Reliability of Emerging High-Speed Silicon Photonic Modulators

Recent advances in cloud computing, artificial intelligence training, and high-performance computing systems push the demand for data transmission rates. Optical interconnects offer a more sustainable alternative to the currently used copper-based interconnects. While Optical I/O has been used in long-distance, undersea data communications, recent research focuses on short-distance, high-speed communications for data center and on-chip applications. The key enabler is silicon photonics, which leverages the mature silicon-based semiconductor manufacturing technology to miniaturize optical components and combine them into a photonic integrated circuit (PIC). A key component in a PIC is the high-speed semiconductor modulator [1], which transforms electrical data into optical signals. This PhD study will investigate the reliability of the modulators for these advanced applications.

Silicon photonic modulators operate under a strong electric field and are irradiated with high-power laser light, which may introduce a reliability concern. This can lead to device performance changing over operational time, ultimately causing a malfunction in a PIC. It can be caused by defects in the device, either after fabrication or during reliability testing. The properties of these defects, their interactions with electrons/photons, and how they degrade device performance over time are critical to the reliability. However, there is little fundamental understanding of the reliability and degradation mechanisms of these modulators.

The purpose of this PhD topic, therefore, is to systematically investigate the fundamental degradation physics and related defect kinetics of emerging high-speed silicon photonic modulators fabricated at imec. The focus will be on Ge/Si-based modulators, with possible extension to group III-V-based modulators.

[1] Rahim, Abdul, et al. "Taking silicon photonics modulators to a higher performance level: state-of-the-art and a review of new technologies." Advanced Photonics 3.2 (2021): 024003-024003. DOI: https://doi.org/10.1117/1.AP.3.2.024003

What will you do:

• Perform in-depth electro-optical characterization to monitor degradation behaviors and develop new failure-mechanism-oriented test sequences, where necessary.
• Conduct systematic analysis (statistical data analysis, TCAD simulations, comparative studies, etc.) to better understand the underlying reliability physics.
• Develop physics-based electro-optical models to describe experimental data, which will enable accurate prediction of device lifetime at operating conditions.
• Using advanced material analysis techniques (such as TEM/EDS, SSRM, electron-beam-based nanoprobing, etc., collaborating with expertise at imec) to verify degradation mechanisms.
• Provide constant feedback (from a reliability perspective) to device designers and process engineers in imec’s optical I/O program. Work closely with imec’s industrial partners worldwide.
• Opportunities for publishing in high-impact journals and presenting at international conferences.

Who you are:

• You have a solid background in electrical engineering, nanotechnology, physics, or material science. Prior knowledge in semiconductor device physics, optoelectronics, and statistics is a plus.
• Having preliminary experience in one (or more) of the fields listed here is advantageous, but not mandatory. (i) Hands-on device characterization, (ii) Data analysis, (iii) Compact modeling, and (iv) TCAD simulations.
• You can work independently, having a strong feeling of responsibility. On top of that, you are a team player who enjoys communicating/cooperating with people.
• ‘A PhD is a marathon, not a sprint’. You have sufficient motivation, curiosity, and patience to devote yourself to solving fundamental research questions. You pay attention to details and are open to feedback/ideas from different perspectives.

Feel free to reach out to this email if you would like to learn more about this PhD opportunity: ping-yi.hsieh@imec.be