Transfer printing for heterogeneous silicon PICs

Photonic integrated circuits (PICs), implementing optical functions such as light generation, modulation, routing and detection on a single chip, are emerging as a powerful platform to realize miniaturized optical systems. These chips find applications in various fields, ranging from high-speed optical transceivers to disposable biosensors, LiDARs for detection and ranging, spectroscopic analytical sensors, etc. Silicon photonics is the field that is using silicon fabrication technologies, developed over the last decades for advanced electronic integrated circuits, to realize PI Cs. Using this approach advanced PICs can be realized on 200 mm or 300 mm wafers in high volume and at low cost. On the silicon photonics platform many device structures are readily available: Si or SiN waveguides, micro-heaters for tuning/switching, Si or Ge based modulators and photodetectors. However, other optical functions such as light generation require the integration of III-V semiconductors on the silicon wafers. This can be realized using different approaches ranging from hybrid assembly over die-towafer bonding to monolithic integration. Every approach has its advantages and disadvantages. An interesting approach that we are developing is the use of microtransfer- printing technology for the integration of III-V semiconductor devices on a silicon photonic wafer, which is a scalable and minimally-invasive approach.