Carsten Schaeffer

The Field Stop IGBT (FS IGBT). A new power device concept with a great improvement potential

By a vertical shrink of the NPT IGBT to a structure with a thin n/sup -/ base and a low doped field stop layer a new IGBT can be realized with drastically reduced overall losses. Especially the combination of the field stop concept with a trench transistor cell results in the almost ideal carrier concentration for a device with minimum on state voltage and lowest switching losses.

Investigations on the ruggedness limit of 6.5 kV IGBT

The save operating area (SOA) of high voltage 6.5 kV IGBTs has been investigated. The ruggedness of the IGBT with planar cell structure is limited by the hole current density in the cell structure arriving from the avalanche generation under turn-off conditions. The impact of current density, V/sub cc/ and vertical IGBT structure on the ruggedness has been taken into account. With a modified cell design the avalanche generation can be reduced significantly. Simulations with a trench IGBT promises additional SOA improvement.

1700 V-IGBT3: field stop technology with optimized trench structure

The IGBT3 technology, which combines a specific trench cell and the field stop concept, was first introduced for devices with 1200 V blocking voltage. It is now transferred to higher blocking voltage ratings. A new series of 1700 V devices is introduced, which compared with conventional NPT (= non punch through) devices has greatly reduced static and dynamic losses and preserves the well known ruggedness of NPT devices. With this new 1700 V chip generation a new product line of modules with up to 50% higher current capability in the same housing is available.

trend setting for the high power applications in industry and traction

A reverse conducting IGBT in trench technology is presented. By this approach no carrier life time means are necessary to balance static and dynamic losses of the diode. The diodes p-emitter efficiency can be dynamically tailored by the applied gate voltage due to inversion charge carriers in the vicinity of the gate trench. This opens up the opportunity for a variety of gate control schemes with the aim of a charge carrier reduction before commutation thus reducing the recovery and the corresponding IGBT turn-on losses while the on-state diode losses remain low. A simple substitution of the IGBT and diode dies by the RCDC chips in the industry standard packages enables a significant increase of the power density (e.g. up to 30% for typical traction application) due to a thermal benefit given by lower thermal resistances as well as by a reduction of the dynamic losses due to special gate control.