In Situ Reaction Mechanism Studies on Atomic Layer Deposition of ZrO2 from (CpMe)2Zr(OMe)Me and Water or Ozone

摘要

Reaction mechanisms in the atomic layer deposition of ZrO2 from (CpMe)2Zr(OMe)Me and deuterated water or ozone were studied in situ with a quadrupole mass spectrometer and a quartz crystal microbalance at 350 °C. In the D2O process the detected reaction byproducts were as expected MeD, MeOD, and DCpMe. About 80% of the MeD, 40% of the MeOD, and 60% of the DCpMe were formed during the (CpMe)2Zr(OMe)Me pulse in reactions with surface —OD groups and the rest during the D2O pulse. In the ozone process the most important reaction byproducts were CO2 and H2O. Interestingly, about 20% of both of these were released already during the (CpMe)2Zr(OMe)Me pulse and the rest during the O3 pulse. In addition, some MeH and HCpMe were formed during the (CpMe)2Zr(OMe)Me pulse. Furthermore, D2O was used to probe the state of the surface after the (CpMe)2Zr(OMe)Me pulse in the O3 process. Thereby, it could be stated that about 50% of the Me— ligands, 40% of the MeO— ligands, and 60% of the -CpMe ligands were eliminated during the (CpMe)2Zr(OMe)Me pulse. Similarly, ZrCl4 was used to probe the surface after the O3 pulse. Thereby, the surface was found to be covered with only about 10% —OH concentration as compared to the water process. To explain the observations, some active oxygen was concluded to be left on the surface after the O3 pulse.