Image sensor and method of manufacturing image sensor
An image sensor is provided, the image sensor comprises a first semiconductor substrate; a photoelectric conversion layer in the first semiconductor substrate; a color filter on a first surface of the first semiconductor substrate; a micro lens covering the color filter; a first transistor on the first semiconductor substrate; a first insulating layer on a second surface; a second semiconductor substrate in contact with the first insulating layer, the second semiconductor substrate including a gate trench exposing at least a portion of the first gate structure; a second transistor on the second semiconductor substrate; a second insulating layer on the fourth surface; and a metal layer in the second insulating layer.
1 . An image sensor comprising:
a first semiconductor substrate including a first surface and a second surface opposite to the first surface;
a photoelectric conversion layer in the first semiconductor substrate;
a color filter on the first surface of the first semiconductor substrate;
a micro lens covering the color filter;
a first transistor on the second surface, the first transistor including a first gate structure adjacent to the photoelectric conversion layer, the first gate structure including a first gate electrode;
a first insulating layer on the second surface;
a second semiconductor substrate including a third surface in contact with the first insulating layer and a fourth surface opposite to the third surface, the second semiconductor substrate including a gate trench exposing at least a portion of the first gate electrode;
a second transistor on the fourth surface, the second transistor including a second gate structure;
a second insulating layer on the fourth surface; and
a metal layer in the second insulating layer,
wherein the first gate electrode is electrically connected with the metal layer via a first contact different from the first gate electrode and electrically contacting the metal layer and the first gate structure,
wherein a width of the gate trench is greater than a width of an upper surface of the first gate electrode, and
wherein a lower surface of the second gate structure is on the fourth surface, and an upper surface of the second gate structure and an upper surface of the first gate structure extend in a direction parallel to a surface of the second insulating layer.
2 . The image sensor of claim 1 , wherein an uppermost surface of the first gate structure protrudes past the fourth surface.
3 . The image sensor of claim 2 , wherein the uppermost surface of the first gate structure is between an uppermost surface of the second gate structure and the fourth surface.
4 . The image sensor of claim 2 , wherein the uppermost surface of the first gate structure is at a same height as an uppermost surface of the second gate structure.
5 . The image sensor of claim 2 , wherein the second insulating layer includes at least a portion of the first contact.
6 . The image sensor of claim 5 , wherein the second insulating layer further includes a second contact between the metal layer and the second gate structure, the second contact electrically connecting the metal layer and the second gate structure.
7 . The image sensor of claim 5 , wherein the first insulating layer does not include a metal line, extended in parallel with the first insulating layer, between the first semiconductor substrate and the second semiconductor substrate.
8 . The image sensor of claim 1 , wherein the second semiconductor substrate includes a thickness within a range of 5 nm to 10 nm in a vertical direction when viewed in cross-section.
9 . The image sensor of claim 1 , wherein the second transistor is configured to operate as at least one of a reset transistor, a source follower transistor, or a selection transistor.
10 . An image sensor including:
a first semiconductor substrate including a first surface and a second surface opposite to the first surface;
a photoelectric conversion layer in the first semiconductor substrate;
a color filter on the first surface;
a micro lens covering the color filter;
a first transistor on the second surface of the first semiconductor substrate, the first transistor including a first gate structure adjacent to the photoelectric conversion layer, the first gate structure including a first gate electrode;
a first insulating layer on the second surface;
a second semiconductor substrate including a third surface, which is in contact with the first insulating layer, and a fourth surface opposite to the third surface, the second semiconductor substrate including a gate trench exposing the first gate electrode;
a second transistor on the fourth surface of the second semiconductor substrate, the second transistor including a second gate structure;
a second insulating layer on the fourth surface of the second semiconductor substrate; and
a metal layer in the second insulating layer,
wherein the first gate electrode is electrically connected with the metal layer via a first contact different from the first gate electrode and electrically contacting the metal layer and the first gate structure, and
wherein the first gate electrode protrudes past the fourth surface.
11 . The image sensor of claim 10 , wherein a lower surface of the second gate structure is on the fourth surface, and an upper surface of the second gate structure and an upper surface of the first gate structure extend in a direction parallel to a surface of the second insulating layer.
12 . The image sensor of claim 10 , wherein an uppermost surface of the first gate structure is between an uppermost surface of the second gate structure and the fourth surface.
13 . The image sensor of claim 10 , wherein an uppermost surface of the first gate structure is at a same height as that of an uppermost surface of the second gate structure.
14 . The image sensor of claim 10 , wherein the second insulating layer includes at least a portion of the first contact.