Fin field effect transistor and method of forming the same

Abstract

The present invention relates to a fin-type field effect transistor and a formation method thereof. The fin-type field effect transistor comprises a silicon substrate on an insulating body, wherein the silicon substrate on the insulating body comprises a top silicon layer, a bottom silicon layer and a buried layer located between the top silicon layer and the bottom silicon layer, and the top silicon layer is used as a fin part of the fin-type field effect transistor; a second opening located in the top silicon layer to expose the surface of the buried layer; a first isolation layer located at the side wall of the second opening; a third opening located in the buried layer to expose the surface of the bottom silicon layer, wherein the position of the third opening corresponds to the position of the second opening; an epitaxial silicon layer for filling the second and third openings, wherein the top surface of the epitaxial silicon layer is higher than the surface of the top silicon layer, and the epitaxial silicon layer and the bottom silicon layer form a back gate; a second isolation layer located on the top surface of the epitaxial silicon layer; and a side wall located at the side wall of the second isolation layer and a part of epitaxial silicon layer and on the surface of the top silicon layer. When a voltage is applied on the back gate, a threshold-voltage of the fin-type field effect transistor is easy to control.

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] With the continuous development of semiconductor process technology, as the process node gradually decreases, gate-last (gate-last) process has been widely used to obtain an ideal threshold voltage and improve device performance. However, when the feature size (CD, Critical Dimension) 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. Fin field effect transistor (Fin FET) as Substitution of conventional devices has received extensive attention. [0003] figure 1 A schematic diagram of a three-dimensional structure of a fin field effect transistor in the prior art is shown. like figure 1 As shown, it includes: a semiconductor substrat...

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Problems solved by technology

[0005] However, with the continuous reduction of device size, the threshold voltage of fin field effect transistors is difficult to control

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