An image sensor array includes a substrate layer, a metal layer, an epitaxial layer, a plurality of imaging pixels, and a contact dummy pixel. The metal layer is disposed above the substrate layer. The epitaxial layer is disposed between the substrate layer and the metal layer. The imaging pixels are disposed within the epitaxial layer and each include a photosensitive element for collecting an image signal. The contact dummy pixel is dispose within the epitaxial layer and includes an electrical conducting path through the epitaxial layer. The electrical conducting path couples to the metal layer above the epitaxial layer.