Fabrication and characterization of buried silicide layers on SOI substrates for BICMOS-applications

The successful fabrication of a silicon on metal on insulator (SOMI) substrate with a structured buried silicide layer for BICMOS applications is shown in this paper. The cobalt silicide is used as the buried silicide layer in the SOMI substrate because of its high thermal stability, low resistivity and easier fabrication process. Conventional cobalt salicide process was used to form CoSi2 structures. The SOMI substrate was fabricated on the wafer level using wafer bonding, CMP and back grinding technologies. A SOMI substrate, consisting of a 300 nm thick top-Si, a buried thin CoSi2 layer, a buried SiO2 layer on a silicon substrate, was formed using an SOI substrate as the starting material. The buried silicide layer has a resistivity of 16.3 µohm cm and shows a high thermal stability which is sufficient for device applications.