Understanding the factors affecting contact resistance in nanowire field effect transistors (NWFETs) to improve nanoscale contacts for future scaling

Abstract

In this paper, dry etched vertical nanowires (VNWs) are used in transmission line/transfer length analysis to study the contacts of gate-all-around devices for future technology nodes. VNW resistors with Mo and Pd based metal stack contacts to p-InGaAs show Schottky behavior, unlike the planar counterpart. The resistance for Mo contact is higher than Pd, however, Pd was found to form an alloy with InGaAs at temperatures as low as 190 °C, and the length of Pd diffusion into the InGaAs increased at smaller NW dimensions, hindering future scalability. The minimum extracted specific contact resistivity ( ρC) values are 1.6 × 10−5 Ω cm2 (Mo) and 4.2 × 10−6 Ω cm2 (Pd) for a doping level of 1 × 1019 cm−3. An apparent dependence of ρC on the NW diameter was also observed. This has been attributed to the surface states under the un-gated region of NW devices and found to dominate at smaller diameters. An analytical model to account for such geometrical effects has also been developed and validated with technology computer-aided design simulations. The analysis presented in this paper effectively captures the 3D aspects of an NW contact at nanoscale dimensions and can be applied irrespective of the semiconductor and contact metal used.

Homojunction Interface Boosts Hole-Carrier Injection in p-Type CuI Nanoribbon Field-Effect Transistors

“…Integrating 1D nanostructures into FETs presents challenges, such as contact resistance, selective doping, electrode selection, Fermi level pinning, and interface effects, which collectively influence the efficiency of interfacial charge transfer. To address these issues, researchers have conducted numerous studies focused on locally adjusting carrier concentrations or doping levels within the metal–semiconductor nanowire interface .…”

“…Specifically, the smaller size and precise geometry of nanoribbons (NRs) facilitate better gate control, enabling fine-tuned modulation of FET characteristics and enhanced switching behavior. The NR-based FETs exhibit high-performance characteristics, including elevated on/off current ratios, indicating improved switching behavior. − Therefore, exploring CuI NR fabrication has significant potential for developing next-generation, high-performance electronic components.…”

Resistor-to-Schottky barrier analytical model for ohmic contact test structures

“…Circular TLM and its variants, such as the twocontact circular test structure [30], multi-ring CTLM [31], and coaxial circular test structure [32], simplify the fabrication process, offering a more efficient alternative to the rectangular patterns of linear TLM test structures. The aforementioned test structures all use a distributed network to model contact resistance, enabling the derivation of differential equations for each segment (dx) [29,33]. Solving these equations yields analytical expressions to evaluate SCR, sheet resistance, and transfer length.…”

Electrical Activity and Extremes of Individual Suspended ZnO Nanowires for 3D Nanoelectronic Applications

“…In such configurations, the substrate can serve as the primary source of current leakage and scattering in the NW. , Therefore, the substrate’s effect on the NW’s electrical and thermal conductivity may not be negligible, which is likely to have a significant impact on electron mobility in the NW. In addition, a large electrical contact resistance involved in the characterization technique introduces a large error when determining the electrical and thermal conductivity of the NW. − Nonetheless, these techniques necessitate costly nanomanufacturing techniques to suspend the NW between the electrodes and isolate it from the substrate, and the experimenter faces the challenges of manipulating the nanostructure. Consequently, a consistent and reliable technique for characterizing the physical properties of suspended NWs is essential as an initial step.…”