Practical Mobility Estimations for Transistors With 1-D Channels Based on the Landauer–Büttiker Equation

Practical mobility expressions are derived for transistors with one-dimensional (1-D) semiconductors in the channel, such as carbon nanotubes (CNTs) based on the 1-D Landauer-Büttiker equation covering the ballistic as well as the non-ballistic transport regime. By decomposing the impact of serial resistances capturing the voltage drops across the metal-CNT interfaces and the supply lines as well as the impact associated with the quantum resistance, definitions for the mobility have been derived allowing a meaningful evaluation of the semiconductor material. The definitions involve measurable quantities in contrast to previous publications with hidden quantities and they are applied to synthetic and experimental data of single-tube CNT field-effect transistors of different channel lengths, Schottky barrier heights, diameters, and doping. Peak extracted mobility values agree with results from a physics-based diameter-dependent mobility model. The length-independent channel mobility obtained in this work is a useful parameter for technology evaluation, especially for short channel devices.