Mocvd precursor delivery monitored and controlled using UV spectroscopy

摘要

The glyme adducts of bis (1,1,1,5,5,5,-hexafluoro-2,4-pentanedionate)barium, Ba(hfac)_2 glyme, are frequently employed as precursors in the MOCVD fabrication of HTSC thin films. The physical properties of these precursors can be modified by changing the glyme ligand in the barium complex. In this study, gas phase concentrations of two barium complexes as a function of purge time and bubbler temperature have been examined by in-situ UV spectroscopy. Also presented are the details of a UV spectrophotometric-based feedback control system designed to maintain constant gas phase concentration of 2,2,6,6-tetramethyl-3,5-heptadionate (thd) precursors, Cu(thd)_2 and Y(thd)_3, during MOCVD growth of mixed metal oxide films.