LED (light-emitting diode) epitaxial wafer, LED structure and formation method of LED structure

Abstract

The invention provides an LED (light-emitting diode) epitaxial wafer which comprises a substrate, a first porous structure layer formed on the top layer of the substrate, a second porous structure layer formed on the first porous structure layer and an LED structure layer formed on the second porous structure layer, wherein the porosity and aperture of the second porous structure layer are smaller than those of the first porous structure layer, and the LED structure layer at least comprises a first-type semiconductor layer, a luminous layer and a second-type semiconductor layer. An LED structure which has the characteristics of large porosity and great thermal mismatch between an epitaxy on porous silicon and a Si (silicon) material is adopted, thereby enabling a weak porous silicon layer to deform partially, releasing thermal mismatch stress, ensuring the integrity of the epitaxial LED structure, forming the large-size epitaxial LED structure, and improving the quality of an epitaxial crystal of the LED structure layer through the second porous structure layer.

Description

technical field [0001] The invention relates to the technical field of light emitting diodes (LEDs), in particular to an LED epitaxial wafer, an LED structure and a method for forming the LED structure. Background technique [0002] In recent years, LED has been widely used in display screens, backlight sources, special lighting and other fields due to its long life, high luminous efficiency, small size, durability, and rich colors. The core of the LED is the LED epitaxial wafer, and its main structure includes: a substrate, a buffer layer, an N-type semiconductor layer, a light-emitting layer, an electron blocking layer, and a P-type semiconductor layer. The light-emitting layer as the core of the LED epitaxial wafer is between the N-type semiconductor layer and the P-type semiconductor layer, so that the interface between the P-type semiconductor layer and the N-type semiconductor layer forms a PN junction. However since Al 2 o 3 (Sapphire) or SiC substrates are very ex...

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Problems solved by technology

However, due to the large thermal stress mismatch between the Si material and these III-V compound semiconductor materials, the thermal stress mismatch will cause cracks in the film when the epitaxial thickness is large, and the quality of the epitaxial film is not good. , thus limiting the growth thickness and growth quality of the film, resulting in Si material substrates not being well applied in LED devices

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