Nickel-based contacts are envisioned for the integration of III–V devices (such as emitters and detectors) on a 300 mm platform. We have thus investigated the structural, morphological and electrical properties of Ni/p-In0.53Ga0.47As and Ni0.9Pt0.1/p-In0.53Ga0.47As systems. The phase sequence obtained for the Ni/InGaAs system was consistent with the existing literature. In the as-deposited state and at low temperature, an intermixed and amorphous layer of a-NixInGaAs was formed. At 250 ℃, the Ni3InGaAs phase grew. This phase was stable up to 350 ℃. Then, an evolution of its stoichiometry was observed. At 400 ℃, the NiAs phase started to grow. The analysis of element distribution suggested that, at higher temperature, a NixGay phase was formed, most likely γ-Ni3Ga2. The morphology of this system stayed relatively smooth over the whole studied range of temperature, yielding a high stability of the electrical properties. The addition of Pt in the system made solid-state reactions more complicated. It had an impact on the Ni3InGaAs phase stoichiometry and led to the formation of PtxIny compounds, namely Pt3In7 and PtIn2. At high temperature, the presence of these compounds impacted the system morphology and, consequently, electrical properties.