MOS (Metal Oxide Semiconductor) transistor and fabricating method thereof

Abstract

The invention provides an MOS (Metal Oxide Semiconductor) transistor and a fabricating method thereof. The fabricating method of the MOS transistor comprises the steps of: providing a semiconductor substrate, wherein an active area in the semiconductor substrate comprises a channel area of the MOS transistor; introducing a first ion in the active area of the semiconductor substrate to form an isolation well; introducing a second ion in the active area of the semiconductor substrate to adjust the threshold voltage of an MOS transistor to be formed; and introducing a carbon ion in the channel area of the MOS transistor, wherein the step of the introduction of the carbon ion is carried out before or after the introduction of the first ion, or before or after the introduction of the second ion. Accordingly, the invention also provides an MOS transistor fabricated by the fabricating method. By introducing the carbon ion in the channel area of the MOS transistor, the invention stops ions injected in the channel area of the MOS transistor later from diffusing in a subsequent process for forming a gate dielectric layer by oxidization, thereby achieving the aim of inhibiting the transient enhanced diffusion effect.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a MOS transistor and a manufacturing method thereof. Background technique [0002] As the gate length of transistors continues to shrink, oxidation-enhanced diffusion (Oxidation-Enhanced Diffusion, OED) has become a key factor affecting the diffusion of boron and phosphorus ions. Due to the OED effect, transient enhanced diffusion effect (TED) is caused, and the transient The enhanced diffusion effect not only causes the short channel effect of the transistor, but also affects the channel mobility, junction capacitance and junction leakage current of the transistor. [0003] The prior art discloses a method of using implanted carbon clusters to form shallow junctions to control the diffusion of boron ions in the source and drain electrodes of transistors, and to form stress in the silicon substrate by implanting carbon clusters at a high dose. , see below for details Fig...

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Problems solved by technology

In the existing process for forming MOS transistors, it is usually necessary to implant ions in the channel to adjust the threshold voltage of the transistor. The implanted ions are usually boron ions for nMOS transistors, and phosphorus ions for pMOS transistors. The carbon in the above technical solution The step of ion implantation fails to suppress the defects caused by the process before the formation of the source / drain extension region such as the above-mentioned channel implantation and gate oxide layer growth to form the gate dielectric layer. Due to the existence of these defects and the subsequent low temperature process The process will lead to enhanced diffusion of impurities in the channel region, affecting the control and matching of the threshold voltage of the transistor

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