Structural and electrical characterization of microcrystalline silicon films prepared by a layer-by-layer technique with a plasma-enhanced chemical-vapor deposition system

Microcrystalline silicon films have been prepared on indium-coated glass ut ilizing a layer-by-layer technique with a plasma-enhanced chemical-vapor de position system. The microcrystalline films were fabricated by varying the number of cycles from 10 to 60 under a fixed H-2 time (t(2)) of 120 s, wher e the corresponding deposition time (t(1)) of amorphous silicon thin film w as 60 s. Structural properties, such as the crystalline volume fraction (X- c) and grain sizes were analyzed by using Raman spectroscopy and a scanning electron microscopy. The carrier transport was characterized by the temper ature dependence of dark conductivity, giving rise to the calculation of ac tivation energy (E-a). Optical energy gaps (E-g) were also investigated usi ng an ultraviolet spectrophotometer. In addition, the process under differe nt hydrogen plasma time (t(2)) at a fixed number of 20 cycles was extensive ly carried out to study the dominant role of hydrogen atoms in layer-by-lay er deposition. Finally, the correlation between structural and electrical p roperties has been discussed on the basis of experimental results. (C) 2000 American Institute of Physics. [S0021-8979(00)09903-5].