Filter-less vertical integrated RGB color sensor for light monitoring

A BiCMOS RGB color sensor for ambient light monitoring is presented. It can be used in applications like white balancing, color measurement and TFT monitor backlight control. The effect of different penetration depths in silicon for different wavelengths is used to determine the color of the incident light. The sensor is formed by three vertically stacked photodiodes - a shallow diode for blue, a middle diode for green and a deep diode for red light. The sensor is manufactured in standard BiCMOS technology using an epi-layer starting wafer. Thus this device can be easily integrated with RGB LED drivers or acquisition circuits into a single chip.