AUGER-ELECTRON SPECTROSCOPY STUDY OF THE SOLID-PHASE REACTIONS IN AL3ZR ZR/SI CONTACT SYSTEMS/

To obtain the fundamental understanding on the capability to apply the Zr film to Al metallization technology for Si-LSI, interfacial solid- phase reactions in Al/Zr/Si, Al-Zr/Zr/Si, and Al3Zr/Zr/Si contact syst ems have been investigated by AES analysis. In the Al/Zr/Si system, Al and Zr layers reacted spontaneously and interdiffused each other even before the heat treatment. In the Al-Zr/Zr/Si system, in which the Al overlayer was replaced with the Zr-doped Al film, well-separated inte rfaces of Al-Zr/Zr and Zr/Si were observed before the heat treatment. But when heat treated at 400 degrees C, Zr atoms in the Zr layer migra ted into the Al-Zr overlayer and the interposed Zr layer became too th in prior to the formation of the distinct Zr silicide layer. In the Al 3Zr/Zr/Si system, the amorphous overlayer with the composition of Al3Z r recrystallized into a stable Al3Zr intermetallic compound during the heat treatment above 400 degrees C. In this system, because the therm al equilibrium state is realized at the Al3Zr/Zr interface, a possible solid-phase reaction is restricted only at the Zr/Si interface. There fore, the system tolerates the temperatures up to 500 degrees C and a stable Zr-silicide layer can be formed at the Zr/Si interface.