It is possible to avoid switching losses given with Qrr by
using 600V SiC Schottky diode witch haven’t reverse
recovery effect but their losses are related to capacitance
reverse current peak in simplicity. A Solution combine
good properties of PN and Schottky diode was developed
recently and is called Merged-Structure. Both devices are
connected together with low impedance p regions to the
anode of the device (Fig. x1). This concept used
advantages of the wide bandgap potential of SiC, witch
under normal conditions have relatively high junction
voltage (3-4V). This fact prevents conduction of PN
structure. In overload conditions the forward drop of
Schottky diode will rise to value of junction voltage so PN
structure provides hole-carrier injection for conductivity
modulation in the drift region. Task of p bodies is
concentrating the maximum electric field away from
Schottky barrier surface. This allows working with higher
blocking voltage and another advantage is higher
ruggedness of device. Due to the material characteristics of
the SiC and other facts is reverse recovery charge is
essentially unmeasurable. In basics, connecting these two
diodes together should result in the lower forward
dissipation of the Schottky at current levels up to a few
times the rated forward current of the diode, with the large
overload capability and higher peak current of the PN
structure