Evaluation of 320 x 240 pixel LEC GaAs Schottky barrier X-ray imaging arrays, hybridized to CMOS readout circuit based on charge integration

320 x 240 pixels GaAs Schottky barrier detector arrays were fabricated, hyb ridized to silicon readout circuits, and subsequently evaluated. The detect or chip was based on semi-insulating LEC GaAs material. The square shaped p ixel detector elements were of the Schottky barrier type and had a pitch of 38 mu m. The GaAs wafers were thinned down prior to the fabrication of the ohmic back contact. After dicing, the chips were indium bump, flip-chip bo nded to CMOS readout circuits based on charge integration, and finally eval uated. A bias voltage between 50 and 100 V was sufficient to operate the de tector. Results on I-V characteristics, noise behaviour and response to X-r ay radiation are presented. Images of various objects and slit patterns wer e acquired by using a standard dental imaging X-ray source. The work done w as a part of the XIMAGE project financed by the European Community (Brite-E uram). (C) 1999 Elsevier Science B.V. All rights reserved.