As the feature size of semiconductor devices decreases, the short-channel effect becomes more pronounced. In order to mitigate the short-channel effect, fin field effect transistors (FinFETs) are used instead of planar transistors. Furthermore, ultra-shallow and abrupt junctions are being used to improve the short-channel effect of core devices.
However, as finFET devices further scale, the FinFET devices may face many problems, in particular, a large contact resistance value between the source/drain and the channel region may reduce the channel current. Furthermore, the source, drain or halo doping of FinFET devices may cause a portion of dopants to diffuse into the channel region, resulting in an undesired doping of the channel region, which will reduce the current in the channel region and the carrier mobility and increase the leakage current of the FinFET devices.