Mechanism of aluminum-induced layer exchange upon low-temperature annealing of amorphous Si/polycrystalline Al bilayers

The aluminum-induced layer exchange (ALILE) process occurring upon annealing amorphous Si/polycrystalline Al bilayers (a-Si/c-Al) has been observed at a temperature as low as 165 °C. The diffusion length of Si along Al grain boundaries is proposed as a tool for determining the annealing conditions, i.e., temperature and time, for the occurrence of the c-Al→c-Si layer exchange. Analysis of the local and global energy changes upon layer exchange reveals that a tiny driving force controls the kinetics of layer exchange and leads to a general interpretation of the mechanism of the ALILE process.