Optics for Laser Crystallization Technology

Excimer laser based crystallization has become a workhorse in preparing poly-Si films for the manufacture of back plates for active matrix liquid crystal displays. Alternative laser techniques applying cw laser sources provide high quality crystal films however at a very slow rate. Line Beam optics combined with 300 W power excimer lasers to scan large area electronics substrates are achieving fast processing and very homogeneous poly-Si films. Very good laser beam homogeneity is critical for the near complete melt process. Furthermore high resolution diffraction limited optics systems are described for the sequential lateral solidification of amorphous silicon films. High quality films with electron mobility of 100-300 cm2/Vs can be produced. The generation of films for microelectronic circuits is an additional potential of the laser based crystallization process, thus even the application to the formation of shallow junctions for submicron technology is considered.