Pulsed excimer (KrF) laser melting of amorphous and crystalline silicon layers

We have investigated depth of melting as a function of pulse energy density in amorphous and crystalline silicon layers. The melting threshold for KrF laser pulses (λ=0.249 μm, τ=24×10−9 s) in amorphous (7660-Å-thick) and crystalline silicon layers were determined to be 0.16±0.02 and 0.75±0.05 J cm−2, respectively. The formation of fine- and large-polycrystalline regions was clearly identified in the amorphous silicon layers for energy densities below that needed for complete annealing. The role of explosive recrystallization in the formation of the fine polycrystalline region is discussed.