Effect of Si/Fe ratio on the boron and phosphorus doping efficiency of β-FeSi2 by magnetron sputtering

• Published in: Thin solid films Vol. 520; no. 1; pp. 515 - 518
• Main Authors: Xu, Jiaxiong, Yao, Ruohe
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 31.10.2011
• Subjects: Boron; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Doping; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Energy of formation; Exact sciences and technology; Iron; Magnetron sputtering; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Phosphorus; Physics; Silicon; Thin films; Electrical conductivity; Doping efficiencies; Doping; X-ray diffraction; Iron; XRD; Phosphorus additions; Thin films; Cathode sputtering; Boron; Magnetron sputtering; Physical vapor deposition; Formation energy; Silicon; IV characteristic; Electrical property measurements; Electrical properties; Iron silicide; Electrical measurement; Experimental result; Phosphorous; β-FeSi; Heterojunctions; Boron additions; Sputter deposition; Carrier density
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.07.047

Boron-doped or phosphorus-doped beta -FeSi2 thin films have been prepared on silicon substrate by magnetron sputtering. Effects of Si/Fe ratio on the boron and phosphorus doping efficiencies have been studied from the resistivities of doped beta -FeSi2 thin films and current-voltage characteristics of doped beta -FeSi2/Si heterojunctions. The experimental results reveal that the carrier concentration and doping efficiency of boron or phosphorus dopants at the Fe-rich side are higher than that at the Si-rich side. The effect of Si/Fe ratio can be deduced from the comparison of the formation energies under two extreme conditions. At the Fe-rich limit condition, the formation energy of boron or phosphorous doping is lower than that at the Si-rich condition. Therefore, the activation of impurities is more effective at the Fe-rich side. These results demonstrate that the boron-doped and phosphorous-doped beta -FeSi2 thin films should be kept at the Fe-rich side to avoid the unexpected doping sites and low doping efficiency.