We seek to answer these questions. What drives technological progress forward? Precision and innovation play a pivotal role in not only meeting but surpassing consumer expectations. ActLight places a strong emphasis on these principles, particularly in the realm of advancing light sensing technology. Within the cutting-edge CMi cleanroom facilities in Lausanne, Switzerland, our research endeavors take shape, serving as the cornerstone of our commitment to innovation. This article delves deep into the intricate processes involved in the development of ActLight’s Dynamic PhotoDetector (DPD), in this instance, reducing the internal capacitance of the DPDs and increasing therefore their sensitivity. In this purpose, a new technique for better carrier collection inside the device is designed. We go on to highlight why DPD offers profound benefits to companies operating within the wearable tech industry. Specifically, we explore the significant impact of our DPD technology on smartwatches, illuminating its potential to revolutionise this sector
The Two Faces of Dynamic PhotoDetector Technology
ActLight has developed two versions of its Dynamic PhotoDetector (DPD):
- Embedded DPD: Based on CMOS technology, this version integrates seamlessly with standard semiconductor processes, offering a cost-effective solution for a wide range of applications.
- Standalone DPD: Built in-house using a custom process at the Cmi cleanroom, this version allows for complete control over process parameters, doping profiles, and sizing, with dimensions ranging from hundreds of micrometers up to 1 cm.
Research at EPFL-CMI: Enhancing Sensitivity and Precision
The core objective of our recent work at CMI has been to reduce the internal capacitance of the DPDs, thereby increasing their sensitivity. This is particularly crucial for applications in low-light conditions, such as heart rate monitoring in smartwatches. To achieve this, a new technique for better carrier collection inside the device has been designed. Here’s a detailed look at the process:
- Silicon Wafer Preparation: The journey begins with silicon wafers treated by an external company, which grows epitaxial layers with well-defined p/n doping profiles. This ensures a high-quality starting material essential for the performance of our DPDs.
- Backend Processing: ActLight performs the backend processing at EPFL-CMI, employing several advanced techniques:
- Advanced Lithography: Due to the small resolution of some patterns, the design is translated to a mask and lithography steps are performed using a Deep Ultraviolet (DUV) stepper with a 4x optical shrink. This ensures high resolution and precision, maintaining the high standards expected of Swiss-made technology.
- Wafer Protection and Dicing: After fabrication, a thick resist layer is spin-coated on the wafer to protect the DPDs from dust during the dicing step. Finally, the resist is stripped at the chip level, making the DPDs ready for placement and bonding on PCBs.
The Strategic Importance for Wearable Technology
ActLight’s rigorous research and fabrication process result in DPD technology that stands out for its high precision, energy efficiency, and cost-effectiveness. Here’s why this technology is crucial for the future of wearable technology:
- High Precision: Essential for Swiss watch companies renowned for meticulous craftsmanship, our DPDs offer unparalleled accuracy and performance, ensuring reliable heart rate and blood oxygen measurements even in low-light conditions.
- Swiss-Excellence: Leveraging the reputation of Swiss engineering, our technology assures quality and performance, aligning with the high standards of the watch industry.
- Enhanced Sensitivity: Our advancements in reducing internal capacitance result in better signal-to-noise ratios, leading to more precise biometric measurements. This is ideal for smartwatches, where accurate health monitoring is critical.
- Energy Efficiency: Operating at low voltages, our DPDs minimize power consumption, making them perfect for integration into compact, energy-efficient smartwatches.
- Cost-Effectiveness: By using standard CMOS technology and minimizing silicon area, we keep manufacturing costs low, providing a competitive edge in the market.
Learn more about DPD.
Strategic Benefits for Smartwatch Manufacturers
Integrating ActLight’s DPD technology brings several key advantages to manufacturers. Firstly, our DPDs deliver precise heart rate and blood oxygen monitoring, significantly improving the reliability and value of smartwatches. The high-quality performance, driven by Swiss precision engineering, helps companies differentiate themselves in a competitive market.
Moreover, our DPDs operate at low voltages, making them highly energy-efficient and perfect for compact, energy-saving smartwatches. The use of standard CMOS technology and minimized silicon area also ensures cost-effective production. Additionally, with our robust intellectual property and patents, companies can integrate our technology smoothly and avoid potential legal complications.
Conclusion
By continuously refining our processes and focusing on innovation, we aim to provide smartwatch manufacturers with cutting-edge solutions that enhance product performance and reliability. Our commitment to Swiss precision ensures that our DPDs set new benchmarks in the industry, offering significant advantages in terms of sensitivity, energy efficiency, and cost-effectiveness. As we continue to push the boundaries of what is possible in heart-rate monitoring, we invite you to read more on our website or reach out directly to our CCO, Roberto Magnifico.
For more information on ActLight’s technology and its potential applications, visit our website and explore our latest white papers and research findings.
