UC Riverside

Advancing electronic devices requires not just new ideas but also the scalable and industry-friendly synthesis of innovative materials. As copper interconnects continue to shrink to the nanoscale, their resistivity rises sharply due to surface and grain boundary scattering, pushing the need for alternative solutions. Quasi-one-dimensional (quasi-1D) transition metal trichalcogenides, with their promising metallic properties, stand out as potential replacements. In our previous research, we successfully grew TaSe₃ nanowires with cross-sectional areas as small as 7 nm, and notably, their resistivity did not increase at these small scales. These nanowires also showed an electromigration activation energy twice that of copper and could handle current densities far beyond what copper can endure. These promising results highlight TaSe₃ as a viable candidate for downscaled electronic devices, a topic explored in detail in Chapter 1 as the driving motivation for this study.Chapter 2 dives into the history of the materials relevant to this research, focusing on transition metal trichalcogenides and elemental tellurium. It explores their unique electronic properties, which make them attractive alternatives to conventional interconnect materials. Chapter 3 shifts to the experimental side, describing the techniques used in this study, with a particular emphasis on the chemical vapor deposition (CVD) process. This process was adapted to grow ZrTe₃ and Te nanowires, overcoming specific challenges related to the activation properties of selenium and tellurium. The fine-tuning of CVD parameters led to the successful deposition of high-quality nanowires on SiO₂ substrates. Chapter 4 presents the results from these optimized processes, comparing the performance of ZrTe₃ and Te nanowires, and highlighting their impressive current-carrying capabilities and stability under varying conditions. These findings reinforce the potential of quasi-1D van der Waals materials for next-generation microelectronic applications, providing a promising route to address the scaling challenges that traditional interconnect materials like copper currently face. Chapter 5 explores the impact of ion implantation on the electrical properties of CVD-grown Te nanowires, focusing on the enhancement of conductivity through ion beam-induced modifications. The chapter details the fabrication of multi-terminal devices and examines the effects of varying ion fluence on the current-voltage characteristics of Te nanowires. The findings demonstrate that ion implantation significantly improves the nanowires' electrical performance by introducing defects that enhance charge carrier mobility. These results underscore the potential of ion implantation as a precise doping method to tailor the electronic properties of quasi-1D materials, paving the way for their integration into advanced semiconductor devices. Chapter 6 investigates the patterned growth of TaSe₃ nanowires on lithographically prepared substrates, employing techniques such as UV optical photolithography and electron-beam lithography to direct the growth and alignment of nanowires. By designing specific patterns and creating artificial defects, the chapter showcases the controlled nucleation and guided growth of TaSe₃, achieving desired orientations and interconnections. The study highlights the scalability of these methods for microelectronic applications and sets the foundation for future work on device fabrication, comparing the electrical properties of pre-patterned nanowires to single nanowire counterparts. This approach aims to establish TaSe₃ nanowires as viable alternatives for on-chip interconnections, addressing the limitations of traditional materials.