Langmuir, Vol.31, No.18, 5057-5062, 2015
Enhanced Step Coverage of TiO2 Deposited on High Aspect Ratio Surfaces by Plasma-Enhanced Atomic Layer Deposition
Plasma-enhanced atomic layer deposition (PEALD) provides multiple benefits compared to thermal ALD including lower possible process temperature,and a wider palette of possible materials. However, coverage Of high aspect ratio (AR) structures is limited due to the recombination rates of the radical plasma species. We study the limits of conformality in 1:30 AR, structures for TiO2 :based on tetrakis(dimethylamido)titanium (TDMA-Ti) and O-2 plasma through variation in plasma exposure and substrate temperature. Extending plasma exposure duration and decreasing substrate temperature Within the ALD window both serve to improve the conformality of the deposited film, with coverage >95% achievable. Additionally, the changes in morphology of the TiO2 were examined with crystallites of anatase and brookite found.