Patent ID: 9705023
Date: 2017-07-11
CPC Classifications: G02B,H01L,Y02E

Claim:
1. An avalanche photodiode (APD) comprising: a germanium-on-insulator (GeOI) substrate; an intrinsic-germanium (I—Ge) absorption layer disposed on the GeOI substrate and configured to: a second p-type silicon-germanium (SiGe) layer disposed on the I—Ge absorption layer; a first p-type SiGe layer disposed on the second p-type SiGe layer, wherein a germanium (Ge) content in either the first p-type SiGe layer or the second p-type SiGe layer is less than or equal to 20%; a first silicon dioxide (SiO a second SiO a first SiGe layer disposed on the first SiO a second SiGe layer disposed on the first SiO a first taper type silicon (Si) waveguide layer disposed on the second SiO a second taper type Si waveguide layer disposed on the first SiGe layer; a heavily-doped n-type Si multiplication layer disposed on the second SiGe layer and the first p-type SiGe layer; a cathode electrode is disposed on the heavily-doped n-type Si multiplication layer; and anode electrodes are disposed on the GeOI substrate, wherein the first taper type Si waveguide layer, the second taper type Si waveguide layer, the first SiGe layer, and the second SiGe layer form an evanescent wave coupling structure, wherein the first SiGe layer, the second SiGe layer, the first p-type SiGe layer, and the second p-type SiGe layer form a taper type structure, and wherein the first SiGe layer, the second SiGe layer, the first p-type SiGe layer, the second p-type SiGe layer, and the I—Ge absorption layer form an evanescent wave coupling structure.