The electrical properties of the Sb/Zn/Au/Nb ohmic contacts to p-type InP were investigated, where a slash (/) indicates the deposition sequence. The first Sb layer improved the contact resistivity and reduced the optimum annealing temperature, compared with the Au/Zn/Au/Nb contacts whose first layer was Au. The minimum contact resistivity of 4x10(-5) Omega cm(2) was obtained from the Sb(3 nm)/Zn(5 nm)/Au(10 nm)/Nb(50 nm) contacts annealed at 325 degrees C for 2 min. The interfacial microstructure was studied using the cross-sectional transmission electron microscope. It was considered that the deposited Sb deoxidized and removed the native oxides of the InP surface and that facilitated the upper Au and Zn diffusion into InP.