Mechanical and Electrical Characterization of Low-resistivity Contact Materials for Mg2Si☆

Abstract In this work, the characterization of different metal-semiconductor contacts on n -type polycrystalline Mg 2 Si and p -type HMS substrates for the application in thermoelectric devices is presented. Metal (e.g. Au, Cu, Ni, Al, and Ti) contacts were deposited by DC magnetron sputtering or melted onto Mg 2 Si samples.Moreover, brazing alloy was applied on Mg 2 Si and HMS samples. Compositional and morphological characterization of the pellets and coatings were obtained by Field Emission Scanning Electron microscopy (FE-SEM) coupled with Energy Dispersive Spectroscopy(EDS). Tribological measurements and in situ FE-SEM observation as a function of temperature were carried out in order to evaluate adhesion properties of the film electrodes deposited onto Mg 2 Si substrate. The electrical properties of the different metal-semiconductor interfaces were investigated in terms of their Ohmic or Schottky properties. The resistivity of the samples and the interface contact resistance was obtained with I-V characteristics and a custom-built μ-probe apparatus. The lowest contact resistances measured were 4.43×10 –5 Ω cm 2 for a n -type Mg 2 Si leg and 5.29×10 –5 Ω cm 2 for a p -type HMS, both with a braze Cu electrode.