× 10 −3 50-nm PEALD aluminium oxide (100 W, 1 s) (8.5 ± 2.4) × 10 −3 50-nm TALD aluminium oxide (7.7 ±2.3) × 10 −3 Table 2 WVTRs with mean deviation of TALD aluminium oxide films with layer see more thicknesses from 25 to 100 nm, measured at 60℃ and 90% RH Thickness [nm] WVTR [gm −2 d −1] 25 (8.5 ± 2.2) × 10 −2 50 (7.7 ± 2.3) × 10 −3 100 (6.4 ±1.2) × 10 −3 In GSK2118436 purchase order to investigate the correlation between process conditions and barrier performance, the carbon content of different aluminium oxide
films, given in Table 3, was detected by energy-dispersive X-ray spectroscopy (EDX). All samples had a layer thickness of 150 nm to achieve sufficient measuring signals. It may be worthy to note that the hydrogen atoms cannot be traced by EDX, and that is why the unit weight percent (wt.%) is used instead of atomic percent (at.%). To exclude a contamination of the analytical chamber, a clean silicon wafer was also investigated. Its
carbon content was determined to be 0 wt.%. The data expose a relation between the process conditions and the carbon content. Longer plasma pulse times lead to significantly lower impurities. At 400 W, an AZ 628 elongation of the pulse time from 1 to 10 s clearly reduces the residual carbon from 6 to 3.1 wt.%. But the plasma power also has an impact on the composition of the AlO x films. The carbon itself probably originates from hydrocarbons due to incomplete surface reactions [27, 28]. The thermally grown AlO x had a C content of 4.6 wt.%, which is more than the best plasma-assisted grown film included (3.1 wt.% at 400 W and 10-s pulse time). A thermally grown aluminium oxide film at 200℃ exhibited a C content Dolichyl-phosphate-mannose-protein mannosyltransferase of only 2.2 wt.% which may also be attributed to a lower content of hydrocarbons in the film. It is known from previous researches that in low-temperature and low-power PALD aluminium oxide films, respectively, hydroxy groups are also contained in a significant amount, resulting in a lower film density [29]. Albeit the change of the refractive indices, also given
in Table 3, is quite small, it can serve as an indicator as well that increasing the amount of oxygen radicals can lead to denser films. It is believed that both types of impurity allow water molecules not only to walk through pinholes or cracks but also to diffuse through the AlO x itself. Table 3 Carbon content and refractive index at 633 nm of aluminium oxide films at different process conditions, deposited at 80℃ Plasma power [W] Plasma pulse time [s] C [wt.%] n 400 10 3.1 1.62 400 1 6 1.60 100 10 4.6 1.61 100 1 7 1.60 Thermally grown 4.6 1.60 Conclusions A combination of a PEALD and PECVD process in one reactor chamber was demonstrated in order to accelerate the fabrication of thin moisture barrier layers with a high film quality. For hybrid multilayers of 3.5 dyads, a steady-state WVTR of 1.2 × 10 −3 gm −2 d −1 at 60℃ and 90% RH could be achieved, which is nearby the value of a glass lid encapsulation.