Patent ID: 11973159
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 4:
5. A photodetector comprising:
a silicon (Si) substrate;
a lower clad layer formed on the Si substrate;
a core layer formed on the lower clad layer, the core layer including a waveguide layer configured to guide signal light, and including a first Si slab doped with first conductive impurity ions and a second Si slab doped with second conductive impurity ions;
a germanium (Ge) layer formed on the core layer, the Ge layer configured to absorb light and including a Ge region doped with the first conductive impurity ions;
an upper clad layer formed on the core layer and the Ge layer; and
electrodes respectively connected to the first and second Si slabs and the Ge region,
wherein the first Si slab is formed immediately below a region in which the core layer and the Ge layer are in contact with each other, and the two second Si slabs are formed in a region other than a region immediately below the region in which the core layer and the Ge layer are in contact with each other,
wherein a region of the core layer sandwiched between the first and each of the two second Si slabs operates as an amplification layer which is formed in two portions to extend over a line immediately below two facing sides of the region in which the core layer and the Ge layer are in contact with each other, and the same electric field is applied to each of the two portions,
wherein an electric field applied to each of the region of the core layer sandwiched between the first and the two second Si slabs that is stronger than the electric field applied to each of a region of the core layer sandwiched between the Ge region and the second Si Slabs and causes avalanche amplification.