Abstract: An amorphous silicon thin film is formed on a substrate first. Then the thin film is irradiated by a laser plus having an irradiation interval along a first direction to re-crystallize the thin film into a polysilicon thin film. A light source is thereafter focused into a micro spot having a diameter smaller than the irradiation interval, and the polysilicon thin film is irradiated by the micro spot moving along the first direction and having a relative moving distance to obtain a spectrum.

Abstract: A method for fabricating a low temperature polysilicon thin film transistor incorporating a channel passivation step is described. The method achieves dopant ion activation in a polysilicon gate by using laser irradiation, however, with an additional insulating material layer such as SiOx or SixNy overlying and protecting the channel portion of the polysilicon gate. Any possible contamination by residual photoresist material after a photoresist removal step on the channel portion of the polysilicon gate can thus be avoided. Furthermore, deficiencies such as dopant ions out-diffusion and lateral diffusion can be avoided. The leakage current of the thin film transistors formed by the present invention method is significantly reduced when compared to those formed by a conventional method.

Abstract: A method for fabricating a low temperature polysilicon thin film transistor incorporating a channel passivation step is described. The method achieves dopant ion activation in a polysilicon gate by using laser irradiation, however, with an additional insulating material layer such as SiOx or SixNy overlying and protecting the channel portion of the polysilicon gate. Any possible contamination by residual photoresist material after a photoresist removal step on the channel portion of the polysilicon gate can thus be avoided. Furthermore, deficiencies such as dopant ions out-diffusion and lateral diffusion can be avoided. The leakage current of the thin film transistors formed by the present invention method is significantly reduced when compared to those formed by a conventional method.

Abstract: A method for fabricating a low temperature polysilicon thin film transistor incorporating a multi-layer channel passivation stack, and for activating dopant ions in a polysilicon gate in the TFT structure has been described. In the method, a multi-layer channel passivation stack consisting of a first insulating material layer, a metal layer and a second insulating material layer are first deposited on a polysilicon gate to shield a channel region in the gate during a laser irradiation process for activating the dopant ions in the gate. Any damages to the channel region of the polysilicon gate by the laser irradiation or the rapid thermal annealing step can be avoided, as well as the dopant impurity out-diffusion and lateral diffusion problems.