AuGeNi and AuZnNi metallizations to n- and p-InP were studied as a function of the annealing temperature in a Rapid Thermal Annealing (RTA) system. For n-InP (S:8Ã—1018cm-3) a broad minimum existed from 385Â°C to 500Â°C, in which the specific contact resistance, rc, was about 10-7 Â¿cm2. The lowest value of 7Ã—10-8 Â¿cm2 for n-InP occurred after RTA for 20 sec. at 450Â°C. For p-InP (Zn:5Ã—1018 cm-3) the lowest value of rc, 7Ã—10-6 Â¿cm2, was obtained for AuZn without any Ni. Metallurgical investigations indicated, that low rc values were associated with interfacial reactions and the formation of stable barrier-lowering metal-phosphides.