NMOS transistor and method for forming same

Abstract

An NMOS transistor comprises a grid structure, source / drain extension areas, source / drain electrodes and carbon ions doping areas, wherein the grid structure is arranged on a semiconductor substrate, the source / drain extension areas and the source / drain electrodes are located on both sides of the grid structure and in the semiconductor substrate, the carbon ions doping areas are located on both sides of the grid structure and in the semiconductor substrate, and the depth of the carbon ions doping areas is between the surface of the semiconductor substrate and the source / drain electrodes. Correspondingly, the invention further provides a method for forming the NMOS transistor. The NMOS transistor decreases the indirect band-gaps between silicon crystals by the introduction of the carbon ions doping areas around the source / drain extension areas, thereby affecting the shape of energy bands to increase electron mobility and to more easily excite the charged ions simultaneously. The NMOS transistor increases the current drive capability under the condition of keeping the threshold voltage unchanged.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an NMOS transistor and a forming method thereof. Background technique [0002] With the development of semiconductor devices to high density and small size, metal-oxide-semiconductor (MOS) devices are the main driving force, and driving current and hot carrier injection are the two most important parameters in the design. Traditional design achieves expected performance by controlling gate oxide, channel region, well region, source / drain extension doping shape, pocket implant region, source / drain implant shape and thermal budget, etc. . The implanted dopant ions are usually elements with three or five valence electrons. Few studies have focused on implanting elements with 4 valence electrons, including heavier ions such as germanium, as pre-amorphization implant materials to reduce channeling induced by subsequent low-doped source / drain implants (LDD) or pocket implants....

AI Technical Summary

Problems solved by technology

However, the prior art does not disclose the implantation of carbon ions at the position of the source / drain extension region to form a carbon ion doped region and its impact on the performance of NMOS transistors

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