This investigation considers ohmic contact structures Si/Pt/n-InP and Au/Si/Pt/n-InP. The processing conditions achieving low specific contact resistance were derived. Experimental results indicated that the Si/Pt/n-InP showed poor ohmicity; while a low specific contact resistance of 3.32 x 10(-5) &UOmega; cm(2) was obtained on the Au/Si/Pt/n-InP contact after rapid thermal annealing (RTA) at 550 ° C for 30 s. Additionally, the Si/Pt/n-InP contact underwent a sintering reaction. The Au/Si/Pt/n-InP was formed in an alloying reaction and the contact morphology was a little rough after thermal annealing. The ohmicity of the Au/Si/pt/n-InP contact was attributed to Si doping, and determined by the alloyed reaction and the decomposition of the epitaxial layer of the metallization/InP interface. The Au/Si/Pt/n-Inp also exhibited good thermal stability without degradation, with a low maintained specific contact resistance of 2.77 x 10(-5) &UOmega; cm(2) after 400 ° C for 80 h of thermal aging. © 2004 Elsevier B.V. All rights reserved.