Fin field effect transistor (FET) and manufacturing method thereof

Abstract

The invention discloses a FinFET and its manufacturing method. The FinFET manufacturing method comprises the following steps: a doping punchthrough stop layer is formed inside a semiconductor substrate; a semiconductor fin is formed by the utilization of a part of the semiconductor substrate above the doping punchthrough stop layer; a gate stack across the semiconductor fin is formed, the gate stack contains a gate dielectric and a gate conductor, and the gate conductor separates from the semiconductor fin by the gate dielectric; a gate side wall which encircles the gate conductor is formed; and a source region and a drain region are formed in parts of the semiconductor fin at two sides of the gate stack. As the semiconductor fin separates from the semiconductor substrate by the doping punchthrough stop layer, a leakage current path through the semiconductor substrate between the source region and the drain region can be disconnected.

Description

[0001] This application is a divisional application of the invention patent application No. 201210507134.3 entitled "FinFET and its manufacturing method" submitted to the China Patent Office on November 30, 2012. technical field [0002] The present invention relates to semiconductor technology, and more particularly, to FinFETs and methods of making the same. Background technique [0003] As the size of semiconductor devices becomes smaller and smaller, the short channel effect becomes more and more obvious. To suppress short-channel effects, FinFETs formed on SOI wafers or bulk semiconductor substrates have been proposed. A FinFET includes a channel region formed in the middle of a fin (fin) of semiconductor material, and source / drain regions formed at both ends of the fin. The gate electrode surrounds the channel region on both sides of the channel region (ie a double gate structure), thereby forming an inversion layer on each side of the channel. Since the entire chann...

AI Technical Summary

Problems solved by technology

However, ion implantation performed to form the punch-through preventing layer may introduce undesired dopants in the channel region of the semiconductor fin

This additional doping results in random dopant concentration fluctuations in the channel region of the FinFET

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