Solid phase epitaxy of Ge films on CaF2/Si(1 1 1)

• Published in: Applied surface science 2007-10, Vol.254 (1), p.143-147
• Main Authors: RUGERAMIGABO, E. P, DEITER, C, WOLLSCHLÄGER, J
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron and ion emission by liquids and solids; impact phenomena; Electron diffraction and scattering; Electron impact: auger emission; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Low-energy electron diffraction (leed) and reflection high-energy electron diffraction (rheed); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Solid phase epitaxy; growth from solid phases; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.07.167

At room temperature deposited Ge films (thickness < 3nm) homogeneously wet CaF2/Si(111). The films are crystalline but exhibit granular structure. The grain size decreases with increasing film thickness. The quality of the homogeneous films is improved by annealing up to 200 deg C. Ge films break up into islands if higher annealing temperatures are used as demonstrated combining spot profile analysis low energy electron diffraction (SPA-LEED) with auger electron spectroscopy (AES). Annealing up to 600 deg C reduces the lateral size of the Ge islands while the surface fraction covered by Ge islands is constant. The CaF2 film is decomposed if higher annealing temperatures are used. This effect is probably due to the formation of GeFx complexes which desorb at these temperatures.