A Study of Thin Film Encapsulation on Improving Electrical Characteristics and Reliability for Flexible OLEDs

In this work, we investigated the effect of thin film encapsulation on V th shift in a-IGZ0 TFTs. The result shows that decreasing the NH 3 flow rate of deposited SiON films, the trend of V th shift under the operation mode can vary from negative to positive direction, which can be attributed to lower amount of hydrogen diffused from SiON to the a-IGZO TFTs. Beside, we designed the TFE with stable inorganic-organic-inorganic stack structure, of which the CVD1 deposited with low NH 3 flow rate and the CVD2 with high barrier property, and a 16.9-inch high performance flexible OLED panel with controlled V th shift and RA lifetime over 475 h was achieved at the condition of 85 °C and 85% RH. This study demonstrates the influence of TFE on a-IGZO TFTs, and offers an optimized TFE structure which promises both electrical characteristics and reliability for flexible OLEDs.