Arc-shaped fin top forming method and fin field effect transistor

Abstract

The invention discloses an arc-shaped fin top forming method and a fin field effect transistor. The method comprises the following steps that: a fin structure is provided; atomic layer etching is carried out on the top of the fin structure, and whether etching is carried out again is determined according to the etching amount of the fin structure; if yes, atomic layer etching on the top of the fin structure continues to be executed, and whether the etching process is conducted again or not is determined according to the etching amount of the fin structure; and if not, etching is stopped. The atomic layer etching process is circularly executed on the top of the fin structure to form the arc-shaped fin top, although the etching rate of the circulating process is lower than that of an existing mode, the circulating process does not damage the surface, and the pattern size and the loading density can be minimized. As the surface is not damaged, charge trapping is not formed, and the electrical characteristics of the device are not influenced by the reduction of the gate threshold voltage of the device.

Description

technical field [0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a method for forming an arc-shaped fin top and a fin field effect transistor. Background technique [0002] In the manufacturing process of Fin Field Effect Transistor (Fin FET), the manufacturing of fins is a very important part. As for the shape of the fin top, the sharper it is, the easier it is to cause electrical failure of the gate insulating film due to the electric field crowding effect. Therefore, the fin top is usually made into a circular arc shape. [0003] In the related art, an arc-shaped fin top is formed by adopting a dry etching process based on RIE (Reactive Ion-assisted Etching, reactive ion etching). [0004] However, reactive ion etching uses high-energy plasma to achieve arc-shaped fin tops. This high ion energy will cause damage, resulting in damage to the fin surface, lattice distortion (lattice distortion), and the by-produc...

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Problems solved by technology

[0004] However, reactive ion etching uses high-energy plasma to achieve arc-shaped fin tops. This high ion energy will cause damage, resulting in damage to the fin surface, lattice distortion, and the by-products Entering the gate channel induces charge trapping, and the drop in gate threshold voltage affects the electrical characteristics of the device

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