Alcohol-Based Digital Etch for III–V Vertical Nanowires With Sub-10 nm Diameter

This letter introduces a novel alcohol-based digital etch technique for III-V FinFET and nanowire MOSFET fabrication. The new technique addresses the limitations of the conventional water-based approach in enabling structures with sub-10-nm 3-D features. Using the same oxidation step, the new technique shows an etch rate of 1 nm/cycle, identical to the conventional approach. Sub-10 nm fins and nanowires with a high mechanical yield have been achieved. InGaAs nanowires with a diameter of 5 nm and an aspect ratio greater than 40 have been demonstrated. The new technique has also been successfully applied to InGaSb-based heterostructures, the first demonstration of digital etch in this material system. Vertical InGaAs nanowire gate-all-around MOSFETs with a subthreshold swing of 70 mV/decade at V
_DS
= 50 mV have been obtained at a nanowire diameter of 40 nm, demonstrating the good interfacial quality that the new technique provides.