Deposition of nanocrystalline silicon mediated by ultrathin aluminum underlayers by PCVD and sputter-deposition at 500 K

• Published in: Thin solid films 1999-01, Vol.337 (1), p.41-44
• Main Authors: Drüsedau, Tilo P, Diez, Anette, Bläsing, Jürgen
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Magnetron-sputtering; Materials science; Metal-induced crystallization; Methods of deposition of films and coatings; film growth and epitaxy; Nanocrystallites; PCVD; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)01387-X

Silicon layers were deposited by standard PCVD from undiluted silane or sputter-deposition, respectively, onto aluminum underlayers of 4–32 nm thickness. Above a critical thickness of the Al-layer around 8 nm, the growth of nanocrystalline silicon is observed. The intentional introduction of hydrogen into the sputter-deposited bilayers showed a weak effect on crystallite formation. In contrast, the argon pressure during Si-sputtering was found to strongly affect the formation of nc-Si. Effective growth of Si-crystallites is accompanied by a consumption of Al from the underlayer and an increased diffusion of Al into the silicon as detected by X-ray methods and concentration in-depth profiles, respectively. As found by atomic force microscopy, the typical rough surface of the Al-underlayers is preserved during the growth of the Si-overlayers. The effect of the aluminum-mediated growth is explained by a migration of Al-crystallites from the underlayer into the growing film.