Electrical properties of polycrystalline silicon films formed from amorphous silicon films by flash lamp annealing

摘要

The electrical properties of polycrystalline silicon (poly-Si) films formed from amorphous silicon (a-Si) films by flash lamp annealing (FLA) are investigated by Hall effect measurement. The impurity-doping concentration dependences of resistivity, carrier density, and Hall mobility of such flash-lamp-crystallized (FLC) poly-Si films show the effect of carrier trapping at grain boundaries (GBs). Potential barrier height formed at GBs, estimated from the temperature dependences of Hall mobility and electrical conductivity, decreases with an increase in doping concentration, due to the complete filling of trapping states at GBs. The density of trapping states at GBs is estimated to be on the order of 10~(12) cm~(-2) from such barrier heights, which is almost equivalent to those of poly-Si films prepared by other techniques such as solid-phase crystallization or laser annealing of a-Si films.