5th Trento Workshop (2010) - Submitted Abstracts

Abstract No. Author(s) Title Abstract Comment Contact email
1 Mathieu Benoit, Abdenour Lounis, Nicoleta Dinu Simulation of charge multiplication and trap-assisted tunneling in irradiated n-in-p planar pixel sensors We present a model for the TCAD simulation of charge multiplication and trap-to-band tuneling to explain the discrepancies between the experimentally observed charge collection in highly irradiated planar pixel sensors and the predictions made using Hambourg model. DC and transient TCAD simulations of one and two dimensional n-in-p diodes were performed and reproduce well the observed behavior of diode irradiated at fluences of the order of $10^{15-16}\:n_{eq}cm^{-2}$. The results of the simulations show that impact ionization and detrapping due to tunelling qualitatively explain the behavior of irradiated sensors observed experimentally. We finally discuss the use of TCAD simulation tools for the design of novel planar pixel structures enhancing charge collection efficiency using the charge multiplication and trap-to-band tuneling effects. benoit@lal.in2p3.fr
2 Alessandro La Rosa 3D/FBK pixel sensors measurements. 3D-Si pixel sensors fabricated at FBK-irst with DDTC approach have been tested in laboratory, in 1.6 Tesla magnetic field with a 180 GeV pions beam at CERN and irradiated with a 24 GeV protons beam at CERN PS.   Selected results from the electrical and functional characterization with radioactive sources will be presented. Full author list: Maurizio Boscardin (FBK-irst), Gian-Franco Dalla Betta (INFN and Univ. Trento), Giovanni Darbo (INFN Genova), Claudia Gemme (INFN Genova), Alessandro La Rosa (CERN), Heinz Pernegger (CERN), Marco Povoli (INFN and Univ. Trento) and Sabina Ronchin (FBK-irst). alessandro.larosa@cern.ch
3 Michael Koehler Beam Test Measurements with Irradiated 3D-DDTC Silicon Strip Detectors Detectors in 3D-DDTC (Double-Sided Double Type Column) design combine the intrinsic radiation hardness of 3D detectors with a simplified processing technology. Columnar electrodes are etched into the wafer from two sides but do not penetrate the substrate completely. This talk presents preliminary results of beam test measurements performed at the CERN SPS with 3D-DDTC silicon strip detectors. The reference tracks were measured with the CMS Silicon Beam Telescope (SiBT). The detectors under test have been irradiated at the proton cyclotron in Karlsruhe with fluences up to 2*10^15 Neq/cm˛. The presented results focus on the highly increased signal of the irradiated detectors due to charge multiplication. Michael.Koehler@cern.ch
4 Yoichi Ikegami (KEK) Development of silicon strip-module for very high radiation environment We have been developing a silicon strip-module for very high radiation environment, such as ATLAS SCT upgrade toward the super LHC project. This proposal has involved by Univ. Geneva, Univ. Tsukuba and KEK. The proposed silicon strip detector includes a 4-segmented short strip silicon detector system in order to cope with the high track density. The module has about 10,000 readout channels. In order to minimize the number of hybrids, a hybrid reads out 2 segments of strips with two rows of readout chips; one row in each edge. 20 ABCN chips, made with 0.25 µm deep-submicron CMOS technology, are mounted on the hybrid. The characteristics of the module, focusing on the electrical performance, is evaluated and discussed. ikegami@post.kek.jp
5 Angela Kok, Thor-Erik Hansen, Trond A. Hansen, Geir Uri Jensen, Nicolas Lietaer and Anand Summanwar Status of 3D Sensor Processing at SINTEF MiNaLab Manufacturing full 3D sensors with active edge on a production scale has been attempted at SINTEF MiNaLab. During the first prototype run, problems such as wafer fragility and difficulties in lithography were encountered, resulted a very low overall wafer yield. These issues have now been addressed in the second prototype run and the wafer yield has increased from 10% to about 80%. Electrical measurements on individual ATLAS FE-I3 and CMS 1ROC detectors are also promising. A leakage current of less than 0.5 nA per pixel at full depletion had been measured on selected FE-I3 detectors and 1ROC detectors with a breakdown voltage of about 120V. This talk will discuss the current status of 3D sensor development at SINTEF MiNaLab. The latest results on fully completed detectors and the performance variations after under bump metallisation (UBM) will also be discussed. angela.kok@sintef.no
