Effects of Side Surface Roughness on Carrier Mobility in Tri-Gate Single Silicon Nanowire Metal-Oxide-Semiconductor Field-Effect Transistors

In this paper, the effects of side surface roughness on mobility behaviors in single-silicon-nanowire metal-oxide-semiconductor field-effect transistors (MOSFETs) are discussed on the basis of intrinsic carrier mobility data obtained by direct split capacitance-voltage (C-V) method measurement for the first time. To investigate the mechanisms that dominate the mobility degradation in narrower nanowires, low-temperature measurements are performed. It is found that phonon scattering has little dependence on nanowire width, indicating that the mobility degradation in our tri-gate nanowire MOSFETs is caused by surface roughness scattering. It is also found by analyzing the nanowire width dependence of mobility that the process-induced roughness on the side surface is the main source of mobility degradation in nanowire pFETs, while the degradation caused by the side surface roughness is negligible in nanowire nFETs. (C) 2013 The Japan Society of Applied Physics