EXCIMER LASER PHOTOLYSIS OF ORGANOMETALLIC COMPOUNDS FOR ZN DEPOSITION

The mechanism of dimethylzinc (DMZn) and diethylzinc (DEZn) photofragmentation through two-photon resonant absorption to the lowest electronic dissociative states (A1A, B1∏u) has been investigated by tunable dye-laser multiphoton ionization time-of-flight (MPI-TOF) mass spectroscopy. In the second part of the work, DEZn was chosen as the precursor compound for zinc film photodeposition, since MPI-TOF measurement had shown that the main dissociative channel at 248 nm (KrF emission) produced Zn atoms. The organometallic was photolyzed by a focused KrF excimer laser beam perpendicularly impinging onto a quartz substrate. Localized zinc depositions with thicknesses in the range 300-3000 angstrom have been obtained, and the deposition process has been investigated by monitoring the time evolution of the fraction of a He-Ne laser beam transmitted by the growing zinc film.