A high-power gate-controlled switch (GCS) using new lifetime control method

A high-power gate-controlled switch (GCS) with high switching speed was developed using a new method for controlling minority-carrier lifetime where both iron and gold were doped into the device. An improved temperature dependence of the forward voltage drop of the device was obtained because each of the forward voltage drops determined by iron and gold has opposite temperature dependence. The lifetime was controlled reproducibly by two-step diffusion of lifetime killers, that is, iron diffusion at high temperature and gold diffusion at lower temperatures afterwards. The relation between the forward voltage drop and the lifetime was theoretically analyzed and the agreement between the theory and experimental results was fairly good. The GCS of 0.15-cm
²
active area has the ratings of blocking voltage of 1500 V, available turn-off current of 160 A, forward voltage drop of 3 V at anode current of 100 A, and turn-off gain of 9. The turnoff time and turn-on time of less than 2 µs could be obtained. The
dv/dt
and
di/dt
are 1000 V/µs and 500 A/µs, respectively. The operation of 50 kHz at 100 A/1000 V could be realized with the inductive load of 50 µH by the GCS. The SIPOS (SemiInsulating POlycrystalline-Silicon) passivation was applied to the GCS in order to obtain the high reliability.