Epitaxy of Si nanocrystals by molecular beam epitaxy on a crystalline insulator LaAlO3(0 0 1)

✍ Scribed by Hussein Mortada; Didier Dentel; Mickael Derivaz; Jean-Luc Bischoff; Emmanuel Denys; Reda Moubah; Corinne Ulhaq-Bouillet; Jacques Werckmann

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 738 KB
• Volume: 323
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2010.10.007

✦ Synopsis

We have studied the Si initial growth mechanisms on LaAlO 3 (0 0 1), a crystalline oxide with a high dielectric constant (high-k material). The clean LaAlO 3 (0 0 1) substrate exhibits a c(2 Â 2) reconstruction that can be attributed to surface O vacancies.

Si deposit by molecular beam epitaxy was studied as a function of both deposition temperature and thickness. Epitaxy was obtained only above 550 1C. In this case, a Volmer-Weber mode is observed. The associated nanodots are relaxed and formed by pure Si as ascertained by the Si 2s XPS peak, which remains for 1 and 10 ML at the binding energy corresponding to Si-Si bonds. Moreover the islands have an abrupt interface with the LaAlO 3 (0 0 1) substrate without the formation of silicate or silica. A unique epitaxial relationship between LaAlO 3 and the crystallized Si islands is pointed out by RHEED and confirmed by HRTEM, where the Si(0 0 1) planes are parallel to the LaAlO 3 (0 0 1) ones, but rotated by 451 in the [0 0 1] direction. This orientation leads to mismatch and strain minimization of the Si film.