Schottky barrier metal oxide semiconductor (MOS) transistor and preparation method thereof

Abstract

The invention discloses a Schottky barrier metal oxide semiconductor (MOS) transistor, which comprises a ring-shaped gate electrode (3), a ring-shaped gate dielectric layer (2), a ring-shaped gate electrode side wall (4), a semiconductor substrate, a source region (5) and a ring-shaped drain region (6). The Schottky barrier MOS transistor is characterized in that: the semiconductor substrate is provided with a convex step structure; the source region is positioned on a high plane of a convex step; the ring-shaped drain region surrounds the convex step and is positioned on a low plane; the gate dielectric layer and the gate electrode are positioned at a corner of the convex step, surrounds the step and is raised into a ring shape; and the gate electrode side wall is ring-shaped, surrounds on the outer side of the gate electrode and has a certain thickness to serve as a shelter to form an underlap structure of a drain terminal. The Schottky barrier MOS transistor adopts a step structurecombining a ring-shaped gate structure and an asymmetric source / drain structure, so on the basis of inheriting advantages of traditional SB-MOSFET, the on-state conduction current is improved, a dipolar effect is inhibited, and the process is simplified.

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), and specifically relates to a Schottky barrier MOS transistor combined with a step structure, a ring gate structure and an asymmetric source / drain structure and its preparation method. Background technique [0002] As early as the late 1960s, Lepselter and Sze proposed the Schottky Barrier MOSFET (Schottky Barrier MOSFET) structure. The source and drain are replaced with metal or silicide for traditional doping, and the direct tunneling barrier of carriers at the source end is used to achieve conduction. As the size of metal-oxide-silicon field-effect transistors (MOSFETs) continues to shrink, short-channel effects are increasingly affecting the devices. For traditional MOS field effect transistors, in order to suppress the short-channel effect, ultra-shallow junctions and abruptly doped source / drain regions must be...

AI Technical Summary

Problems solved by technology

First of all, since the on-state current mainly comes from the tunneling of the source carrier, the on-state current is limited, and the small on-state current becomes one of the main reasons for limiting the application of SB-MOSFET; secondly, SB-MOSFET has a serious bipolar effect, that is, when the gate is reverse-biased, the device will also generate a large conduction current, so that the gate will appear when a certain forward and reverse bias is applied. Large conduction current

Images