PUB - Publikationen an der Universität Bielefeld

The thermolysis behavior of tetramethyl- and tetraethyldistibine (Sb2Me4 and Sb-2 Et-4) was investigated using a mass spectrometer coupled to a tubular flow reactor under near-chemical vapor deposition (CVD) conditions. Sb2Me4 undergoes a gas-phase disproportionation with an estimated activation energy of 163 kJ/mol. This reaction leads to the formation of methylstibinidine, SbMe, that reacts on the surface to produce antimony film and SbMe3. Unfortunately, this clean decomposition pathway is limited to a narrow temperature range of 300-350 degrees C. At temperatures exceeding 400 degrees C, SbMe3 decomposes following a radical route with a consequent risk of carbon contamination. In contrast, Sb2Et4 disporportionates at the hot wall of the reactor. According to mass-spectrometric data, this reaction is significant starting at a temperature of 100 degrees C, with an apparent activation energy of 104 kJ/mol. Within the temperature range of 100-250 degrees C, the precursor decomposition leads to the formation of antimony films and SbEt3, whereas different molecular reaction pathways are significantly activated above 250 degrees C. The use of Sb2Et4 lowers the risk of carbon contamination compared to Sb2Me4 at high temperature. Therefore, Sb2Et4 is a promising CVD precursor for the growth of antimonuy films in the absence of hydrogen atmosphere in a wide temperature range. (J Am Soc Mass Spectrom 2008, 19, 1336-1342) (C) 2008 American Society for Mass Spectrometry.