Microstructure of Thin Si-Sn Composite Films

Abstract

Microstructure investigations of thin Si-Sn alloy films were carried out, by using Auger and Raman spectroscopies, X-ray fluorescence analysis, and electron microscopy. The films were produced by the thermal-vacuum coevaporation of Si and Sn. The properties of films with the Sn content ranging from 1 to 5 wt.% are studied. A significant influence of the tin impurity on the formation of a film surface microrelief and nanocrystals in the amorphous matrix is found. The size of quasispherical formations on the film surface can be of the order of 100 nm. The volume fraction of the silicon nanocrystalline phase in a film can reach 90%. The roles of fabrication conditions and growth rate on the distributions of Sn and technological impurities C and O over the film surface and across the film thickness are analyzed. K e y w o r d s: Microstructure of thin composite films, Auger method, Raman spectroscopy.

Tin-Induced Crystallization of Amorphous Silicon under Pulsed Laser Irradiation

“…i.e. about 350 ∘ C, which agrees with the data of previous works concerning the temperature of the tininduced crystallization of amorphous silicon [18][19][20][21].…”

“…One of the promising ways in this direction is the application of the phenomenon of metal-induced crystallization (MIC) of amorphous silicon (a-Si) [13][14][15][16][17]. In particular, a possibility to form Si nanocrystals 2-7 nm in dimensions and with a phase volume fraction of up to 80% in the a-Si matrix with the help of the low-temperature tin-induced Si crystallization was demonstrated in [18][19][20]. Those experimental results were interpreted with the use of a new mechanism of MIC, which was proposed in works [20][21][22] and considerably differs from those known for other metals [13,[15][16][17].…”

Tin-induced crystallization of amorphous silicon assisted by a pulsed laser irradiation

“…In particular, the possibility to form Si nanocrystals in amorphous Si matrix at 2 to 5 nm sizes and the phase volume fraction up to 80% was shown by means of tin-stimulated crystallization of amorphous Si at low temperatures [18][19][20]. These experimental results interpreted by the new MIC mechanism proposed in the papers [20][21][22].…”

Tin doping effect on crystallization of amorphous silicon obtained by vapor deposition in vacuum

“…The first reports about crystallization of Si a  films doped by Sn from the gaseous phase in the process of film formation were made in [9]. Their results were further confirmed in [10], where the dominant size of Si crystals in amorphous matrix was close to few nanometers. However, the distribution of Sn atoms inside the film of Si:Sn alloy produced by the authors of [9] was very heterogeneous.…”

“…The films were deposited on silica or monocrystalline Si substrates at the temperature 300 C and residual pressure 10 -3 Pa. The parameters of sputtering ensured a uniform distribution of Sn impurity in 100 nm thick surface layer of the film [10]. Phase composition of the films was determined by analyzing the spectra of Raman scattering (RS) activated by Ar-Kr + -laser at the wavelength 514.5 nm.…”