Three-dimensional mapping of tellurium inclusions in CdZnTe crystals by means of improved optical microscopy

Zambelli, N.; Marchini, L.; Zha, M.; Zappettini, A.

doi:10.1016/j.jcrysgro.2010.10.203

Cited by 12 publications

(5 citation statements)

References 12 publications

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“…visible grains of ingots. Many other defects can be revealed with infrared (IR) inspection of wafers or cuboids of the grown material [9,10]. Defects, such as grain boundaries, fractures or precipitates lead inevitably to reduced detector performance.…”

Section: Materials Characterizationmentioning

confidence: 99%

Advanced processing of CdTe pixel radiation detectors

et al. 2017

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We report a fabrication process of pixel detectors made of bulk cadmium telluride (CdTe) crystals. Prior to processing, the quality and defect density in CdTe material was characterized by infrared (IR) spectroscopy. The semiconductor detector and Flip-Chip (FC) interconnection processing was carried out in the clean room premises of Micronova Nanofabrication Centre in Espoo, Finland. The chip scale processes consist of the aluminum oxide (Al 2 O 3 ) low temperature thermal Atomic Layer Deposition (ALD), titanium tungsten (TiW) metal sputtering depositions and an electroless Nickel growth. CdTe crystals with the size of 10 × 10 × 0.5 mm 3 were patterned with several photo-lithography techniques. In this study, gold (Au) was chosen as the material for the wettable Under Bump Metalization (UBM) pads. Indium (In) based solder bumps were grown on PSI46dig read out chips (ROC) having 4160 pixels within an area of 1 cm 2 . CdTe sensor and ROC were hybridized using a low temperature flip-chip (FC) interconnection technique. The In-Au cold weld bonding connections were successfully connecting both elements. After the processing the detector packages were wire bonded into associated read out electronics. The pixel detectors were tested at the premises of Finnish Radiation Safety Authority (STUK). During the measurement campaign, the modules were tested by exposure to a 137 Cs source of 1.5 TBq for 8 minutes. We detected at the room temperature a photopeak at 662 keV with about 2 % energy resolution.

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Section: Materials Characterizationmentioning

confidence: 99%

Advanced processing of CdTe pixel radiation detectors

et al. 2017

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“…The impact is even more important in pixelated detectors whose pitch is of the same order of magnitude as the larger inclusions (>100

) because their presence may completely hamper the functioning of one or more pixels, depending on their positioning along the crystal thickness. Therefore, before depositing gold contacts, we performed a thorough 3-D mapping of the whole crystals by means of IR microscopy using the setup as described in Zambelli et al [ 30 ].…”

Section: Materials and Methodsmentioning

confidence: 99%

“…For inclusions with a diameter greater than 1 µm, this method can be considered reliable. Further details are given in the related patent [30].…”

Section: D Inclusion Mappingmentioning

confidence: 99%

Fabrication of Small-Pixel CdZnTe Sensors and Characterization with X-rays

Tsigaridas

Zanettini²,

Bettelli

et al. 2021

Sensors

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Over the past few years, sensors made from high-Z compound semiconductors have attracted quite some attention for use in applications which require the direct detection of X-rays in the energy range 30–100 keV. One of the candidate materials with promising properties is cadmium zinc telluride (CdZnTe). In the context of this article, we have developed pixelated sensors from CdZnTe crystals grown by Boron oxide encapsulated vertical Bridgman technique. We demonstrate the successful fabrication of CdZnTe pixel sensors with a fine pitch of 55 m and thickness of 1 mm and 2 mm. The sensors were bonded on Timepix readout chips to evaluate their response to X-rays provided by conventional sources. Despite the issues related to single-chip fabrication procedure, reasonable uniformity was achieved along with low leakage current values at room temperature. In addition, the sensors show stable performance over time at moderate incoming fluxes, below 106 photons mm−2s−1.

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“…After the growth, the crystals were cooled at 30 C/h. The tellurium inclusion concentration was determined by infrared optical microscopy, using a set up recently developed in our labs [11].…”

Section: Experimental Methodsmentioning

confidence: 99%

Growth and Characterization of CZT Crystals by the Vertical Bridgman Method for X-Ray Detector Applications

Zappettini

Marchini

Zha

et al. 2011

IEEE Trans. Nucl. Sci.

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CdZnTe crystals were grown by the vertical Bridgman method in closed quartz ampoules. The crystalline quality and the impurity content of these crystals were studied. Several X-ray detectors were cut out of these crystals. The resistivity, emission spectra, product, and spectroscopic characteristics of these detectors were extensively measured and compared with the characteristics of detectors obtained from CdZnTe crystals grown by the boron oxide encapsulated vertical Bridgman technique. The detectors prepared from crystals grown without boron oxide show good value, spectroscopic resolution, and higher reproducibility. The influence of growth method on impurity content and on detector response was discussed.Index Terms-Boron oxide vertical Bridgman, CdZnTe, mobility-lifetime product, vertical Bridgman, X-ray detectors.

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Three-dimensional mapping of tellurium inclusions in CdZnTe crystals by means of improved optical microscopy

Cited by 12 publications

References 12 publications

Advanced processing of CdTe pixel radiation detectors

Advanced processing of CdTe pixel radiation detectors

Fabrication of Small-Pixel CdZnTe Sensors and Characterization with X-rays

Growth and Characterization of CZT Crystals by the Vertical Bridgman Method for X-Ray Detector Applications

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