1.9 nm wide ultra-high aspect-ratio bulk-si FinFETs

FinFETs are foreseen as a solution for the suppression of short-channel effects (SCE) from the 22 nm node onwards because of their superior electrostatic integrity achieved with a fabrication technique that is similar to bulk CMOS processes [1]. To keep SCEs under control the width of the etched fins must be reduced as the gatelength is scaled down. The fin-height is typically reduced as well to keep the same aspect ratio between the finheight and fin-width which allows the same fin-etching processes to be used also for smaller devices. This work focuses on FinFETs with high aspect-ratio and thus a wide MOSFET channels in each fin, which translates into higher device density per chip area and more efficient use of the silicon real-estate. Moreover, in analog applications where multi-fin devices are required for wider transistors, a small number of taller fins is preferable to a large number of shorter fins in terms of gate resistance and gate capacitance which improves high-frequency performance [2, 3]. The fabrication process is designed to keep the fin-width in the 10 nm range while at the same time tall fins are etched [4].