This inhibits vapour phase reactions and allows a very homogeneous and self-limiting film growth within one reaction cycle [16]. Additionally, plasma-enhanced atomic layer deposition (PEALD) reduces the process time at temperatures below 100℃ since there is no need to remove residual water molecules. Furthermore, for AlO x , a higher growth per cycle (GPC) can be achieved compared to the thermal ALD (TALD) process. A benefit of hybrid multilayers (ML) is that the separation into several oxide layers leads to a decoupling of morphological 4SC-202 defects, e. g. caused by particles, which prolongs the permeation path trough the barrier [8].

A more detailed introduction into moisture P505-15 concentration barrier layers is given elsewhere [17]. A popular method to measure the WVTR of permeation barriers is the electrical calcium test [18–20]. Calcium (Ca) heavily hydroxylates at contact with water. At temperatures below 70℃, the dominating

reaction is (3) An oxidation caused by molecular oxygen can be neglected [21–23]. Whereas pure calcium has a good electrical conductivity, Ca(O H)2 is an insulator. If a current is applied to a thin calcium film, its corrosion can easily be detected as a change of the resistance which allows an immediate calculation of the WVTR. Since the deposition of hybrid multilayers by TALD/plasma-enhanced chemical vapour deposition (PECVD) has already been shown [24], in this paper, the preparation of MLs by PEALD/PECVD, carried out in one reactor, will be demonstrated. The WVTRs of moisture barrier layers were

measured with electrical Ca tests. A correlation of the barrier performance of aluminium oxide layers and their impurity content will also be discussed. Methods Sample preparation In order to determine the WVTR, the thin film of interest was coated on a 200- μm-thick polyethylene naphthalate substrate (Teonex Q65, DuPont Teijin Films, Luxembourg) with a size of 25 × 25 mm 2. The polymer foils were cleaned before with acetone, isopropanol and ultrasonic treatments. Prior to deposition, the substrates were stored in the reactor for 72 h at 120℃ to remove residual water in the polymer. Layer deposition The AlO x and the plasma polymer (PP) films were 4-Aminobutyrate aminotransferase deposited in a newly developed plasma system from SENTECH Instruments (patent pending), placed in an ISO class 6 clean room environment. The system was developed and designed for both inductively coupled plasma-enhanced chemical vapour deposition (ICPECVD) and ALD in the same reactor using flexible system architecture. The used plasma source is an inductively coupled planar triple spiral antenna (ICP PTSA 200). A high radio-frequency current flows from the centre through the three arms to the periphery and induces the electric field for generating the high-density plasma [25].