Effect of metals and annealing on specific contact resistivity of GeTe/metal contacts

The circular transfer length method was employed to extract the specific contact resistivity, ρc of GeTe (amorphous and crystalline state) with metals (Ni, W, TiW) to quantify the series contact resistance. The ρc of amorphous-GeTe with metals was also determined for different annealing conditions. Higher metal work functions produce lower ρc for both GeTe states and the ρc was reduced further for annealing temperatures greater than the GeTe crystallization temperature. This is suggested to be a consequence of the higher temperature required to diffuse sufficient interstitial metallic atoms to transform the GeTe covalent bonding at the interface to metallic bonding.