Pt/ri low resistance non-alloyed ohmic contacts to p-InP-based contact layers in photonic devices, which were formed by rapid thermal processing (RTP), were studied. E-gun evaporated Pt/Ti metallization deposited onto 1.5· 1019 cm−3 Zn doped In0.53Ga0.47 As yielded the best electrical performance. These contacts were ohmic as deposited with a specific contact resistance value of 3.0 · 10−4 Ωcm2. RTP at higher temperatures led to decrease of the specific contact resistance to 3.4 · 10−8 Ωcm2 (0.08Ωmm) as a result of heating at 450°C for 30 sec. This heat treatment caused only a limited interfacial reaction (about 20 nm thick) between the Ti and the InGaAs, resulted in a thermally stable contact and induced tensile stress of 5.6 · 109 dyne · cm−2 at the metal layer but without degrading the adhesion. Heating at temperatures higher than 500°C resulted in an extensive interaction and degradation of the contact.