The role of hydrogen in the formation of microcrystalline silicon

The growth mechanisms of microcrystalline silicon thin films at low tempera tures (100-250 degrees C) by plasma CVD are still a matter of debate. We ha ve shown that mu c-Si:H formation proceeds through four phases (incubation, nucleation, growth and steady state) and that hydrogen plays a key role in this process, particularly during the incubation phase in which hydrogen m odifies the amorphous silicon network and forms a highly porous phase where nucleation takes place. In this study we combine in-situ ellipsometry and dark conductivity measurements with ex-situ high resolution transmission el ectron microscopy to improve our understanding of microcrystalline silicon formation. (C) 2000 Elsevier Science S.A. All rights reserved.