Effects of a buffer layer (Al���O���) between channel (HAZO) and gate oxide (SiO���) on the characteristics of thin film transistors

In this study, hafnium-doped aluminum-zinc-oxide (HAZO) films were deposited on glass and Si substrates at room temperature via co-sputtering by varying the electric power applied to the Hf target. The transfer curves of thin film transistors, which were fabricated using the HAZO film as the active layer, were measured. The experimental results confirmed that the properties of HAZO films strongly depended on the Hf sputtering power. For enhancing the device characteristics of the HAZO-TFTs, the buffer layer of Al 2 O 3 were inserted by using the atomic layer deposition (ALD) method between the active layer (HAZO) and the insulator layer (SiO 2 ). The device parameters of the HAZO-TFTs, such as on/off ratio and subthreshold swing, were improved by inserting the buffer layer