Novel selenium implant and segregation for reduction of effective Schottky barrier height in NiGe/n-Ge contacts

We report the demonstration of a new effective Schottky barrier height (Φ_Bn) reduction technology for NiGe/n-type Germanium (n-Ge) contacts using ion implantation of selenium (Se) or sulfur (S) followed by their segregation at the NiGe/n-Ge interface. Both Se and S are found to segregate at NiGe/n-Ge interface after germanide formation, giving Φ_Bn as low as ~0.1 eV. Nickel monogermanide was formed for samples annealed at 350 °C for 30 s. In addition, both Se and S implants cause surface amorphization which possibly leads to improved uniformity of NiGe thickness.