Solid-state imaging device and method for manufacturing the same
Provided is a solid-state imaging device including a first substrate that performs photoelectric conversion and a second substrate that reads photoelectric-converted photocurrent, the first substrate and the second substrate being stacked. The first substrate includes a photoelectric conversion part, a first insulating film that is disposed closer to the second substrate than the photoelectric conversion part and accumulates and transfers charge photoelectric-converted by the photoelectric conversion part, a first electrode disposed closer to the second substrate than the first insulating film and disposed facing the photoelectric conversion part, a second electrode disposed closer to the second substrate than the first insulating film and disposed apart from the first electrode, and an impurity ion diffusion region disposed facing the second electrode and disposed in a depth direction of the photoelectric conversion part from an interface between the photoelectric conversion part and the first insulating film.
1 . A solid-state imaging device, comprising:
a first substrate configured to execute photoelectric conversion; and
a second substrate configured to read photoelectric-converted photocurrent based on the execution of the photoelectric conversion, wherein
the first substrate and the second substrate are stacked, and
the first substrate includes:
a photoelectric conversion part;
a first insulating film that is closer to the second substrate than the photoelectric conversion part, wherein the first insulating film is configured to:
accumulate a charge that is photoelectric-converted by the photoelectric conversion part, and
transfer the accumulated charge;
a first electrode that is closer to the second substrate than the first insulating film and faces the photoelectric conversion part;
a second electrode that is closer to the second substrate than the first insulating film and is apart from the first electrode; and
an impurity ion diffusion region that faces the second electrode and is in a depth direction of the photoelectric conversion part from an interface between the photoelectric conversion part and the first insulating film.
2 . The solid-state imaging device according to claim 1 , wherein
the impurity ion diffusion region is in the photoelectric conversion part,
the impurity ion diffusion region faces a region including a projected area, and
the projected area is obtained based on projection of the second electrode on a surface of the photoelectric conversion part.
3 . The solid-state imaging device according to claim 1 , further comprising a semiconductor layer between the impurity ion diffusion region and the first insulating film, wherein the semiconductor layer has a wider band gap than the impurity ion diffusion region.
4 . The solid-state imaging device according to claim 1 ,
wherein the first substrate further includes:
a plurality of pixels, wherein each pixel of the plurality of pixels includes the photoelectric conversion part; and
a third electrode that is closer to the second substrate than the first insulating film, wherein
the third electrode is along a boundary between pixels of the plurality of pixels,
the third electrode is set to a fixed potential, and
at least a part of the impurity ion diffusion region is in a region that faces the third electrode in the photoelectric conversion part.
5 . The solid-state imaging device according to claim 4 , wherein
the impurity ion diffusion region is in the photoelectric conversion part,
the impurity ion diffusion region faces a region including a projected area, and
the projected area is obtained based on projection of the third electrode on a surface of the photoelectric conversion part.
6 . The solid-state imaging device according to claim 4 , wherein
the impurity ion diffusion region includes:
a first diffusion region in a region that faces the second electrode in the photoelectric conversion part; and
a second diffusion region in a region that faces the third electrode in the photoelectric conversion part, and
the first diffusion region is in contact with the second diffusion region.
7 . The solid-state imaging device according to claim 4 , wherein
the impurity ion diffusion region includes:
a first diffusion region in a region that faces the second electrode in the photoelectric conversion part; and
a second diffusion region in a region that faces the third electrode in the photoelectric conversion part, and
the first diffusion region is apart from the second diffusion region.
8 . The solid-state imaging device according to claim 4 , wherein
the first substrate has a contact electrically connected to the impurity ion diffusion region for the each pixel of the plurality of pixels, and
the impurity ion diffusion region is set to a specific potential by a voltage applied to the contact.
9 . The solid-state imaging device according to claim 1 , further comprising a contact outside an effective pixel region in which the photoelectric conversion part is present, wherein
the contact is electrically connected to the impurity ion diffusion region, and
the impurity ion diffusion region is set to a specific potential by a voltage applied to the contact.
10 . The solid-state imaging device according to claim 1 ,
wherein the impurity ion diffusion region is a region in which impurity ions having a polarity opposite to a polarity of the charge accumulated and transferred by the first insulating film are diffused.
11 . The solid-state imaging device according to claim 1 , further comprising a second insulating film between the first insulating film and the first electrode, wherein the second insulating film contains a material different from a material of the first insulating film.
12 . The solid-state imaging device according to claim 1 , further comprising a columnar body in the depth direction of the photoelectric conversion part from the interface between the photoelectric conversion part and the first insulating film,
wherein the impurity ion diffusion region is along a surface of the columnar body.
13 . The solid-state imaging device according to claim 1 , wherein
the first substrate further includes a third electrode on a side opposite to the first electrode with the photoelectric conversion part between the first electrode and the third electrode, and
the impurity ion diffusion region is in contact with the third electrode.
14 . The solid-state imaging device according to claim 1 , wherein
the impurity ion diffusion region has a first diffusion region and a second diffusion region,
a depth of the first diffusion region is different from a depth of the second diffusion region from the interface between the photoelectric conversion part and the first insulating film, and
the first diffusion region is adjacent to the second diffusion region.
15 . The solid-state imaging device according to claim 14 , wherein
the first diffusion region is in contact with a surface of the photoelectric conversion part on an opposite side to the interface, and
the second diffusion region is up to a depth position shallower than the surface on the opposite side of the photoelectric conversion part.
16 . The solid-state imaging device according to claim 1 ,
wherein the impurity ion diffusion region is diffused from the interface between the photoelectric conversion part and the first insulating film in a curved surface shape in the depth direction of the photoelectric conversion part.
17 . The solid-state imaging device according to claim 1 ,
wherein a potential of the first insulating film in a case of the accumulation of the photoelectric-converted charge from the photoelectric conversion part is different from a potential of the first insulation film in a case of transfer of the accumulated charge to the second electrode.