(WO9850955-A1)      Semiconductor imaging device has a semiconductor radiation substrate (11). Conductive charge output contacts (13) are formed on one face, and another contact (12) is formed on the other face for applying a bias voltage to form an electric field. It has a covering of a different material (20) which may be a conductive, non-conductive, semiconductor or passivation material, e.g. aluminium nitride, deposited by sputtering, evaporation or electrolysis.    The substrate is made of CdZnTe, CdTe, PbI, HgI, GaAs or Ge. The device comprises a number of detector cells within the substrate, each having a respective charge output contact. A readout substrate with an array of image cell circuits receives charge from the cells. It is bonded to the detector substrate, and they are encapsulated to form the device.    ADVANTAGE -   Linear detector behaviour is retained at all combinations of exposure and x-ray tube voltage.    (GB2325081-B)      Semiconductor imaging device has a semiconductor radiation substrate (11). Conductive charge output contacts (13) are formed on one face, and another contact (12) is formed on the other face for applying a bias voltage to form an electric field. It has a covering of a different material (20) which may be a conductive, non-conductive, semiconductor or passivation material, e.g. aluminium nitride, deposited by sputtering, evaporation or electrolysis.    The substrate is made of CdZnTe, CdTe, PbI, HgI, GaAs or Ge. The device comprises a number of detector cells within the substrate, each having a respective charge output contact. A readout substrate with an array of image cell circuits receives charge from the cells. It is bonded to the detector substrate, and they are encapsulated to form the device.    ADVANTAGE -   Linear detector behaviour is retained at all combinations of exposure and x-ray tube voltage.    (US6188089-B1)      Semiconductor imaging device has a semiconductor radiation substrate (11). Conductive charge output contacts (13) are formed on one face, and another contact (12) is formed on the other face for applying a bias voltage to form an electric field. It has a covering of a different material (20) which may be a conductive, non-conductive, semiconductor or passivation material, e.g. aluminium nitride, deposited by sputtering, evaporation or electrolysis.    The substrate is made of CdZnTe, CdTe, PbI, HgI, GaAs or Ge. The device comprises a number of detector cells within the substrate, each having a respective charge output contact. A readout substrate with an array of image cell circuits receives charge from the cells. It is bonded to the detector substrate, and they are encapsulated to form the device.    ADVANTAGE -   Linear detector behaviour is retained at all combinations of exposure and x-ray tube voltage.