Semiconductor photodetecting element

Abstract

Abstract PURPOSE:To improve excessive noise characteristic of a photodetecting element using Ge by employing the layer structure of p<+> in type only at the light acceptance layer region and employing pn structure at the guard ring region and its external region. CONSTITUTION:The light acceptance portion 11 consisting of the p<+> layer and the guard ring consisting of the p type layer are formed on the surface of n type Ge substrate 10. Moreover, the i (intrinsic) type constant field strength layer 13 is provided only between the region being in contact with the light sensible portion 11 and the substrate 100. According to this structure, while the guard ring effect is sufficiently maintained, the maximum field intensity in the region between the light acceptance portion and active layer can be lowered and the ionization coefficient in this region can be lowered. Thereby, the coefficient of contribution to multiplication of the holes is improved and low noise can be realized. As a result, an excessive noise of avalanche photo diode having the light acceptance wavelength region in the wavelength of 1mum can be improved.

Inventors

• 👤 Shuzo Kagawa
• 👤 修三 香川
• 👤 Takao Kaneda
• 👤 隆夫 金田
• 👤 Takashi Mikawa
• 👤 孝 三川

Bibliographic Details