| abstract |
A photodetection semiconductor device is constructed in such a manner that a photodiode light absorbing layer includes an Si/SiGe super-lattice layer (6), which forms a layer in parallel with the surface of a silicon substrate (1), and upper and lower P type low Ge concentration SiGe epitaxial layers (5) and (7), which sandwich the Si/SiGe super-lattice layer between them and contain Ge lower than a Ge content in the Si/SiGe super-lattice layer, a highly dense P+ type Si contact layer (8) is directly formed on the upper SiGe epitaxial layer (7) and a highly dense N+ type epitaxial layer (2) is formed immediately below the lower SiGe epitaxial layer (5). Preferably, Ge concentration in each of the upper and lower SiGe epitaxial layers (5) and (7) is set to be at least 1% or higher. |