Charge transport in 4H-SiC detector structures under conditions of a high electric field

Transport of nonequilibrium charge packets in a structure with a Schottky barrier fabricated on a CVD-grown n-4H-SiC film has been studied at the maximum strength of an electric field at 1.1 MV/cm. The charge was introduced by separate α-particles and recorded by nuclear spectrometric techniques. A superlinear rise in the recorded charge as a function of the reverse bias applied to the structure was observed. Simultaneously, and also superlinearly increased the scatter in the spectrum of the charge amplitude. The observed effect is attributed to the initial stage of impact ionization. The manifestation of the process at unconventionally low fields (∼1 MV/cm) is accounted for by specific features of the process of charge generation. Carriers generated by slowing-down α-particles are “hot” from the very beginning.