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

Claim 3:
4. 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 a region of the core layer sandwiched between the first and second Si slabs operates as an amplification layer,
wherein an electric field applied to a gap between the first and second Si slabs is stronger than an electric field applied to a gap between the Ge region and the second Si slab and causes avalanche amplification,
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 region of the core layer is not formed immediately below the region in which the core layer and the Ge layer are in contact with each other.