Chemical Vapor Deposition Mechanism of Copper Films on Silicon Substrates

Abstract

A versatile metal-organic chemical vapor deposition (MOCVD) system was designed and constructed. Copper ilms were deposited on silicon (100) substrates by chemical vapor deposition (CVD) using Cu(hfac)2 as a recursor. The growth of Cu nucleus on silicon substrates by H2 reduction of Cu(hfac)2 was studied by atomic force microscopy and scanning electron microscopy. The growth mode of Cu nucleus is initially olmer-Weber mode (island), and then transforms to Stranski-Rastanov mode (layer-by-layer plus island). The mechanism of Cu nucleation on silicon (100) substrates was further investigated by X-ray photoelectron spectroscopy. From Cu2p, O1s, F1s, Si2p patterns, the observed C=O, OH and CF3/CF2 should belong to u(hfac) formed by the thermal dissociation of Cu(hfac)2. H2 reacts with hfac on the surface, producing H. With its accumulation, OH reacts with hfac, forming HO-hfac, and desorbs, meanwhile, the copper xide is reduced, and thus the redox reaction between Cu(hafc)2 and H2 occurs.