CHARACTERISTICS OF TOP-GATE THIN-FILM TRANSISTORS FABRICATED ON NITROGEN-IMPLANTED POLYSILICON FILMS

Abstract

The electrical characteristics of top-gate thin-film transistors (TFT's) fabricated on the nitrogen-implanted polysilicon of the doses ranging from 2 x 10(12)-2 x 10(14) ions/cm(2) were investigated in this work, The experimental results showed that nitrogen implanted into polysilicon followed by an 850 degrees C 1 h annealing step had some passivation effect and this effect was much enhanced by a following H-2-plasma treatment. The threshold voltages, subthreshold swings, ON-OFF current ratios, and field effect mobilities of both n-channel and p-channel TFT's were all improved, Moreover, the hot-carrier reliability was also improved, A donor effect of the nitrogen in polysilicon was also found which affected the overall passivation effect on the p-channel TFT's.