Morphology and stability of (Ti_0.9Zr_0.1) Si₂ thin films on Si(111) and Si(100) formed in UHV

This study explores the temperature stability and surface morphology of (Ti_0.9Zr_0.1)Si₂ films formed from reaction of TiZr alloys on Si. Titanium and zirconium alloy films (200 Å) were deposited on atomically clean Si surfaces in an ultra high vacuum (UHV) electron beam deposition system, and the wafers were annealed in UHV to form the alloy silicide. In-situ Raman experiments were performed to identify the phases of the (Ti_0.9Zr_0.1)Si₂ films. The surface morphologies were studied using scanning electron microscopy, and the root mean square surface roughness was measured using atomic force microscopy. Sheet resistivity measurements were also performed. The results indicate that (Ti_0.9Zr_0.1)Si₂ films are stable in the C49 phase for temperatures up to 1000 °C. In addition, the surface roughness is substantially less than similarly prepared TiSi₂ films at high temperatures indicating that agglomeration is reduced for the C49 alloy films. The sheet resistances of the alloy films are less than those of the TiSi₂ films annealed at the same temperatures (>800 °C) because of decreased agglomeration. The (Ti_0.9Zr_0.1Si₂ films showed little degradation of sheet resistance for annealing temperatures up to 900 °C.