An extensive Raman spectroscopic investigation of ultrathin Co1-xNixSi2 films grown on Si(100)
2012 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, no 4, 041511-041518 p.Article in journal (Refereed) Published
Ultrathin silicide films were formed by starting from 1-8 nm thick Co1-xNix (x = 0, 0.25, 0.5, 0.75, and 1) at 350 degrees C-900 degrees C. For each composition x, there exists a critical thickness above which the transition temperature from monosilicides CoSi and NiSi to a disilicide-like phase increases with increasing film thickness. Below this thickness, the disilicide phase seems to form without exhibiting the monosilicides within the detection resolution limits of transmission electron microscopy and Raman spectroscopy. Raman spectroscopic analysis seems to indicate that Ni could be dissolved in the CoSi lattice to a certain fraction despite the fact that CoSi and NiSi are distinct with different crystallographic structures. Moreover, the disorder-induced Raman scattering in NiSi2 is found to be enhanced by Co incorporation. The observed annealing behaviors are attributed to variations in free energy change for phase transition caused by differences in metal thickness.
Place, publisher, year, edition, pages
2012. Vol. 30, no 4, 041511-041518 p.
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject Engineering Science with specialization in Electronics
IdentifiersURN: urn:nbn:se:uu:diva-180107DOI: 10.1116/1.4726295ISI: 000306142800045OAI: oai:DiVA.org:uu-180107DiVA: diva2:548153