Lateral drift-field photodetector for high speed 0.35m CMOS imaging sensors based on non-uniform lateral doping profile
A novel photodetector concept for high charge transfer speed and low image lag is presented. The key feature of the so-called Lateral Drift-Field Photodetector (LDPD) is a lateral electric drift field inside the photoactive area of the device. This results in a significant acceleration of the charge collection compared to conventional diffusion based detectors and, therefore, this device is an ideal candidate for high speed applications like 3D Time-of-Flight imaging. Furthermore, the LDPD concept shows a superior noise performance as the charge collection node is decoupled from the readout node. The LDPD device was developed in a standard 0.35m CMOS process with only one additional mask step being necessary in order to implement the lateral doping gradient.