Experimental Investigations on Carrier Transport in Si Nanowire Transistors: Ballistic Efficiency and Apparent Mobility

As devices continue scaling down into nanometer regime, carrier transport becomes critically important. In this paper, experimental studies on the carrier transport in gate-all-around (GAA) silicon nanowire transistors (SNWTs) are reported, demonstrating their great potential as an alternative device structure for near-ballistic transport from top-down approach. Both ballistic efficiency and apparent mobility were characterized. A modified experimental extraction methodology for SNWTs is adopted, which takes into account the impact of temperature dependence of parasitic source resistance in SNWTs. The highest ballistic efficiency at room temperature is observed in sub-40-nm n-channel SNWTs due to their quasi-1-D carrier transport. The apparent mobility of GAA SNWTs are also extracted, showing their close proximity to the ballistic limit as shrinking the gate length, which can be explained by Shur´s model. The physical understanding of the apparent mobility in SNWTs is also discussed using flux´s scattering matrix method.