Highly manufacturable FinFETs with sub-10nm fin width and high aspect ratio fabricated with immersion lithography

Abstract

We investigate scalability, performance and variability of high aspect ratio trigate FinFETs fabricated with 193 nm immersion lithography and conventional dry etch. FinFETs with fin widths down to 5nm are achieved with record aspect ratios of 13. Excellent nMOS and pMOS performance is demonstrated for narrow fins and short gates. Further improvement in nMOS performance can be achieved by eliminating access resistance that is currently attributed to poor re-crystallization of implantation damage in narrow fins. Fully-depleted FinFETs show strongly improved short channel effect (SCE) control when the fin width is scaled, even without halo-implants. Nearly ideal DIBL and sub-threshold slope (SS) are achieved down to 30nm gate length. Low leakage devices are realized by combining a fully depleted channel, HfSiO high-k dielectric, mid-gap TiN metal electrodes, and aggressive fin width scaling. Symmetrical threshold voltages (±0.35 V) are achieved. It is demonstrated that selective epitaxial growth on source and drain regions is essential to limit parasitic resistance in narrow fin devices. Parametric spread is dominated by gate length variations in short devices but within-die fin width variations are still evident for long devices.