On January 31, Belgium-based semiconductor research hub Imec announced that it demonstrated co-integration of its high-quality silicon nitride waveguide technology with its silicon photonics platform—without performance degradation of the high-bandwidth active devices. An important upgrade for imec's silicon photonics platform, the result enables the synthesis of high-quality wavelength-selective devices and other optical passive functions that benefit from accurate optical phase control, meeting market demands for optical transceivers for datacom, LiDAR, and other applications.
Low propagation loss, accurate phase control, low-loss light coupling, lower thermal variation, and high-power handling are some of the reasons why adding a high-quality silicon nitride (SiN) boosts silicon photonics integrated circuits (PIC). High-quality SiN layers achieving low optical losses and excellent control over the material properties, such as thickness and refractive index variability, are crucial for improving the energy efficiency of Si-based optical transceivers. Since such high-quality SiN layers are deposited by the low-pressure chemical vapor deposition (LPCVD) method at elevated temperatures, it is vital to avoid degrading the performance of the co-integrated baseline Si and Ge devices.
Imec has tackled those integration challenges within its silicon photonics platform "iSiPP," which is available for industrial partners. Thanks to various engineering updates and changes in the process flow, imec has, for example, shown a more than four times reduction of the variability of the resonant wavelength of SiN-based micro-rings compared to the same device made with lower quality PECVD silicon nitride, currently used in the imec platform, without degrading the co-integrated active devices.
According to Philippe Absil, vice president at imec: "We are excited to have achieved this major upgrade of our silicon photonics platform. The ability to co-integrate high-quality SiN devices with our baseline technology is important to broaden our offering to our partners who can now consider system simplification with single PIC solutions to combine active and SiN passive functions."
