Advanced Course on Image Sensor Technology
October 27 - 28, 2016
. Grenoble, France
We recommend you to submit your preliminary or
firm registration at least 4 weeks before course start to ensure a
seat on the course.
PLEASE OBSERVE: In October 2016 a 2-day
version of this course will be given, Thursday-Friday October
27-28. The outline will be updated in June to suit the autumn
Highly sophisticated CMOS image sensors are key components of
modern cameras. Technology as well as device architectures are
optimized to obtain peak performance of the image sensor and the
camera system. The most advanced CMOS image sensors show pixel
sizes beyond 1 µm. The imagers demonstrate a light sensitivity
comparable to that of the human eye.
Another feature, the back-side illumination, is no longer limited
to high-end professional applications. In addition, the modern
camera systems can present a dynamic range of 120 dB or more. The
equivalent noise level is in the range of sub-electron noise. Even
if all these incredible features cannot be combined in one single
CMOS image sensor simultaneously, they will allow for new
technology breakthroughs and new imaging applications.
Furthermore, the image sensor fabrication technology is not yet
pushed to its ultimate limits. Image sensors make use of CMOS
technologies that are lagging 2 or 3 generations behind those of
digital integrated circuits or solid-state memories. Even more
interesting developments can thus be expected in the near future.
Will imagers ever outperform the human eye as far as light
sensitivity is concerned?
COURSE CONTENT AND OBJECTIVES
This is an advanced course focusing on the solid-state
image sensor technology. It is intended for the specialists in the
field. A very good background of digital imaging is needed to get
the most out of this course. It can be regarded as a continuation
#13 Digital Imaging: Image Capturing Image Sensors,
Technologies and Applications. The content is based on
comments, suggestions, and remarks received from previous
participants in courses #13 and
#14 Digital Camera Systems.
What is new in CMOS image sensor pixels after the introduction of
the pinned photodiode? The pinning layer created a real
breakthrough in CMOS imaging, but does the pixel development stop
with the pinned photodiode?
An interesting concept to create very small pixels is the
so-called shared pixel architecture, primarily based on pinned
photodiodes as well. Advantages and disadvantages of the shared
pixels will be discussed.
Global Shutter Pixels
The Rolling Shutter is still an issue in CMOS imagers that are
being used for instance in broadcast, machine vision, and other
applications. What are the alternatives in pixel design to turn the
rolling shutter into a global shutter? Pixels with 4, 5, 6, 7 and 8
transistors will be compared to each other.
Wide-Dynamic Range Pixels
Pixels are getting smaller and the specs on dynamic range are
becoming tighter. What kind of architectures can be implemented to
extend the dynamic range?
CMOS IMAGER SYSTEMS
Noise on Pixel Level
At present, the pixels and the in-pixel circuitry are the limiting
noise factors. From where is the remaining noise coming? What kind
of new developments can be expected? Topics such as Transfer Gate
noise, RTS noise and 1/f noise will be discussed.
Noise on System Level
Noise can be used as an interesting measurement tool in the
so-called Photon Transfer Curve method. Parameters such as
conversion gain, dynamic range, saturation level, noise floor,
quantum efficiency, PRNU can be deduced. If the method is performed
in darkness, dark current levels as well as DRNU can be measured.
Further elaboration of the method will explain that this technique
is not only a useful measurement tool but a diagnostic tool as
Back-side illumination to obtain extremely high quantum
efficiencies is becoming very popular. Several fabrication methods
will be compared. A crucial part of the technology is the
passivation of the backside of the sensors. The background of the
passivation issues will be highlighted.
In case of extremely low light level, the EM-CCD is a
very interesting and powerful image sensor. This device is
characterized by the fact that an electron multiplication stage is
included just before the output amplifier. In this way a gain can
be applied to the signal in the CCD without amplifying the noise of
the output stage. Equivalent noise levels of sub-electrons are
Sensing the third dimension (3D) is becoming more and more
important. The course will discuss one of the most appealing
techniques to measure the distance of object in front of the camera
lens by means of a non-contact method : time-of-flight (ToF).
The principle of ToF will be explained, as well as an analysis of
the accuracy will be given.
If time permits, the first and the second day will end with a
few calculations: for instance, a noise analysis of a pixel or a
calculation of the number of electrons in an illuminated pixel.
Said about the
course from previous participants:
"The practical examples implemented have helped me a lot
to finally understand the theoretical equations. Good lecture
notes, fresh up-to-date information, practical arrangements. Very
inspiring teacher. If any of my teachers at University had been
half as professional and inspiring I would have been a much happier