Room Temperature Thermoelectric Properties of Epitaxially Grown Si-Ge Thin Films on SOI Substrates

Thermoelectric properties of epitaxially grown SiGe based thin films prepared by ion beam sputtering technique were investigated. Although carrier concentration was considered to be the highest in B doped SiGe sample, it showed the highest thermoelectric power of ∼1 mVK−1 corresponding to the three times larger value than bulk SiGe. On the other hand, the electrical resistivity decreased by increasing the growth temperature due to the impurity activation and crystallization. As a result, SiGeB epitaxial films prepared at growth temperatures of more than 773 K showed twice larger power factor than bulk SiGe at 300 K. Moreover, the thermoelectric power was found to decrease and resistivity to increase in the polycrystalline phase, concluding that the improvement of thermoelectric performances was achieved by introducing the epitaxially grown phase.