Large single crystal layer production

摘要

A process for producing a single crystal layer from amorphous or polycrystalline semiconductor material on an amorphous foreign substrate involves forming a nucleation centre point by laser melting with a single laser pulse of preset spot size and then linearly advancing a resulting solidified small crystallisation front by alternate steps of changing of the radiation location in the submicron range and emitting further laser pulses. The novelty comprises a further process stage of (a) matching the laser pulse spot size (9) to the long edge length (8) of the elongated single crystal (6) formed in the preceding stage; and (b) linearly advancing one or both long edges of the crystal as a broad crystallisation front (10) by alternate steps of changing of the radiation location in the submicron range and emitting further laser pulses (3) having the broadened spot size (9). Also claimed is an apparatus for carrying out the above process.