Low Schottky barrier semiconductor structure and formation method thereof

Abstract

The invention provides a low Schottky barrier semiconductor structure. The semiconductor structure comprises a substrate, a gate stack, one or more layers of side walls, metal source and drain electrodes and an insulating layer film, wherein the gate stack is formed on the substrate, the one or more layers of side walls are located at two sides of the gate stack, the metal source and drain electrodes are formed at two sides of the gate stack and located in the substrate, and the insulating layer film is located between the substrate and the metal source and drain electrodes. Through the embodiment of the invention, the insulating layer film formed between the substrate and the metal source and drain electrodes can prevent the band gap state caused by the metal source and drain electrodes from entering a channel, thereby the Fermi energy level pinning phenomenon is relieved, the Schottky barrier height is reduced, and the switching current ratio of a transistor is increased.

Description

technical field [0001] The invention relates to the technical field of semiconductor design and manufacture, in particular to a low Schottky barrier semiconductor structure and a forming method thereof. Background technique [0002] The continuous development of current Si channel transistors mainly faces two major problems: one is the maximum saturation current limit caused by hot carrier injection from the source to the channel, and the other is that the subthreshold characteristics do not follow the principle of proportional scaling. leakage problem. The application of non-Si channel materials in the semiconductor field is considered to be an important means to improve the performance of transistors. Among them, Ge material has good low field mobility and smaller band gap than Si material, and the manufacturing process of Ge channel device can be compatible with traditional Si transistor process, so Ge ​​is considered to be a very good choice for Si channel material. Pr...

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Problems solved by technology

However, the traditional field effect transistor of Ge channel material also faces its own problems: such as BTBT interband leakage caused by narrow band gap, it is difficult to obtain a good interface between the germanium substrate and the gate insulating layer dielectric, and the drain-source injection activation rate is too low. Implanted doping is very easy to diffuse at high temperature, resulting in a series of problems such as too deep junction

[0003] In particular, Ge transistors are limited by the solid solubility of impurities in Ge, the diffusion coefficient and the melting point of Ge materials when the source and drain are fabricated. quite unfavorable

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