Stable and low contact resistance electrical contacts for high temperature SiGe thermoelectric generators

Abstract

The thermal stability and contact resistance of TaAlN thin films as electrical contacts to SiGe thermoelectric elements are reported. We demonstrate that a sharp interface is maintained after the device annealed at 800 °C for over 100 h, indicating that no interdiffusion takes place between TaAlN and SiGe. A specific contact resistivity of (2.1 ± 1.3) × 10−6 Ω-cm2 for p-type SiGe and (2.8 ± 1.6) × 10−5 Ω-cm2 for n-type SiGe is demonstrated after the high temperature annealing. These results show that TaAlN is a promising contact material for high temperature thermoelectrics such as SiGe.