Carrier injection at silicide/silicon interfaces in nanowire based-nanocontacts
Résumé
In this article, we investigate the silicide/Si nanowire (Si NW) interface properties based on a detailed characterization of PtSi/NW nanocontacts. For that purpose, we fabricate two-terminal structures implemented on vertical Si NWs arrays defined by a top-down approach with an ultra-high density. Each termination of Si NWs is silicided and contacted to an external metal line. The temperature dependence and the non-linearity of current-voltage (I-V) characteristics are identified as a clear signature indicating that contacts dominate the overall resistance of the Si NW arrays. It is demonstrated that this trend remains valid in the limit of extremely small NW radii and that trap-induced surface depletion also reduces the contact injection cross-section. In this context, the electrostatic landscape at the vicinity of the silicide-to-semiconductor contact interface is dominated by the field effect imposed by peripheral surface states and not by the Schottky barrier height.