US 12,453,124 B2
Thin film transistor substrate, display device, and manufacturing method for thin film transistor substrate
Kazunari Sasaki, Kameyama (JP); Kimihiko Hayashi, Kameyama (JP); Ryuji Matsumoto, Kameyama (JP); and Takashi Terauchi, Kameyama (JP)
Assigned to Sharp Display Technology Corporation, Kameyama (JP)
Filed by Sharp Display Technology Corporation, Kameyama (JP)
Filed on Oct. 12, 2022, as Appl. No. 17/964,823.
Claims priority of application No. 2021-170986 (JP), filed on Oct. 19, 2021.
Prior Publication US 2023/0120056 A1, Apr. 20, 2023
Int. Cl. H10D 30/67 (2025.01); H10D 30/01 (2025.01); H10D 86/40 (2025.01)
CPC H10D 30/6732 (2025.01) [H10D 30/0316 (2025.01); H10D 86/441 (2025.01)] 8 Claims
OG exemplary drawing
 
1. A thin film transistor substrate comprising:
a substrate; and
a thin film transistor of a bottom gate type, the thin film transistor including a gate electrode, a channel portion, a source electrode, and a drain electrode formed on the substrate,
wherein a gate insulating film is disposed between the gate electrode and the channel portion,
the gate electrode is made of a first conductive film disposed on a lower layer side of the gate insulating film,
the channel portion is made of a semiconductor film disposed on an upper layer side of the gate insulating film, and the channel portion is disposed to overlap the gate electrode,
the source electrode is made of a second conductive film disposed on an upper layer side of the semiconductor film, and the source electrode is disposed such that to include at least a portion overlapping the channel portion,
the drain electrode is made of a portion of the second conductive film that is different from a portion of the source electrode, and is disposed such that to include at least a portion overlapping the channel portion at a position spaced from the source electrode,
the gate insulating film includes a first insulating portion overlapping the gate electrode and a second insulating portion that is disposed not to overlap the gate electrode but to overlap the source electrode and the drain electrode, and that has a film thickness greater than a film thickness of the first insulating portion,
a lower layer portion that is made of a lower layer film disposed on a lower layer side of the first conductive film and that includes at least a portion overlapping the gate electrode,
the gate insulating film includes a first gate insulating film disposed on an upper layer side of the first conductive film, and a second gate insulating film disposed on an upper layer side of the first gate insulating film,
the first insulating portion includes at least the second gate insulating film,
the second insulating portion includes the first gate insulating film and the second gate insulating film,
a portion of the second insulating portion formed by the first gate insulating film has a film thickness that is equal to or greater than a sum of a thickness of the lower layer portion and a thickness of the gate electrode, and
an upper surface of the first insulating portion and an upper surface of the second insulating portion form one flat surface.