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For the first time an element other than a metal was deposited by atomic layer deposition (ALD). Pure and conformal thin films of elemental antimony were prepared by ALD using SbCl3 and (Et3Si)3Sb as precursors. In situ reaction mechanism studies showed that the dehalosilylation reactions involved are very efficient in eliminating the ligands from the growing surface enabling the use of low growth temperatures down to 95 °C. Various antimony compounds, such as GeSb, Sb2Te, GaSb, and AlSb, can also be deposited by reacting (Et3Si)3Sb with other metal halides or mixing Sb growth cycles with other ALD processes. The new antimony ALD process is a major step in the realization of non-volatile phase change random access memories (PCRAM) and ALD of III−V compounds.

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.

Reaction mechanisms in three atomic layer deposition (ALD) processes using Ir(acac)3 as a precursor were studied: Ir(acac)3–O2 process at 300 °C for Ir deposition, Ir(acac)3–O3 process at 195 °C for IrO2 deposition, and Ir(acac)3–O3–H2 process at 195 °C for Ir deposition. Reactions were studied in situ with a quadrupole mass spectrometer (QMS) and a quartz crystal microbalance (QCM). The byproducts in all processes were CO2 and H2O. Only in the Ir(acac)3–O2 process these were partially released during the Ir(acac)3 pulse (14% of CO2 and 57% of H2O as compared to a complete ALD cycle). To explain this, some oxygen atoms were concluded to chemisorb on the surface during the O2 pulse. In the other two processes, the adsorption of Ir(acac)3 appeared to be molecular on a plain surface of the film material.

Reaction mechanisms in the atomic layer deposition (ALD) of Sb 2 Te 3 from SbCl 3 and (Et 3 Si) 2 Te at 60 °C and GeTe from GeCl 2 3 C 4 H 8 O 2 (1,4-dioxane complex of GeCl 2 ) and (Et 3 Si) 2 Te at 90 °C were studied in situ with a quadrupole mass spectrometer (QMS) and a quartz crystal microbalance (QCM). Also some experiments were conducted on reactions in ALD of the phase change material GST (germanium antimony telluride, Ge 2 Sb 2 Te 5 ). The byproduct in both the binary telluride processes was found to be Et 3 SiCl, and about 78% (36%) of it was released during the SbCl 3 (GeCl 2 3 C 4 H 8 O 2 ) pulse. Obviously -Te(SiEt 3 ) surface groups serve as reactive sites for the metal precursors, cf. -OH surface groups in the oxide ALD processes that use water as the oxygen source. The dioxane, on the other hand, was expectedly found to be released entirely during the GeCl 2 3 C 4 H 8 O 2 pulse. When depositing GST the mechanism of the SbCl 3 -(Et 3 Si) 2 Te reaction was found to change so that only about 50% of the byproduct Et 3 SiCl was released during the SbCl 3 pulse. The same effect was experienced when the SbCl 3 -(Et 3 Si) 2 Te process was executed on surfaces of Al 2 O 3 and Au.