Figure 2

Microstructure of the prepared TiO₂ films.

The cross-section transmission electron microscopy images of (a, b) PEALD and (c, d) sputtered TiO₂ films. The PEALD TiO₂ film has a rather random grain growth structure, whereas the sputtered TiO₂ film shows a more columnar structure on the thin amorphous layer (~10 nm) above the bottom electrode. The thin amorphous layer may act as a buffer layer that promotes rutile phase formation which is not stable phase at the growth temperature (~100°C). HRTEM images correspond to the red square in low magnification images.