Under thermal annealing, the crystallization temperatures of a-Si in a-Si/ Cu and a-Si/ Al bilayer recording films were significantly reduced to around 485 and 357°C, respectively, and the activation energies for crystallization were reduced to about 3.3 eV. The formation of Cu 3 Si phase prior to crystallization of a-Si was found to occur at around 175°C in a-Si/ Cu, while no Al silicide was observed in a-Si/ Al before crystallization of a-Si. The reaction exponents for a-Si/ Cu and a-Si/ Al were determined to be around 1.8 and 1.6, respectively, corresponding to a crystallization process in which grain growth occurs with nucleation, and the nucleation rate decreases with the progress of grain growth. Under pulsed laser irradiation, the precipitation of Cu 3 Si phases and crystallization of a-Si were observed in a-Si/ Cu, while the crystallization and reamorphization of a-Si took place sequentially in a-Si/ Al. The reaction exponents for a-Si/ Cu and a-Si/ Al, determined to be about 2.0 and 2.2, respectively, are slightly higher than those under thermal annealing, indicating that the crystallization processes of a-Si/ Cu and a-Si/ Al under pulsed laser irradiation are similar to those under thermal annealing. However, the decrease of nucleation rate with the progress of grain growth is slower. At the same time, the activation energies for crystallization of a-Si/ Cu and a-Si/ Al, estimated to be about 0.18 and 0.22 eV, respectively, are nearly an order of magnitude lower than those under thermal annealing. This may be explained by the explosive crystallization of a-Si by mechanical impact, with a high power pulsed laser.