Microstructure of α-alumina thin films deposited at low temperatures on chromia template layers
| Autor: | Ulf Helmersson, P. Jin, Jon M. Andersson, Zs. Czigany |
|---|---|
| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 22:117-121 |
| ISSN: | 1520-8559 0734-2101 |
| DOI: | 10.1116/1.1636157 |
| Popis: | Radio frequency sputtering has been used to deposit α-alumina (α-Al2O3) thin films at substrate temperatures of 280–560 °C. The films are shown to be single phased and hard. Nanoindentation gives values of 306±31 and 27±3 GPa for elastic modulus and hardness, respectively, for a substrate temperature of 280 °C. Growth of the α phase was achieved by in situ predeposition of a chromia template layer. Chromia crystallizes in the same hexagonal structure as α-alumina, with a lattice mismatch of 4.1% in the a- and 4.6% in the c-parameter, and is shown to nucleate readily on the amorphous substrates (silicon with a natural oxide layer). This results in local epitaxy of α-alumina on the chromia layer, as is shown by transmission electron microscopy. The alumina grains are columnar with grain widths increasing from 22±7 to 41±9 nm, as the temperature increases from 280 to 560 °C. This is consistent with a surface diffusion dominated growth mode and suggests that α-alumina deposition at low temperatures is possibl... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|