Metallization options and annealing temperatures for low contact resistance ohmic contacts to n-type GaSb

The quest for faster electronic devices combined with the requirement of low power dissipation has revived the interest in the near 6.1 Å lattice constant antimony containing III-V compounds. Among the known III-V semiconductors, InSb has the highest electron mobility and GaSb the highest hole mobility. In addition favorable bandgap alignments are predicted with related III-V ternaries and quaternaries suitable for high-speed heterostructure transistors, lasers, and optoelectronic devices. The device fabrication technology of antimony containing III-V compounds however, is in its infancy and considerable work needs to be performed. In this work, we report the development of a low contact resistance ohmic contacts for n-type GaSb suitable for heterostructure device applications, with over an order of magnitude improvement in contact resistance and specific contact resistivity. The MBE growth of Te doped n-type GaSb and crucial device processing and pre-metallization surface treatment will be discussed. A variety of metallization schemes containing Au, Ge, In, Ni, Pd, and Pt and the effects of annealing temperature are examined