CMOS-compatible transition metal disilicide for integrated thermoelectric applications

We report on the fabrication of CMOS-compatible transition metal disilicides (CoSi2, TaSi2, and TiSi2) and investigate the transport properties such as Seebeck coefficient and electrical resistivity. Thin film properties such as thickness, crystallinity, microstructure, and elemental distribution are studied via spectroscopic ellipsometry, XRD, SEM and ToF-SIMS. Prior to the silicidation process, the dopants (boron or phosphorus) are embedded in silicon via in-situ doping technique. The dopant redistribution in silicide post-thermal treatment and its effect on thermoelectric properties are investigated. Microstructure analysis reveals boron impediment for the cobalt-silicon process and buckling effect for TaSi2 films. CoSi2 and TiSi2 show low electrical resistivity, but TaSi2 exhibit comparatively high electrical resistivity due to unreleased stress after thermal treatment. Doped CoSi2 has negligible effect on transport properties, but doped TiSi2 and TaSi2 show varied improvement in temperature range between 20 - 100 degrees C.