Polysilicon films have been grown, in a resistance heated furnace, by chemical vapor deposition of silane. To minimize the gas-phase reaction a cooled entry system has been developed. The dominance of surface reaction control resulted in columnar growth. The role of the grain boundaries, characterizing polycrystals, were examined. For transport properties measurements the polysilicon layers were isolated by a chemical vapor deposited silicon dioxide film on a silicon substrate. Deep lying electron and hole trapping center concentrations were related to grain sizes. The characteristic measured mobility minima as a function of carrier concentrations, were associated to the crossing of the Fermi energy the appropriate deep lying impurity level. The criteria of impurity band formation, associated to grain boundaries introduced dangling bonds, were examined. The calculated mobilities, characterizing the transport properties of a random system, introduced in this case by the formation of an impurity band, were correlated to the measured values at the mobility minima, in polycrystalline silicon.