Asymmetric Schottky source-drain transistor and preparation method thereof

Abstract

The invention discloses a ring gate MOS transistor combining a vertical channel and an asymmetric Schottky barrier source / drain structure. The ring gate MOS transistor comprises the ring semiconductor channel (4) in the vertical direction, a ring gate electrode (6), a ring gate dielectric layer (5), a source region (2), a drain region (3) and a semiconductor substrate (1), wherein the source region is located at the bottom of the vertical channel (4) and connected with a substrate, the drain region is located on the top of the vertical channel, the gate dielectric layer and the gate electrode annularly surround the vertical channel, Schottky contacts with different barrier heights can be formed by the source region and the channel and the drain region and the channel respectively, and the source region and the drain region are made of different metal materials. The ring gate MOS transistor is compatible with an existing CMOS technology, various advantages of the traditional GAA are reserved, the leakage current is reduced through the asymmetric Schottky barrier source / drain structure, the technology requirement is lowered, the limitation of processing photoetching extremity is broken through via the vertical channel and the ring gate structure, and the integrity is improved.

Description

technical field [0001] The invention belongs to the field of field-effect transistor logic devices and circuits in CMOS ultra-large integrated circuits (ULSI), in particular to a gate-around MOS transistor combined with a vertical channel and an asymmetric Schottky barrier source / drain structure and a preparation method thereof . Background technique [0002] Driven by Moore's Law, the feature size of traditional MOSFETs has been shrinking, and now it has entered the nanometer scale. As a result, the negative effects of short-channel effects on devices have become more serious. The effects of leakage-induced barrier reduction and band-band tunneling increase the off-state leakage current of the device. In the research on new device structures, the source-drain doped Gate All Around transistor (GAA) structure is currently the most concerned one. GAA devices have better gate control characteristics, which can meet the sharpest characteristic requirements, so as to meet the n...

AI Technical Summary

Problems solved by technology

In addition, the introduction of nanowires makes the source and drain design of GAA more complex than planar devices and multi-gate devices

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