EXAFS investigation about Metal Induced Crystallization (MIC) of a-Si thin films doped with Ni, has been carried Out at the K edge of Ni. Several a-Si films deposited on quartz and annealed at different temperatures and a non-annealed sample have been analyzed in Order to study the variation of the nickel Surroundings as a function of temperature. Nickel particles were co-sputtered together with silicon to obtain a metal percentage of about at. 0.5%. In all the annealed samples it was found that nickel, in its first shell, is 8-fold coordinated to silicon while a weak signal Corresponding to the second shell appears in the Fourier transform of the spectra as in crystalline nickel di-silicide (c-NiSi2) used as reference compound. No presence of Ni Clustering has been ascertained. In the non-annealed sample, where the NiSi2 formation has never been observed, EXAFS shows a deformed first shell environment on Ni similar to that of NiSi2. (c) 2008 Elsevier Ltd. All rights reserved.
XAFS study of Ni surroundings in metal induced crystallization of thin film amorphous silicon
Rocca, Francesco;
2008-01-01
Abstract
EXAFS investigation about Metal Induced Crystallization (MIC) of a-Si thin films doped with Ni, has been carried Out at the K edge of Ni. Several a-Si films deposited on quartz and annealed at different temperatures and a non-annealed sample have been analyzed in Order to study the variation of the nickel Surroundings as a function of temperature. Nickel particles were co-sputtered together with silicon to obtain a metal percentage of about at. 0.5%. In all the annealed samples it was found that nickel, in its first shell, is 8-fold coordinated to silicon while a weak signal Corresponding to the second shell appears in the Fourier transform of the spectra as in crystalline nickel di-silicide (c-NiSi2) used as reference compound. No presence of Ni Clustering has been ascertained. In the non-annealed sample, where the NiSi2 formation has never been observed, EXAFS shows a deformed first shell environment on Ni similar to that of NiSi2. (c) 2008 Elsevier Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
