Ab-initio study of NiGe/Ge Schottky contact

Germanium is a promising material for next-generation electronic and photonic devices, and engineering ohmic contacts to it can be expected to be a key challenge therein. The sensitivity of the Schottky barrier height of the NiGe/Ge contact to the detailed interfacial structure is revealed using the ab-initio study of pseudo-epitaxial NiGe(001)/Ge(100) contact using the computationally efficient meta-generalized-gradient-approximation, which can overcome the well-known bandgap underestimation problem. The p-type Schottky barrier height for an atomically flat pseudoepitaxial NiGe(001)/Ge(100) contact is calculated to be 260 meV, an overestimate of about 160 meV compared to experiments. However, the estimated modulation of this barrier height, by about 270 meV, due to interface morphology points to a possible explanation for this discrepancy and suggests ways to engineer the contact for lesser resistivity. Published by AIP Publishing