Anomalous evaporation characteristics of vitrificated K(DPM) and stable gas supply using disk-shaped K(DPM) precursors for metalorganic chemical vapor deposition

In this paper, we report a unique sublimation method of a solid precursor for metalorganic chemical vapor deposition (MOCVD). We found out that the vaporization rate of dipivaloylmethanatopotassium [K(DPM)] was much improved by carrying out the single-melting and re-solidification (vitrification) process. Although the contact area of re-solidified K(DPM) and carrier gas was greatly decreased, a higher-concentration gas supply exceeding powder-like K(DPM) was attained by using this method. Furthermore, the long-time stability of the vaporization rate was also attained by stacking several disks formed of re-solidified K(DPM) in a precursor container. By using the re-solidified disk-shaped K(DPM) as a potassium precursor, an adequate deposition rate and the reproducibility of stable potassium niobate (KNbO3) crystal film preparation were confirmed.