Semiconductor structure and manufacture method thereof

Abstract

The invention discloses a semiconductor structure and a manufacture method thereof. The semiconductor structure comprises a recess in base material, a non-doped epitaxial layer and a doped epitaxial layer. The non-doped epitaxial layer is on an internal surface of the recess and is composed of silicon and epitaxial material essentially. The non-doped epitaxial layer covers a bottom and a sidewall of the internal surface of the recess, and thickness of the bottom is not larger than 120% of thickness of the sidewall. The non-doped epitaxial layer and the doped epitaxial layer fill the recess together.

Description

technical field [0001] The invention relates to a composite epitaxial layer structure and a method for forming the composite epitaxial layer structure. In particular, the present invention relates to a composite epitaxial layer structure comprising a non-doped epitaxial layer and a doped epitaxial layer, and a method for forming the composite epitaxial layer structure, so as to ensure the electrical stability of the gate channel. Background technique [0002] In the manufacturing process of semiconductor devices, it is always a challenge for those skilled in the art to continue to reduce critical dimensions while maintaining the performance of semiconductor devices. One of the challenges is to maintain sufficient carrier mobility in the gate channel, namely electrons and holes. It is known that as long as proper stress is applied to the gate channel, the mobility of carriers in the gate channel of metal oxide semiconductors, such as N-MOS or P-MOS, can be adjusted. One way...

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Problems solved by technology

Although the recessed source and drain regions of this specific shape can further increase the stress on the gate channel, it may also be due to the back-diffusion of dopants in the doped epitaxial layer, such as boron, into the gate channel. adverse short channel effect

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