Circuit and Device Technologies for CMOS functional Image Sensors

Circuit and device technologies for CMOS-based functional image sensors are reviewed and discussed. A key device technology that enhances the image quality of CMOS image sensors to be comparable to or even better than the CCD is a pinned photo diode. However, the performance of the CMOS image sensors also largely owes to the design of readout circuits. Several examples that successfully achieve the extreme performance using circuit techniques are reviewed in the aspects of sensitivity, noise, dynamic range and speed. For special functions such as 3-dimensional imaging, the development of new device technologies is also particularly important. As an example, a time-of-flight range finding CMOS imager with a modified CMOS process and a special pixel structure is presented