The knowledge of pre-exponential factors and activation energies for low temperatures and short annealing times in nanoscaled systems is important for the downscaling of thermal processes. Here, the diffusion coefficients in aluminum–nickel, aluminum–titanium, titanium–silicon, and aluminum–copper bilayers were determined using rapid thermal annealing. The annealing time was set to 500 s and the investigated bilayer thin film thicknesses were 2 µm. The temperatures ranged from 389 to 613 K depending on the bilayer system. For the various material combinations, the diffusion coefficients were determined by elemental depth profiling and compared to literature values. For the aluminum–copper system, a good agreement with literature and a single set of values was found, whereas for aluminum–nickel, aluminum–titanium, and titanium–silicon two or more sets of values were observed.