SEMICONDUCTOR LIGHT RECEIVING ELEMENT

摘要

PROBLEM TO BE SOLVED: To prevent leaking transmission light or the stray light of transmission light from coming in due to the incompleteness of WDM by installing the first absorbing layer of an InGaAsP on one side of a substrate and installing the second absorbing layer of the InGaAsP above the substrate and just below a light receiving layer. SOLUTION: An InGaAsP layer 67 is formed at the rear face of an n+-type InP substrate 57 as a first absorbing layer and a second n+-type InGaAsP light absorbing layer 58 and an n-type InGaAs light receiving layer 59 are epitaxially grown on the surface side of the substrate. The reception light A ofλ2 is made to pass through the absorbing layer 67, the substrate 57 and the absorbing layer 58 from the rear face and it reaches the depletion layer 62 of the light receiving layer 59. The depletion layer 62 absorbs it and a pair of electronic holes are generated. Most of leaking light B ofλ1, which enters from the rear face, is absorbed by the first n-InGaAsP absorbing layer 67. The second absorbing layer 58 absorbs the stray light C ofλ1 from obliquely below.