Irradiating by electron beams has been widely adapted in the fabrication of fast switching power thyristors. However

accompanying beneficial reduction in switching speed there is a deleterious increase in forward voltage drop. Methods which minimize the voltage drop increase as the switching speed is reduced are highly desirable

one such method would achieve this by introducing the traps or recombination centers into well defined narrow regions where they will be more effective in reducing the switching speed than in increasing the forward voltage drop. Because the proton rang-energy relationship is relatively well defined

such kind of well defined narrow region can be formed by the precise control of irradiation proton energy. Dual energy proton beams from the HI-13 tandem accelerator were used in the experiments. The results indicate that this is a preferred technique for processing fast switch thyristors with superior characteristics.