48 research outputs found
Development of New 3D Pixel Sensors for Phase 2 Upgrades at LHC
We report on the development of new 3D pixel sensors for the Phase 2 Upgrades
at the High-Luminosity LHC (HL-LHC). To cope with the requirements of increased
pixel granularity (e.g., 50x50 or 25x100 um2 pixel size) and extreme radiation
hardness (up to a fluence of 2e16 neq cm-2), thinner 3D sensors (~100 um) with
electrodes having narrower size (~ 5 um) and reduced spacing (~ 30 um) are
considered. The paper covers TCAD simulations, as well as technological and
design aspects relevant to the first batch of these 3D sensors, that is
currently being fabricated at FBK on 6-inch wafers.Comment: 4 pages, 8 figures, 2015 IEEE Nuclear Science Symposium and Medical
Imaging Conferenc
First Production of New Thin 3D Sensors for HL-LHC at FBK
Owing to their intrinsic (geometry dependent) radiation hardness, 3D pixel
sensors are promising candidates for the innermost tracking layers of the
forthcoming experiment upgrades at the Phase 2 High-Luminosity LHC (HL-LHC). To
this purpose, extreme radiation hardness up to the expected maximum fluence of
2e16 neq.cm-2 must come along with several technological improvements in a new
generation of 3D pixels, i.e., increased pixel granularity (50x50 or 25x100 um2
cell size), thinner active region (~100 um), narrower columnar electrodes (~5
um diameter) with reduced inter-electrode spacing (~30 um), and very slim edges
(~100 um). The fabrication of the first batch of these new 3D sensors was
recently completed at FBK on Si-Si direct wafer bonded 6-inch substrates.
Initial electrical test results, performed at wafer level on sensors and test
structures, highlighted very promising performance, in good agreement with TCAD
simulations: low leakage current (<1 pA/column), intrinsic breakdown voltage of
more than 150 V, capacitance of about 50 fF/column, thus assessing the validity
of the design approach. A large variety of pixel sensors compatible with both
existing (e.g., ATLAS FEI4 and CMS PSI46) and future (e.g., RD53) read-out
chips were fabricated, that were also electrically tested on wafer using a
temporary metal layer patterned as strips shorting rows of pixels together.
This allowed a statistically significant distribution of the relevant
electrical quantities to be obtained, thus gaining insight into the impact of
process-induced defects. A few 3D strip test structures were irradiated with
X-rays, showing inter-strip resistance of at least several GOhm even after 50
Mrad(Si) dose, thus proving the p-spray robustness. We present the most
important design and technological aspects, and results obtained from the
initial investigations.Comment: 8 pages, 7 figures, 2016 IWORI
Development of 3D-DDTC pixel detectors for the ATLAS upgrade
We report on the development of n-on-p, 3D Double-Side Double Type Column
(3D-DDTC) pixel detectors fabricated at FBK-irst (Trento, Italy) and oriented
to the ATLAS upgrade. The considered fabrication technology is simpler than
that required for full 3D detectors with active edge, but the detector
efficiency and radiation hardness critically depend on the columnar electrode
overlap and should be carefully evaluated. The first assemblies of these
sensors (featuring 2, 3, or 4 columns per pixel) with the ATLAS FEI3 read-out
chip have been tested in laboratory. Selected results from the electrical and
functional characterization with radioactive sources are here discussed.Comment: 20 pages, 14 figures, presented at 7th International "Hiroshima"
Symposium on Development and Applications of Semiconductor Tracking Devices
International Conference Center Hiroshima, Japan, Aug. 29-Sep.1, 200
Intrinsic time resolution of 3D-trench silicon pixels for charged particle detection
In the last years, high-resolution time tagging has emerged as the tool to
tackle the problem of high-track density in the detectors of the next
generation of experiments at particle colliders. Time resolutions below 50ps
and event average repetition rates of tens of MHz on sensor pixels having a
pitch of 50m are typical minimum requirements. This poses an important
scientific and technological challenge on the development of particle sensors
and processing electronics. The TIMESPOT initiative (which stands for TIME and
SPace real-time Operating Tracker) aims at the development of a full prototype
detection system suitable for the particle trackers of the next-to-come
particle physics experiments. This paper describes the results obtained on the
first batch of TIMESPOT silicon sensors, based on a novel 3D MEMS (micro
electro-mechanical systems) design. Following this approach, the performance of
other ongoing silicon sensor developments has been matched and overcome, while
using a technology which is known to be robust against radiation degradation. A
time resolution of the order of 20ps has been measured at room temperature
suggesting also possible improvements after further optimisations of the
front-end electronics processing stage.Comment: This version was accepted to be published on JINST on 21/07/202
Development of LGAD sensors with a thin entrance window for soft X-ray detection
We show the developments carried out to improve the silicon sensor technology
for the detection of soft X-rays with hybrid X-ray detectors. An optimization
of the entrance window technology is required to improve the quantum
efficiency. The LGAD technology can be used to amplify the signal generated by
the X-rays and to increase the signal-to-noise ratio, making single photon
resolution in the soft X-ray energy range possible. In this paper, we report
first results obtained from an LGAD sensor production with an optimized thin
entrance window. Single photon detection of soft X-rays down to 452~eV has been
demonstrated from measurements, with a signal-to-noise ratio better than 20.Comment: 10 pages, 6 figure
Characterization of iLGADs using soft X-rays
Experiments at synchrotron radiation sources and X-ray Free-Electron Lasers
in the soft X-ray energy range (eV--keV) stand to benefit from the
adaptation of the hybrid silicon detector technology for low energy photons.
