Polymorphous Si thin films from radio frequency plasmas of SiH4 diluted inAr: A study by transmission electron microscopy and Raman spectroscopy

In this study, we present a detailed structural characterization by means o f transmission electron microscopy and Raman spectroscopy of polymorphous s ilicon (pm-Si:H) thin films deposited using radio-frequency dust-forming pl asmas of SiH4 diluted in Ar. Square-wave modulation of the plasma and gas t emperature was varied to obtain films with different nanostructures. Transm ission electron microscopy and electron diffraction have shown the presence of Si crystallites of around 2 nm in the pm-Si:H films, which are related to the nanoparticles formed in the plasma gas phase coming from their diffe rent growth stages, named particle nucleation and coagulation. Raman scatte ring has proved the role of the film nanostructure in the crystallization p rocess induced "in situ" by laser heating. (C) 2001 American Institute of P hysics.