RuOx films were deposited by chemical vapor deposition with different oxygen flow rates on sputtered Ru film, and the annealing effects on the properties of the bi-layers were investigated. Films deposited with an oxygen flow rate of 800 sccm and less have the structure of hcp Ru, while a flow rate of O2 of 1200 sccm and above results in RuO2 films. The post-deposition thermal treatments were performed in N2 (for 60 s and 30 min) and forming gas (for 30 min) ambients at the temperature range of 100-750 °C. In all films, resistivity decreases as the treatment temperature increases, and this behavior is independent of the treatment ambient and time. Rapid thermal annealing (RTA) in N2 ambient or annealing in forming gas result in samples with low resistivity compared to N2 flow furnace annealing; the higher resistivity of the latter case is attributed to oxidation from residual oxygen. Ru films prepared with 800 sccm O2 flow become highly (001) textured after thermal treatment due to a re-crystallization process. The RuO2 phase films develop cracks after forming gas annealing due to an oxygen reduction reaction. The RuO2 phase changes to Ru after 750 °C RTA by the volatilization process. After RTA at 600 °C, the stress increases in all films due to the densification or/and phase change from RuO2 to Ru.
- Organometallic vapor deposition
- Ruthenium oxide