High-Voltage Silicon-Carbide Thyristor with an n-type Blocking Base

The possibility of creating a high-voltage SiC thyristor with an n-type blocking base is analyzed. It is shown that a thyristor structure fabricated as an "analog" of a modern thyristor structure with a p-type blocking base, i.e., with the same layer thicknesses and replaced doping types (donors instead of acceptors, and vice versa), cannot be turned-on at any input signal level. At room temperature, a structure with an n-type blocking base and acceptable parameters can only be obtained in the absence of a stop layer. In this case, however, the maximum blocking voltage is approximately two times lower than that for a thyristor with a p-type blocking base of the same thickness. In the presence of a stop layer, a portion of an S-shaped negative differential resistance appears at room temperature in the forward current–voltage characteristic of the thyristor with an n-type blocking base. This effect is due to the violation and subsequent restoration of neutrality. At ambient temperatures of T ≥ 150°C, the current–voltage characteristics of the thyristor with the n-type blocking base become quite acceptable even in the presence of a stop layer.