Constrained Film Sintering of Nanocrystalline TiO ₂

The sintering of thin, nanocrystalline TiO 2 films either 140 or 65 nm thick is characterized and compared with the sintering of bulk material. Grain size, pore size distribution, and density data are obtained. Observation of the microstructural evolution during sintering suggests that grain growth, as well as pore growth, at low density can be attributed to differential sintering. A continuum mechanical model for the intermediate stage is useful until the grain size becomes one‐half the film thickness. From then on, the ratio of grain size to film thickness affects the degree by which both densification and grain growth decrease, as compared with the continuum computation results.