Application of electron holography to extended defects: Schottky barriers at NiSi2 precipitates in silicon



Thin NiSi2 precipitates in n-type Si were analyzed by electron holography. A phase shift of the electron wave was observed around the precipitate and gives direct evidence about the existence of an internal Schottky barrier. The barrier at the interface between the precipitate and the Si matrix, doped with 4 × 1014 cm–3 phosphorus, was estimated to be about 90 mV. This value is about five times smaller than the dark barrier. The lowering of the barrier can be explained as a consequence of excess charge carriers generated by the incident electron beam. Additional artifacts like variation of mean inner potential, dead layers, and dynamical diffraction are discussed as well. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)