[摘要]：The authors investigated the integrity of the interface between a Ni film and a Si substrate treated by in situ chemical dry-cleaning using ammonium fluorosilicate, or (NH4)(2)SiF6. In the conventional cleaning scheme, imperceptible fluoride residue at the interface between Ni and Si, even after subliming at 120 degrees C, was detected by synchrotron x-ray photoelectron spectroscopy. The authors found that the fluoride residue could be removed by additional subliming at 200 degrees C in a separate chamber following the conventional cleaning scheme (two-step sublimation cleaning). The sheet resistance of nickel monosilicide (NiSi) films fabricated by two-step sublimation cleaning was lower and the NiSi-Si interface was more uniform than for those fabricated by conventional cleaning. This suggests that the fluoride residue triggered the formation of a rough interface between the Ni and Si layers, thus leading to the performance degradation of the NiSi films. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3622301]