6 Liv Wiik Testbeam Measurements of Planar n-on-p Microstrip Detectors We report on the results of testbeam measurements of irradiated and unirradiated planar n-on-p silicon microstrip detectors from the official ATLAS07 prototype programme. These sensors were irradiated with protons at the Forschungszentrum Karlsruhe with fluences up to Φeq= 3 · 10^15/cm^2, which corresponds to the expected fluence for the inner strip layers at the sLHC. The testbeam was then performed at the CERN SPS H2 beamline using the CMS Silicon Beam Telescope(SiBT).We present measurements of the charge collection efficiency, the signal-to-noise ratio and the resolution of these detectors. lwiik@mail.cern.ch
7 A. Macchiolo, L. Andricek, M. Beimforde, H.G. Moser, R. Nisius, R.H. Richter Thin planar pixel sensors and a novel interconnection technology for the upgrade of the ATLAS pixel system We present a new pixel module concept under development in view of the upgrade of the ATLAS pixel detector for the Super-LHC (SLHC). The new devices combine thin pixels sensors with a vertical integration technology developed by the Fraunhofer IZM. The pixel sensors, with an active thickness of 75 and 150 microns, have been produced by the Semiconductor Laboratory of the Max-Planck-Institut using both the n+-in-n and n-in-p technology. The results of the pre-irradiation characterization of the pixel sensors will be presented, together with the first measurements of Charge Collection Efficiency performed on micro-strip sensors produced on the same wafers and irradiated with 26 MeV protons up to fluences of 3E15 cm-2 1 MeV n eq. The plans for a second production of 150 micron thick n-in-p pixels designed for the ATLAS IBL project will be illustrated. In the framework of the ATLAS SLHC upgrade we are assemblying a demonstrator module where the thin sensors are connected to the ATLAS pixel ASIC by the novel Solid-Liquid Interdiffusion process in alternative to the bump-bonding technique. In addition we plan to route the signals through Inter-Chip Vias to the ASIC wafer backside where post-processing bonding pads will be created. We will present the layout and the results obtained with a production of test-structures designed to investigate the SLID interconnection efficiency as a function of different parameters, i.e. the pixel size and pitch, and the planarity of the underlying layers. annamac@mppmu.mpg.de
8 Anthony Affolder, Phil Allport, Gianluigi Casse Investigation of the effects of thickness, pitch, and manufacturer on charge multiplication properties of highly irradiated n-in-p FZ silicon strips Recently, charge multiplication has been shown to be a significant component of the collected charge for highly irradiated silicon sensors. In order to better understand this effect, we have measured the collected charge of n-in-p FZ planar silicon strips after fluences up to 1e16 neq cm^-2 26 MeV protons. We will present new comparisons of three different sensor thicknesses (140, 300, 500 um), two different manufacturers (Micron and Hamamatsu), and three different pitches (74.5, 80, and 100 um). We find that while the thickness does effect the charge collected, the manufacturer and pitch does not within our measurement precision. affolder@hep.ph.liv.ac.uk
9 Juha Kalliopuska, Simo Eränen, Tuula Virolainen, Lukas Tlustos Characterization of Medipix2 edgeless pixel detectors VTT has developed a straightforward and fast process to fabricate edgeless (active edge) microstrip and pixel detectors on 6" (150 mm) wafers. The presentation summarizes the fabrication process of 150 μm thick p-on-n and n-on-n prototypes having dead layer at the edge below a micron. Electrical and radiation response characterization of 1.4x1.4 cm2 edgeless detectors has been done by coupling them to the Medipix2 readout chips. The leakage currents were measured to be ~90 nA/cm2. Radiation response characterization includes a X-ray tube and source responses. These results show that the edge response depends dramatically on the active edge distance from the nearest pixels. juha.kalliopuska@vtt.fi
10 Sudeep Chatterji (1), Anton Lymanets (2) and Johann Heuser (1) 3D-TCAD simulations of double-sided Si micro-strip detectors The intense radiation environment of the planned Compressed Baryonic Matter (CBM) experiment at the international Facility for Antiproton and Ion Research (FAIR) makes radiation hardness one of the important issues for the Silicon Tracking System (STS). The STS will consist of eight stations of Double Sided Strip Detectors (DSSD) at a distance between 25 cm to 100 cm downstream of the target. It is expected that the total integrated fluence will reach 1x10^15 cm^-2 1-MeV neutrons equivalent. The major macroscopic effect of radiation damage in determining the viability of long-term operation of silicon sensors is the change in the effective charge carrier concentration (Neff), leading to type inversion. For efficient operation over several years of beam time, the detectors are required to sustain very high voltage