Negatively charged layer to reduce image memory effect

摘要

An image sensor pixel includes a photodiode region having a first polarity doping type disposed in a semiconductor layer. A pinning surface layer having a second polarity doping type is disposed over the photodiode region in the semiconductor layer. The second polarity is opposite from the first polarity. A first polarity charge layer is disposed proximate to the pinning surface layer over the photodiode region. An contact etch stop layer is disposed over the photodiode region proximate to the first polarity charge layer. The first polarity charge layer is disposed between the pinning surface layer and the contact etch stop layer such that first polarity charge layer cancels out charge having a second polarity that is induced in the contact etch stop layer. A passivation layer is also disposed over the photodiode region between the pinning surface layer and the contact etch stop layer.

主权项

1. An image sensor pixel, comprising:
a photodiode region having a first polarity doping type disposed in a semiconductor layer; a pinning surface layer having a second polarity doping type disposed over the photodiode region in the semiconductor layer, wherein the second polarity is opposite from the first polarity; a first polarity charge layer disposed proximate to the pinning surface layer over the photodiode region; a contact etch stop layer disposed over the photodiode region proximate to the first polarity charge layer, wherein the first polarity charge layer is disposed between the pinning surface layer and the contact etch stop layer such that first polarity charge layer cancels out charge having a second polarity that is induced in the contact etch stop layer; and a passivation layer disposed over the photodiode region between the pinning surface layer and the contact etch stop layer, wherein the passivation layer is disposed over the photodiode region between the first polarity charge layer and the contact etch stop layer.