Experimental behavior of single-chip IGBT and COOLMOS devices under repetitive short-circuit conditions

This work presents the behavior of single-chip insulated gate bipolar transistors (IGBT) devices under repetitive short-circuit operations. The 600 and 1200 V nonpunch through IGBTs as well as 600 V COOLMOS (trademark of Infineon Technologies) have been tested. The repetition of these severe working conditions is responsible for devices ageing, and results unavoidably in the components failure. A series of experimental tests were made in order to determine the number of short-circuit operations the devices can support before failure for different dissipated energies. The temperature influence has been also investigated. Results show two distinct failure modes depending on the dissipated energy during the tests. A critical value of short-circuit energy has been pointed out which separates these failure modes. Experimental and numerical investigations have been carried out in order to analyze these failure modes. A detailed analysis of the physical mechanisms occurring during the short-circuit failures for dissipated energies equal or lightly higher than the critical value is presented.

I. Introduction

Power semiconductor devices may suffer from extremely hard working operations, resulting from an accident in the case of short-circuit conditions, depending on the application circuit and its environment. So, it is important to carry out investigations on the behavior of power devices under such severe repetitive working operations. The questions which are still in abeyance are as follows. •

How many short-circuit pulses can support a given device before failure for given operating conditions?

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Can we observe any ageing effect on the devices and is there any electrical characteristic ageing criterion?