THIN FILM TRANSISTOR, AND DISPLAY DEVICE INCLUDING THE THIN FILM TRANSISTOR

PROBLEM TO BE SOLVED: To provide a thin film transistor and a display device including a thin film transistor, in which the deterioration of a thin film transistor can be suppressed and the processing can be facilitated.SOLUTION: A thin film transistor according to the present embodiment includes: an oxide semiconductor layer provided above an insulating substrate and including a source region, a drain region, and a channel region between the source region and the drain region; a first insulating film provided in a region corresponding to the channel region on the oxide semiconductor layer; a gate electrode provided on the first insulating film; a first protective film provided on the oxide semiconductor layer, the first insulating film, and the gate electrode and serving as an insulating film containing metal; a second protective film provided on the first protective film; and a third protective film provided on the second protective film and serving as an insulating film containing metal.SELECTED DRAWING: Figure 1 【課題】薄膜トランジスタの劣化を抑制し、加工を容易化することが可能な薄膜トランジスタ、及び薄膜トランジスタを備えた表示装置を提供する。【解決手段】本実施形態に係る薄膜トランジスタは、絶縁基板上方に設けられ、ソース領域、ドレイン領域、及び前記ソース領域と前記ドレイン領域との間のチャネル領域を有する酸化物半導体層と、酸化物半導体層上のチャネル領域と対応する領域に設けられた第１の絶縁膜と、第１の絶縁膜上に設けられたゲート電極と、酸化物半導体層、第１の絶縁膜、及びゲート電極上に設けられ、金属を含む絶縁膜としての第１の保護膜と、第１の保護膜上に設けられた第２の保護膜と、第２の保護膜上に設けられ、金属を含む絶縁膜としての第３の保護膜と、を具備している。【選択図】図１