Patent ID: 8546800

Claim:
A thin film transistor comprising: a substrate; a gate electrode formed on the substrate; a gate insulating layer formed on the gate electrode; a channel region formed on the gate insulating layer; a source region and a drain region formed at two opposite ends of the channel region, respectively; a first etching block layer and a second etching block layer formed in sequence on the channel region, the second etching block layer defining a groove in a center thereof to expose a part of the first etching block layer, the groove dividing the second etching block layer into a first region and a second region; and a source electrode extending from the source region to the first region, and a drain electrode extending from the drain region to the second region, the source electrode above the channel region having at least a part thereof which is separated from the channel region by the first etching block layer and the first region of the second etching block layer, the drain electrode above the channel region having at least a part thereof which is separated from the channel region by the first etching block layer and the second region of the second etching block layer, wherein the first etching block layer is made of oxide, and the second etching block layer is made of nitride, wherein the first etching block layer is made of a material selected from SiOx, AlOx, HfOx and YOx and wherein the second etching block layer is made of SiNx.