Morphological stability of TiO2 thin films with isolated columns

We have investigated the stability of the morphologies of obliquely deposit ed TiO2 thin films against annealing and humidity. For the thin films with closely distributed columns, the thickness decreases by more than 10% by an nealing at 500 degreesC. and the columnar structure is destroyed by exposur e to hot water vapor. However. the thin films with isolated columns show no significant change in the thickness and morphology. This can be understood in terms of the stress induced in the thin films with columns which are in contact or isolated. The stable morphologies of the thin films with isolat ed columns and their shape-related functions are useful for devices that re quire thermal processing and those used under humid conditions.