Characterization of HV-CMOS detectors in BCD8 technology and of a controlled hybridization technique

Radiation detectors built in high-voltage and high-resistivity CMOS technology are an interesting option for the large area pixel-trackers sought for the upgrade of the Large Hadron Collider experiments. A characterisation of the BCD8 technology by STMicroelectronics process has been performed to evaluate its suitability for the realisation of CMOS sensors with a depleted region of several tens of micrometer. Sensors featuring 50 7250 \u3bcm2 pixels on a 125 \u3a9cm resistivity substrate have been characterized. The response to ionizing radiation is tested using radioactive sources and an X-ray tune, reading out the detector with an external spectroscopy chain. Irradiation tests were performed up to proton fluences exceeding 5 c51015 p/cm2 and they show the depletion and breakdown voltages increases with irradiation. A hybridization process for capacitive coupling has been developed. Assemblies have been performed using the ATLAS FE-I4 readout ASIC and prototype CMOS sensors. Measurements show a planarity better than 1.5 \u3bcm peak-to-peak on the 5 mm length of the HV-CMOS chip. To evaluate more precisely the achievable uniformity dummy chips of FE-I4 sizes have been made on 6-inch wafers. The measurement of the 24 capacitors on each chip is expected to achieve a precise estimation of the real thickness uniformity. The goal is to achieve less then 10% variation on the glue thickness ( 3c0.5 \u3bcm)

Prototype ATLAS IBL Modules using the FE-I4A Front-End Readout Chip

The ATLAS Collaboration will upgrade its semiconductor pixel tracking detector with a new Insertable B-layer (IBL) between the existing pixel detector and the vacuum pipe of the Large Hadron Collider. The extreme operating conditions at this location have necessitated the development of new radiation hard pixel sensor technologies and a new front-end readout chip, called the FE-I4. Planar pixel sensors and 3D pixel sensors have been investigated to equip this new pixel layer, and prototype modules using the FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test results are presented, including charge collection efficiency, tracking efficiency and charge sharing.Comment: 45 pages, 30 figures, submitted to JINS

ATLAS pixel detector electronics and sensors

The silicon pixel tracking system for the ATLAS experiment at the Large Hadron Collider is described and the performance requirements are summarized. Detailed descriptions of the pixel detector electronics and the silicon sensors are given. The design, fabrication, assembly and performance of the pixel detector modules are presented. Data obtained from test beams as well as studies using cosmic rays are also discussed

Study of indium bumps for the ATLAS pixel detector

The bump-bonding technology is used to join the front-end read-out chips to the silicon substrate of the ATLAS pixel detector. We review the current status of the technology used by Alenia Marconi Systems and we report on the electrical and mechanical properties and the defect rate of the indium bumps. (1 refs)

HV-CMOS detectors for high energy physics: Characterization of BCD8 technology and controlled hybridization technique

Radiation detectors built in high-voltage and highresistivity CMOS technology are an interesting option for the large area pixel trackers sought for the upgrade of the Large Hadron Collider experiments. A possible architecture is a hybrid design, where CMOS sensors are readout by front-end electronics coupled through a thin dielectric layer. A critical requirement is the radiation hardness of both the sensor and the front-end circuitry, up to a total dose ranging from 100 Mrad to 1 Grad (1 MGy to 10 MGy), depending on the distance from the interaction region. This paper explores the suitability of the BCD8 technology provided by STMicroelectronics for the construction of radiation-hard pixel detectors together with a technique to achieve reliability and repeatability of the hybridization process between the detector and the readout chip

Analysis of the production of ATLAS indium bonded pixel modules

The ATLAS collaboration is currently building 1500 pixel modules using the indium bump bonding technique developed by SELEX Sistemi Integrati (former AMS). The indium deposition and flip-chip process are described together with an overview of the chip stripping machine that allows defective modules to be reworked. The prodn. is half-way through at the time of this writing. This paper also discusses the problems encountered during prodn. and the adopted solns

HV-CMOS detectors in BCD8 technology

This paper presents the first pixel detector realized using the BCD8 technology of STMicroelectronics. The BCD8 is a 160 nm process with bipolar, CMOS and DMOS devices; mainly targeted for an automotive application. The silicon particle detector is realized as a pixel sensor diode with a dimension of 250 \uc3\u97 50 \uce\ubcm2. To support the signal sensitivity of pixel diode, the circuit simulations have been performed with a substrate voltage of 50 V. The analog signal processing circuitry and the digital operation of the circuit is designed with the supply voltage of 1.8 V. Moreover, an analog processing part of the pixel detector circuit is confined in a unit pixel (diode sensor) to achieve 100 % fill factor. As a first phase of the design, an array of 8 pixels and 4 passive diodes have been designed and measured experimentally. The entire analog circuitry including passive diodes is implemented in a single chip. This chip has been tested experimentally with 70 V voltage capability, to evaluate its suitability. The sensor on a 125 \uce\ua9cm resistivity substrate has been characterized in the laboratory. The CMOS sensor realizes a depleted region of several tens of micrometer. The characterization shows a uniform breakdown at 70 V before irradiation and an approximate capacitance of 80 fF at 50 V of reverse bias voltage. The response to ionizing radiation is tested using radioactive sources and an X-ray tube

Results on 0.7% X0 thick pixel modules for the ATLAS detector

Modules are the basic building blocks of the ATLAS pixel detector system, they are made of a silicon sensor tile containing ~46000 pixel cells of 50 mu m*400 mu m, 16 front-end chips connected to the sensor through bump bonding, a kapton flex circuit and the module controller chip. The pixel detector is the first to encounter particles emerging from LHC interactions, minimization of radiation length of pixel modules is therefore very important. We report here on the construction techniques and on the operation of the first ATLAS pixel modules of 0.7% radiation length thickness. We have operated these modules with threshold of 3700*10+or-300*10, mean noise value of 225*10 and 0.3% dead channels. (3 refs)

HV-CMOS detectors in BCD8 technology

This paper presents the first pixel detector realized using the BCD8 technology of STMicroelectronics. The BCD8 is a 160 nm process with bipolar, CMOS and DMOS devices; mainly targeted for an automotive application. The silicon particle detector is realized as a pixel sensor diode with a dimension of 250 × 50 μm2. To support the signal sensitivity of pixel diode, the circuit simulations have been performed with a substrate voltage of 50 V. The analog signal processing circuitry and the digital operation of the circuit is designed with the supply voltage of 1.8 V. Moreover, an analog processing part of the pixel detector circuit is confined in a unit pixel (diode sensor) to achieve 100 % fill factor. As a first phase of the design, an array of 8 pixels and 4 passive diodes have been designed and measured experimentally. The entire analog circuitry including passive diodes is implemented in a single chip. This chip has been tested experimentally with 70 V voltage capability, to evaluate its suitability. The sensor on a 125 Ωcm resistivity substrate has been characterized in the laboratory. The CMOS sensor realizes a depleted region of several tens of micrometer. The characterization shows a uniform breakdown at 70 V before irradiation and an approximate capacitance of 80 fF at 50 V of reverse bias voltage. The response to ionizing radiation is tested using radioactive sources and an X-ray tube