The specific contact resistance (rc) of NiGeAu and PdGeTiPt ohmic contacts to n‐GaAs and TiPd and PdGeTiPt ohmic contacts to p+‐GaAs were determined as a function of temperature between 4.2 and 350 K. The low rc obtained for some of the contacts at 4.2 K implies that much of the total contact resistance measured at 4.2 K in two‐dimensional electron gas structures lies across the n–n heterojunction(s) in series with the metal semiconductor junction. Although NiGeAu contacts have a lower contact resistance to n‐GaAs, PdGeTiPt contacts, which have much better edge definition, can be substituted for the NiGeAu when they are properly annealed. Also, contacts with low rc values at 4.2 K can be made to p+‐GaAs using either TiPd or properly annealed PdGeTiPt contacts. The rc versus temperature curves for the TiPd and alloyed NiGeAu contacts fit the field emission model. The other contacts have a larger temperature dependence suggesting that tunneling occurs via thermionic field emission directly through the barrier or via defect states. © 1996 American Institute of Physics.