Thin film transistors on large single crystalline regions of silicon induced by cw laser crystallization

Large area, 60 μm × 700 μm, single crystalline silicon regions are produced by using a sickle shaped beam of the second harmonic of a cw Nd:YVO4 laser (532 nm). This not obvious technique is discussed here. Moreover, large thin film transistors (channel width to length ratio W/L=63 μm/22 μm) with all the channel area in the single crystalline region are made. Very high performance, with a mobility value larger than 600 cm2/V s, is obtained. However the negative threshold voltage shows the need to control it by a doping of the channel.