Preparation of PbTiO3 thin film by mist source plasma enhanced chemical vapor deposition (CVD) using heptane solvent

Heptane has been proposed as a new solvent for liquid source chemical vapor deposition (LSCVD) and liquid source mist chemical vapor deposition (LSMCV D) instead of tetrahydrofuran (THF). The range of the explosive limit of he ptane is much narrower than that of THF, and heptane does not have self-exp losive characteristics unlike THF. The boiling point of heptane is higher t han that of THF, therefore, selective vaporization of the solvent can be av oided. The preparation of PbTiO3 thin films was attempted using a liquid so urce in which Pb(DPM)(2) and Ti(O-i-Pr)(4) were dissolved in heptane. The s ubstituent exchange reaction was not perceived in heptane. Moreover, fine m ists of the solution could be generated using an ultrasonic nebulizer. Thes e facts indicate that heptane is an excellent solvent. The solution was app lied to the plasma-enhanced LSMCVD apparatus and PbTiO3 thin films having s toichiometric composition and smooth and flat microstructures were prepared on Pt/Ti/SiO2/Si substrates. The dielectric and ferroelectric properties o f PbTiO3 thin films agree well with those reported in literature.