Permeation barrier properties of an Al2O3/ZrO2 multilayer deposited by remote plasma atomic layer deposition

Abstract We report the permeation barrier properties of Al 2 O 3 /ZrO 2 multi-layers deposited by remote plasma atomic layer deposition. Electrical Ca degradation tests were performed to derive the water vapor transmission rate (WVTR) of Al 2 O 3 , ZrO 2 and Al 2 O 3 /ZrO 2 multi-layers at 50 °C and 50% relative humidity (RH). Al 2 O 3 /ZrO 2 multi-layers exhibit better barrier properties than Al 2 O 3 and ZrO 2 layers, and when more individual layers were deposited in the same total thickness, the WVTR value was reduced further, indicating a better barrier property. The WVTR of the Al 2 O 3 and ZrO 2 layers were 9.5 × 10 −3 and 1.6 × 10 −2  g/m 2  day, respectively, but when deposited alternatively with 1 cycle of each layer, the WVTR decreased to 9.9 × 10 −4  g/m 2  day. X-ray diffraction results indicated that ZrO 2 has a monoclinic structure but Al 2 O 3 and Al 2 O 3 /ZrO 2 multi-layers show an amorphous structure. Cross sectional Al 2 O 3 /ZrO 2 multi-layer structures and the formation of a ZrAl x O y phase are observed by transmission electron microscopy (TEM). X-ray photoelectron spectrometry (XPS) results indicate that Al 2 O 3 and ZrO 2 contain 33.7% and 37.8%, respectively, Al–OH and Zr–OH bonding. However, the ZrAl x O y phase contained 30.5% Al–OH and Zr–OH bonding. The results of transmittance measurement indicate that overall, Al 2 O 3 , ZrO 2 and Al 2 O 3 /ZrO 2 multi-layers show high transmittance greater than 80% in the visible region.