CPC H01L 27/14614 (2013.01) [H01L 27/14621 (2013.01); H01L 27/14627 (2013.01); H01L 27/1463 (2013.01); H01L 27/1464 (2013.01); H01L 27/14645 (2013.01); H01L 27/14689 (2013.01)] | 20 Claims |
1. An image sensor comprising:
a semiconductor substrate including a first surface and a second surface opposite to each other;
a buried transfer gate electrode arranged in a transfer gate trench extending from the first surface of the semiconductor substrate into the semiconductor substrate, wherein the buried transfer gate electrode has an upper surface arranged at a level lower than that of the first surface of the semiconductor substrate with respect to the second surface of the semiconductor substrate; and
a transfer gate spacer arranged on an upper sidewall of the transfer gate trench and on the buried transfer gate electrode,
wherein the transfer gate spacer includes a first portion and a second portion, wherein the first portion is disposed above a first sidewall of the buried transfer gate electrode and has a first thickness, and
wherein the second portion is disposed above a second sidewall of the buried transfer gate electrode and has a second thickness that is different from the first thickness.
|