A low-resistance, thermally stable Ohmic contact to n-GaSb -: art. no. 033703

Ohmic contacts to gallium antimonide have been studied in recent years in an attempt to develop a low-resistance, thermally stable metallization. We present a study of Pd3In7/X/Au (X=Pt, W, WSi2, or WSiN) contacts that utilize Pd and In to obtain a low contact resistance, and a diffusion barrier (X) to ensure thermal stability of the contact beneath the gold cap. Contacts utilizing WSiN as the diffusion barrier exhibit specific contact resistance values comparable to the best previously reported, but with greatly improved thermal stability and shallow reaction morphology. The Pd3In7/WSiN/Au contact provides a specific contact resistance of 1.8x10(-6) Omega cm(2) after annealing at 325 degrees C for 1 min or 350 degrees C for 30 s (n congruent to 2x10(18) cm(-3)). Field emission is identified as the mechanism for current transport in these contacts. The reaction depth of the contact remains less than 30 nm after at least 400 h at 250 degrees C in an evacuated ampoule, along with an increase in specific contact resistance to 7x10(-6) Omega cm(2). (c) 2005 American Institute of Physics.