Apparatus and method for image sensor with carbon nanotube based transparent conductive coating

A backside illuminated image sensor having a reduced part count, comprising:

• a substrate having a front surface and a back surface;
• an array of light sensitive pixels formed in the front surface of the substrate, each pixel including at least one photodiode;
• a carbon nanotube conductive coating disposed over the back surface of the substrate to facilitate applying a uniform bias voltage to respective portions of the back surface of the substrate in electrical contact with each photodiode in the array of pixels;
• the carbon nanotube conductive coating comprising carbon nanotubes embedded in a carrier with carbon nanotubes characteristics determining an optical absorption spectra, the carbon nanotube characteristics and a thickness of the carbon nanotube conductive coating being selected so that the carbon nanotube conductive coating is at least semi-transparent at each wavelength of visible light that the array of light sensitive pixels is designed to detect;
• the carbon nanotube characteristics being further selected so that the carbon nanotube conductive coating acts as a wavelength selective optical filter for backside illumination of the array of pixels to filter at least one deleterious wavelength of light that degrades performance of the backside illuminated image sensor.