Effect of argon sputtering on XPS depth-profiling results of Si/Nb/Si

• DOI: 10.1016/j.elspec.2017.09.009
• Publication Date: 2017-09-29T08:45:45Z
• Authors: Iraida N. Demchenko; Yevgen Melikhov; Yevgen Syryanyy; Irina Zaytseva; Pavlo Konstantynov; Maryna Chernyshova
• Keywords: 02 engineering and technology; 0210 nano-technology; QC

Ultrathin Si/Nb/Si trilayer is an excellent example of a system for which dimensionality effects, together with other factors like type of a substrate material and growth method, influence strongly its superconducting properties. This study offers some important insights into experimental investigation of density of states of such a system with the aim to identify an electronic structure of the interface as a function of niobium layer thickness. For that, two Si/Nb/Si trilayers with 9.5 and 1.3 nm thick niobium layer buried in amorphous silicon were studied using high-resolution (HR) XPS depth-profile techniques. Strong influence of sputtering was observed, which resulted in severe intermixture of Si and Nb atoms. Nevertheless, a sharp top interface and metallic phase of niobium were detected for the thicker layer sample. On the contrary, a Nb-rich mixed alloy at top interface was observed for the thinner layer sample.