Growth mechanisms of MOCVD processed Ni thin films

The main gaseous by-products during the processing of nickel films by MOCVD from nickelocene have been analyzed by on-line mass spectrometry. The evolution of relative concentration of CH4, C5H6 C5H8, and C5H10 with time, pressure, temperature, and hydrogen flow has been quantified and related with the characteristics, mainly carbon content, of the Ni films. The obtained results allowed to investigate the dissociation of nickelocene leading to the growth of Ni films. Two possibilities are proposed to prevail: Either the metal-ligand bond is dissociated, and the ligand is hydrogenated and desorbed, or the ligand itself is decomposed on the surface leading to the incorporation of carbon in the deposits. The process is controled by a Langmuir-Hinshelwood mechanism based on a competitive coverage of the surface by nickelocene or hydrogen atoms.