Hybrid mono-crystalline silicon and lithium niobate thin films [Invited]

The heterogeneous integration of silicon thin film and lithium niobate (LN) thin film combines both the advantages of the excellent electronics properties and mature micro-processing technology of Si and the excellent optical properties of LN, comprising a potentially promising material platform for photonic integrated circuits. Based on ion-implantation and wafer-bonding technologies, a 3 inch wafer-scale hybrid mono-crystalline Si/LN thin film was fabricated. A high-resolution transmission electron microscope was used to investigate the crystal-lattice arrangement of each layer and the interfaces. Only the H-atom-concentration distribution was investigated using secondary-ion mass spectroscopy. Highresolution X-ray-diffraction omega-2 theta scanning was used to study the lattice properties of the Si/LN thin films. Raman measurements were performed to investigate the bulk Si and the Si thin films. Si strip-loaded straight waveguides were fabricated, and the optical propagation loss of a 5-mu m-width waveguide was 6 dB/cm for the quasi-TE mode at 1550 nm. The characterization results provide useful information regarding this hybrid material.

Automated summary

By combining the advantages of silicon's excellent electronics properties and mature micro-processing technology with the excellent optical properties of lithium niobate, a potentially promising material platform for photonic integrated circuits has been created. A 3-inch wafer-scale hybrid mono-crystalline Si/LN thin film was successfully fabricated using ion-implantation and wafer-bonding technologies. Characterization techniques such as high-resolution transmission electron microscopy, secondary-ion mass spectroscopy, X-ray diffraction, and Raman measurements were used to investigate the crystal-lattice arrangement, H-atom-concentration distribution, and lattice properties of the Si/LN thin films. The optical propagation loss of Si strip-loaded straight waveguides at 1550 nm was found to be 6 dB/cm for the quasi-TE mode. The characterization results provide valuable information about this hybrid material platform.