title: Impact of contact resistance on the electrical properties of MoS2transistors at practical operating temperatures.
abstract: Molybdenum disulphide (MoS2) is currently regarded as a promising material for the next generation of electronic and optoelectronic devices. However, several issues need to be addressed to fully exploit its potential for field effect transistor (FET) applications. In this context, the contact resistance,RC, associated with the Schottky barrier between source/drain metals and MoS2currently represents one of the main limiting factors for suitable device performance. Furthermore, to gain a deeper understanding of MoS2FETs under practical operating conditions, it is necessary to investigate the temperature dependence of the main electrical parameters, such as the field effect mobility (μ) and the threshold voltage (Vth). This paper reports a detailed electrical characterization of back-gated multilayer MoS2transistors with Ni source/drain contacts at temperatures fromT= 298 to 373 K, i.e., the expected range for transistor operation in circuits/systems, considering heating effects due to inefficient power dissipation. From the analysis of the transfer characteristics (ID-VG) in the subthreshold regime, the Schottky barrier height (ΦB≈ 0.18 eV) associated with the Ni/MoS2contact was evaluated. The resulting contact resistance in the on-state (electron accumulation in the channel) was also determined and it was found to increase withTasRCproportional toT3.1. The contribution ofRCto the extraction of μ andVthwas evaluated, showing a more than 10% underestimation of μ when the effect ofRCis neglected, whereas the effect onVthis less significant. The temperature dependence of μ andVthwas also investigated. A decrease of μ proportional to 1/Tαwith α = 1.4 ± 0.3 was found, indicating scattering by optical phonons as the main limiting mechanism for mobility above room temperature. The value ofVthshowed a large negative shift (about 6 V) increasing the temperature from 298 to 373 K, which was explained in terms of electron trapping at MoS2/SiO2interface states.
authors.affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Strada VIII, n 5, 95121 Catania, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Giannazzo
authors.affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Strada VIII, n 5, 95121 Catania, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Fisichella
authors.affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Strada VIII, n 5, 95121 Catania, Italy; Department of Physics and Chemistry, University of Palermo, Via Archirafi 36, 90143 Palermo, Italy; Department of Physics and Astronomy, University of Catania, Via Santa Sofia, 64, 95123 Catania, Italy.
authors.forename: Aurora
authors.initials: A
authors.lastname: Piazza
authors.affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Strada VIII, n 5, 95121 Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Di Franco
authors.affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Strada VIII, n 5, 95121 Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Greco
authors.affiliation: Department of Physics and Chemistry, University of Palermo, Via Archirafi 36, 90143 Palermo, Italy.
authors.forename: Simonpietro
authors.initials: S
authors.lastname: Agnello
authors.affiliation: Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi, Strada VIII, n 5, 95121 Catania, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Roccaforte
keywords: MoS2; contact resistance; mobility; temperature dependence; threshold voltage