A pixel array of an image sensor includes multiple red, green, blue and panchromatic pixels. The red, green and blue pixels are formed on a substrate during a first process. Planarization material is deposited to form the panchromatic pixels on the substrate and to form a planarization layer on the red, green and blue pixels during the same second process subsequent to the first process. The planarization material of the panchromatic pixels and the planarization layer is characterized in high transmittance and high aspect ratio.