Development of a method for investigating carbon removal processes during photoassisted thin film growth using organometallic precursors
Description
The photoassisted growth of films from (Me)3MeCpPt(IV), (Me) 3EthylCpPt(IV), and (Me)3t-butylCpPt(IV) precursors in the presence of H2 or D2 is examined. In these experiments, emphasis is placed on determining the mechanism by which carbon is removed from the growth surface. In the parent compounds, carbon is present in two fundamentally different functional groups: the cyclopentadienyl ring and the methyl group. Experimentally, an apparatus combining laser-assisted growth with electron impact time-of-flight mass spectroscopy allows us to monitor products that leave the growth surface during platinum deposition. A 308 nm pulse source activates growth in the chamber and is turned off after several minutes. The main reaction chamber is maintained at high pressure. As the deposition occurs, carbon removal products produced at the surface move through a differentially-pumped system to the mass spectrometer. Deuterated experiments showed that as time passes, the deuteration that occurs at the radical site is extended across the entire molecule. Deposition surfaces in the form of substrates are removed from the experimental apparatus during the growth process. The platinum film on each substrate can be directly correlated to a specific period in the mass spectrum. These substrates are analyzed with X-ray photoelectron spectroscopy and Auger electron spectroscopy specifically for platinum to carbon ratios. The ratio of platinum to carbon increases as time passes, implying that the quality of the film improves as time passes. Consequently, film attributes and insight into the mechanism for carbon removal as a function of experimental conditions can be gleaned