Electrical Characteristics of CNT-FETs with Symmetric Field-Effect-Free-on Source and Drain

• Main Authors: Lee, W.Y., Lai, C.Y., Weng, C.H., Juang, Z.Y., Leou, K.C., Chang-Liao, K.S., Tsai, C.H.
• Format: Conference Proceeding
• Language: English
• Subjects: Carbon nanotubes; CNTFETs; Electric variables; electrical characteristics; Electrodes; Electrostatics; field-effect-free-on; Hysteresis; Nickel; Robust stability; Schottky barriers; Silicon; Wet etching
• ISSN: 2159-3523
• DOI: 10.1109/NANOEL.2006.1609756

The carbon-nanotube field-effect-transistors (CNTFETs) have been explored and proposed to be the promising candidates for the next generation integrated-circuit (IC) devices. The so-called Schottky barrier (SB)-FET is widely used to characterize the operation behavior of a CNTFET, and the Schottky barriers are affected by the gate fields at the metal-nanotube interfaces. By using the double-layered catalyst configuration (nickel and upper SiO 2 layer), SWNTs were in-situ grown across two catalytic pads on a substrate with a thinner thermal oxide layer above the channel and thicker ones at the two source/drain junction terminals. The uni-polar characteristics of a p-type CNTFET was consequently achieved by electrostatic engineering. The turn-off current (I off ) was significantly reduced and the turn-on current (I on ) to I off ratio was then increased up to ∼ 10 4 . The p to n conversion was observed after several cycles of measurement in a vacuum environment presumably due to removal of adsorbed O 2 molecules. On the other hand, the hysteresis behavior of transfer characteristics was still observed, suggesting that the CNTFET could be used in non-volatile memory applications.