β-SiC-on insulator waveguide structures for modulators and sensor systems

In this work waveguide structures using the cubic polytype of SiC are analyzed. The β-SiC-on-insulator wageguides were fabricated by two different methods. In the first case, a technological process similar to that used for SIMOX material was used, a buried SiO₂ layer being formed by high-energy (2 MeV) ion implantation of oxygen in SiC/Si wafers. For the second case, the heteroepitaxy of SiC on SOI (SIMOX) wafers was used. The losses of the waveguides have been measured at 0.633, 1.3 and 1.55 μm in both TE and TM polarization and a detailed analysis and interpretation of the different loss mechanisms is presented. Using these two types of waveguides we have designed waveguide modulators using the Pockels effect. A 2D semiconductor device simulator was used to determine the electric field configuration in a double-Schottky diode structure and the local modulation of the refractive index was used to determine the effective index modulation of the guided mode. Optical simulations were performed using the spectral index and the effective index methods. Different 2D geometries are analyzed and the material parameters needed for fabricating such a device are determined. Such devices have potential for high-speed Si-based photonic devices compatible with silicon technology.