operation, well exceeding the bias voltage needed to fully deplete the heavily irradiated sensors. Thus, the main effort in the development of silicon sensors is concentrated on a design that avoids p-n junction breakdown at operational biases. We perform 3-dimensional TCAD simulations using TCAD tools from SYNOPSYS like Sentaurus Device and Workbench to develop DSSDs for the CBM STS. We have developed a 3D simulation grid that represents the complicated structure of our device namely 50 um pitch, 20 um width and stereo angle of +-7.5 deg on either side. We can simulate transients by passing a minimum ionizing particle at various angle of inclination. We have also been able to extract the interstrip parameters relevant to understand Signal/Noise ratio like Interstrip Capacitance (both DC and AC), Interstrip Resistance using Mixed Mode Simulation. We have simulated the radiation damage in our simulation by varying the effective doping concentration, surface oxide charge and minority carrier lifetime. We plan to compare the simulation results with measurements on detector test structures before and after irradiation. (1) GSI, Darmstadt, Germany (2) FIAS, Univ. of Frankfurt, Germany CBM Collaboration (www-cbm.gsi.de) S.Chatterji@gsi.de, J. Heuser@gsi.de
11 G.-F. Dalla Betta (*), M. Boscardin, G. Darbo, C. Da Via, S. Dong, T.-E. Hansen, J. Hasi, C. Kenney, A. Kok, S. Parker, G. Pellegrini, S. Watts The common floor-plan of the ATLAS IBL 3D sensor prototypes During the past year all industrial partners of the 3D ATLAS R&D Collaboration started a joint effort aimed at a common design and processing strategy for the production of 3D sensors for the ATLAS pixel Insertable B-Layer (IBL). In this project a new layer will be inserted as close and 3.4cm from the beam inside the existing pixel layers of the ATLAS experiment. The proximity to the interaction point will therefore require new radiation hard technologies for both the sensors and the front end electronics. The latter, called FE-I4 is currently being processed at IBM and will be the biggest front end of this kind with a surface of about 4 cm2. 3D sensors are competing together with a new planar design and diamond for the IBL. Decisions will be taken at the end of 2010 following a review of all technologies after sensors will be connected to the FE-I4 front end. The “3D processing working group” studied the best strategy for the production of 3D sensors for 2010. At the base of this strategy is the design of a ‘common flor-plan’ layout which would allow full mechanical compatibility and equivalence in performance of all 3D sensor produced in the different foundries. The success of this strategy would determine the chances of 3D sensors being the choice for the IBL. The key design aspects and device fabrication plans during the prototyping phase in 2010 will be discussed. (*) Presenting author on behalf of the “3D processing working group” dallabe@disi.unitn.it
12 Jens Weingarten Status of the PPS R&D project The PPS R&D project aims towards the development of improved silicon pixel sensors based on planar technology for the high-luminosity ATLAS Inner Detector Upgrade. Recent activities and results will be presented jens.weingarten@uni-goettingen.de
13 G.Kramberger, V. Cindro, I. Mandić, M. Mikuž, M. Milovanović, M. Zavrtanik Investigation of irradiated p type silicon strip detectors by Edge-TCT A Transient Current Technique (TCT) utilizing IR laser with 100 ps pulse width and beam diameter of FWHM=8 um was used to evaluate non-irradiated and irradiated p-type silicon micro-strip detectors. The beam was parallel with the surface and perpendicular to the strips (Edge-TCT) so that the electron hole pairs were created at known depth in the detector. The induced current pulse shapes in a detector irradiated to 5e15 cm-2 revealed that avalanche charge multiplication takes place near the strips at high bias voltages. The evolution of charge multiplication was followed during the long term annealing. Gregor.Kramberger@ijs.si
14 Y. Unno Development of n-in-p silicon microstrip and pixel sensors for very high radiation environments We have been developing n-in-p silicon microstrip and pixel sensors for very high radiation environments up to 10^16 1-MeV-neutron-equivalent/cm^2. We carried out investigations to the key technologies such as high voltage operation, n-implant isolation, protection against beam splash, edge space, etc, in the test structures and in full sensors. We report the latest results of our development. yoshinobu.unno@kek.jp
15 Graeme Stewart 3D Testbeam Analysis The analysis of the data from the TimePix testbeam of 2009 will be presented. The efficiency of the detector at different angles and voltages will be discussed. gd.stewart@physics.gla.ac.uk