Thin Film CdZnTe Detector Arrays for Digital Mammography

The objective of this program has been to develop large-area, flat-panel detectors for digital mammography using CdTe or CdZnTe deposited by metalorganic chemical vapor deposition (MOCVD) directly on thin-film transistor (TFT) active matrix arrays for image readout. CdTe and CdZnTe have the potentia...

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Bibliographic Details
Main Author: Sudharsanan, Rengarajan
Format: Report
Language:English
Subjects:
AMORPHOUS MATERIALS
BREAST CANCER
CADMIUM ZINC TELLURIDES
CHEMICAL VAPOR DEPOSITION
COMPUTER AIDED DIAGNOSIS
Cybernetics
DETECTION
DIGITAL MAMMOGRAPHY
GALLIUM ARSENIDES
HETEROJUNCTION
INDIUM COMPOUNDS
LEAKAGE(ELECTRICAL)
MAMMOGRAPHY
MEDICAL COMPUTER APPLICATIONS
Medical Facilities, Equipment and Supplies
MOCVD(METALORGANIC CHEMICAL VAPOR DEPOSITION)
OPTIMIZATION
ORGANOMETALLIC COMPOUNDS
PHOTODIODES
POLYSILICONS
RADIATION
Radiobiology
RESISTANCE(BIOLOGY)
SCREEN FILM MAMMOGRAPHY
TFT(THIN FILM TRANSISTOR)
THIN FILMS
X RAY DIFFRACTION
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Summary:The objective of this program has been to develop large-area, flat-panel detectors for digital mammography using CdTe or CdZnTe deposited by metalorganic chemical vapor deposition (MOCVD) directly on thin-film transistor (TFT) active matrix arrays for image readout. CdTe and CdZnTe have the potential to meet the requirements for digital mammography due to their high x-ray absorption, large band gap and good carrier transport. Activities during the first three years have been directed primarily toward optimization of physical and electrical properties of MOCVD-deposited CdTe and CdZnTe and improved understanding of CdS/Cd(Zn)Te heterojunctions used to reduce the leakage currents. Leakage currents to date have been too high for compatibility with TFT arrays, and this fact has,made it impossible to advance to subsequent steps in the program. In the third year our efforts concentrated on transferring growth to a different MOCVD reactor to improve safety and provide the capability for large-area deposition, modeling of absorption efficiency for Cd(Zn)Te compared to alternative materials, i investigation of the possibility of depositing films at low temperature for compatibility with amorphous silicon TFT arrays. Our results indicate that deposition on polysilicon TFTs is the most viable approach, since CdSe TFTs are no longer commercially available.