Analysis of the turn-on process in 6 kV 4H-SiC junction diodes

摘要

The switch-on process in 6 kV 4H-SiC junction diodes has been investigated experimentally and theoretically. The results of a detailed computer simulation are compared with the data furnished by the analytical theory. It is demonstrated that, at high current densities exceeding the critical value j(cr) = eN(D)v(s) (e is the elementary charge, N-D is the base doping level, and v(s) is the carrier saturation velocity) and rather short current rise time (1 ns), an extremely fast base modulation can be achieved. In this mode, the base is spanned by an electron front that moves from the n(+)-n to the p(+)-n emitter with a velocity v(s) and by a relatively slow quasi-neutral hole front moving in the opposite direction, from the p(+)-n to the n(+)-n junction.