Patent ID: 7064017

Claim:
A method of forming a Type-I transistor and a Type-II transistor suitable for a liquid crystal display (LCD), comprising: providing a substrate; forming a first polysilicon layer and a second polysilicon layer corresponding to the Type-I transistor and the Type-II transistor respectively on the substrate; blanket depositing a gate insulating layer on the first polysilicon layer, the second polysilicon layer, and the substrate; forming a first gate and a second gate on the gate insulating layer respectively corresponding to the first polysilicon layer and the second polysilicon layer; performing a first doping using a first type dopant to form a first heavily doped region in the first polysilicon layer beside the first gate; and performing a second doping using a second type dopant to simultaneously form a second heavily doped region in the second polysilicon layer beside the second gate and form a lightly doped region in parts of the first heavily doped region beside the first gate, wherein the dosage of the second type dopant is smaller than that of the first type dopant.