Mechanisms of Contact Failure in Semiconductor Devices

A study of the mechanisms of failure in ohmic and expanded contacts, including metal-semiconductor contacts and bonds to metalization in semiconductor devices, indicates that within a number of systems degradation or catastrophic failure has been produced by diffusion which produces solid solutions and/or compound formation. A great many systems are thermodynamically capable of interaction, but the important consideration is not whether they interact at all but whether the reaction proceeds at a rate which will result in metallurgical changes which adversely affect device reliability. The material systems studied are used or are considered for use in the fabrication of semiconductor devices. The systems include Ag-Cr, Ag-Ni, Ag-Pb, Ag-Sn, Al-Au, Al-Cr, Al-Ni, Al-Si, Al-SiO, Al-SiO2, Al-(AlxSiOy), Al-Ta, Al-Ti, Au-Cr, Au-Mo Au-Ti, Cr-Cu, Cr-Ta, Al-(Ni-Cr), Au-(Ni-Cr), Au-(Sb-Sn), Ti-Al-Si and Ti(Pt-Si).