High-performance p⁺-InGaAs/i-InGaAs/n⁺-Si photodetector achieved by low-quality crystalline Ge interlayer wafer...

Area of Science:

• Semiconductor device fabrication
• Optoelectronics
• Materials science

Background:

• Fabricating high-quality Indium Gallium Arsenide (InGaAs) on Silicon (Si) heterojunctions is challenging due to lattice and thermal mismatches.
• Existing methods often result in defects, limiting device performance in photodetectors.
• Advanced integration of dissimilar materials is crucial for next-generation optoelectronic devices.

Purpose of the Study:

• To present a novel wafer bonding technique for fabricating high-quality InGaAs/Si heterojunctions.
• To demonstrate the effectiveness of a low-quality crystalline germanium (LC-Ge) interlayer in mitigating material mismatches.
• To characterize the performance of fabricated InGaAs/Si PIN photodetectors.

Main Methods:

• Utilized a low-quality crystalline germanium (LC-Ge) interlayer wafer bonding technique.
• Fabricated InGaAs/Si PIN photodetectors incorporating the LC-Ge interlayer.
• Characterized device performance, including dark current density, ideality factor, responsivity, and 3-dB bandwidth.

Main Results:

• Achieved a defect-free InGaAs/Si heterojunction interface, enhancing carrier transport.
• Demonstrated InGaAs/Si PIN photodetectors with low dark current density (0.24 mA/cm² at -2 V) and a near-unity ideality factor (1.09).
• Obtained high responsivity (0.75 A/W at 1550 nm) and a 3-dB bandwidth up to 24 GHz.

Conclusions:

• The LC-Ge interlayer effectively resolves lattice and thermal mismatch issues between InGaAs and Si.
• The fabricated InGaAs/Si PIN photodetectors exhibit excellent performance characteristics.
• This approach offers a promising pathway for advanced InGaAs/Si photodetector applications.