Low Specific Contact Resistivity to n-Ge and Well-Behaved Ge Diode Achieved by Multiple Implantation and Multiple Annealing Technique

摘要

In this letter, the specific contact resistivity of metal on n-doped germanium is significantly reduced to $3.8times 10^{-7}~Omegacdot {rm cm}^{2}$ by ${rm P}^{+}$ 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 $1times 10^{20}~{rm cm}^{-3}$ is demonstrated by the spreading resistance profiling analysis. In addition, the fabricated germanium ${rm n}^{+}/{rm p}$ diode by ${rm P}^{+}$ MIMA technique exhibits an $I_{rm ON}/I_{rm OFF}$ ratio over $10^{5}$ with low ideality factor of 1.11. The low specific contact resistivity of metal on n-doped germanium and well-behaved germanium ${rm n}^{+}/{rm p}$ diode are beneficial for the performance improvement of Ge nMOSFETs.