Modeling of High-Current Polycrystalline Silicon Thin Film Transistors by Incorporating Buried Electrode

For display applications, high current and large on/off current ratio are pursued for driving and switching transistors. In this article, a thin film transistor (TFT) device incorporating a buried electrode is proposed, which enables increasing the driving current by reducing the channel length, with the channel length only at the drain side. This lateral short-channel TFT enables increasing the on-current while maintaining the field effect mobility, in comparison to our experimental short-channel vertical TFT structure. Another advantage of the proposed structure lies in the suppression of the Schottky barrier at the source and drain contacts when using high-work-function source/drain contacts for an N-type TFT, with an increased on/off current ratio reaching approximately 10(6). The suppression of Schottky barrier at the source/drain has been verified by the contact resistance measurements. Even though high driving current is obtained, the off-current is still high due to the weakened electric field at the source/drain sides and needs to be further optimized.

Automated summary

This article proposes a thin film transistor (TFT) device incorporating a buried electrode, which can increase driving current by reducing channel length and maintaining mobility, as well as suppress the Schottky barrier at source/drain contacts to improve on/off current ratio. However, further optimization is needed to reduce off-current due to weakened electric field at source/drain sides.