Effect of thermal annealing on the microstructure and morphology of erbium films

The effects of thermal annealing on the microstructure and morphology of erbium films were investigated by X-ray diffraction and scanning electron microscopy. All the erbium films were fabricated by electron-beam vapor deposition. The columnar grain sizes of as-received erbium films increased with the substrate temperatures and were enlarged by the coalescence and migration of grains during the high temperature annealing. The intrinsic stresses of erbium films, fabricated at a low substrate temperature (200 °C), were relaxed accompanied with the appearance of cracks on the films surface. The films deposited at 200 °C had (002) preferred orientation, and the film deposited at 450 °C had mixed (100) and (101) texture. The peak positions and the full width at half maximum of (100), (002), and (101) diffraction lines of erbium shift towards higher angles and sharply decrease during the annealing process, indicating that the stress inside the film was relaxed. - Highlights: ► Effect of thermal annealing on the microstructure of erbium film was investigated. ► Grain size of erbium film is enlarged by annealing processing. ► Annealing processing will relax the film stress and produce cracks on film surface. ► The crystalline structure of erbium is affected by the annealing processing.