MANUFACTURING METHOD OF THIN FILM TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To suppress leakage current when a thin film transistor is turned off even if threshold voltage is not set to be high, and to prevent the deterioration of driving capacity of the thin film transistor. SOLUTION: An amorphous silicon film 2 is crystallized by a heating processing such as laser annealing so as to form a polysilicon film 3. For controlling threshold voltage of the thin film transistor, impurity is ion-implanted into the polysilicon film 3. The polysilicon film 3 is selectively dry-etched or wet-etched so as to form a polysilicon island 3I. The end of the polysilicon island 3I is etched so that it becomes a taper shape with a condition of isotropic etching. COPYRIGHT: (C)2007,JPO&INPIT