Can you share with us your background in the image sensor industry and why you have decided to present at Image Sensors Americas 2019?
I started working on CMOS image sensors over 20 years ago. At the time, I was looking for solutions for pixel detectors for X-ray imaging. It was mainly hybrid detectors, but then I read the first papers about the modern CMOS sensors. It was a new whole lot of possibilities opening up for all sorts of imaging applications. In the early 2000, I started a CMOS sensor design group in a national laboratory in the UK and in 2015 we span off a company specialized in large area sensors. I was part of the executive team there for a couple of years before starting my own design house in 2017. The last two years have been very exciting and as the company is growing nicely, I thought it was a good moment to start sharing our experience at your conference. Since many years, I have been in the Advisory Board of IS Europe, but this will be my first time here in the US edition and I look forward to being on the other side of the Atlantic and meeting old and new colleagues in the industry.
You’ve been in this industry for some time – what progress have you seen with regard to sensor performance, particularly with the use in advanced applications, bio-medical, industrial etc. and what challenges lay ahead?
Looking at sensors for advanced applications, I think one of the most remarkable improvements has been in the noise levels. For advanced applications, users often require noise levels as low as possible. They can now buy imagers with noise levels close or lower than 1 electron of noise, close to the levels required for photon counting. Single photon avalanche detectors can give accurate timing information on single photons. They are finding more and more their way into 3D imaging applications, with SPAD being the detector of choice for flash lidar. On top of this, SPADs are being used for more advanced applications, for example in bio-medical applications to measure the lifetime of biomedical markers or the time of flight of photons in medical applications.
The advent of stacked imagers also allows alternative designs to be implemented. In stacked imagers, the different layers can be optimized in different ways: the sensing layer can be made in the best technology for the photon detection, and the other layers can have a different CMOS flavor, more suitable for the specific functions they have to cover. Stacked imagers are still fairly rare in advanced applications, possibly as the technology remains difficult to reach for non-consumer applications. The use of stacked technologies could help a lot in advanced applications, where performances are pushed to the limit in many directions, e.g. speed, time resolution or quantum efficiency. Having the possibility of optimizing the different layers in different ways could provide key advantages in many applications.
In the field of large area sensors for X-ray detection, I would also mention photon counting. It is a desired goal, which has not found a good solution yet. At IMASENIC we aim at achieving this goal with a cost-effective solution.
What opportunities does the scientific market provide to CMOS image sensor manufactures?
The scientific market, as well as other advanced applications markets, often provide sensing challenges, for example being able to detect light outside the visible region, being able to collect more information on the photons, like their timing, their wavelength or their polarization. Manufacturing companies can help in addressing these challenges. At IMASENIC, we work closely with foundries so that we can achieve the best sensing performance and fully exploit the characteristics of our designs.