High performance GeSi avalanche photodiode operating beyond Ge bandgap limits

US8786043B2 · kind B2 · utility

Assignee

• SiFotonics Technologies Co., Ltd. · KY

Inventors

• Mengyuan Huang · Cupertino, US
• Pengfei Cai · Beijing, CN
• Dong Pan · Taipei, TW

Key dates

• Filing date: Sep 6, 2012
• Grant date: Jul 22, 2014
• Expiry date: Sep 6, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F30/2255

Abstract

Avalanche photodiodes (APDs) having at least one top stressor layer disposed on a germanium (Ge)-containing absorption layer are described herein. The top stressor layer can increase the tensile strain of the Ge-containing absorption layer, thus extending the absorption of APDs to longer wavelengths beyond 1550 nm. In one embodiment, the top stressor layer has a four-layer structure, including an amorphous silicon (Si) layer disposed on the Ge-containing absorption layer; a first silicon dioxide (SiO2) layer disposed on the amorphous Si layer, a silicon nitride (SiN) layer disposed on the first SiO2 layer, and a second SiO2 layer disposed on the SiN layer. The Ge-containing absorption layer can be further doped by p-type dopants. The doping concentration of p-type dopants is controlled such that a graded doping profile is formed within the Ge-containing absorption layer to decrease the dark currents in APDs.