Download presentation
Presentation is loading. Please wait.
Published byJemima Baker Modified over 9 years ago
1
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 1 Fully Depleted Monolithic Active Pixel Sensor in SOI Technology Presented by Wojciech Kucewicz a on behalf of A.Bulgheroni b, M. Caccia b, K. Domanski c, P. Grabiec c, M. Grodner c, B. Jaroszewicz c, M. Jastrzab a, A. Kociubinski c, M. Kozioł, K. Kucharski c, S.Kuta a, J. Marczewski c, H. Niemiec a, M. Sapor a, D. Tomaszewski c a AGH-Univ. of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland b Università dell’Insubria, via Valleggio 11, 22100 Como, Italy c Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
2
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 2OutlineOutline Principle of the SOI sensor Principle of the SOI sensor Preliminary test of the small area SOI sensors on the high resistive substrates Preliminary test of the small area SOI sensors on the high resistive substrates Design of the full size SOI sensor – layout and readout scheme Design of the full size SOI sensor – layout and readout scheme The SOI project is partially supported by the G1RD-CT-2001-000561
3
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 3 Principle of SOI monolithic detector The wafer bonding technics was choosen for SOI technology Thin low resistivity layer – readout electronics circuit High resistivity support – sensitive area Termochemical bonding 1-1,5 m
4
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 4 Principle of SOI monolithic detector The idea: Integration of the pixel detector and readout electronics in the wafer- bonded SOI substrate Electronics Electronics Device layer Low resistive (9-13 cm, CZ) 1.5 m thick Standard CMOS technology Detector Detector Support layer High resistive (> 4 k cm,FZ) 300 m thick Conventional p + -n DC-coupled
5
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 5MotivationMotivation As a monolithic device eliminates bump-bonding process and allows reduction of total sensor thickness reduction of multiple scattering As a monolithic device eliminates bump-bonding process and allows reduction of total sensor thickness reduction of multiple scattering Allows using high resistive detector substrates and operation in fully depleted region good detection efficiency, enables detection of particles with limited range in the silicon without backthinning process Allows using high resistive detector substrates and operation in fully depleted region good detection efficiency, enables detection of particles with limited range in the silicon without backthinning process Gives possibility to use both type of transistors in readout channels increased flexibility of the design, design optimisation for different application Gives possibility to use both type of transistors in readout channels increased flexibility of the design, design optimisation for different application Advantages of the SOI detectors: The SOI sensor may merge the advantages of the monolithic and hybrid detectors Advantages of the SOI detectors: The SOI sensor may merge the advantages of the monolithic and hybrid detectors
6
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 6 Test structures of the SOI detector
7
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 7 Test structures of the SOI detector Small readout matrices (8x8) with associated detector diodes or input pads for external signal sources were fabricated on the SOI wafers at the IET, Warsaw Two readout channel configurations – with NMOS transistor switch (cell dimensions 140x122 m 2 ) and with transmission gate (140x140 m 2 ) Contact to the detector placed in the V-shape cavity. Row selection signals led by two parallel lines with opposite polarization, body of the structure densely grounded reduction of the cross-talk between the electronics and detector
8
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 8 Detector Readout Operation in un-triggered mode (for imaging applications) Analogue serial readout organisation Readout sequence similar to rolling-shutter but double sampling performed for every pixel External subtraction of samples for CDS Well defined integration time and short dead time Exercised and validated on the prototype chip designed in commercial AMS 0.8 technology
9
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 9 SUCIMA Imager DAQ for the SOI Detector 4 independent analogue input channels USB 2.0 port The DAQ is equipped with 4 independent analogue input channels with 12 bit ADCs, 1MB fast static RAM, the FPGA Virtex II XC2V1000 chip for advanced algorithms and the high speed USB 2.0 port for a fast data transfer to and from a PC computer. GUI – developed in LabVIEW environment, allows setting: the matrix size to be readout, readout frequency; It provides: the CDS or last frame readout mode, masking noisy pixels, subtracting pedestals, suppressing signals bellow threshold and writing data to the file. Dedicated DAQ system called „SUCIMA imager” was developed for the SUCIMA project by INF in Cracow. 14 cm 9.5 cm
10
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 10 Stand Alone Detector Diodes and Electronics with Input Pads Transfer characteristics were measured with external voltage pulse signal with NMOS transistor switch Measured DC output dynamic range up to 1.0 V with transmission gate Measured DC output dynamic range up to 1.8 V non-linearity at the middle range was reduced in the latest designs Readout Electronics Pixel leakage current: From 200 nA down to 10 nA per cm 2 depending on the process Detector full depletion voltage: 60 V down to 50 V for different iterations Detector Diodes 0 0.4 0.8 1.2 1.6 Vin [V] Vout [V] 2.01.51.00.50.0
11
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 11 Tests with the Laser Light Laser light not focused, shining from the backplane (biased by a metal mash) Wavelength = 850 nm 4 s wide light pulses – simulate particles passing through detector active volume (each corresponding to 3.4 MIP) Integration time = 1 ms Detector polarization=60V 10 000 events recorded and averaged Input signal scaled assuming the sensor gain of 11mV/MIP Good detector sensitivity for the ionising radiation and linear response as a function of the generated charge was observed. Linearity of Sensor Response
12
