Semiconductor structure forming method

Abstract

The invention discloses a semiconductor structure forming method. The method comprises the following steps of providing a semiconductor substrate; forming a fin part on the semiconductor substrate surface; forming an isolating layer on the surface of the semiconductor substrate; forming a gate dielectric layer on the surfaces of the fin part and the isolating layer; forming a gate electrode stretching across the fin part on a part of the gate dielectric layer surface; forming a side wall material layer on the gate dielectric layer and the gate electrode surface; performing first-angle plasma etching on the side wall material layer to remove the side wall material layer on the side wall located on one side of the fin part; performing second-angle plasma etching on the side wall material layer to remove the side wall material layer on the side wall located on the other side of the fin part and the remaining side wall material layer on the gate dielectric layer; and forming a side wall located on the gate electrode side wall surface. By means of the above-mentioned method, the side wall is formed on the gate electrode side wall while the side wall material layer on the fin part side wall surface is removed. The performance of a formed fin type field effect transistor is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for forming a semiconductor structure. Background technique [0002] With the continuous development and progress of semiconductor technology, the integration level of integrated circuits is getting higher and higher, and the size of transistors is getting smaller and smaller. When the size of the transistor shrinks, the length of the gate will also become shorter, which will easily lead to adverse effects such as the short channel effect of the transistor, and affect the performance of the transistor. [0003] In the planar MOS transistors in the prior art, after the gate structure is formed, sidewalls can be formed on the surface of the sidewalls of the gate structure, and lightly doped in the semiconductor substrate on both sides of the gate structure using the sidewalls as a mask Ion implantation to form a lightly doped region and improve the short channel ef...

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Problems solved by technology

Since the sidewall material layer also covers the sidewall surface of the fin, it is difficult to remove the sidewall material layer located on the sidewall surface of the fin in the existing process, resulting in the surface of the fin being partially covered by the sidewall material layer. When lightly doped ion implantation is performed on the fins on both sides of the gate structure, the remaining sidewall material layer will block the ion implantation, affecting the effect of the lightly doped ion implantation, thereby affecting the formed fin field effect transistor. performance

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