Mode-transition optimized 4.5 kV IGTT (IGBT mode turn-off thyristor)

A 4.5 kV IGBT mode turn-off thyristor (IGTT) with optimized mode-transition for realizing a low power loss, that is, a low forward voltage drop (V_f) and a low turn-off loss (E_off) is described for the first time. The device concept of optimizing the vertical carrier distribution was demonstrated by the IGBT mode turn-off operation combined with the proton(H⁺)-irradiation technique. The E_off value of 18 mJ/cm² was attained with V _f of 2.1 V at an anode current density of 25 A/cm². This value of E_off is 30 to 35% smaller than that for conventional MOS-gated thyristors. As a result, the trade-off relation between V_f and E_off is greatly improved for 4.5 kV devices