| 摘要 |
There is provided a semiconductor photodetector which comprises (i) an InP substrate( 1 ), (ii) an optical waveguide( 5 ) having an N-type semiconductor layer( 32 ) formed on the InP substrate( 1 ), an optical waveguide core layer( 3 ) formed on a partial area of the N-type semiconductor layer( 32 ), and an upper cladding layer( 4 ) formed on the optical waveguide core layer( 3 ), and (iii) an avalanche photodiode( 17 ) constructed by forming a photo absorbing layer( 33 ), a heterobarrier relaxing layer( 34 ), an underlying layer( 14 a) of a N-type field dropping layer( 35 ), an overlying layer( 14 b) of the N-type field dropping layer( 35 ), a carrier multiplying layer( 36 ), and a P-type semiconductor layer( 37 ) in sequence on another area of the N-type semiconductor layer( 32 ), and coupled to the optical waveguide( 5 ), wherein a side surface of the underlying layer( 14 a) of the N-type field dropping layer( 35 ) comes into contact with a side surface of the optical waveguide core layer( 3 ), and a part of the overlying layer( 14 b) of the N-type field dropping layer( 35 ) is formed on the optical waveguide core layer( 3 ).
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