Preparation method of patterned composite substrate

Abstract

The invention provides a preparation method of a patterned composite substrate. The preparation method comprises the steps of: step 1, placing a sapphire substrate on a laser cutting machine for cutting, and forming a plurality of periodic channel arrays which are arranged in a vertically staggered manner on the surface of the sapphire substrate; step 2, realizing a dielectric thin film layer on the surface of the cleaned sapphire substrate; step 3, forming a periodic strip grating mask pattern on the sapphire substrate provided with the dielectric thin film layer; step 4, and transferring themask pattern onto the dielectric thin film layer and the sapphire substrate, wherein a strip-shaped grating microstructure pattern is formed on the surface of the sapphire substrate, forming a aluminum nitride single crystal thin film layer on the surface after cleaning the sapphire substrate, and finally realizing the patterned composite substrate. The preparation method effectively avoids the problem of photoelectric performance damage of an LED chip, greatly improves the luminous efficiency of the LED chip, improves the process yield and reduces the production cost.

Description

technical field [0001] The invention relates to a patterned composite substrate, in particular to a method for preparing a patterned composite substrate mainly used in the epitaxy of high-efficiency GaN-based light-emitting diodes (GaN-based LED). Background technique [0002] The third-generation semiconductor materials mainly consist of gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN) and their ternary and quaternary alloy materials, because their energy band width can range from 0.7eV to 6.2eV is continuously adjustable, and both are direct bandgap, and its excellent physical and chemical stability, high saturation electron mobility and other characteristics make it the first choice for GaN-based light-emitting diodes (LEDs), lasers, electronic power devices and other optoelectronic devices Material. However, because it is very difficult to prepare GaN single crystal materials, and it is difficult to find substrate materials that match the GaN lattice,...

AI Technical Summary

Problems solved by technology

However, the difference between the refractive index of sapphire (n≈1.78) and the refractive index of GaN material (n≈2.5) is only about 0.7, which is not conducive to further improving the light extraction efficiency of LEDs; at the same time, factors such as the large lattice mismatch between PSS itself and GaN Limits the further improvement of quantum efficiency in LED

In addition, due to the large chemical bond energy and stable performance of sapphire materials, it is difficult to prepare PSS and the cost is high.

In addition, in the process of LED chip processing, when the wafer is divided into LED chip units by using ultraviolet laser cutting method, the laser ablation will damage the edge area of ​​the LED chip and affect the electrical performance; in addition, the residue generated during the cutting process falls on the chip. The surface is not easy to clean, which affects the light extraction efficiency

In particular, for small-sized chips such as Mini-LED and Micro-LED, if laser cutting is still used for chip separation, the damage ratio of the chip area will be relatively large, and the effective light-emitting area will be reduced, which will inevitably affect the photoelectric performance of the LED chip. Serious impact, and reduced yield during mass production

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