Gate assisted Kelvin test structure to measure the electron and hole flows at the same nanowire contacts

Abstract

A gate assisted Kelvin test structure based on Si nanowire field effect transistors has been designed and fabricated for the characterization of the transistor source/drain contacts. Because the Si nanowire field effect transistors exhibit ambipolar characteristics with electron current slightly lower than the hole current, we can select the type of carriers (electrons or holes) flowing through the same contacts and adjust the current by the applied gate voltage. In this way, we are able to measure the characteristics of the same contact with either pure electron or hole flow. In addition, we found that the nanowire contacts behave very differently depending on the current flow directions. This indicates that the source and drain contact resistance can be dramatically different. Such a gate assisted Kelvin Test structure will lead to future metrology and applications in nanoelectronics.

Field effects of current crowding in metal-MoS2 contacts

“…Our previous work has shown that using the gate-assisted test structures is an excellent approach to measure properties of the metal contacts to low-dimensional materials. 31 Here, we present a study on current crowding in metal-MoS 2 contacts determined by using both gate-assisted Kelvin structures and four-probe structures where the channel current is effectively tuned by a top gate.…”