Characterization of 4 inch GaAs:Cr wafers

Producing of large area matrix detectors based on semiconductor materials with high atomic number suitable for the registration of the synchrotron radiation of high intensity in the photon energy range 20–90 keV is a relevant technological challenge of our time. This will develop a fundamentally new experimental base of scientific research conducted at leading X-ray synchrotron centers with high luminosity beams. The paper analyzes the possibility of using 4 inch gallium arsenide wafers to create a high-resistive GaAs:Cr detector quality structures on their basis and detector arrays of large area

Chromium-Compensated GaAs Detector Material and Sensors

Results obtained from numerical calculations of and experimental studies on the pulse height distribution inherent in ionizing radiation gallium arsenide sensors as a function of the design features of the devices and electrophysical characteristics of the detector material are presented. It is shown that the pulse height distribution is defined by the distribution pattern of the nonequilibrium charge carrier lifetime and by the electric field profile in the bulk of the sensor. Investigations on the detector sensitivity to X-ray energies in the range between 40 and 150 keV were performed. The sensor polarization was found to produce only a marginal effect compensated by an increase in the bias voltage. Prototype pixel sensors measuring 256 × 256 and 512 × 768 pixels with a 55 μm pitch and a 500 μm thick sensitive layer were produced. The dependence of the photocurrent and count rate on the X-ray radiation intensity and bias voltage applied to the sensor was examined. In the 40–80 keV energy range, the maximum count rate amounted to 800 kHz/pixel for a negative sensor bias voltage of 800 V. The sensors are demonstrated to provide spatial resolution varying with the pixel pitch and to enable high-quality X-ray images to be obtained

Characterization of 4 inch GaAs:Cr wafers

Producing of large area matrix detectors based on semiconductor materials with high atomic number suitable for the registration of the synchrotron radiation of high intensity in the photon energy range 20–90 keV is a relevant technological challenge of our time. This will develop a fundamentally new experimental base of scientific research conducted at leading X-ray synchrotron centers with high luminosity beams. The paper analyzes the possibility of using 4 inch gallium arsenide wafers to create a high-resistive GaAs:Cr detector quality structures on their basis and detector arrays of large area