Patent ID: 7115449

Claim:
A method for fabrication of polycrystalline silicon thin film transistors, comprising the following steps of: a) obtaining a substrate; b) forming a buffer oxide on said substrate; c) depositing a first amorphous silicon on said buffer oxide; d) depositing a low-temperature oxide on said first amorphous silicon, wherein said low-temperature oxide is to be a stop layer for anisotropic plasma etching on a silicon film, a thermal insulating layer to prevent heat dissipation for laser annealing, and a hard mask for removing a silicon spacer after recrystallization; e) by using a photoresist as a hard mask, etching said low-temperature oxide by way of anisotropic plasma etching and partially etching said first amorphous silicon; and f) after removing said photoresist, depositing a second amorphous silicon, wherein said second amorphous silicon is connected with said first amorphous silicon; forming a silicon spacer by way of anisotropic plasma etching; recrystallizing said second amorphous silicon by a continuous-wave laser or an excimer laser; and at the end, removing said silicon spacer and said low-temperature oxide on an active layer by way of anisotropic plasma etching.