The achievement of near-theoretical-minimum contact resistance to InP

We have investigated the electrical and metallurgical behavior of the InP/Au/Ni contact system. We show that when a layer of Au, 100 Å or more in thickness, is introduced between n-InP and Ni contact metallization, specific contact resistivity Rc values in the low 10−8 Ω cm2 range are achieved after sintering. It is suggested that these ultralow values of Rc are due to the presence, at the metal-InP interface, of a Ni3P layer combined with a stoichiometry change in the InP surface. We show, in addition, that it is possible to achieve very low Rc values with this system without incurring device destroying sinter-induced metallurgical interdiffusion.