MAX phase coating could have interesting technical applications in many fields. This paper describes the synthesis of the Mn+1AXn phase Ti3SiC2 by a rapid thermal annealing process of physical vapor deposited TiCSi multilayer thin films on Si (100) and SiO2 substrates. Annealing temperatures of 800–1000 °C affected the solid state reaction of titanium, carbon and silicon creating titanium-carbides, -silicides, and Ti3SiC2. The film structures and chemical compositions were observed by grazing incidence X-ray diffraction, transmission electron microscopy, and glow discharge optical emission spectroscopy. Analysis after the rapid thermal processing revealed the formation of the polycrystalline Mn+1AXn phase Ti3SiC2 in coexistence with TiSi2, TiC and Ti5Si3, even within a 0 s annealing process. This synthesis method has a high potential for the formation of MAX phases as a high temperature electrical contact material.