Light emitting device and fabricating method thereof

摘要

The present invention provides an inexpensive light emitting device and an inexpensive electric appliance. By reducing the number of photolithography steps in the fabrication of TFTs, the yield of the light emitting devices can be enhanced and the manufacturing period can be shortened. The present invention is substantially characterized in that a gate electrode is formed of a conductive film made of a plurality of layers and the concentration of impurity regions formed in the inside of an active layer can be adjusted by making use of the selection ratio at the time of etching these layers.