AbstractWe report on a systematical study of growth rate, surface morphology, hydrogen and oxygen incorporation, optical and electrical properties in Ge:H and GeYSi1-Y:H, Y> 0.85 films, deposited in a capacitive reactor by low frequency PE CVD. Silane and germane were used as feed gases diluted by hydrogen. Hydrogen dilution characterized by R= QH2/[QSiH4+QGeH4], where QH2, QSiH4, and QGeH4 are gas flows of hydrogen, silane and germane, respectively. The flow was varied in the range of R=20 to 80. Composition of the films was characterized by SIMS profiling. We did not observed a significant change of the deposition rate Vd in GeYSi1-Y:H films in all the range of R, while for Ge:H films Vd was significantly reduced after R=50. AFM characterization of the surface morphology demonstrated that at R=50 average height <H>(R) reached maximum in both Ge:H and GeYSi1-Y:H films, while average diameter <D>(R) had a minimum in GeYSi1-Y:H films and maximum in Ge:H films. Both Ge:H and GeYSi1-Y:H films demonstrated change of E04 in the studied range of R, and a minimum clearly appeared in E at R=50-60 suggesting significant reduction in weak bonds of these films. The activation energy of conductivity Ea slightly increases with R in Ge:H films and shows no definitive trend in GeYSi1-Y:H: films. Both FTIR and SIMS data show a general trend of reducing hydrogen and oxygen content with R. These two types of films showed different behavior and correlations between surface morphology and optical and electrical properties.
Study of surface morphology and optical characterization of crystalline and multi-crystalline silicon surface textured in highly diluted alkaline solutions
