Semiconductor device

A semiconductor device comprising:

• a gate electrode on a substrate;
• a gate insulating layer on the gate electrode;
• an oxide semiconductor layer on the gate insulating layer;
• a source electrode and a drain electrode on the oxide semiconductor layer;
• a protective layer on the source electrode and the drain electrode;
• and
• a conductive layer on the protective layer;
• wherein:
• the source electrode and the drain electrode directly contact with a side wall and a part of an upper surface of the oxide semiconductor layer, respectively;
• the protective layer includes a first silicon oxide layer and a first silicon nitride layer and overlaps the oxide semiconductor layer, the source electrode, and the drain electrode, in a plan view,
• the first silicon oxide layer is in contact with the oxide semiconductor layer, the source electrode, and the drain electrode,
• the gate insulating layer includes a second silicon nitride layer and a second silicon oxide layer,
• the second silicon oxide layer is in contact with the oxide semiconductor layer, the source electrode, and the drain electrode,
• the oxide semiconductor layer includes a first region located between the source electrode and the drain electrode, in a plan view,
• the first region includes an overlapping region with the conductive layer and a non-overlapping region with the conductive layer, in a plan view, and
• the conductive layer overlaps one of the source electrode or the drain electrode and does not overlap the other of the source electrode or the drain electrode, in plan view.