Patterned substrate, preparation method and light-emitting diode

Abstract

The invention provides a patterned substrate, a preparation method and a light-emitting diode. A dielectric layer is deposited on the surface of the substrate with a plurality of bulges, and the amorphous body characteristic of the dielectric layer is utilized, so that aluminum nitride layers deposited on platforms on the side surfaces and top surfaces of the bulges through a PVD method are amorphous, and aluminum nitride arranged on the smooth surfaces of bulge gaps in a covering manner is polycrystal consisting of micro crystal particles. Then, when the substrate is applied to an MOCVD method to deposit gallium nitride-based epitaxial layers to form the light-emitting diode, by utilizing characteristics that the aluminum nitride polycrystal grows more easily on the smooth surfaces and the amorphous aluminum nitride is unlikely to deposit the gallium nitride-based epitaxial layers, the epitaxial layers selectively grow on the aluminum nitride layers on the smooth surfaces of the bulge gaps, and the platforms on the side surfaces and top surfaces of the bulges are unlikely to grow, so that the growth of the gallium nitride-based epitaxial layers on the side surfaces is reduced, the quantity of defects when the gallium nitride-based epitaxial layers in lateral growth and the gallium nitride-based epitaxial layers in positive growth on the smooth surfaces are merged is reduced, and the performance of the finally formed semiconductor element is promoted. Moreover, the growth of the lateral gallium nitride-based epitaxial layers is inhibited, and the gallium nitride-based epitaxial layers in positive growth are merged into a smooth surface more easily.

Description

technical field [0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a patterned substrate for reducing crystal defects, a preparation method and a light-emitting diode. Background technique [0002] Now mainstream LEDs use patterned substrates for epitaxial growth. On the one hand, the pattern on the surface provides a variety of growth crystal phase options for the growth of the GaN epitaxial layer in the later stage, so that the GaN epitaxial layer is changed from the traditional two-dimensional The growth becomes three-dimensional growth, thereby effectively reducing the dislocation density in GaN-based LED materials, avoiding the generation of cracks, and improving the internal quantum luminous efficiency of LEDs; on the other hand, because the array pattern structure increases light scattering, The optical circuit of the LED is changed to form diffuse reflection, thereby improving the light extraction efficien...

AI Technical Summary

Problems solved by technology

However, due to the large lattice mismatch between the widely used sapphire substrate and the gallium nitride-based material layer, nucleation and growth are difficult, and in order to overcome the problem of difficult nucleation, it was proposed to heat the substrate at about 1000 °C Finally, grow a low-quality low-temperature buffer layer, and then turn to high-temperature conditions to grow high-quality GaN-based epitaxial layers

Due to the high and low temperature conversion in this process, the efficiency of the MOCVD machine is reduced; at the same time, the large temperature difference between different layers increases the stress between different layers, thus affecting the crystal performance.

[0003] Therefore, it has been proposed to deposit a layer of aluminum nitride on the surface of the patterned substrate to reduce the lattice difference between the substrate and the GaN-based epitaxial layer. The current common process is to place the patterned substrate on PVD The aluminum nitride layer is deposited on the surface of the substrate, and because the commonly used sapphire substrate has a small lattice mismatch with the aluminum nitride layer, the aluminum nitride layer not only covers the raised gap surface of the patterned substrate , while also covering the raised side and top platform, when the substrate is placed in a chemical vapor deposition chamber to grow a gallium nitride-based buffer layer, an N-type semiconductor layer, a light-emitting layer and a P-type semiconductor layer When forming a semiconductor element, serious epitaxial layers compete to grow on the side of the protrusion and the surface of the gap, resulting in uneven surface of the buffer layer and increased dislocation defects; and dislocation lines will extend to the light-emitting region along the crystal growth direction, affecting Device performance

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