Pixel Conductor Layout for High-Frequency Distance Sensing

The pixel structure is segmented into distinct functional regions: a photoelectric conversion unit for generating carriers, a light receiving region for collecting photons, and charge accumulation regions for storing carriers. This segmentation allows each region to be optimized independently, enabling efficient charge distribution even at high drive frequencies by providing dedicated pathways and storage areas that prevent charge loss.

Different regions within the pixel are assigned different impurity densities to optimize their specific functions. The photoelectric conversion unit has a base impurity density, while the charge accumulation regions have higher impurity densities to enhance carrier collection efficiency. This local quality differentiation ensures that each region performs its function optimally, maintaining charge distribution efficiency at high drive frequencies.

The charge accumulation regions are positioned and configured in advance to receive and store carriers generated during the light receiving phase. By pre-positioning these accumulation regions with appropriate impurity densities and electrical potentials, the system ensures that carriers are efficiently collected and stored before the next drive cycle begins, maintaining reliable charge transfer even at increased drive frequencies.

The charge accumulation regions act as intermediary structures between the light receiving region and the output circuitry. These regions with higher impurity densities serve as buffer zones that facilitate efficient carrier collection and transfer, mediating the charge transfer process to maintain reliability despite higher drive frequencies that would otherwise cause charge loss.