Comparison of thermal and mass-transport properties of Bi(tmhd)3, Bi(p-tol)3, and Bi(o-tol)3 MOCVD precursors

Metal-organic (MO)CVD processes using three different precursors (Bi(tmhd)(3), Bi(p-tol)(3), and Bi(o-tol)(3)) have been investigated. Combined, thermal, and mass spectroscopic investigations have provided information on their thermal robustness during sublimation processes. In-situ Fourier-transform infrared (FTIR) measurements have allowed the monitoring of mass-transported precursors during MOCVD experiments. Temperature windows of 190-277 degrees C, 170-270 degrees C, and 150-220 degrees C have proved suitable for the efficient vaporization of Bi(tmhd)(3), Bi(p-tol)(3), and Bi(o-tol)(3), respectively, even though aryl precursors have proved to be more stable than beta-diketonate during the sublimation and transport processes. Above 350 degrees C, decomposition during the MOCVD processes has been observed for all the precursors. In the case of Bi(tmhd)3 and Bi(o-tol)(3) it involves the ligand fragmentation, while for Bi(P-tol)(3), dissociation of the intact aryl ring seems to occur.