Collector Engineered Bidirectional Insulated Gate Bipolar Transistor With Low Loss

The collector engineered bidirectional insulated gate bipolar transistor (CEB-IGBT) with p-buffer and semi-superjunction (Semi-SJ) is proposed. The structural modification at collector side provides support to reverse breakdown voltage (
$\text {BV}_{R}$
) in two ways. First, the p-buffer layer allows the device to deplete completely and eliminates premature breakdown effects. Second, the Semi-SJ region introduces an electric field component in the
${x}$
-direction (
${E}_{X}$
) in order to further improve the
$\text {BV}_{R}$
. The overall increased electric field, which is a resultant of
${E}_{X}$
and
${E}_{Y}$
, improves
$\text {BV}_{R}$
by 53.83% compared to nonpunchthrough IGBT (NPT-IGBT). The efficient potential distribution in the drift region provides support to forward breakdown (
$\text {BV}_{F}$
) as well. The n-layer below p-body acts as a field stop (FS) layer, which reduces the leakage current during the OFF-state condition. The p-buffer, which injects higher minority charges along the drift side and n-layer with charge storage effect collectively, provides conductivity modulation in the epitaxial region in order to increase current handling capability. This high collector current density leads to reduce
${V}_{ \mathrm{\scriptscriptstyle ON}}$
by 14.5% compared to NPT-IGBT. Furthermore, the charge coupling effect of Semi-SJ region enables the proposed device to turn-off quickly with higher pillar doping and reduces turn-off loss (
${E}_{ \mathrm{\scriptscriptstyle OFF}}$
) in comparison with NPT-IGBT.