PHOTODIODE WITH A FIELD ELECTRODE FOR REDUCING THE SPACE CHARGE REGION

摘要

The photodiode device comprises a doped region (2) contiguous with a contact region (3) of the same conductivity type located at the substrate surface (1'), an appertaining anode or cathode connection (7, 11), a further contact region (5) of an opposite conductivity type at the substrate surface, and a further anode or cathode connection (8, 12). The contact region (3) is arranged at least on opposite sides of an active area of the substrate surface that covers the further contact region (5). A lateral pn junction (16) and an associated space charge region is formed at the substrate surface by a boundary of one of the contact regions, the boundary facing the other contact region. A field electrode (6) is arranged above the lateral pn junction, separated from the lateral pn junction by a dielectric material (10), and is provided with a further electrical connection (9, 13) separate from the anode and cathode connections. By the field electrode (6), the space charge region at the surface (1') is reduced and the peripheral dark current of the photodiode decreases considerably.