Semiconductor structure and forming method thereof

Abstract

The invention provides a semiconductor structure comprising a first semiconductor material substrate, a first porous structure layer, a second porous structure layer and a second semiconductor material layer, wherein the first porous structure layer is formed on the first semiconductor material substrate; the second porous structure layer is formed on the first porous structure layer; the porosity and the aperture of the second porous structure layer are both less than the porosity and the aperture of the first porous structure layer; and the second semiconductor material layer is formed on the second porous structure layer. The invention can release the thermal mismatch stress of Si materials and epitaxial materials through the porous structure layers, prevent the problems of cracking and the like of an epitaxial film with larger thickness and enhance the quality of an epitaxial film crystal, thereby extending an epitaxial material layer (such as GaN and the like) which has large thickness and higher thermal mismatch stress with the Si materials on a Si substrate; and in addition, the porous Si materials can be removed in a subsequent process, therefore a subsequent device process can not be influenced.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing and design, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] In recent years, light emitting diodes (light emitting diodes, LEDs) have been widely used in display screens, backlight sources, special lighting, and other fields due to their 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, an active region light-emitting layer, an electron blocking layer, and a P-type semiconductor layer. As the core of the LED epitaxial wafer, the light-emitting layer in the active area 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...

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Problems solved by technology

[0003] However, there is a large thermal stress mismatch between Si 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 thickness of the film

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