Ohmic contacts to n-type and p-type GaSb

We report the specific contact resistance at zero bias, R_c, and the barrier heights of rapidly thermally alloyed AuGe contacts on 10 ¹⁷ cm ^-3n-GaSb. An alloying step of 1 min at about 300°C provides a minimum contact resistance of about 0.4 Ωcm ². Addition of Ni in the form of a AuNiGe process has little effect on R_c, but reduces the minimum alloying temperature to about 250°C. The further step of an added gold overlayer in the {Au}/{AuNiGe} process further reduces the minimum alloying temperature to about 200°C. For contacts on 10 ¹⁷ cm ^-3p-GaSb, TiAu proved superior in conductance compared to Ti and Cr. Alloying at 300°C slightly improved the quality of the contacts. The optimized processes provide compatible bipolar ohmic metallization for minimum thermal budget.