Evaluation of Inorganic Mg-Zn-F Thin-Film Passivation for OLED Application

Abstract

In this study, we have manufactured a Mg-Zn-F target by using magnesium uoride (MgF2), which has better optical characteristics than the conventional oxide group passivation thin lm and Zinc (Zn). Deposition was done by radio frequency (RF) magnetron sputtering to make a novel passivation thin lm; then, its gas permeation properties were examined. The target was manufactured with various mixture ratios of MgF2 to Zn, 6 : 4, 5 : 5, 4 : 6 and 3 : 7; among those, thin lms manufactured with a 4 : 6 ratio target showed the best gas barrier property. The thin lms were deposited with targets having various ratios on polyethylene naphthalene (PEN) substrates by using a RF sputtering method. The thickness of the manufactured passivation lm was about 200 nm and the water vapor transmission rate (WVTR) was 1 10 3 g/(m2 day), below the limit of the measuring equipment, when the humidity and the temperature were 90 % and 38 , respectively and the optical transmission was above 80 %. From the experimental results, we found that inserting the Zn component improved the physical density of the MgF2 lm and the gas barrier characteristics compared to oxide and oxynitride group passivations. Thus, the possibility of a new-type of inorganic thin lm was con rmed.