The specific contact resistance, rho(c), of Au/Zn/Au, Ni/Zn/Ni/Au, Pd/Zn/Pt/Au and Pd/Mn/Sb/Pd/Au contacts to p-In(0.53)G(0.47)As/InP has been measured as a function of layer thickness of Zn or Mn. All of the as-deposited contacts were ohmic, with rho(c) = 1 - 2 x 10(-5) Omega cm(2). Increasing thickness of the Zn layer above 200 Angstrom in the Au/Zn/Au contacts resulted in a minor decrease in rho(c) while producing no change in the Ni/Zn/Ni/Au metallization. For the as-deposited Pd/Mn/Pd/Au contacts, the value of rho(c) was independent of thickness of the Mn layer but differences in rho(c) emerged at annealing temperatures of greater than or equal to 250 degrees C. The analysis of these structures by Rutherford backscattering spectroscopy (RBS) has shown an extensive intermixing of the interfacial layers at an annealing temperature of 450 degrees C, In the Pd/Zn/Pt/Au contacts, the value of rho(c) was reduced to a minimum value of 8 x 10(-6) Omega cm(2) by annealing at a temperature of 500 degrees C. An examination of the Pd/Zn/Pt/Au configuration by RES has shown that the Pt layer acted as a barrier for the in-diffusion of the Au. A comparison has been made with the electrical properties of the Pt/Ti/Pt/Au/p-In0.53Ga0.47As/InP contact which contained an unreactive interfacial layer and no dopant layer. The as-deposited Pt/Ti/Pt/Au contacts were rectifying in current/-voltage (I-V) characteristics although a value of rho(c) of 4 x 10(-5) Omega cm(2) was obtained after annealing at 500 degrees C for 60 s with a negligible degree of intermixing of the layers.