Bulk-Si FinFET technology for ultra-high aspect-ratio devices

FinFETs with 1 µm tall fins have been processed on (110) bulk silicon wafers using crystallographic etching of silicon by TMAH to form fins with nearly vertical sidewalls of an (111) surface orientation. The concept of tall, narrow fins offers more efficient use of silicon area and better performance of multi-fin devices in high-frequency analog applications. N-channel FinFETs with 1.9-nm-wide fins and a height of the active part of the fin up to 650 nm have been fabricated and demonstrate the scaling potentials of the proposed technology. This extreme reduction of the fin width degrades electron mobility as compared to devices with 15-nm-wide fins, which have been used here to investigate the current conduction capability of FinFETs with (111) sidewalls.