Diode and display device comprising diode

摘要

A thin film transistor which includes a microcrystalline semiconductor film over a gate electrode with a gate insulating film interposed therebetween to be in an inner region in which end portions of microcrystalline semiconductor film are in an inside of end portions of the gate electrode, an amorphous semiconductor film which covers top and side surfaces of the microcrystalline semiconductor film, and an impurity semiconductor film to which an impurity element imparting one conductivity is added, and which forms a source region and a drain region, wherein the microcrystalline semiconductor film includes an impurity element serving as a donor is provided to reduce off current of a thin film transistor, to reduce reverse bias current of a diode, and to improve an image quality of a display device using a thin film transistor.