Sensing device and fabricating method of the same
A sensing device including a substrate, a switching element, a sensing element and a common electrode is provided. The switching element is disposed on the substrate and includes a source electrode. The sensing element is disposed at one side of the switching element and includes a lower electrode, a photoelectric conversion layer and an upper electrode. The lower electrode is electrically connected to the source electrode. The photoelectric conversion layer is disposed on the lower electrode. The upper electrode is disposed on the photoelectric conversion layer. The common electrode is electrically connected to the upper electrode and belongs to the same film layer as the source electrode. A fabricating method of a sensing device is also provided.
1 . A sensing device, comprising:
a substrate;
a switching element, disposed on the substrate, and comprising a bottom gate electrode, a top gate electrode, a drain electrode, a source electrode, a semiconductor layer located between the bottom gate electrode and the top gate electrode, a first island-shaped gate insulating layer disposed between the bottom gate electrode and the semiconductor layer, and a second island-shaped gate insulating layer disposed between the top gate electrode and the semiconductor layer,
wherein the source electrode and the drain electrode are arranged along a first direction,
wherein each of the first island-shaped gate insulating layer and the second island-shaped gate insulating layer has a first side surface and a second side surface opposite to the first side surface, and the first side surface and the second side surface are arranged along a second direction perpendicular to the first direction,
wherein the top gate electrode has two parts extend downward along a normal direction of the substrate to respectively cover the first side surfaces and the second side surfaces so that two end portions of the top gate electrode respectively physically contact two end portions of the bottom gate electrode to form an annular gate completely surrounding the semiconductor layer, wherein the two end portions of the top gate electrode are arranged along the second direction, and the two end portions of the bottom gate electrode are arranged along the second direction;
a sensing element, disposed at one side of the switching element, and comprising:
a lower electrode, electrically connected to the source electrode;
a photoelectric conversion layer, disposed on the lower electrode; and
an upper electrode, disposed on the photoelectric conversion layer;
a top insulating layer disposed on the sensing element and the top gate electrode of the switching element, having a first through hole, a second through hole, a third through hole and a fourth through hole, wherein the drain electrode is electrically connected to a drain region of the semiconductor layer through the first through hole, the source electrode is electrically connected to a source region of the semiconductor layer through the second through hole, and the lower electrode is electrically connected to the source electrode through the third through hole; and
a common electrode extending along the second direction, electrically connected to the upper electrode and belonging to a same film layer as the source electrode, wherein the upper electrode is electrically connected to the common electrode through the fourth through hole of the top insulating layer,
wherein a spacing between the lower electrode and the substrate is less than a spacing between the semiconductor layer and the substrate, with the proviso that the lower electrode is in contact with the photoelectric conversion layer.
2 . The sensing device as claimed in claim 1 , wherein the top gate electrode and the lower electrode belong to a same film layer.
3 . The sensing device as claimed in claim 1 , further comprising a data line, and the data line and the source electrode belonging to a same film layer.
4 . The sensing device as claimed in claim 3 , further comprising a scan line, wherein a spacing between the scan line and the data line is 3,000-12,000 Å in a direction normal to the substrate.
5 . The sensing device as claimed in claim 1 , wherein the photoelectric conversion layer completely overlaps the lower electrode, and the upper electrode completely overlaps the photoelectric conversion layer.
6 . The sensing device as claimed in claim 1 , wherein an orthographic projection of the lower electrode on the substrate is outside an orthographic projection of the semiconductor layer on the substrate.
7 . The sensing device as claimed in claim 1 , wherein the source electrode electrically connects the semiconductor layer with the lower electrode, and a portion of the source electrode between the semiconductor layer and the lower electrode has a step profile in a cross-sectional view cut through the semiconductor layer and the lower electrode.
8 . The sensing device as claimed in claim 1 , wherein a central axis of the annular gate is located in the semiconductor layer.
9 . The sensing device as claimed in claim 1 , wherein the drain electrode is disposed at a side of the annular gate opposite the source electrode.