and the period of the periodic pattern (the distance between the axes of the two patterns, represented by the letter A) is 0.2-50 microns, preferably 1-10 microns. The diameter of the bottom surface of the periodic pattern (indicated by the letter W) is 0.1-50 microns, and preferably 0.8-9 microns. The height of the periodic pattern (indicated by the letter d) is 0.1-3 microns, preferably 0.5-1.8 microns.

The periodic figure of the present invention can also be a conical pit, a columnar pit, a trapezoidal conical pit, a triangular conical pit, a triangular truncated pit, a square conical pit, a square pit, etc. Columnar pit, trapezoidal square platform pit and five-sided conical pit, five-sided cylindrical pit, trapezoidal five-sided terraced pit, hexagonal conical pit, hexagonal cylindrical pit, trapezoidal six-sided terraced pit, 12-sided conical pit Pit, 12-sided columnar pit, trapezoidal 12-sided terraced pit and other multilateral conical pits, multilateral cylindrical pits and trapezoidal multilateral terraced pits.

The concave periodic pattern described in the present invention can also be completely made of heterogeneous materials, such as SiO ₂ , Si ₃ N ₄ , SiC, Si, ZnO, GaAs series materials and other materials, as shown in Figure 6c; It can be composed of heterogeneous materials and sapphire layered in a certain proportion. The ratio of heterogeneous material to sapphire varies from heterogeneous material layer thickness: sapphire graphic layer thickness = 0.05:0.95 to the graphic is completely heterogeneous material, as shown in Figure 6d.

The size range of the concave periodic pattern is shown in Figure 6a and Figure 6b, and the period of the periodic pattern (the distance between the central axes of the two figures, represented by the letter A) is 0.2 to 50 microns, preferably 1 to 10 microns . The diameter of the bottom surface of the periodic pattern (indicated by the letter W) is 0.1-50 microns, and preferably 0.8-9 microns. The height of the periodic pattern (indicated by the letter d) is 0.1-3 microns, preferably 0.5-1.8 microns.

Embodiment one:

Completely SiO ₂ prepares a patterned substrate with periodic patterns, see accompanying drawing 9:

Step 1. Select a 2-inch sapphire substrate 3 with a thickness of 430 microns; the first step of accompanying drawing 9 is a 2-inch sapphire substrate with a thickness of 430 microns;

Step 2. Utilize PECVD technique to grow on the sapphire substrate 3 with a thickness of 1.5 micron SiO ₂ thin film 2, the second step of accompanying drawing 9 is the 430 micron thick 2-inch sapphire substrate 3 grown with 1.5 micron thick SiO 2 thin _film 2;

1-1.5 micron thick SiO2 film ₂ , 2-430 micron thick sapphire substrate;

Step 3. Utilize the glue throwing machine to evenly coat the photoresist 1 with a thickness of 1.5 microns on the surface of the _SiO2 substrate prepared in step 2; ₂ / Sapphire substrate;

1-1.5 micron photoresist 1, 2-1.5 micron thick SiO2 film ₂ , 3-430 micron thick sapphire 3;

Step 4. Expose the SiO ₂ /sapphire substrate coated with 1.5 micron photoresist 1 through a step exposure machine, and develop to form a cylindrical pattern with a surface period of 3 microns and a cylinder diameter of 2 microns, as shown in Figure 9 As shown in the fourth step;

The fourth step of accompanying drawing 9 is the SiO ₂ /sapphire substrate with photoresist patterns after development;

A periodic cylindrical photoresist pattern with a period of 3 microns and a cylinder diameter of 2 microns;

1.5 micron thick SiO ₂ , 430 micron thick sapphire1;

Step 5. Put the sample with periodic pattern photoresist 1 into ICP (Reaction Coupled Ion Etching Equipment), select pure boron trichloride gas for etching, and the etching time is 22 minutes. After taking it out, use dilute HCL, acetone, alcohol, and deionized water to wash once to obtain a complete _SiO2 patterned substrate with a periodic pattern of 3.15 microns, a height _of 1.5 microns, and a bottom diameter of 2.7 microns. As shown in Figure 10.

