Epitaxial nickel disilicide with low resistivity and excellent reliability

Abstract

Ultra-thin epitaxial NiSi2 was formed, and its structure was examined by electron microscopy and x-ray diffraction. Compared with previous reports, the measured resistivity of the epitaxial NiSi2 was unprecedentedly low, reaching 7 μΩ cm in the experimental results and up to 14.93 μΩ cm after modification. The reliability, which was investigated under different temperatures and current densities to understand its electronic characteristics, was 1.5 times better than that of the conventional polycrystalline counterpart. Black's equation and the measured mean-time-to-failure (MTTF) were used to obtain the reliability characteristics of epitaxial and poly-NiSi2. Confidence intervals at 95% for each MTTF confirmed the single failure mode. The electromigration phenomenon was observed to be the failure mechanism. Our results provide evidence that epitaxial NiSi2 is a promising contact material for future electronics.

Epitaxial silicides: the case of Fe, Ni, and Ti

“…This fabrication technique is much more reliable as compared to previous methods in which accurate application of a very thin Ni layer is required to control the metal thickness. Moreover, the composition ratio of the intermixed layer (Ni : Si) was close to the stoichiometric ratio of the compound, based on our previous report, 18 which contributed to a low formation temperature as a result of lowered Gibbs free energy. In this case, the intermixing layer tended to form high-temperature silicides at relatively low temperatures, accompanied by epitaxial growth.…”

“…1. 18 It was possible to alter the atomic ratio in the intermixed layer if we modified our process steps by including a second sputtering. When another sputtering was performed on the sample that already had a Ni/Si intermixed layer formed on the top of the substrate, the structure and free energy of the intermixed layer could be altered.…”

Enhancement of Electromigration Reliability of Electroless-Plated Nanoscaled Copper Interconnects by Complete Encapsulation of a 1 nm-Thin Self-Assembled Monolayer

“…Black's equation is based on empirical studies and is universal to predicting EM reliability and failure modes of various metal interconnect lines. 41,42 If EM failure was purely induced by void nucleation, the interconnect would readily fracture soon after EM testing, and the current-density scale factor would be 2, whereas a failure caused merely by void growth would result in a longer MTF, associated with a smaller scale factor of 1. 43,44 Here, the scale factor of the asfabricated, unpassivated Cu interconnects in the low current density regime (<4.8 × 10 8 A cm −2 ) is 1.25, signifying that a void-growth mechanism dominates their failure.…”

Suppressed Umklapp scattering ofβ-FeSi2thin film and single crystalline nanowires

“…All of the Si substrates were cleaned by a standard Radio Company of America process and dilute hydrofluoric acid dipping prior to the growth process [17][18][19]. Iron silicide nanowires were synthesized in a horizontal furnace by a chemical vapor transport method [20,21].…”