Characteristics of cobalt films deposited by metal organic chemical vapor deposition method using dicobalt hexacarbonyl tert-butylacetylene

Abstract

Cobalt films were deposited by metal organic chemical vapor deposition (MOCVD) usino C12H10O6(Co)(2) (dicobalt hexacarbonyl tert-butyl acetylene, 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, 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 degrees C were 2.8 at. % and less than I at. %, respectively. As the H, 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. 12 mu m wide and 1.8 mu m deep. The phase transition was analyzed with X-ray diffraction (XRD) depending on RTA temperature. CoSi was observed at 500 degrees C annealing, and was transformed to CoSi2 at 600 degrees C annealing. In addition, Auger electron spectroscopy (AES) data showed a 1 : 2 atomic ratio of Co : Si in the CoSi2 layer.