12 Tests with the 90 Sr Beta Source Sensor sensitivity tested with 90 Sr beta source Measurements conditions: complete depletion (V det = 70 V), integration time: T int = 720 s, source placed at the top of the sensor. Detector output signal amplified (k 2.5) before digitalisations On-line CDS processing, off-line pedestal subtraction, common mode suppression and cluster search Recorded Event Cluster Size Gaussian distribution of the noise Landau distribution of the measured signals 27 ADC The most probably value of signal per MIP: 27 ADC 1.5 to 2 ADC Noise for the seed pixels: 1.5 to 2 ADC
13
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 13 Tests with the Alpha Particles Alpha source placed at the distance of 1 cm from the detector backplane Initial energy of particles = 5.5 MeV Detector fully depleted (V D =70V), integration time 720 s On-line CDS processing, off-line pedestal subtraction, common mode suppression and cluster search
14
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 14 cluster pulse height 200 ADC Typical measured cluster pulse height 200 ADC – corresponding to about half of the alpha particles initial energy. 1.5 ADC Pedestal width – about 1.5 ADC, S/N for cluster pulse height 130. Broad spectrum due to energy straggling in air. Noise Spectrum Alpha Spectrum Cluster Size Tests with the Alpha Particles
15
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 15 Design of a full size detector layout Dimensions: 24x24 mm 2 128 x 128 = 16 384 channels 4 sub-segments with independent parallel analogue outputs Cell dimensions: 150x150 m 2 Possibility to extend to ladders with dimensions up to 72x24 mm 2 and small dead areas Detector cavity
16
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 16 Full size detector ADC 24mm 24 mm
17
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 17 „Baby Detector” – backup solution of the SOI sensor Smaller number of the transistors, simpler functionality: Smaller number of the transistors, simpler functionality: 48 x 48 readout channels, area 1.2 cm x 1.2 cm, no digital control blocks Reset and Column/Row selection signal must be generated externally (NRow and NColumn signals are generated internally) Reset and Column/Row selection signal must be generated externally (NRow and NColumn signals are generated internally) Configuration of the analogue block is the same as on the main detector. Configuration of the analogue block is the same as on the main detector. Two versions – with dashed guardring (like on the main chip) and continuous guardring – reliability and effectiveness of both solutions will be compared. Two versions – with dashed guardring (like on the main chip) and continuous guardring – reliability and effectiveness of both solutions will be compared. Dashed guardring Continuous guardring
18
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 18 New Test Structure Several units of the old test structure for the crosscheck of the parameters between different wafers Several units with different transistor layouts for matching, noise and radiation hardness studies Test structure for direct IV and CV characteristics measurements of the detector diodes Small matrix of the sensor with modified readout configuration New Test Structure exploits the experience gained with the old test structure. It consists of:
19
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 19 New Test Structure Matrix of 16x16 readout channels with reduced capacitance at the input node – higher signal per MIP Readout electronics configuration the same like on the main sensor Input (charge integrating) capacitance reduced by disconnecting the polySi plate covering pixel cavity from the input and connection to the VSS (in case of the short between input and polySi layer no negative influence of the faulty pixel on the neighbours performance). Estimated pixel contact capacitance: C pixcon 27 fF, estimated total input capacitance: C tot 190 fF signal per MIP: S 14 15 mV This circuit was also placed separately (outside Test Structure chip) at several localization on the wafer – another backup solution in case of the problems with the big detectors.
20
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 20 New Test Structure Matrix of 8x16 readout channels with the conventional CSA configuration Matrix of 8x16 readout channels with the conventional CSA configuration 8x8 channels with the standard contact and 8x8 with the reduced input capacitance Charge integration mode – controlled by RES signal Global reset and sampling&hold Signal: 140 mV/MIP, lower noise. Weak DC feedback loop – stabilize the operation point of the input transistor – no protection diode required Partial leakage current compensation is possible by adjustment of the PBF – may operate for leakage current of the order of 10nA/cm 2 up to 100 nA/cm 2 Auto-polarization of the feedback transistor Single cell dimensions: 329 m x 357 m Much more sensitive for the device characteristics changes than the 3T cell
21
W.Kucewicz2004 Nuclear Science Symposium, Rome, October 16-22, 2004 21SummarySummary An alternative solution of a monolithic active pixel detector, which allows efficient detection in high resistive substrate, has been proposed. An alternative solution of a monolithic active pixel detector, which allows efficient detection in high resistive substrate, has been proposed. First small area SOI pixel sensors have been fabricated. First small area SOI pixel sensors have been fabricated. The tests results prove: The tests results prove: sensitivity of the test matrices for the MIP signals (measurements with 90 Sr), wide dynamic range (measurements with laser spot and alpha particles), detector suitability for the detection of particles with limited range in silicon (measurements with alpha particles), effectiveness of the charge integration mechanism implemented in the readout circuit. Following the positive results of the tests of the small area SOI sensors a larger and fully functional SOI sensor (128x128 readout channels, active area of 2 cm x 2 cm, optimised for medical imaging applications) have been designed and produced. Following the positive results of the tests of the small area SOI sensors a larger and fully functional SOI sensor (128x128 readout channels, active area of 2 cm x 2 cm, optimised for medical imaging applications) have been designed and produced.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.