Correlation Between the Performance and Microstructure of Titanium Based Ohmic Contacts to p-type Silicon Nanowires
Abhishek Motayed, John E. Bonevich, Sergiy Krylyuk, Albert Davydov, Geetha G. Aluri, Rao V. Mulpuri
Understanding the contact formation mechanism at nanoscale geometries is essential for the realization of low-resistance, stable metallization schemes suitable for the next-generation of nanoelectronic devices. Metal contacts deposited on faceted silicon nanowire cross-sections are three-dimensional structures with minuscule volume. Conventional techniques like x-ray diffraction and transmission electron microscopy can not be used for such geometries for studying metal diffusion, and formation of intermetallic compounds resulting from thermal processing of the contacts. In this study, we present detailed microstructural characteristics of Ti-silicon nanowire contact cross-sections annealed at various temperatures. By using focused ion beam cross-sectioning technique and scanning transmission electron microscopy, we have studied the microstructure of the source/drain metal contacts of working p-type silicon nanowire (SiNW) field-effect transistors (FETs) annealed at temperatures ranging from 450 °C to 750 °C. Formation of Ti-silicide is observed in the 750 °C annealed junctions. Extensive Si out-diffusion from the nanowire leading to void formation was observed in 750 °C annealed cross-sections, which highlighted the impact of the study. Electrical measurements revealed that the devices with 550 °C annealed contacts had linear characteristics; where as the devices with contacts annealed at 750 °C had best characteristics in terms of linearity, symmetric behavior, and yield. A direct correlation between the microstructure and the performance of these contacts is established in this study.
, Bonevich, J.
, Krylyuk, S.
, Davydov, A.
, Aluri, G.
and Mulpuri, R.
Correlation Between the Performance and Microstructure of Titanium Based Ohmic Contacts to p-type Silicon Nanowires, Nanotechnology, [online], https://doi.org/10.1088/0957-4484/22/7/075206
(Accessed December 8, 2023)