Conductivity and Hall measurements were carried out on highly boron-implanted (5×1015 cm−2) low-pressure chemical vapor deposited silicon films. Polycrystalline films were annealed using a rapid thermal annealing (RTA 10 and 20 s) at 950, 1050, and 1150 °C, or standard furnace annealing [conventional thermal annealing (CTA) 950 °C, 30 min]. The Hall mobility and carrier density of the RTA films were higher than those of CTA films. Moreover, the temperature dependence of the mobility in RTA films showed a very striking behavior at high temperatures, i.e., the mobility decreased with increasing temperature, whereas CTA films showed thermally activated mobility. These results are analyzed in terms of the electrical activity of grain boundaries.