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|Though our technology has its
origin in microelectronics our fabrication process differs substantially
from microelectronics standards. Purity reasons, the demand for a
fully doublesided process as well as large detector surfaces are
the main causes making our fabrication process neither adaptable
nor directly transferable into a conventional microelectronics process
unit. We are in the unique position to have a production line which
combines processes for ultra-pure silicon wafers with the small-scale
technology of very large system integration (VLSI) electronics. Except
ion implantation which is outsourced to service providers, processing
is done exclusively in our 1,000 square meter cleanroom.
A variety of technology key features distinguishes the MPG HLL from
|Design & Simulation|
The development of new detector concepts
requires a deep insight into device physics and technology. The new
device ideas have to undergo a thorough examination through detailed
simulations of the fabrication process as well as the electrical behaviour before
becoming structures in silicon. A profound detector simulation
is mandatory to reduce the number of fabrication cycles until the
final application in an experiment. All silicon detectors invented,
designed, fabricated and tested at the MPG HLL are optimized by means
of two and three dimensional device and process simulation.
|The need for bigger and faster multi channel X-ray detectors generates ever growing amounts of data. Deploying modern integrated electronics is required to build an adequate data acquisition system. It has to control the detector, to process analog data, to convert the analog signals into digital values and store data in computer memory. Algorithms are working on raw data and generating real images and spectra.||
|A challenging part of data
acquisition is the extraction of an information signal from a noisy
detector output which is usually carried out by analog filtering
stages integrated in one silicon chip. To combine the various components
of electronics sophisticated printed circuit boards and delicate
mountings are necessary. We improve our detector developments by
the design of readout electronics. In cooperation with partners the
MPG HLL integrates complex working detector systems.
|Within these areas there are the following research topics:|
|Silicon Strip Detectors|
|Silicon strip detectors were the first devices using the lithographic capabilities of microelectronics to produce a detector with high position resolution. A strip detector is an arrangement of strip like shaped implants acting as charge collecting electrodes. Placed on a low doped fully depleted silicon wafer these implants form a one-dimensional array of diodes. By connecting each of the metalized strips to a charge sensitive amplifier a position sensitive detector is built.|
|Two dimensional position measurements
can be achieved by applying an additional strip like doping on the
wafer backside by use of a double sided technology.
[more... PDF 151kB]
|Silicon Drift Detectors – made by MPG HLL|
|The development of Silicon Drift Detectors (SDDs) was one of the first activities in the MPG HLL. E. Gatti and P. Rehak were visiting the MPG für Physik just after their invention and inspired the local researchers. But it took about 15 years after the first publications until the first units were getting an industrial product.|
|Silicon drift detectors
have been used in many scientific fields: astrophysics, high energy
physics, material research, medicine, synchrotron radiation research
and solid state physics – to mention a few. In addition
to their use in basic research, SDDs are offered as spectrometers
for industrial applications.
[more... PDF 268 kB]
|The pnCCDs have been developed for the precise detection of photons, the visible and near infrared light, UV light, and X-rays as well as particles, such as minimum ionizing particles, electrons, protons, Alpha particles etc. pnCCDs measure the arrival time of the radiation with a precision of milliseconds, the energy of X-rays and particles with a precision of approximately 100 eV, if fully stopped in the silicon and their position within a range of a few micrometers.|
pnCCD detectors have responsive surfaces of the order of 10 cm².
The sensitive volume can be as thick as 1 mm, allowing for an efficient
detection of X-rays up to 50 keV.
[more... PDF 189 kB]
|DEPFET Active Pixel Sensors|
|Being the most consequent application
of the principle of sideward depletion, the combined detector-amplifier
structure DEPFET is one of the most advanced concepts in the MPG HLL
portfolio. DEPFET structures can be used as building blocks for a large
variety of different devices ranging from optical photon sensors to
X-ray imagers and particle trackers. Due to their extremely low detector
capacitance they exhibit excellent signal-to-noise ratio and energy
resolution. Currently, DEPFET based active pixel detectors are developed
for X-ray astronomy, planetology and particle physics.
[more... PDF 218 kB]
|Avalanche Amplifying Devices|
|Arrays of avalanche photo diodes operated in Geiger mode are forming so called Silicon Photomultiplier (SiPM). MPG HLL is developing SiPMs in which the fill factor of those devices is maximized as the passive components needed for the successful operation of those devices are placed in the bulk underneath the sensitive region - SiMPl concept.
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