X-ray imaging characteristics of a direct conversion detector using selenium and thin film transistor array

1997 ◽  
Author(s):  
Brian Rodricks ◽  
Denny L. Lee ◽  
Lawrence K. Cheung ◽  
Lothar S. Jeromin ◽  
Eugene F. Palecki
Keyword(s):  
Thin Film ◽  
Thin Film Transistor ◽  
Direct Conversion ◽  
X Ray ◽  
Imaging Characteristics ◽  
X Ray Imaging

Thin-film transistor array technology for high-performance direct-conversion x-ray sensors

1998 ◽  
Author(s):  
Willem den Boer ◽  
Steven Aggas ◽  
Young H. Byun ◽  
Tieer Gu ◽  
Johnny Q. Zhong ◽  
...  
Keyword(s):  
Thin Film ◽  
High Performance ◽  
Thin Film Transistor ◽  
Direct Conversion ◽  
X Ray ◽  
Array Technology

Radiographic imaging characteristics of a direct conversion detector using selenium and thin film transistor array

1997 ◽  
Author(s):  
Denny L. Y. Lee ◽  
Lawrence K. Cheung ◽  
Lothar S. Jeromin ◽  
Eugene F. Palecki ◽  
Brian G. Rodricks
Keyword(s):  
Thin Film ◽  
Thin Film Transistor ◽  
Direct Conversion ◽  
Radiographic Imaging ◽  
Imaging Characteristics

Charge Collection I.N A Se Photoconductor on a Thin Film Transistor Array during X-Ray Imaging

1997 ◽  
Vol 467 ◽  
Author(s):  
A. Brauers ◽  
N. Conrads ◽  
G. Frings ◽  
U. Schffibel ◽  
M. J. Powell ◽  
...  
Keyword(s):  
Thin Film ◽  
Spatial Resolution ◽  
Dark Current ◽  
Thin Film Transistor ◽  
Medical Applications ◽  
Temporal Response ◽  
X Ray ◽  
X Ray Imaging ◽  
Pixel Array ◽  
Current Characteristics

ABSTRACTThis paper deals with performance aspects of a selenium photoconductor on a thin film transistor array when used in x-ray imaging, e.g. for medical applications. We present the effects of doping structures within the Se on the spatial resolution, temporal response and dark current characteristics. Measurements were done on a 1922 pixel array with 200 μm pitch and a collecting electrode covering 50 % of the pixel area. Without additional measures the detector has a prohibitively slow response. With properly chosen doping structures the lateral conductivity can be engineered in a manner that the speed of the Se-TFT detector is increased to a level acceptable for video rate imaging. There is also a critical relationship between doping structures in the photoconductor and the spatial resolution of the detector. An idea of how these doping structures work in terms of resolution and speed of the detector is presented, together with proposals for an optimized doping scheme.

Process Integration of A-Si:H Schottky Diode and thin Film Transistor for Low-Energy X-Ray Imaging Applications

1998 ◽  
Vol 507 ◽  
Author(s):  
B. Park ◽  
R.V.R. Murthy ◽  
A. Sazonov ◽  
A. Nathan ◽  
S.G. Chamberlain
Keyword(s):  
Thin Film ◽  
Schottky Diode ◽  
Fill Factor ◽  
Process Integration ◽  
Thin Film Transistor ◽  
Sampling Period ◽  
Low Energy ◽  
Large Area ◽  
X Ray ◽  
X Ray Imaging

ABSTRACTIn this paper, we discuss the various design and fabrication issues related to the process integration of a molybdenum/amorphous silicon (Mo/a-Si:H) Schottky diode and a thin film transistor (TFT), for realization of an X-ray pixel intended for large area and low energy imaging applications. Here, the Schottky diode serves as the sensor and the TFT as a switching element for charge readout. Different pixel configurations are fabricated and compared taking into consideration design aspects such as leakage current, process sequence in terms of mask count, fill factor, and mechanical integrity of various layers. Preliminary X-ray response measurements, over the range (40 – 115) kVp, yield a pixel sensitivity of (1–10) million electrons for a readout sampling period of 16·7 ms.

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