A comprehensive study of magnetoresistance mobility in short channel transistors: Application to strained and unstrained silicon-on-insulator field-effect transistors

Magnetoresistance (MR) measurements is used to extract the electron mobility on strained and unstrained thin film fully depleted silicon-on-insulator metal-oxide-semiconductor field-effect transitors (MOSFETs) with channel length down to 40 nm, and in a wide temperature range from 300 down to 20 K. In particular the signature of Coulomb scattering (CS) on MR mobility is carefully studied and experimentally clarified. We demonstrate that MR mobility corrected for nonstationary effects can be extracted. The mobility data thus corrected for series resistance and ballistic effects show that an additional scattering really occurs in deep-100-nm scaled MOSFETs. This mobility degradation is effective for both strained and unstrained short channel devices, over the whole gate voltage range. The temperature and inversion carrier density dependences, as well as the analysis of the strain effect on mobility reveal a strong additional CS in short channel devices. Despite this dominant mechanism, a mobility gain as high as 50% at room temperature is still observable for strained deeply scaled MOSFETs.