AC-coupled n-in-p pixel detectors on MCz silicon with atomic layer deposition (ALD) grown thin film

Gädda, A.; Ott, J.; Bharthuar, S.; Brücken, E.; Kalliokoski, Matti; Karadzhinova-Ferrer, A.; Bezak, M.; Kirschenmann, S.; Litichevsky, V.; Golovleva, M.; Martikainen, L.; Winkler, Alexander; Chmill, V.; Tuovinen, E.; Luukka, P.; Härkönen, J.

doi:10.1016/j.nima.2020.164714

Cited by 5 publications

(5 citation statements)

References 113 publications

(173 reference statements)

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“…The ALD-based thin-film deposition process was optimized and repeatedly applied in our detector fabrication process [29,30]. Our scanning TCT measurements indicate good homogeneity over large areas and effective electrical isolation between pixels of high density.…”

Section: Discussionmentioning

confidence: 93%

“…The results are presented in Refs. [21,29,48]. An illustrative example of such a TCT scan is shown in Figure 8.…”

Section: Detector Characterization and Selected Resultsmentioning

confidence: 99%

“…A detailed process description, as well as the device design for large-area p-type pixel detectors, is presented in Refs. [27][28][29]. A tentative process flow is shown in Figure 2.…”

Section: Design and Processing Of P-type Mcz-si Pixel Detectorsmentioning

confidence: 99%

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Processing and Interconnections of Finely Segmented Semiconductor Pixel Detectors for Applications in Particle Physics and Photon Detection

Härkönen¹,

Ott²,

Gädda³

et al. 2021

Front. Phys.

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Radiation hardness is in the focus of the development of particle tracking and photon imaging detector installations. Semiconductor detectors, widely used in particle physics experiments, have turned into capacitive-coupled (AC-coupled) detectors from the originally developed conductively coupled (DC-coupled) detectors. This is due to the superior isolation of radiation-induced leakage current in AC-coupled detectors. However, some modern detector systems, such as the tracking detectors in the CERN LHC CMS or ATLAS experiments, are still DC-coupled. This originates from the difficulty of implementing AC coupling on very small pixel detector areas. In this report, we describe our advances in the detector processing technology. The first topic is the applications of the atomic layer deposition processing technology, which enables the very high densities of capacitance and resistance that are needed when the dimensions of the physical segmentation of pixel detectors need to be scaled down. The second topic is the flip-chip/bump-bonding interconnection technology, which is necessary in order to manufacture pixel detector modules on a large scale with a more than 99% yield of noise-free and faultless pixels and detector channels.

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Section: Discussionmentioning

confidence: 93%

“…The results are presented in Refs. [21,29,48]. An illustrative example of such a TCT scan is shown in Figure 8.…”

Section: Detector Characterization and Selected Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Processing and Interconnections of Finely Segmented Semiconductor Pixel Detectors for Applications in Particle Physics and Photon Detection

Härkönen¹,

Ott²,

Gädda³

et al. 2021

Front. Phys.

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“…The silicon wafers possess a resistivity and thickness of ∼4-8 kΩ-cm and 320 μm, respectively. Fabrication of the devices measured in this study have been provided in articles [4][5][6].…”

Section: Samples Measured and Methodsmentioning

confidence: 99%

Characterisation of gamma-irradiated MCz-silicon detectors with a high-K negative oxide as field insulator

et al. 2022

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The high-luminosity operation of the Tracker in the Compact Muon Solenid (CMS) detector at the Large Hadron Collider (LHC) experiment calls for the development of silicon-based sensors. This involves implementation of AC-coupling to micro-scale pixel sensor areas to provide enhanced isolation of radiation-induced leakage currents. The motivation of this study is the development of AC-pixel sensors with negative oxides (such as aluminium oxide — Al2O3 and hafnium oxide — HfO2) as field insulators that possess good dielectric strength and provide radiation hardness. Thin films of Al2O3 and HfO2 grown by atomic layer deposition (ALD) method were used as dielectrics for capacitive coupling. A comparison study based on dielectric material used in MOS capacitors indicate HfO2 as a better candidate since it provides higher sensitivity (where, the term sensitivity is defined as the ratio of the change in flat-band voltage to dose) to negative charge accumulation with gamma irradiation. Further, space charge sign inversion was observed for sensors processed on high resistivity p-type Magnetic Czochralski silicon (MCz-Si) substrates that were irradiated with gamma rays up to a dose of 1 MGy. The inter-pixel resistance values of heavily gamma irradiated AC-coupled pixel sensors suggest that high-K negative oxides as field insulators provide a good electrical isolation between the pixels.

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“…Detailed information behind the processing of the MOS devices and detectors has been provided in articles- Ott et al (2020); Gädda et al (2021); Härkönen et al (2021); Ott et al (2021). Each of the abovementioned samples have either Al 2 O 3 or Al 2 O 3 + HfO 2 to permit better capacitive coupling.…”

Section: Measured Device Specificationsmentioning

confidence: 99%

Characterization of Heavily Irradiated Dielectrics for Pixel Sensors Coupling Insulator Applications

et al. 2022

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An increase in the radiation levels during the high-luminosity operation of the Large Hadron Collider calls for the development of silicon-based pixel detectors that are used for particle tracking and vertex reconstruction. Unlike the conventionally used conductively coupled (DC-coupled) detectors that are prone to an increment in leakage currents due to radiation, capacitively coupled (AC-coupled) detectors are anticipated to be in operation in future collider experiments suitable for tracking purposes. The implementation of AC-coupling to micro-scale pixel sensor areas enables one to provide an enhanced isolation of radiation-induced leakage currents. The motivation of this study is the development of new generation capacitively coupled (AC-coupled) pixel sensors with coupling insulators having good dielectric strength and radiation hardness simultaneously. The AC-coupling insulator thin films were aluminum oxide (Al2O3) and hafnium oxide (HfO2) grown by the atomic layer deposition (ALD) method. A comparison study was performed based on the dielectric material used in MOS, MOSFET, and AC-coupled pixel prototypes processed on high resistivity p-type Magnetic Czochralski silicon (MCz-Si) substrates. Post-irradiation studies with 10 MeV protons up to a fluence of 1015 protons/cm2 suggest HfO2 to be a better candidate as it provides higher sensitivity with negative charge accumulation on irradiation. Furthermore, even though the nature of the dielectric does not affect the electric field within the AC-coupled pixel sensor, samples with HfO2 are comparatively less susceptible to undergo an early breakdown due to irradiation. Edge-transient current technique (e-TCT) measurements show a prominent double-junction effect as expected in heavily irradiated p-type detectors, in accordance with the simulation studies.

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AC-coupled n-in-p pixel detectors on MCz silicon with atomic layer deposition (ALD) grown thin film

Cited by 5 publications

References 113 publications

Processing and Interconnections of Finely Segmented Semiconductor Pixel Detectors for Applications in Particle Physics and Photon Detection

Processing and Interconnections of Finely Segmented Semiconductor Pixel Detectors for Applications in Particle Physics and Photon Detection

Characterisation of gamma-irradiated MCz-silicon detectors with a high-K negative oxide as field insulator

Characterization of Heavily Irradiated Dielectrics for Pixel Sensors Coupling Insulator Applications

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