Semiconductor device and manufacturing method thereof

Abstract

The invention discloses a semiconductor device and a manufacturing method thereof. The example method comprises steps that: a first semiconductor layer and a second semiconductor layer are sequentially formed on a substrate; the first semiconductor layer and the second semiconductor layer are laid out to form fins; an isolation layer is formed on the substrate, one part of the isolation layer is exposed out of the first semiconductor layer, ion injection at the substrate below the fins is carried out to form a break-through blocking portion; a grid stack crossing the fins is formed on the isolation layer; the grid stack is taken as a mask film, the second semiconductor layer is selectively etched to expose the first semiconductor layer; the first semiconductor layer is selectively etched to form a gap below the second semiconductor layer; a third semiconductor layer is formed on the substrate, and source / drain regions are formed.

Description

technical field [0001] The present disclosure relates to the field of semiconductors, and more particularly, to a semiconductor device and a manufacturing method thereof. Background technique [0002] As the size of planar semiconductor devices becomes smaller and smaller, the short channel effect becomes more and more obvious. For this reason, three-dimensional semiconductor devices such as FinFETs (Fin Field Effect Transistors) have been proposed. In general, a FinFET includes a fin formed vertically on a substrate and a gate stack intersecting the fin. In addition, an isolation layer is formed on the substrate to isolate the gate stack from the substrate. Therefore, the bottom of the fin is surrounded by the isolation layer, so that it is difficult for the gate to effectively control the bottom of the fin. As a result, leakage current between the source and the drain via the bottom of the fin tends to occur. Contents of the invention [0003] An object of the presen...

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Problems solved by technology

Therefore, the bottom of the fin is surrounded by the isolation layer, so that it is difficult for the gate to effectively control the bottom of the fin.

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