Homogeneous Si films on CaF2/Si(111) due to boron enhanced solid phase epitaxy

Biaxially oriented CaF2 films on amorphous substrates

“…In the present work, we focus on the creation of biaxial CaF 2 films using the oblique angle deposition technique on Si wafers covered with a layer of amorphous native oxide. CaF 2 has been known as an excellent buffer layer material for the growth of a variety of semiconductor materials including Si [10][11][12][13][14] and compound semiconductors [15][16][17]. The heteroepitaxial structures with CaF 2 have promising applications in many advanced devices [14], such as resonant tunneling diodes [12] and electrooptical modulators [14,18].…”

Surfactant enhanced solid phase epitaxy of Ge/CaF2/Si(111): Synchrotron x-ray characterization of structure and morphology

“…Using Sb or B as surfactant, it was demonstrated for 11-nmthick Si films, which were deposited at room temperature on CaF 2 /Si(111) and subsequently annealed to 635 C, that the Ge films were very smooth with rms-roughness of less than 1 nm. 20,21 Compared to these results, the Ge film is much rougher (rms-roughness 4.1 nm), although the tendency to form 3D islands should be less pronounced for Ge compared to Si, since the Ge surface energy is smaller than the Si surface energy. Furthermore, the Ge surface energy is additionally decreased by the adsorbed Sb.…”

“…17 Recently, it has been shown that the homogeneity of Si films deposited on CaF 2 / Si(111) is improved if solid phase epitaxy (SPE) is combined with the use of surfactants (e.g., B, Sb), which are deposited during the annealing. [19][20][21] Electronic devices, which were fabricated on the base of this technique, perform much better than devices fabricated with other techniques. [22][23][24] Furthermore, due to its passivating property, the surfactant As has been applied after removal of fluorine from the CaF 2 interface by electron exposure prior to Si deposition.…”

Multifractal analysis of sputtered CaF2 thin films

“…Physical vapor deposition techniques have been primarily used for the preparation of CaF 2 thin films. Some of these are molecular beam epitaxy, electron beam evaporation (EBE), thermal evaporation, radio frequency magnetron sputtering, etc. Understanding the surface growth of thin films is of both theoretical and practical interest.…”