Inverse Low Gain Avalanche Diode (iLGAD) sensors provide an internal gain,
enhancing the signal-to-noise ratio and allowing single photon detection below
keV using hybrid detectors. In addition, an optimization of the entrance
window of these sensors enhances their quantum efficiency (QE). In this work,
the QE and the gain of a batch of different iLGAD diodes with optimized
entrance windows were characterized using soft X-rays at the
Surface/Interface:Microscopy beamline of the Swiss Light Source synchrotron.
Above eV, the QE is larger than for all sensor variations, while
the charge collection efficiency is close to . The average gain depends
on the gain layer design of the iLGADs and increases with photon energy. A
fitting procedure is introduced to extract the multiplication factor as a
function of the absorption depth of X-ray photons inside the sensors. In
particular, the multiplication factors for electron- and hole-triggered
avalanches are estimated, corresponding to photon absorption beyond or before
the gain layer, respectively.Comment: 16 pages, 8 figure
Development of 3D detectors at FBK-irst
We report on the development of 3D detectors at Fondazione Bruno Kessler - irst in the framework of the CERN RD-50 Collaboration. Technological and design aspects dealing with the 3D Single Type Column detectors are reviewed, and selected results from the electrical and functional characterization of prototypes are reported and discussed. A new detector concept, namely 3D Double-side Double Type Column detectors, allowing for significant performance enhancement while maintaining a reasonable process complexity, is final ly addressed
Sicilia—silicon carbide detectors for intense luminosity investigations and applications
Silicon carbide (SiC) is a compound semiconductor, which is considered as a possible alternative to silicon for particles and photons detection. Its characteristics make it very promising for the next generation of nuclear and particle physics experiments at high beam luminosity. Silicon Carbide detectors for Intense Luminosity Investigations and Applications (SiCILIA) is a project starting as a collaboration between the Italian National Institute of Nuclear Physics (INFN) and IMM-CNR, aiming at the realization of innovative detection systems based on SiC. In this paper, we discuss the main features of silicon carbide as a material and its potential application in the field of particles and photons detectors, the project structure and the strategies used for the prototype realization, and the first results concerning prototype production and their performance
High-performance PIN photodiodes on TMAH thinned silicon wafers
The electro-optical characteristics of PIN photodiodes fabricated on high-resistivity silicon substrates locally thinned by bulk micromachining techniques are discussed. Experimental results and numerical simulations demonstrate that devices fabricated by the proposed approach have leakage current, quantum efficiency and speed performance comparable to the best commercially available Si PIN photodiodes, with the additional advantage of possible back-side illumination, making them suitable for the implementation of two-dimensional arrays having a read-out electronic chip connected to the front-side
Tappered walls via holes manufactured using DRIE variable isotropy process
This paper describes a method to manufacture through wafer via holes with tapered walls for RF applications. The main purpose was the need to obtain tapered walls for via holes that allow to deposit seed and barrier layers by Physical Vapor Deposition (PVD). Method consist in consecutively using of the two basic process types for DRIE technique: isotropic and anisotropic etchings. Thus via holes with 20μm and 100μm having tapered walls with angles between 14° and 18° were manufactured. Also, thin metal layers were deposited on the walls by e-beam technique