Patent attributes
A four-division photodetector where a formation process of an element isolation structure is simplified is provided. On a P-sub layer that is a common anode of PIN photodiodes (PIN-PD) for every partition, a high resistivity epitaxial layer that is an i layer of the PIN-PD is grown. At a boundary of the partitions, ion implantation is applied from a substrate surface to form an isolation region that is a P+ region. When a cathode region formed for every partition and the P-sub layer are reverse-biased to operate the PIN-PD, the isolation region is set at a ground potential together with the P-sub layer to operate as an anode. As a result, in the epitaxial layer at a position sandwiched between the isolation region and the P-sub layer, a potential barrier to electrons is formed. As a result, electrons generated owing to light absorption in the respective partitions can be inhibited from moving to adjacent partitions and element isolation can thus be realized.
