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

Reaction mechanisms in the atomic layer deposition of ZrO 2 from (CpMe) 2 Zr(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 D 2 O 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) 2 Zr(OMe)Me pulse in reactions with surface −OD groups and the rest during the D 2 O pulse. In the ozone process the most important reaction byproducts were CO 2 and H 2 O. Interestingly, about 20% of both of these were released already during the (CpMe) 2 Zr(OMe)Me pulse and the rest during the O 3 pulse. In addition, some MeH and HCpMe were formed during the (CpMe) 2 Zr(OMe)Me pulse. Furthermore, D 2 O was used to probe the state of the surface after the (CpMe) 2 Zr(OMe)Me pulse in the O 3 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) 2 Zr(OMe)Me pulse. Similarly, ZrCl 4 was used to probe the surface after the O 3 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 O 3 pulse.