Pin semiconductor light receiving device.

摘要

A PIN semiconductor light receiving device includes a light absorbing layer (3), a cap layer (4) provided on the light absorbing layer, and a conduction region (5) of a conduction type different from that of the cap layer which is formed in a predetermined depth of the cap layer. The bandgap energy of the cap layer is increased as the distance from the boundary interface between the cap layer and the light absorbing layer is increased, continuously or in a step-wise manner. Consequently, a PIN semiconductor receiving device of high speed response can easily be fabricated without the necessity of controlling the position of a p-n junction to high precision.