Vorticity and quantum interference in ultra-small SOI MOSFETs

As scaling and performance needs of industry has continued, silicon-on-insulator technology appears to be a viable option. However, the small sizes of these structures require a quantum treatment for the transport. In this paper, we present results from a full three-dimensional (3-D) quantum simulation and describe the effects of quantum interference and vorticity arising from the discrete nature of the dopant atoms. In wide (∼18 nm) channel devices, as the electrons travel from the source to the drain of the device, vortices in their motion form, based on the 3-D positions of the dopant atoms in the device. For a narrow-channel device (∼8 nm), the quantum interference effects are exacerbated, as seen in the output currents. The vorticity of the electron density is not suppressed at low drain biases. However, at higher drain biases, the vortices are washed out due to increased interaction with the channel dopants and increased carrier energy.