Fin type field effect transistor formation method

Abstract

The invention relates to a fin type field effect transistor formation method. The method comprises steps that, a semiconductor substrate is provided, and more than two independent and parallel fin portions are formed on the surface of the semiconductor substrate; an isolation layer is formed, and the surface of the isolation layer is lower than top surfaces of the fin portions; a grid structure crossing the multiple fin portions is formed on the surface of the isolation layer; first ion injection is carried out at the one-side fin portions of the grid structure, an injection direction of the first ion injection is projected on the surface of the semiconductor substrate, an acute included angle formed by the projection of the injection direction and the length direction of the fin portions is a first torsion angle, the first torsion angle is greater than 0 EDG and is smaller than 45 DEG, second ion injection is carried out at the other-side fin portions of the grid structure, an injection direction of the second ion injection is projected on the surface of the semiconductor substrate, an acute included angle formed by the projection of the injection direction and the length direction of the fin portions is a second torsion angle, and the second torsion angle is greater than 0 EDG and is smaller than 45 DEG. Through the method, ion injection block effects of the adjacent fin portions can be reduced, and thereby performance of fin type field effect transistors is improved.

Description

Technical field [0001] The present invention relates to the field of semiconductor technology, and in particular to a method for forming a fin field effect transistor. Background technique [0002] With the continuous development of semiconductor process technology, process nodes are gradually reduced, and the gate-last process has been widely used to obtain an ideal threshold voltage and improve device performance. However, when the feature size of the device is further reduced, even if the gate-last process is adopted, the structure of the conventional MOS field effect transistor can no longer meet the requirements for device performance, and the multi-gate device as an alternative to the conventional device has received extensive attention. [0003] Fin field effect transistor is a common multi-gate device, such as figure 1 Shown is a schematic diagram of the structure of an existing fin field effect transistor. The fin field effect transistor includes a semiconductor substrate...

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Problems solved by technology

[0005] However, in the prior art, the effect of the pocket ion implantation on the fin field effect transistor is poor, and it is difficult for the dopant ions implanted in the pocket to enter the part close to the source region and the drain region close to the channel region, thereby affecting The improvement of the performance of the fin field effect transistor is limited, and the process of the pocket ion implantation needs to be further improved to further improve the performance of the fin field effect transistor

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