Hybrid Integration for Photonic Integrated Circuits (HIPIC)

In the field of telecommunications and data processing, there has been an increasing shift from electronic to photonic technologies. Photonic technologies, which use light to transmit and process information, offer faster, more efficient data transfer with less energy usage compared to traditional electronic methods. However, one of the biggest challenges faced in this transition is the fabrication of photonic components by using techniques similar to fabrication methods for electronics. Photonic chips or light sources are traditionally made from III-V and II-VI compounds, which are not compatible with the commonly used silicon-based CMOS fabrication process for electronics. This incompatibility has posed significant fabrication challenges and integration complications, leading to suboptimal solutions, such as off-chip light sources, or additional integration steps after CMOS fabrication. These solutions often compromise the precision, efficiency, and cost-effectiveness of the complete system.

Technology Description

Photonic integrated circuits (PICs) are powerful technical innovations designed to control light on a tiny chip for the purpose of advanced telecommunications and data management. Made with silicon or silicon-compatible materials, PICs are fabricated by using complementary metal-oxide-semiconductor (CMOS) techniques, widely adopted in the electronics industry. However, the usual light sources for PICs are made from materials traditionally incompatible with the silicon-based CMOS fabrication process. To overcome this challenge, a hybrid integration approach uses a recess in the PIC designed to house a non-silicon light source photonic chip securely. This integration not only allows the noncompatible chip to be added after the completion of the CMOS fabrication process but also enables detailed vertical and lateral alignment through the use of mechanical stops and fiducials built during the fabrication phase. Therefore, it is possible to flip-chip bond the photonic chip to the PIC with extreme precision.