A novel CID structure for improved breakdown voltage

Charge injection devices (CIDs) used as infrared detectors incorporate a field plate between the sensing gate electrodes to serve as a channel stop. Two-dimensional computer simulations indicate that such sensing gate/field plate configurations exhibit an enhanced electric field at the edge of the sensing gate electrode. They further show that the edge field enhancement can be eliminated if the field plate is biased into deep depletion. However, in order to preserve the channel isolation, the bias of the field plate cannot be set beyond the flatband voltage. These problems have been solved with an InSb CID cell in which a buffer gate is inserted between the sensing gate and the field plate with a buffer gate electrically tied to the sensing gate, making it an integral whole. This design has shown more than a doubling of the breakdown voltage with a corresponding doubling of the well capacity without degrading other detector characteristics