An image sensor pixel includes one or more photodiodes disposed in a semiconductor layer. Pixel circuitry is disposed in the semiconductor layer coupled to the one or more photodiodes. A passivation layer is disposed proximate to the semiconductor layer over the pixel circuitry and the one or more photodiodes. A contact etch stop layer is disposed over the passivation layer. One or more metal contacts are coupled to the pixel circuitry through the contact etch stop layer. One or more isolation regions are defined in the contact etch stop layer that isolate contact etch stop layer material through which the one or more metal contacts are coupled are coupled to the pixel circuitry from the one or more photodiodes.