Sulfur passivation for shallow Pd/W/Au ohmic contacts to p-InGaSb

摘要

The relationship between the specific contact resistance of nonalloyed Pd/W/Au ohmic contacts to p-In0.25Ga0.75Sb and premetallization surface preparations is examined. The resistance of ohmic contacts is minimized when p-InGaSb is exposed briefly to a dilute (NH4)(2)S solution. This treatment minimizes the thickness of any residual oxide or sulfide layer on the semiconductor and avoids excessive etching of the semiconductor, which would make the contact less shallow. A specific contact resistance of 5.9x10(-7) Omega cm(2) is achieved for a Pd/W/Au (2/50/145 nm) contact that consumes no more than 5 nm of InGaSb. (C) 2004 American Institute of Physics.