Schottky Barrier Height Modulation of Nickel Germanide Schottky Diodes by the Germanidation-Induced Dopant Segregation Technique

Modulation of Schottky barrier height (SBH) is successfully demonstrated by a germanidation-induced dopant segregation technique. The barrier height of NiGe/Ge Schottky diodes is modulated by 0.06-0.15eV depending on annealing temperature. The results show the change of SBH is not attributed to the phase change of nickel germanides but to dopant segregation at the interface of germanides/germanium which causes the upward conduction energy band. In addition, we first observe a Raman peak at about 217cm^-1 corresponding to NiGe, which has not been reported till now. The surface morphology of nickel germanides can be improved by BF₂ implantation before germanidation. The results may provide guidelines for the design of Schottky source/drain germanium-based devices.