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

The influence of tin impurity on amorphous silicon crystallization was investigated using the methods of Raman scattering, Auger spectroscopy at ion etching, scanning electron microscopy and X-ray fluorescence microanalysis in thin films of Si:Sn alloy manufactured by thermal evaporation. Formation of Si crystals of the 2 to 4- nm size has been found in the amorphous matrix alloy formed at the temperature 300 C. Total volume of nanocrystals correlates with the content of tin and can comprise as much as 80% of the film. The effect of tin-induced crystallization of amorphous silicon occurred only if there are clusters of metallic tin in the amorphous matrix. The mechanism of tin-induced crystallization of silicon that has been proposed takes into account the processes in eutectic layer at the interface metal tin – amorphous silicon

Microfluctuations of oxygen impurity concentration as a reason of accelerated oxygen diffusion in silicon

Activation energy of thermal donors annealing increases from 1.7 to 2.5 eV on preliminary heat treatment of the Si crystals at 800⁰C. It is believed that this fact results from the dissolution of oxygen microfluctuations that are considered to be sources of intrinsic elastic strains and thereby to lie at the basis of locally accelerated oxygen diffusion

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

The process of tin-induced crystallization of amorphous silicon under the influence of different types of laser irradiation was investigated using the method of Raman scattering by thin-film Si-Sn-Si structures. The dependences of the size and concentration of Si nanocrystals on the power of laser radiation was experimentally evaluated and analyzed. As sources of excitation pulse laser radiation with the pulses duration equal to 20 ns and 150 s and wavelengths equal to 535 and 1070 nm was used. The possibility of efficient tin-induced transformation of silicon from amorphous phase to crystalline one in the 200-nm thick layers of a-Si under the action of laser pulses with duration equal to 20 ns was shown. The spatial and temporal distributions of laser induced temperature rise was calculated to interpret experimental results