THIN-FILM TRANSISTOR, METHOD FOR FABRICATING THIN-FILM TRANSISTOR, AND DISPLAY DEVICE

摘要

Methods of fabricating a thin-film transistor are provided. The methods include forming a gate electrode above a substrate, a gate insulating layer above the gate electrode, a non-crystalline silicon layer above the gate insulating layer, and a channel protective layer above the non-crystalline silicon layer. The non-crystalline silicon layer and the channel protective layer are processed to form a projecting part. The projecting part has an upper layer composed of the channel protective layer and a lower layer composed of the non-crystalline silicon layer. The projecting part and portions of the non-crystalline silicon layer on sides of the projecting part are irradiated with a laser beam to crystallize at least the non-crystalline silicon layer in the projecting part. An absorptance of the non-crystalline silicon layer for the laser beam is greater in the projecting part than in the portions on the sides of the projecting part.

主权项

1. A method for fabricating a thin-film transistor, the method comprising:
preparing a substrate; forming a gate electrode above the substrate; forming a gate insulating layer above the gate electrode; forming a non-crystalline silicon layer above the gate insulating layer; forming a channel protective layer above the non-crystalline silicon layer; processing the non-crystalline silicon layer and the channel protective layer to form a projecting part, the projecting part having an upper layer composed of the channel protective layer and a lower layer composed of the non-crystalline silicon layer; irradiating, with a laser beam, the projecting part and portions of the non-crystalline silicon layer on sides of the projecting part to crystallize the non-crystalline silicon layer in the projecting part into a crystalline silicon layer, the portions of the non-crystalline silicon layer on the sides of the projecting part remaining the non-crystalline silicon layer; forming a contact layer along at least a side surface of the crystalline silicon layer and on an upper surface of each of the portions of the non-crystalline silicon layer on the sides of the projecting part, the contact layer comprising non-crystalline silicon doped with impurity or polysilicon doped with impurity; and forming source and drain electrodes on the contact layer with the contact layer being between the source and drain electrodes and the crystalline silicon layer and also between the source and drain electrodes and the portions of the non-crystalline silicon layer on the sides of the projecting part, wherein, in the irradiating, an absorptance of the non-crystalline silicon layer for the laser beam is greater in the projecting part than in the portions on the sides of the projecting part.