Performance improvement obtained for thin-film transistors fabricated in prepatterned laser-recrystallized polysilicon

Thin-film transistors (TFT's) are fabricated in polysilicon films that are laser recrystallized either before or after active-area definition. We find the the performance of TPT's fabricated in active areas that are prepatterned before laser recrystallization is dramatically improved. For example, the field-effect mobility is increased by a factor of three, 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 μm/10 μm TFT's. All TFT's discussed utilize gas-immersion laser-doped source and drain junctions and are unhydrogenated.