Nanosheet field effect transistor and preparation method thereof

Abstract

The invention provides a nanosheet field effect transistor and a preparation method thereof, and the method comprises the steps: forming a nanosheet layer and a sacrificial layer on a semiconductor substrate, forming an insulation isolation structure in the nanosheet layer and the sacrificial layer, removing the sacrificial layer through dry etching, etching the insulation isolation structure, andforming a nanosheet supporting part; forming continuous gate insulating layers on the surfaces of the nanosheet and the nanosheet supporting part, and forming a second gate insulating layer between the gate insulating layers on the outer sides of the connecting parts, and forming a metal gate between the gate insulating layer and the second gate insulating layer. According to the invention, the sacrificial layer is removed and the insulation isolation structure is etched to form the nanosheet supporting structure in the same equipment, so the transportation or movement of the structure is avoided, and the nanosheet is prevented from being damaged due to factors such as physical vibration and the like. And the stability of the nanosheet is further improved by the gate insulating layer. Inaddition, dry etching is adopted in the method, and the damage, caused by chemical reagents, to the nanosheet is avoided.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuits, in particular to a nanosheet field effect transistor and a preparation method thereof. Background technique [0002] In integrated circuits, field effect transistors with low power and high operating performance usually have the following characteristics: (1) semiconductor substrate with high mobility; (2) increasingly larger channel width and smaller and smaller channel length; (3) a gate insulating layer with a large capacitance Ci; (4) reducing the interface traps at the interface between the active region channel and the gate insulating layer; (5) reducing the contact resistance between the electrode and the semiconductor layer. In recent years, the field effect transistor structure has undergone a remarkable change from planar type to 3D structures such as fin type or nanowire. [0003] New nanosheet field effect transistors, such as fork type nanosheet field effec...

AI Technical Summary

Problems solved by technology

However, there are many difficulties in forming novel nanosheet structures such as fork-shaped nanosheets

For example, nanosheet damage occurs when removing a sacrificial layer on a nanosheet stack structure

In addition, nanosheets are very fragile and are very sensitive to wet chemical reagents and physical shocks, and are prone to damage to nanosheets during the pretreatment process of forming the gate insulating layer.

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