Ultra-high aspect-ratio FinFET technology

• Published in: Solid-state electronics Vol. 54; no. 9; pp. 870 - 876
• Main Authors: Jovanović, Vladimir, Suligoj, Tomislav, Poljak, Mirko, Civale, Yann, Nanver, Lis K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2010; Elsevier
• Subjects: Applied sciences; Carrier confinement; Channel; Channels; CMOS; Design. Technologies. Operation analysis. Testing; Devices; Electronics; Etching; Exact sciences and technology; FinFET; Fins; Integrated circuits; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; Threshold voltage; TMAH; Transistors; CMOS; Carrier confinement; FinFET; TMAH; Channel; Performance evaluation; Voltage threshold; MOSFET; n channel; Dual gate transistor; Subband; Low field; Aspect ratio; Self aligned technology; Engraving; Complementary MOS technology; Transistor channel; Electron mobility; Silicon; Miniaturization; Series resistance; High frequency; Comparative study; Wafer
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2010.04.021

FinFETs with ultra-large height-to-width ratio have been processed on (1
1
0) bulk silicon wafers by employing crystallographic etching of silicon with TMAH, which results in nearly vertical sidewalls with a (1
1
1)/〈1
1
2〉 surface orientation. Tall fins, which corresponds to wide transistor channels per single fin offer more efficient use of the silicon area and improved performance for multi-fin devices in high-frequency analog applications. N-channel FinFETs with 1.9-nm-wide fins demonstrate the downscaling potential of the technology and devices with a height of the active part of the fin of 625
nm have the largest aspect-ratio of the fins reported thus far. Both devices with highly and moderately scaled fin-widths exhibit excellent subthreshold performance while electrons have higher mobility in 15-nm-wide FinFETs, which gives them larger on-state currents. The comparison between FinFETs and wide tri-gate devices shows that FinFETs have better current drivability in this simple process, even with larger source/drain series resistances. The differences in threshold voltage and low-field electron mobility between 1.9-nm-wide and 15-nm-wide FinFETs have been related to the increase in subband energies due to carrier confinement in the extremely narrow fins.