부산대학교 도서관

In this work, aluminum oxide (Al2O3) films are grown using atomic layer deposition (ALD) with trimethylaluminum (TMA) and water, and inserted into blue mini-light-emitting diodes (mini-LEDs) as a moisture barrier layer to provide chip-level encapsulation. The effect of the inserted Al2O3 layer on the stability of the mini-LED performance is investigated. The experimental results show that the optimized substrate temperature for preparing the Al2O3 films under self-limiting surface reaction conditions and linear growth is in the range of 200 °C–250 °C. The highest film density, lowest impurity content, and lowest water vapor transmission rate (WVTR) can be obtained at 250 °C. The performance of the mini-LEDs with the Al2O3 layer does not degrade after 1000 h in 85% relative humidity (RH) and 85 °C temperature aging conditions, while the device without the moisture layer completely fails after 500 h. The degradation is found to be related to the increased series resistance and ideality factor of the devices. Moreover, it is found that the addition of the Al2O3 moisture layer improves the light intensity of mini-LEDs. The inserted Al2O3 layer with a simple process and thin thickness is therefore capable of providing excellent resistance against high humidity and high temperature environment for mini-LEDs.