Fin field effect transistor and method of forming the same

Abstract

A fin field effect transistor and its forming method, wherein the method includes: providing a semiconductor substrate; sequentially forming several sacrificial unit layers on the semiconductor substrate from bottom to top, the sacrificial unit layer includes a bottom sacrificial layer and a bottom sacrificial layer The top sacrificial layer on top; a protective layer is formed on several sacrificial unit layers, and the material of the protective layer is the same as that of the bottom sacrificial layer; an anisotropic dry etching process is used to etch the protective layer and the sacrificial unit layer until the semiconductor is exposed On the surface of the substrate, a groove is formed that runs through the thickness of the protective layer and the sacrificial unit layer; the sacrificial unit layer and the protective layer on the sidewall of the trench are wet etched, and the etching rate of the top layer sacrificial layer is greater than that of the wet etching. The etch rate of the bottom sacrificial layer; fill the fins in the trenches after wet etching, so that the side walls of the fins have protrusions, and then remove the protective layer and the sacrificial unit layer. The method can enhance the electric field control capability of the grid structure and further improve the short channel effect.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a fin field effect transistor and a forming method thereof. Background technique [0002] MOS transistors are one of the most important components in modern integrated circuits. The basic structure of a MOS transistor includes: a semiconductor substrate; a gate structure located on the surface of the semiconductor substrate, and source and drain regions located in the semiconductor substrate on both sides of the gate structure. The MOS transistor generates a switching signal by applying a voltage to the gate structure and adjusting the current through the channel at the bottom of the gate structure. [0003] With the development of semiconductor technology, the ability of the traditional planar MOS transistor to control the channel current becomes weaker, resulting in serious leakage current. Fin Field Effect Transistor (Fin FET) is an emerging multi-gate device, whic...

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Problems solved by technology

[0005] However, the performance of fin field effect transistors formed by existing technologies needs to be improved

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