Electrical Properties of Excimer-Laser-Crystallized Lightly Doped Polycrystalline Silicon Films

Abstract

The electrical properties of excimer-laser-crystallized lightly phosphorus-doped polycrystalline silicon films were investigated. The electrical conductivity of the films increased from 6.0×10 -7 to 2.3×10 -1 S/cm as the laser energy density increased from 235 to 436 mJ/cm 2 because the carrier concentration varied from 1.0×10 11 to 1.8×10 17 cm -3 . In contrast, the carrier mobility was 37.3 and 8.7 cm 2 /V·s at low- and high-laser-energy regimes, respectively, and showed a minimum value of 0.24 cm 2 /V·s at the intermediate laser energy density of 315 mJ/cm 2 . These results can be well explained by a model featuring the localization of trap states at the grain boundary.