We have investigated the laser-crystallization of slightly oxygen added polycrystaltine silicon (poly-SiOJ films for the application to the new active layer for poly-Si thin film transistors (TFTs). We also proposed a new method to reduce the surface roughness of poly-SiO* films by employing a selective etching of grain boundaries. SEM image showed that the SiOx was well segregated into the grain boundaries after laser-crystallization and the surface morphology was remarkably improved by the selective Buffered-Oxide-Etchant (BOE) etching of the grain boundaries. The activation energy of poly-SiO* and poly-Si films were identical value of 0.52 eV. It may confirm that the oxygen induced defects may not be critical even at the oxygen content of 0.18 at atomic concentration %. The electrical mobility and sub-threshold slope of poly-SiOx TFT were improved compared with those of poly-Si TFT by employing proposed method which smoothen the poly-SiOx/Si02 interface.
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