Charge transfer in the presence of a layer of trapping centers in semiconductor SiC ionizing radiation detectors

The formation of a response signal in the presence of a layer of trapping centers in semiconductor SiC ionizing radiation detectors is considered on the basis of a new model. Since the trapping layer is situated near the detector surface, nuclear particles that possess long tracks partly generate a charge behind this layer. Under certain conditions, the proposed model leads to a paradoxical situation, in which the signal decreases with increasing bias voltage. The application of the model to results obtained using ion-doped 4H-SiC detectors provides a qualitative explanation for the experimentally observed increase in the signal with the temperature in the region of saturation with respect to the bias voltage (i.e., under the conditions of total charge transfer), which were previously unclear.