Formation method of semiconductor structure

Abstract

A method for forming a semiconductor structure comprises the following steps: providing a substrate which comprises a first region; forming a pseudo gate structure on the substrate; forming a sacrificial layer on the substrate between the adjacent pseudo gate structures, wherein the top surface of the sacrificial layer is flush with the top surfaces of the pseudo gate structures; a mask layer is formed on the sacrificial layer of the first area, the mask layer has a first projection on the substrate, the sacrificial layer has a second projection on the substrate, the first projection is located in the second projection, and the area of the first projection is smaller than that of the second projection; etching to remove the sacrificial layer exposed by the mask layer and a part of thickness of the substrate; removing the mask layer and the residual sacrificial layer; etching the substrate between the adjacent pseudo gate structures, and forming a first groove in the first region; and forming an epitaxial layer in the first groove. According to the forming method provided by the embodiment of the invention, the full epitaxial layer can be formed, so that the performance of the semiconductor structure can be improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a semiconductor structure. Background technique [0002] When preparing semiconductor devices, it is often necessary to epitaxially grow two different semiconductor materials in different regions of the semiconductor substrate. For example, it is often necessary to epitaxially grow two different semiconductor materials on the source and drain of NMOS and PMOS. Before the epitaxial growth of semiconductor materials, it is necessary to Trenches are formed in the substrate between adjacent gate structures, and semiconductor material is epitaxially grown along the surfaces of the trenches. [0003] However, in long-channel devices and short-channel devices, due to the different distances between adjacent gate structures, the width and shape of the trenches formed are also different, and the trench width in the long-channel region is larger tha...

AI Technical Summary

Problems solved by technology

[0003] However, in long-channel devices and short-channel devices, due to the different distances between adjacent gate structures, the width and shape of the trenches formed are also different, and the trench width in the long-channel region is larger than that in the short-channel region When the semiconductor material is grown epitaxially, the growth of the semiconductor material in the long channel region is not full enough. When the contact hole on the source and drain is formed later, the contact hole is easy to penetrate the epitaxial layer in the long channel region, resulting in the contact hole The inner metal layer is directly connected to the substrate, forming a Schottky contact, which can easily lead to semiconductor device failure

Images