Low contact resistivity (1.5×10−8 Ω-cm2) of phosphorus-doped Ge by in-situ chemical vapor deposition doping and laser annealing

The electron concentration of 3×10²⁰ cm^-3 in phosphorus-doped Ge is obtained by in-situ chemical vapor deposition doping and laser annealing. The laser annealing effectively improve the crystallinity in the Ge layer. The pulse laser not only activates the phosphorus, but also produces the biaxial tensile strain. With the nickel germanide contact, the contact resistivity is as low as 1.5×10^-8 Ω-cm² by greatly reducing the tunneling distance. The misfit dislocations at the Ge/Si interface lead to the ideality factor of 1.6 for the Ge/Si hetero-junction diode with on/off ratio of ~1×10⁵.