Atomic layer deposition (ALD) of Pt thin films and nanoparticles is gaining increasing interest for applications in catalysis and microelectronics. In this presentation, the reaction mechanisms and the nucleation behavior of Pt ALD will be discussed, and it will be demonstrated how this knowledge can be exploited in the development of novel applications of Pt ALD.
The surface reactions that can take place at a catalytic Pt surface were evaluated from experiments combined with results reported in surface science literature . It was found that the ligands of the MeCpPtMe3 precursor undergo dehydrogenation reactions on the catalytic Pt surface, which has important implications for the self-limiting behavior of the half-reactions, the growth rate, and the temperature-dependence of the process. Moreover, the O2 exposure employed during the O2 half-reaction of the Pt ALD process was identified as a key parameter influencing the nucleation behavior .
The study of the nucleation behavior revealed conditions that could be used for selective growth on seed layer patterns in a novel bottom-up nanopatterning approach. The approach combines the patterning capability of the direct-write patterning technique of electron beam induced deposition (EBID) and the material quality of ALD . A major benefit of this so-called direct-write ALD approach is that it does not involve etching, lift-off steps, or the use of resist films, which eliminates compatibility issues with certain sensitive surfaces. Recent work focuses on the application of direct-write ALD to the fabrication of carbon nanotube field effect transistors (CNTFETs).