M. Nandakumar et Bj. Baliga, MODELING THE TURN-OFF CHARACTERISTICS OF THE BASE RESISTANCE CONTROLLED THYRISTOR (BRT), Solid-state electronics, 38(3), 1995, pp. 703-713
An analytical model is described for the turn-off mechanism in the BRT
. The assumptions which form the basis of the model are drawn from the
results of two-dimensional numerical simulations of the turn-off proc
ess. It is shown that the device turns off when all the charge from th
e P-base is removed by the current flowing through the P-channel MOSFE
T into the diverter region. Based upon this, an expression has been de
rived for the time required for removal of the hole charge from the P-
base (defined as the storage time). An expression for the maximum cont
rollable current for the BRT (where it fails to turn off) has been der
ived by the condition that the storage time becomes infinite. The mode
l predicts a decrease in the maximum controllable current with increas
e in the P-base sheet resistance and PMOS channel resistance. Based on
the model, the maximum controllable current is shown to decrease with
emitter width and increase, with emitter length. These predictions ha
ve been confirmed by experimental resistive load turn-off measurements
on unit cell BRT devices. Consistent with the model, the measurements
indicate no change in the controllable current with load voltages up
to 500V, indicating good RBSOA. The model has also been extended to ca
lculate the holding current of the BRT and its dependence on device pa
rameters.