Reduction of junction leakage current in Sub-10 nm ultra-shallow NiGe/n-Ge Schottky junctions by dopant segregation

The ultra-shallow NiGe/p+-Ge/n-Ge Schottky junctions with dopant segregation have been fabricated using Indium spin-on dopant and thermal diffusion, followed by NiGe growth with microwave annealing technique. The total junction depth of the NiGe/p+-Ge/n-Ge Schottky junction was scaled down to 9 nm, containing 6-nm-thick NiGe and 3-nm-thick p+-Ge region. It is found that the junction leakage current is sufficiently suppressed with the dopant segregation process compared with that of direct NiGe/n-Ge Schottky junction, which is attributed to the increase of effective SBH for electrons in the NiGe/p+-Ge/n-Ge junction.