High performance, waveguide integrated Ge photodetectors

Abstract

Photonic systems based on complementary metal oxide semiconductor (CMOS) technology require the integration of passive and active photonic devices. The integration of waveguides and photodetector is one of the most important technologies. We report a Ge p-i-n photodetector that is monolithically integrated with silicon oxynitride and silicon nitride waveguides. All processes and materials are CMOS compatible and can be implemented in the current integrated circuit process technology. The small size of the devices results in low absolute dark current. The waveguidecoupled Ge devices show high efficiency (~90%) over a wide range of wavelengths well beyond the direct band gap of Ge, resulting in a responsivity of 1.08 A/W for 1550 nm light. The device speed of 7.2 GHz at 1V reverse bias is strongly affected by the capacitance of the probe pads. The high-performance of the devices at low voltage ( </= 1V) facilitates the integration with CMOS circuits.

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

“…These properties make Ge one of the most promising materials for CMOS compatible photonic components including near-infra-red photodetectors [1][2][3][4] and, possibly, lasers [5][6][7] in the important spectral region of 1.3-1.6 lm. However, it is well known that conventional Ge heteroepitaxy on Si is complicated by the 4.2% difference in Ge and Si lattice constants.…”

High-speed Ge photodetector monolithically integrated with large cross-section silicon-on-insulator waveguide

“…This has fueled significant research and development work in this area in the past few years. [1][2][3][4][5][6][7][8][9][10][11] Many silicon-based active photonics components, such as high-speed modulators and Ge photodetectors [4][5][6][7][8][9][10] have been demonstrated on submicron waveguides. However, submicron SOI waveguides still suffer from high fiber coupling loss, high polarization dependent loss, and large waveguide birefringence and phase noise.…”

Low-Temperature Bonding for Silicon-Based Micro-Optical Systems

“…Ge-on-Si photodetector is an example of a monolithically integrated component ( Figure 13) [145]. Here, Si behaves as the waveguide that is interfaced to a Ge optical detector.…”