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Mobility Deception in Nanoscale Transistors: An Untold Contact Story
Author(s) -
Nasr Joseph R.,
Schulman Daniel S.,
Sebastian Amritanand,
Horn Mark W.,
Das Saptarshi
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201806020
Subject(s) - materials science , nanotechnology , nanomaterials , contact resistance , transistor , electron mobility , doping , nanowire , semiconductor , optoelectronics , voltage , electrical engineering , layer (electronics) , engineering
Abstract Mobility is a critical parameter that is routinely used for benchmarking the performance of field‐effect transistors (FETs) based on novel nanomaterials. In fact, mobility values are often used to champion nanomaterials since high‐performance devices necessitate high mobility values. The current belief is that the contacts can only limit the FET performance and hence the extracted mobility is an underestimation of the true channel mobility. However, here, such misconception is challenged through rigorous experimental effort, backed by numerical simulations, to demonstrate that overestimation of mobility occurs in commonly used geometries and in nanomaterials for which the contact interface, contact doping, and contact geometry play a pivotal role. In particular, dual‐gated FETs based on multilayer MoS 2 and WSe 2 are used as case studies in order to elucidate and differentiate between intrinsic and extrinsic contact effects manifesting in the mobility extraction. The choice of 2D layered transition metal dichalcogenides (TMDCs) as the semiconducting channel is motivated by their potential to replace and/or coexist with Si‐based aging FET technologies. However, the results are equally applicable to nanotube‐ and nanowire‐based FETs, oxide semiconductors, and organic‐material‐based thin‐film FETs.