Low Specific Contact Resistivity to n-Ge and Well-Behaved Ge ${\rm n}^{+}/{\rm p}$ Diode Achieved by Multiple Implantation and Multiple Annealing Technique

In this letter, the specific contact resistivity of metal on n-doped germanium is significantly reduced to 3.8×10^-7 Ω·cm² by P⁺ multiple implantation and multiple annealing (MIMA) technique. The dramatic reduction of specific contact resistivity is attributed to the enhanced activation of n-type dopants, and a high electrical activation over 1×10²⁰ cm^-3 is demonstrated by the spreading resistance profiling analysis. In addition, the fabricated germanium n⁺/p diode by P⁺ MIMA technique exhibits an ION/IOFF ratio over 10⁵ with low ideality factor of 1.11. The low specific contact resistivity of metal on n-doped germanium and well-behaved germanium n⁺/p diode are beneficial for the performance improvement of Ge nMOSFETs.