Embodiment two:

SiO ₂ and sapphire layered to form a patterned substrate with periodic patterns

Step 1. Select a 2-inch sapphire substrate 3 with a thickness of 430 microns;

Step 2. Utilizing PECVD technology to grow a thickness of 1.5 microns on the sapphire substrate 3 SiO ₂ film 2;

1-1.5 micron thick SiO2 film ₂ , 2-430 micron thick sapphire substrate 3;

Step 3. Utilize the glue throwing machine to evenly coat the photoresist 1 with a thickness of 1.5 microns on the surface of the substrate _SiO2 prepared in step 2, and become the _SiO2 /sapphire substrate coated with the photoresist of 1.5 microns;

1-1.5 micron photoresist 1, 2-1.5 micron thick SiO ₂ , 3-430 micron thick sapphire substrate 3;

Step 4. Expose the SiO ₂ /sapphire substrate coated with 1.5 micron photoresist 1 through a step exposure machine, and develop to form a cylindrical pattern with a surface period of 3 microns and a cylinder diameter of 2 microns, with a period of 3 microns , a periodic cylindrical photoresist pattern with a cylinder diameter of 2 μm,

1.5 micron thick SiO ₂ , 430 micron thick sapphire;

Step 5. Put the sample with periodic pattern photoresist into ICP (Reaction Coupled Ion Etching Equipment), select pure boron trichloride gas for etching, and the etching time is 30 minutes. After taking it out, wash it once with dilute HCL, acetone, alcohol, and deionized water to obtain SiO 2 with a period of 3.2 microns, a height of 1.2 microns (the thickness of the SiO ₂ layer is 0.6 microns, and the thickness of the sapphire is 0.6 microns), and the bottom diameter of the pattern is 2.8 microns _. Periodically patterned fully _SiO2 patterned substrates. As shown in Figure 11.

Embodiment three:

Patterned Substrate with Periodic Pattern Prepared from Complete Si ₃ N ₄

Step 1. Select a 2-inch sapphire substrate 3 with a thickness of 430 microns, and the first step of accompanying drawing 12 is a 2-inch sapphire substrate 3 with a thickness of 430 microns;

Step 2. Utilize PECVD technology to grow Si ₃ N ₄ film 4 with a thickness of 1.8 microns on the sapphire substrate 3. The second step of accompanying drawing 12 is 430 micron thick 2-inch sapphire grown with 1.8 micron thick Si ₃ N ₄ film 4 Substrate 3;

1-1.8 micron thick Si ₃ N ₄ film 4, 2-430 micron thick sapphire substrate 3;

Step 3. Utilize the adhesive throwing machine to uniformly coat the photoresist 1 with a thickness of 1.5 microns on the surface of the substrate Si ₃ N ₄ film 4 prepared in step 2; the third step of the accompanying drawing 12 is to coat the photoresist with a thickness of 1.5 microns Si ₃ N ₄ /sapphire substrate after 1;

1-1.5 micron photoresist 1, 2-1.8 micron thick Si ₃ N ₄ film 4, 3-430 micron thick sapphire 3;

Step 4. Expose the Si ₃ N ₄ /sapphire substrate coated with 1.5 micron photoresist 1 through a step exposure machine, and develop to form a cylindrical pattern with a surface period of 3 microns and a cylinder diameter of 2 microns, as shown in the figure 12 as shown in the fourth step;

The fourth step of accompanying drawing 12 is Si ₃ N ₄ /sapphire substrate with photoresist pattern after development;

A periodic cylindrical photoresist pattern with a period of 3 microns and a cylinder diameter of 2 microns;

1.8 micron thick Si ₃ N ₄ , 430 micron thick sapphire;

Step 5. Put the sample with periodic pattern photoresist 1 into ICP (Reaction Coupled Ion Etching Equipment), select pure boron trichloride gas for etching, and the etching time is 22 minutes. After taking it out, wash it once with dilute HCL, acetone, alcohol, and deionized water to obtain a complete Si3N4 patterned substrate with a period of 3.15 microns, a height of 1.8 microns, and a pattern bottom diameter of 2.9 microns. Show.

Embodiment four:

Si ₃ N ₄ layered with sapphire to form a patterned substrate with periodic patterns

The specific implementation method is the same as that in the second embodiment, except that in the second step, a Si ₃ N- ₄ layer is grown on the sapphire substrate by PECVD technology.

Embodiment five:

Periodic patterned patterned substrate prepared entirely from ZnO

The specific implementation method is the same as that of the first embodiment, except that in the second step, a 1.5-micron-thick ZnO layer is grown on the sapphire substrate by using the MOCVD method.

Embodiment six:

ZnO and sapphire layered to form a patterned substrate with periodic patterns

The specific implementation method is the same as that in the second embodiment, except that in the second step, a ZnO layer with a thickness of 1.5 microns is grown on the sapphire substrate by MOCVD.

Embodiment seven:

Patterned Substrates with Periodic Patterns Prepared from Complete Square Conical SiO ₂

The specific implementation method is the same as that of the first embodiment, except that in the fourth step, the photoresist is exposed to form square pillars with a length of 2 microns.

