Polysilicon thin film transistors using sputtered HfO2 gate dielectric and SiGe source/drain

We have fabricated polysilicon thin film transistors (TFTs) using sputtered HfO2 gate dielectric and SiGe as source/drain. The polysilicon film is formed by low temperature furnace recrystallization of amorphous silicon. The effective dielectric constant of the HfO2 in the TFTs is 17.7, and the transconductance of the TFTs is about 4.5 times that of those using SiO2 as gate dielectric. The use of SiGe as source/drain requires a lower thermal budget than the conventional technique of impurity implantation in the polysilicon film.