Characteristics of Cobalt Films Deposited by Metal Organic Chemical Vapor Deposition Method Using Dicobalt Hexacarbonyl tert-Butylacetylene

摘要

Cobalt films were deposited by metal organic chemical vapor deposition (MOCVD) using C_(12)H_(10)O_6(Co)_2 (dicobalt hexacarbonyl tert-butylacetylene, CCTBA) as the Co precursor and H_2 reactant gas. The impurity content of the Co films was monitored as a function of the partial pressure of H_2 reactant gas. The carbon and oxygen content of as-deposited Co films greatly decrease with the increase of H_2 partial pressure, and at H_2 partial pressure of 10Torr and a substrate temperature of 150℃ were 2.8 at. % and less than 1 at. %, respectively. As the H_2 partial pressure increased, carbon and oxygen content decreased markedly. Excellent conformality of Co film over 80% was achieved on a patterned wafer with aspect ratio of 15 : 1, 0.12μm wide and 1.8 μm deep. The phase transition was analyzed with X-ray diffraction (XRD) depending on RTA temperature. CoSi was observed at 500℃ annealing, and was transformed to CoSi_2 at 600℃ annealing. In addition, Auger electron spectroscopy (AES) data showed a 1 : 2 atomic ratio of Co : Si in the CoSi_2 layer.