has been proposed, and various coating methods including sol-gel process, physical vapor deposition, and chemical vapor deposition (CVD) have been attempted. [1c,5] The recent progress on atomic layer deposition (ALD) techniques has attracted attention as a potential process to manufacture such polymer-protection ceramic coating films. [6] ALD is capable of producing ceramic and metal thin films at relatively low temperatures. For example, alumina and zinc oxide films can be readily deposited by ALD even at room temperature using volatile and reactive precursors such as trimethylaluminum (TMA) and diethylzinc, respectively. [7] In addition, ALD can be used to fabricate dense and conformal films [8] along complex-shaped contours with high aspect ratios. There have been several reports on coating of trenches, tubes, rods, and particles at the nanoscale using ALD. [9] Due to these characteristics, ALD enables protection coating of polymer films without pinholes, despite the nonflat and irregular surface morphology that might contain pores.Functional groups, such as terminal hydroxyls and carbonyls present at the extremities of the polymeric chain branches or broken chains, are important for the successful ALD growth on polymers, [10] because they provide active sites for the chemisorption of precursors and initial nucleation of the ALD material islands. It is also possible to grow ALD films on certain polymers in the absence of those functional groups, since precursors can react and form solid materials in adsorbed states or even in the gas-phase. [11] However, in this case, there is no chemical binding between the substrate surface and the films, where the ALD layer forms a separated "shell" physically set on the polymer support. For example, ALD films grown on polytetrafluoroethylene (PTFE), whose surface is chemically inert, exhibit poor binding with the substrate and are easily delaminated. [12] It is also well known in PCs that TMA precursors tend to chemisorb poorly on the surface compared to other polymer materials due to the absence of appropriate functional groups. [10a,b] Plasma treatment processes have been used to clean wafers by decomposing organic impurities or to provide functional groups for an improved initiation of the CVD and ALD film growth. [10c,13] Based on this approach, we propose a plasma pretreatment of the PC substrates for the fabrication of high quality ALD This study reports the effect of an O 2 plasma pretreatment of polycarbonate (PC) films for the enhanced integration of Al 2 O 3 films prepared by atomic layer deposition (ALD) on the PC substrate. It is revealed that the plasma treatment produces functional groups on the PC surface, which are essential for the ALD of Al 2 O 3 . Specifically, it is revealed that a significant amount of carbonyl groups, essential for the chemisorption of the precursors and covalent binding with the Al 2 O 3 surface protection layer, are present in the plasma-treated PC surface. To evaluate the chemical resistivity of the PC-ALD alumina film, an...
