Multi-storied photodiode CMOS image sensor for multiband imaging with 3D technology

Abstract

We demonstrated multiband imaging with a multi-storied photodiode CMOS image sensor (CIS), which comprises two individually functioning layered devices that achieve optimized images in different substrates bonded by 3D technology. The sensor is able to capture a wide variety of multiband images, which is not limited to conventional visible RGB (Red Green Blue) images taken with a Bayer filter or to invisible infrared (IR) images, at the same time without any color or image degradation even with an extra IR light source. Its wide range sensitivity enables us to select the specific narrow band light wave with specific optical filter in addition to visible RGB images. This wide selection of specific wavelengths of light is useful for specific applications like medical systems to identify pathological lesions and also enables additional functions on the same sensor to make such systems smarter, smaller, and cheaper than the conventional combination of IR imaging sensors with RGB image ones. A wide selection of multiband images is also possible with our device by modifying the top semiconductor layer thickness or changing the characteristics of a color filter on the top substrate to cover a wide range of application needs.