Surface morphology evolution of amorphous Fe–Si layers upon thermal annealing

• Published in: Journal of physics. D, Applied physics Applied physics, 2008-04, Vol.41 (8), p.085418-085418 (5)
• Main Authors: Sun, C M, Tsang, H K, Wong, S P, Ke, N, Hark, S K
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/41/8/085418

Changes in the surface morphology of ion-beam-synthesized amorphous Fe-Si layers after rapid thermal annealing (RTA) and furnace annealing (FA) were investigated using atomic force microscopy and transmission electron microscopy. Completely amorphous Fe-Si layers were formed by Fe implantation at a dosage of 5 X 1015 cm-2 using a metal vapour vacuum arc ion source under 80 kV extraction voltage and cryogenic temperature. After RTA at 850 deg C, beta-FeSi2 precipitates in Si are completely aggregated from this amorphous Fe-Si layer and the surface of the implanted layer remains flat. To date, no obvious photoluminescence (PL) spectrum has been reported from RTA treated beta-FeSi2 precipitates. However, after annealing at 850 deg C for 40 s, high-quality beta-FeSi2 precipitates in Si are obtained which clearly show 1.5 mum PL at 80 K for the first time. Even though additional long-term FA at 850 deg C can enhance PL intensity to a limited extent, the longer thermal treatment induces the outdiffusion of beta-FeSi2 precipitates and degrades the surface flatness.