Heterogeneously integrated InGaP/Si waveguides for nonlinear photonics.

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Heterogeneous integration of III-V semiconductors with silicon is crucial for merging photonics and electronics.
• Existing methods require high temperatures or complex interfacial layers due to III-V native oxides.
• CMOS processing compatibility is a key challenge in semiconductor integration.

Purpose of the Study:

• To present a novel, low-temperature molecular bonding technique for III-V semiconductors on silicates.
• To demonstrate the successful transfer of Indium Gallium Phosphide (InGaP) waveguides.
• To assess the viability of this integration method for non-linear optics applications.

Main Methods:

• Molecular bonding of structured III-V semiconductors (InGaP waveguides) onto silicon thermal oxide at 150 °C.
• Experimental verification of waveguide transfer with varying widths (4.65, 2.6, 1.22 μm).
• Post-processing to implement double-inverse tapers and testing for non-linear optics via second-harmonic generation.

Main Results:

• Successful transfer of 235 nm thick, 2 mm long InGaP waveguides onto a 4 μm thick Si thermal oxide.
• Demonstrated compatibility with optional cladding (SX AR-N 8200.18) and non-cladded structures.
• Verified the quality of the bonding interface and its suitability for non-linear optics, evidenced by modal phase-matched second-harmonic generation.

Conclusions:

• The developed molecular bonding technique enables low-temperature heterogeneous integration of III-V semiconductors on silicates.
• This method is compatible with CMOS processing temperatures and offers minimal processing requirements.
• The integrated structures show promise for advanced photonic and non-linear optical applications.