Ge—Si P-I-N photodiode with reduced dark current and fabrication method thereof

US9287432B2 · kind B2 · utility

Assignee

• SiFotonics Technologies Co., Ltd. · KY

Inventors

• Tuo Shi · 安丰镇, CN
• Liangbo Wang · Beijing, CN
• Pengfei Cai · Beijing, CN
• Ching-yin Hong · Lexington, US
• Mengyuan Huang · Cupertino, US
• Wang Chen · Beijing, CN
• Su Li · Beijing, CN
• Dong Pan · Taipei, TW

Key dates

• Filing date: Jul 23, 2014
• Grant date: Mar 15, 2016
• Expiry date: Jul 23, 2034

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/547

Abstract

Various embodiments of a germanium-on-silicon (Ge—Si) photodiode are provided along with the fabrication method thereof. In one aspect, a Ge—Si photodiode includes a doped bottom region at the bottom of a germanium layer, formed by thermal diffusion of donors implanted into a silicon layer. The Ge—Si photodiode further includes a doped sidewall region of Ge mesa formed by ion implantation. Thus, the electric field is distributed in the intrinsic region of the Ge—Si photodiode where there is low dislocation density. The doped bottom region and sidewall region of the Ge layer prevent electric field from penetrating into the Ge—Si interface and Ge mesa sidewall region, where a large amount of dislocations are distributed. This design significantly suppresses dark current.