Short channel mobility analysis of SiGe nanowire p-type field effect transistors: Origins of the strain induced performance improvement

The strain effect of three dimensionally stacked p-type SiGe nanowire field effect transistors are investigated by low temperature mobility analysis. Temperature dependent mobility behavior shows that the carrier transport of compressively strained channel is mainly limited by phonon scattering whereas impurity scattering is dominant at the unstrained short channel device. Because the compressive strain limits boron out-diffusion from the source and drain, additional impurity scattering mechanism is reduced comparing to the unstrained device. Thus, the compressively strained SiGe channel has higher immunity against short channel effect and improved effective mobility due to the limitation of dopant diffusion into the channel.