Image sensor and method of forming the same
An image sensor is provided. The image sensor includes a substrate, an isolation structure on the substrate, a photoelectric conversion layer, a transparent electrode layer, an encapsulation layer, a color filter layer, and a micro-lens. The isolation structure is electrically non-conductive and defines a plurality of pixel regions on the substrate. The isolation structure prevents cross-talk of electrical signals among pixels. The photoelectric conversion layer is disposed on the pixel regions defined by the isolation structure. The transparent electrode layer is disposed over the isolation structure and the photoelectric conversion layer. The encapsulation layer is disposed over the transparent electrode layer. The micro-lens is disposed on the color filter layer.
1. An image sensor, comprising:
a substrate;
an isolation structure disposed on the substrate, wherein the isolation structure is electrically non-conductive and defines a plurality of pixel regions on the substrate; and
a photoelectric conversion layer disposed on the pixel regions defined by the isolation structure, wherein the isolation structure prevents cross-talk of electrical signals in the photoelectric conversion layer among the pixel regions;
a transparent electrode layer disposed over the isolation structure and the photoelectric conversion layer;
an encapsulation layer disposed over the transparent electrode layer;
a color filter layer disposed over the encapsulation layer corresponding to the pixel regions; and
a micro-lens layer disposed on the color filter layer,
wherein the isolation structure comprises isolation walls, the isolation walls are portions of the isolation structure between adjacent ones of the plurality of pixel regions, and the isolation walls have a triangular or an inversely trapezoidal shape in a cross-sectional view.
2. The image sensor as claimed in claim 1 , wherein the isolation structure comprises isolation walls, wherein the isolation walls are portions of the isolation structure between adjacent ones of the plurality of pixel regions, and an angle between a sidewall and a bottom surface of the isolation walls is between 60° and 120°.
3. The image sensor as claimed in claim 2 , wherein the photoelectric conversion layer exposes at least a portion of sidewalls of the isolation walls.
4. The image sensor as claimed in claim 2 , wherein the photoelectric conversion layer completely covers sidewalls of the isolation walls.
5. The image sensor as claimed in claim 2 , wherein a height of the isolation walls is between 0.5 μm and 1.5 μm, and an average width of each of the isolation walls is between 10 nm and 100 nm.
6. The image sensor as claimed in claim 2 , wherein a sum of an average width of each of the isolation walls and an average width of the pixel regions is less than 20 μm.
7. The image sensor as claimed in claim 1 , further comprising an isolation cap disposed on a top surface of the isolation structure, wherein a width of the isolation walls is less than a width of the isolation cap.
8. The image sensor as claimed in claim 7 , wherein the isolation cap comprises an inorganic material and the isolation structure comprises an organic material.
9. The image sensor as claimed in claim 1 , wherein the photoelectric conversion layer extends continuously across adjacent ones of the pixel regions.
10. The image sensor as claimed in claim 1 , wherein a refractive index of the isolation structure is between 1.1 and 2.5, and the isolation structure comprises silicon nitride, silicon oxide, aluminum oxide, photoresist, or a combination thereof.
11. The image sensor as claimed in claim 1 , further comprising a sensing device embedded in each of the pixel regions of the substrate, and the sensing device is electrically connected to the photoelectric conversion layer through a conductive portion.
12. The image sensor as claimed in claim 1 , further comprising:
a transparent electrode layer disposed over the isolation structure and the photoelectric conversion layer;
an encapsulation layer disposed over the transparent electrode layer;
a color filter layer disposed over the encapsulation layer corresponding to the pixel regions; and
a micro-lens layer disposed on the color filter layer.