Effects of Geometrical Fin Parameters on Transfer Characteristics in Triple-Gate Fin Field Effect Transistors

Abstract

We examined the effects of device parameters on the transfer characteristics of triple-gate fin field-effect transistors (FinFETs) using three-dimensional device simulations. Channels were observed to form separately in the corner and main regions of triple-gate FinFETs with a heavy channel doping (for threshold voltage control using a polycrystalline silicon gate). The threshold voltages of the corner and main regions were determined using the transconductance change method. The phenomenon of channel separation is present only if high doping concentrations and corners with no radius of curvature are used in long-channel devices. For channel doping concentrations higher than 5 x 10(18) cm(-3), the corner transistor turns on earlier than the main transistor. This effect is significantly reduced by the use of rounded corners, thin gate oxides, and high dielectrics. However, the earlier conduction of corner regions is not effectively suppressed in body-tied FinFETs even though the corner regions are rounded with a large radius of curvature. (C) 2009 The Japan Society of Applied Physics