The alloyed AuGe-based contact is widely used to make ohmic connections to GaAs. It has been presumed that the regrown alloyed region is heavily doped so that carrier transport is by tunneling. The electrical and metallurgical properties of this heterogeneous system have been extensively studied and have been shown to be spatially nonuniform. Details of fabrication technique, analysis, and theoretical interpretation of its behavior will be discussed. It is suggested that the observed (doping)−1 dependence of the contact resistance is due to spreading resistance domination of current paths through submicron regions of the contact area where heavy doping occurs.