Line scan sequential lateral solidification of thin films

A system for preparing a semiconductor film for an active matrix display, the system comprising:

• a laser source providing laser pulses having a pulse frequency of greater than about 4 kHz and having an average power of greater than 100 W;
• laser optics that shape the laser beam into an line beam, the line beam having a length, a width and a length to width aspect ratio greater than 50, the shaped laser beam having a substantially uniform fluence along the length of the line beam;
• a stage for support a sample capable of translation in at least one direction;
• memory for storing a set of instructions, the instructions comprising:
• (a) irradiating a first portion of the film with a plurality of laser pulses, wherein the irradiated film crystallizes after each laser pulse to form one or more laterally grown crystals, wherein the crystals grow substantially perpendicular to the length of the line beam, and wherein the film is laterally displaced relative to the line beam at a constant velocity a first pulse translation distance in the direction of lateral crystal growth after a first laser pulse, to form a first crystalline region;
• and
• (b) without interruption of the film displacement relative to the line beam and in the direction of the lateral crystal growth, irradiating a second portion of the film with a plurality of laser pulses, wherein the irradiated film crystallizes after each laser pulse to form one or more laterally grown crystals and wherein the film is laterally displaced relative to the line beam at a constant velocity a second pulse translation distance in the direction of lateral crystal growth after each laser pulse, to form a second crystalline region,
• wherein said first pulse translation distance after said first laser pulse is different from said second pulse translation distance after said second laser pulse.