Thin film transistor having an oxide semiconductor bilayer, method of manufacturing the same and flat panel display device having the same

摘要

Disclosed is a thin film transistor which has an oxide semiconductor as an activation layer, a method of manufacturing the same and a flat panel display device having the same. The thin film transistor includes an oxide semiconductor layer formed on a substrate and including a channel region, a source region and a drain region, a gate electrode insulated from the oxide semiconductor layer by a gate insulating film, and source electrode and drain electrode which are coupled to the source region and the drain region, respectively. The oxide semiconductor layer includes a first layer portion and a second layer portion. The first layer portion has a first thickness and a first carrier concentration, and the second layer portion has a second thickness and a second carrier concentration. The second carrier concentration is lower than the first carrier concentration.