Field-effect transistor and its manufacturing method

Abstract

The invention provides a field effect transistor and a preparation method thereof. The method comprises the steps of: providing a semiconductor substrate, forming a first gate stack structure on the semiconductor substrate, and forming first side walls on two sides of the first gate stack structure; forming a recessed structure in the semiconductor substrate outside the first side walls; forming an insulating dielectric layer in the recessed structure; performing in-situ doping, forming a drain-source structure on the insulating dielectric layer; and forming an isolation structure on the semiconductor substrate outside the drain-source structure. By using a post-isolation process, when a drain-source area is doped and extended in-site, the semiconductor substrate outside the drain-source area is taken as an epitaxy seed crystal layer, and the epitaxy quality and speed are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of ultra-large-scale integrated circuit manufacturing, and relates to a field-effect transistor and a preparation method thereof. Background technique [0002] For planar MOSFETs, when the channel length shrinks, the short channel effect will become more and more serious. For the advanced FDSOI (Full Depletion Semiconductor on Insulation) substrate material, the short channel effect can be effectively controlled, but SOI has its own shortcomings, mainly self heating effect (Self Heating Effect) and floating body effect (Floating Body Effect), These effects will affect the performance of SOI devices, and in severe cases will cause device failure. Therefore, how to improve the self-heating effect and floating body effect of SOI devices has become a research hotspot in the industry. Among them, a MOSFET device called quasi-SOI can well avoid self-heating effect and floating body effect. Since the channel regi...

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Problems solved by technology

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a field effect transistor and its preparation method, which is used to solve the problem in the prior art that the in-situ doping and epitaxy of the source and drain regions rely on the sidewall of the far-floor extension region as a problem. Due to the epitaxial seed layer, defects are easily generated in the epitaxial layer, and the epitaxial speed is relatively slow, and due to the Salicide process without source and drain regions, the contact resistance of the contact hole and the source and drain regions is relatively large, which in turn affects nanoscale devices. performance problem

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