OPTICAL-PROPERTIES OF POLYCRYSTALLINE SILICON THIN-FILMS DEPOSITED BYSINGLE-WAFER CHEMICAL-VAPOR-DEPOSITION

The ellipsometric study of polycrystalline silicon films deposited usi ng a single wafer rapid thermal chemical vapor deposition reactor unde r varying conditions of temperature and doping is presented. In partic ular, using spectroscopic ellipsometry in the visible spectral range, we determined the thickness of the films and the structural changes as a function of the deposition temperature. A different film structure, from amorphous to polycrystalline, has been found for the different d eposition temperatures. A shift to lower values of the transition temp erature which marks the structural change and a decrease in the deposi tion rate as the doping level is increased are observed. Moreover, fro m the ellipsometric results the optical functions of the different sam ples were evaluated. (C) 1997 Elsevier Science S.A.