High speed imager developments at imec
Piet De Moor
imec, Leuven, Belgium Abstract
Imec has a unique broad set of competences under one roof, from 200 (and 300 mm) wafer size CMOS fabrication facilities, device design and simulation know-how, mixed analog/digital circuit design, and even up to the system level. The combination of all these allow us to perform research and development but also custom development (and low volume manufacturing) of new ultra-fast imaging devices. Regarding process technology, backside illumination helps in collecting all photons. However, special epitaxial structures are required to collect them in a very short time, and to be able to store them. Dedicated micro-lens technologies will further reduce the collection time. Very fast distribution of arriving photo-electrons among different storage nodes will enable high frame rates but also enable determination of the arrival time, resulting in e.g. depth sensing applications. Of course this requires extremely fast analog electronics and fast analog-to-digital conversion, ideally at a reasonable power consumption. Stacking of different active CMOS chips on top of each other allows a vertical fast data flow. An overview of the different relevant technologies for ultra-fast imaging will be given as well as example imager developments for burst and continuous mode operation.