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US 5,475,256 AGranted
Opto-electronic integrated circuit
AssigneeSumitomo Electric Industries, Ltd.
InventorsSosaku Sawada, Goro Sasaki, Hiroshi Yano
Life of this patent
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Abstract
An opto-electronic integrated circuit is arranged to comprise a photodetector and a tunnel emitter bipolar transistor for first-stage amplification of a current generated in the photodetector, as formed on a substrate. The tunnel emitter bipolar transistor can be operated at high speed and has a high amplification factor, so that noise due to the base current can be reduced upon amplification of the current generated in the photodetector by light detection.
Claims13
An opto-electronic integrated circuit comprising:
- a semi-insulating substrate;
- a photodetector having a light receiving portion formed above said substrate and made of a first semiconductor material;
- and
- a tunnel emitter bipolar transistor formed above said substrate, said tunnel emitter bipolar transistor including a base portion made of a second semiconductor material having a first conduction type, a tunnel barrier portion formed in contact with said base portion and made of a third semiconductor material, an emitter portion formed in an opposite-side region of said tunnel barrier portion to said base portion and made of a fourth semiconductor material having a second conduction type, and a collector portion formed in an opposite-side region of said base portion to said tunnel barrier portion and made of a fifth semiconductor material having said second conduction type, wherein a bandgap value of said third semiconductor material is larger than those of said second semiconductor material and said fourth semiconductor material;
- wherein said photodetector and said tunnel emitter bipolar transistor are formed in a monolithic manner.
2 more elements
An opto-electric integrated circuit comprising:
- a semi-insulating substrate;
- a photodetector having a light receiving portion formed above said substrate and made of a first semiconductor material, wherein said photodetector is an avalanche photodiode;
- and
- a tunnel emitter bipolar transistor formed above said substrate, said tunnel emitter bipolar transistor including a base portion made of a second semiconductor material having a first conduction type, a tunnel barrier portion formed in contact with said base portion and made of a third semiconductor material, an emitter portion formed in an opposite-side region of said tunnel barrier portion to said base portion and made of a fourth semiconductor material having a second conduction type, and a collector portion formed in an opposite-side region of said base portion to said tunnel barrier portion and made of a fifth semiconductor material having said second conduction type;
- wherein said photodetector and said tunnel emitter bipolar transistor are formed in a monolithic manner.
2 more elements
Dependencies are inferred from the claim text.