High vacuum chemical vapour deposition of oxides:

The deposition chemistry and the efficiency of the process vary strongly depending on the precursor type. Due to the reduced/absent intermolecular collision events in the gas phase in HV-CVD as compared to LP-CVD, substantial differences in the physics and chemistry of the deposition processes are observed. Efficient precursor decomposition with more than 95% efficiency and deposition rates up to 500 nm/h have been observed for certain alkoxide precursors, whereas the presence of strong oxidizers (O3 or O2 plasma) seems to be indispensable in order to obtain an oxide deposit using β-diketonate precursors. Here, slower deposition rates in the order of tens of nm/h are achieved. The main concern of the applicability of the technique for new oxide materials is the availability of precursors satisfying the requirements for easy precursor delivery, chemical stability in the delivery system, and efficiency of the absorption and decomposition on the substrate in high vacuum.