PERFORMANCE IMPROVEMENT OBTAINED FOR THIN-FILM TRANSISTORS FABRICATEDIN PREPATTERNED LASER-RECRYSTALLIZED POLYSILICON

Thin-film transistors (TFT's) are fabricated in polysilicon films that are laser recrystallized either before or after active-area definitio n. We find the performance of TFT's fabricated in active areas that ar e prepatterned before laser recrystallization is dramatically improved . For example, the field-effect mobility is increased by a factor of t hree, the threshold voltage is reduced from 5.32 V to 0.07 V, and the subthreshold slope is cut in half for W/L = 10 mu m/10 mu m TFT's. All TFT's discussed utilize gas-immersion laser-doped source and drain ju nctions and are unhydrogenated.