Amorphous silicon thin-film transistors (a-Si:H TFTs) have been extensively used as pixel circuits for large-area flat-panel displays and X-ray imagers due to excellent spatial uniformity and low fabrication cost. To use such devices for various analog amplifiers, switches, and AM-OLEDs, a higher drain current and better electrical stability under prolonged bias stress are required.
In this project, we assess the potential of hexagonal (HEX-) TFTs connected in parallel for aforementioned applications by evaluating their electrical stability. We measured threshold voltage shift (ΔVth) induced by current temperature stress of single HEX-TFTs at an elevated temperature (80 °C) and then investigated their contribution to overall ΔVth of multiple HEX-TFTs. The multiple HEX-TFTs show a better electrical stability compared to standard TFT for similar W/L ratio. It is found that one specific HEX unit in the multiple HEX-TFTs does not dominate or/and affect the overall HEX-TFTs electrical instability. These new hexagonal devices show promising electrical characteristics for AM-OLEDs and other flat panel displays. This research was partially supported by LG Display, Korea.
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Amorphous silicon thin-film transistors (a-Si:H TFTs) have been extensively used as pixel circuits for large-area flat-panel displays and X-ray imagers due to excellent spatial uniformity and low fabrication cost. To use such devices for various analog amplifiers, switches, and AM-OLEDs, a higher drain current and better electrical stability under prolonged bias stress are required. 