Analysis of Junction Leakage Current Failure of Nickel Silicide Abnormal Growth Using Advanced Transmission Electron Microscopy

This is the first paper to reveal the formation mechanism of the abnormal growth of nickel silicide that causes leakage-current failure in complementary metal-oxide- semiconductor (CMOS) devices by using advanced transmission electron microscope (TEM) techniques: electron tomography and spatially-resolved electron energy-loss spectroscopy (EELS). We reveal that the abnormal growth of Ni silicide results in a single crystal of NiSi₂ and that it grows toward Si <;110> directions along (111) planes with the Ni diffusion through the silicon interstitial sites. In addition, we confirm that the abnormal growth is related to crystal microstructure and crystal defects. These detailed analyses are essential to understand the formation mechanism of abnormal growths of Ni silicide.