Beom Soo Park

Amorphous-silicon thin-film transistor on soda-lime glass

— Amorphous-silicon (a-Si:H) thin-film transistors (TFTs) on soda-lime glass were fabricated by using a diffusion barrier and a low-temperature process at 200°C. The silicon nitride barrier was optimized in terms of diffusion blocking effectiveness, film adhesion, and surface finish. TFTs on soda-lime glass achieved a saturation mobility 0.47 cm2/V-sec, threshold voltage of 0 V, an off-current of 7.7×10−11 A, and a sub-threshold swing of 1.0 V/dec. From diffusion experiments, a 30,000-hour lifetime for the TFT device at 80°C was estimated, and the robustness of the silicon nitride barrier against long-term migration of sodium was demonstrated.

P-74: Low Temperature a-Si TFT on Soda Lime Glass

Replacing the current non-alkali glass with soda lime glass can significantly reduce the cost of the current TFT-LCD module. One key step in manufacturing is to make TFT backplane on soda lime glass substrate. In this work, we demonstrate low temperature a- Si thin film transistor (TFT) at 200°C on soda lime glass. with the use of SiNx barrier to prevent sodium contamination, we show the TFT properties can be improved significantly and achieve TFT of saturation mobility 0.47cm2/Vs, threshold voltage 0V, off current 77×10−11 A, sub-threshold swing 1.0 V/dec. We also show that our TFT device has comparable or better threshold voltage stability as compared to those made in non-alkali glass. Finally, we show the robustness of SiNx barrier against long term sodium migration.