CVD of conformal aluminathin films via hydrolysis of AlH₃(NMe₂Et)

Deposition of highly conformal alumina thin films has been carried out by hydrolysis of the liquid alane precursor, AlH₃(NMe₂Et). Depositions onto Si wafers, quartz and carbon fibres were all carried out utilizing a hot-wall atmospheric pressure chemical vapour deposition (APCVD) system. Optimum growth conditions were found to be at 165°C and with an AlH₃(NMe₂Et):H₂O ratio of less than 1:25. Films were characterized by SEM, microprobe and electrical conductivity measurements. Growth rates were of the order of 40-80 Å min~1 at 165°C. The conformality of the films was illustrated using silicon wafers that were etched prior to deposition. Deposition onto ZnS EL-phosphor particles was accomplished in a simple fluidized-bed APCVD reactor. The deposited films were conformal and continuous. No significant reduction in the initial brightness or change in the colour balance of the phosphor was observed from the coating process.