The above-mentioned embodiments only express some implementations of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims (8)

1. the preparation method of a patterned substrate prepares a kind of dissimilar materials patterned substrate, utilizes dissimilar materials manufacturing cycle figure, it is characterized in that described method comprises the steps:

1., a Sapphire Substrate is provided, the cleaning back is standby;

2., on Sapphire Substrate the certain thickness monocrystalline dissimilar materials of growth, monocrystalline dissimilar materials thickness is 100 nanometers to 3 micron;

3., adopt the whirl coating technology, on the Sapphire Substrate of certain thickness monocrystalline dissimilar materials of having grown, evenly apply photoresist, utilize the whirl coating technology that photoresist is got rid of evenly;

4., utilizing exposure technique will have periodic graph exposure is formed on the photoresist, utilizes developing technique to make photoresist show periodic pattern;

5., utilize dry etching technology, the Sapphire Substrate that has photoresist, certain thickness monocrystalline dissimilar materials after etching is developed, the photoresist figure is passed through etching, on the certain thickness monocrystalline dissimilar materials that shows, dry etching proceeds to and etches into sapphire surface, or continues etching sapphire certain depth;

6., utilize the remaining photoresists of solution removal such as acetone, or photoresist in dry etching by whole etchings residue not, thereby obtain forming the patterned substrate that periodic pattern or this dissimilar materials and sapphire layering by a certain percentage constitute the periodic pattern of sapphire surface jointly by dissimilar materials.

2. the preparation method of a kind of patterned substrate according to claim 1, it is characterized in that: described step adopts PECVD, MOCVD, CVD or the magnetron sputtering technique certain thickness monocrystalline dissimilar materials of growing in 2. on Sapphire Substrate, described monocrystalline dissimilar materials is SiO ₂, Si ₃N ₄, SiC, Si, ZnO, GaAs series material.

3. the preparation method of a kind of patterned substrate according to claim 1, it is characterized in that: the 4. middle periodic pattern of described step caves in, and depression shape periodic pattern is a conical pit, the cylindricality hole, trapezoidal round platform hole, the triangular pyramidal hole, triangle platform shape hole, side's conical pit, the square column type hole, trapezoidal side's bench-type hole and five limit conical pits, five side column shapes hole, platform shape hole, trapezoidal five limit, the hexagon conical pit, hexagon cylindricality hole, trapezoidal hexagon platform shape hole, 12 limit conical pits, 12 side column shapes hole, the polygon conical pit in platform shape hole, trapezoidal 12 limit, polygon cylindricality hole or trapezoidal polygon shape hole.

4. the preparation method of a kind of patterned substrate according to claim 1 is characterized in that: taper shape, cylindrical, trapezoidal truncated cone-shaped, triangular pyramidal, square taper, square column type, triangle side's bench-type, trapezoidal side's bench-type and five limit tapers, five side column shapes, trapezoidal five limit platform shapes, hexagon taper, hexagon cylindricality, trapezoidal hexagon platform shape, 12 limit tapers, 12 side column shapes, the polygon taper of trapezoidal 12 limit platform shapes, polygon cylindricality or trapezoidal polygon shape that the 4. middle periodic pattern of described step can be a projection.

5. the preparation method of a kind of patterned substrate according to claim 1, it is characterized in that: 4. the cycle of middle periodic pattern is 0.2～50 micron to described step, the bottom surface diameter of periodic pattern is 0.1～50 micron, and the height of periodic pattern is 0.1～3 micron.

6. the preparation method of a kind of patterned substrate according to claim 1, it is characterized in that: the described step 6. periodic pattern of the patterned substrate of middle preparation is made of dissimilar materials, or constitute by dissimilar materials and sapphire layering according to a certain percentage, be that figure top is dissimilar materials, and the bottom of figure is sapphire.

7. the preparation method of a kind of patterned substrate according to claim 3, it is characterized in that: described pitting periodic pattern is made of dissimilar materials;

Perhaps described pitting periodic pattern is to be made of dissimilar materials and sapphire layering by a certain percentage, and dissimilar materials and sapphire ratio are from the dissimilar materials bed thickness: sapphire graphical bed thickness=0.05:0.95 is a dissimilar materials to figure fully.

8. the preparation method of a kind of patterned substrate according to claim 3, it is characterized in that: the cycle of described depression shape periodic pattern is 0.2～50 micron, the bottom surface diameter of periodic pattern is 0.1～50 micron, and the height of periodic pattern is 0.1～3 micron.

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