Analytical model of drain current in nanowire MOSFETs including quantum confinement, band structure effects and quasi-ballistic transport: device to circuit performances analysis

This paper presents an analytical model of the drain current in nanowire MOSFETs (Fig. 1). This architecture is aimed for ultra-scaled devices up to technology nodes sub-11nm and uses silicon films of a few nanometers in thickness. At these dimensions, some emerging physical phenomena can no more be neglected: short-channel effects (SCE) and quasi-ballistic transport (both due to the channel length reduction) and quantum confinement and band structure effects (BSE), due to the strong silicon nanowire thinning. Our analytical model of the drain current includes all these physical phenomena. The proposed model is compared and validated on numerical simulations and experimental data. Finally, a study at the circuit level is performed to assess the impact of BSE and quasi-ballistic transport on the performances of small circuits such as CMOS inverters and ring oscillators based on ultimate nanowire MOSFETs.