Control of subthreshold swing using an in situ PEALD nano-laminated IGZO/Al2O3 multi-channel structured TFT

Abstract

This study presents the development of multi-channel thin-film transistors (TFTs) using plasma-enhanced atomic layer deposition (PEALD) to stack layers of IGZO/Al2O3, with the number of stacking layers ranging from 1 to 10 (1S, 3S, 5S and 10S). To optimize the performance of the AM-LED display, the subthreshold swing (S·S) and mobility of each type of transistor, such as switching and driving transistors, were customized to meet specific requirements. The results show that as the number of stacking layers increased, the field-effect mobility (µFE) improved by 323% from 1.34 to 4.33 cm2/Vs, while S·S improved by 0.14 V/dec from 0.31 to 0.45 V/dec, with no variation in threshold voltage (Vth) and reliability. The study attributes the improvement in µFE and S·S to the formation of multiple electron transport paths as confirmed by a TCAD simulation showing an increase in current density. Overall, this study demonstrates the potential of PEALD in creating multi-channel TFTs with improved performance by customizing oxide semiconductor properties. This research may have important implications in the development of advanced electronic devices that rely on thin-film transistors, as it provides a new approach in enhancing the performance of these devices.

Keywords

• Atomic layer deposition (ALD)
• thin-film transistors (TFT)
• multi-channel TFT
• subthreshold swing control