A Two-Dimensional Model for Interface Coupling in Triple-Gate Transistors

Abstract

The influence of the fin width on substrate-to-gate coupling in long-channel silicon-on-insulator triple-gate transistors is investigated. A complementary analysis, taking into account both the "front coupling" (variation of the front-channel threshold voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T1</sub> , as a function of the substrate bias V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G2</sub> ) and "back coupling" (variation of the back-channel threshold voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T2</sub> ) as a function of the front-gate bias V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G1</sub> ) characteristics has been carried out. It is shown that the back coupling, as opposed to the front coupling, is highly sensitive to the fin width in narrow-channel devices and can even be used in fin width extraction. Simple analytical 2-D models for the body potential, V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T1</sub> , and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T2</sub> have been developed to clarify the experimental data, showing in particular the gradual control of the back interface potential by the lateral gates in narrow fins. The model stands as a 2-D generalization of the Lim and Fossum's well-known 1-D interface coupling model