X-ray micro beam analysis of the photoresponse of an enlarged CVD diamond single crystal

Diamond is one of the most promising materials for developing innovative electronic devices. Chemical vapour deposition (CVD) homoepitaxial growth allows the synthesis of high quality single crystal diamond plates. However, the use of these crystals for electronic applications is hampered by their small area (typically of the order of 10 mm2). Large areas are desired to ensure efficient particle or radiation detection with pixelated devices. By growing a thick CVD layer it is possible to enlarge the initial area of the substrate by a factor of 2 since growth also occurs laterally from the substrate. In this work, by using an X-ray collimated synchrotron radiation beam, the detection and charge collection properties of an enlarged CVD single-crystal diamond are used as a point-to-point probe to study the material quality. It was found that stress and dislocation density are correlated with the detection properties of the enlarged regions. The sensitivity of the device is affected by the vertical-to-lateral growth interface and the enlarged material quality seems to be correlated with the distance from this interface.