In situ monitoring of CVD processes

The chemical complexity of CVD processes in general has been illustrated in Figs. 17.2-17.4, while Fig. 17.7 has shown, in particular, the rich 

Some kinetic considerations of chemical vapour deposition processes Ch. 17 

For the CVD of YBCO, /3-diketonates with the general molecular formula shown below have been found to be the most suitable precursors [56,57]. 

For Y and Cu metal complexes of HTMHD, where TMHD = 2,2,6,6-tetramethylheptane-3,5-dione (i.e., R = R = lBu) are frequently used because of their good volatility and stability. For barium, however, no such 

Initial attempts to obtain mass spectra of precursors used for the MOCVD of HTS thin films were unsuccessful because a number of serious problems were encountered in introducing the heavy molecular weight complexes into the mass spectrometer. These problems were partly associated with contamination of the quadrupole, but, more significantly, with condensation of the precursors at the inlet of the spectrometer. To over- 

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The two processes are becoming closer in concept. For instance, MOCVD is using techniques developed for MBE such as in situ characterization monitoring, load lock, and lower pressure levels, and MBE is now using chemical sources such as organome-tallics, which are typical of CVD. 

The deposition of Si02 by several CVD processes and surface reactions of gaseous reactants with a Si02 surface has been monitored in situ by ATR and the standard FTIR transmission methods [53,119-121]. Using these methods, information about the IR absorption of the surface species, the film, and the ambient gas in the reactor during the film growth can be obtained. It is well known that CVD parameters such as the quality of the film, the rate of deposition, and the profile of chemical composition are sensitive to the transport and reactions of species in the plasma as well as to the surface reactions. The IR absorption of CVD silicon dioxide after deposition (ex situ) was considered in Section 5.2. 

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