A kind of preparation method of mos transistor

Abstract

The invention provides a preparation method of a MOS transistor. During preparation of a source region and a drain region, a V-shaped groove is first of all etched by use of a wet method, afterwards, a stress filling layer is grown in an epitaxial mode in the V-shaped groove, a lightly doped area is formed in the stress filling layer near a gate area, and finally, the source region and the drain region are formed through ion implantation. Compared to horizontal-W-shaped source and drain regions in the prior art, the stress filling layer is formed by filling the V-shaped groove and is taken as the source region and the drain region, so that the source region and the drain region are closer to a channel, and the stress effects which the source region and the drain region apply to the channel are more obvious; a heterojunction is formed at the bottom of the stress filling layer in the V-shaped groove so that there are much tip-end electric leakage at the bottom of the stress filling layer, and the application of the method in the aspect of ESD electrostatic discharge is improved in terms of structure; and the source region and the drain region formed by filling the V-shaped groove are quite far away from each other, so that the effective channel length is increased, the short channel effect is improved, and the working currents are improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices and relates to a preparation method of a MOS transistor. Background technique [0002] With the development of semiconductor technology, the feature size of devices in integrated circuits is getting smaller and smaller. When the manufacturing process of CMOS progresses to the micron level, the channel between the source / drain regions becomes shorter. When the length of the channel region is reduced to a certain value, a short channel will be generated. Channel Effect (Short Channel Effect) and Hot Carrier Effect (Hot Carrier Effect) and thus cause the device to fail to operate. In other words, since the existence of the short channel effect will affect the performance of the device, it also hinders the further reduction of the feature size of the device in the integrated circuit. [0003] In order to avoid short-channel effects and hot-carrier effects, the source / drain design of CM...

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Problems solved by technology

[0010] On the other hand, in the prior art, ion implantation is usually used to form different doping distributions, so as to achieve the purpose of changing the breakdown voltage of the transistor, so that the transistor can be used in ESD electrostatic discharge protection. However, the adjusted The breakdown voltage is limited, and the existing technology has not improved the essential structure of the device

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