Ralf Lerner

Device engineering for a modular 650 V transistor assortment

Using a trench isolated 650 V quasi-vertical n-channel DMOS as a starting point several new 650 V transistor types have been evaluated. Mainly by design measures a 650 V depletion DMOS, a 650 V PMOS and a 650 V IGBT were created for a modular integration into the process flow. Design modifications like increased channel length, well constructions and drain modifications were used to create the new devices. Original n-channel DMOS design features like curvatures or field plate constructions have been re-used. Necessary new process steps for the depletion transistor and for the IGBT were kept to minimum additional process effort and use a flexible process approach with independent addable modules.

PT-IGBT and freewheeling diode for 3.3 kV using lifetime control techniques and low-efficiency emitters

The adjustment of emitter efficiency by variation of doping profiles or application of lifetime control techniques such as irradiation of electrons and helium are two generally recognized concepts for the improvement of power device characteristics. In this work both concepts were studied by use of device simulation for the development of an IGBT and freewheeling diode chipset for 3.3 kV. Simulations were performed using an extended recombination model and recombination center data taken from measurements at different irradiated devices. Finally, this lead to the manufacturing of an IGBT using low-emitter efficiency and an irradiated freewheeling diode. The experimental results are in good accordance with the previously performed simulations and give evidence of the capabilities of present device simulation tools.