High Frequency Capacitive behavior of field stop trench gate IGBTs operating in Short Circuit
A wide experimental characterization about the input capacitance of Field Stop Trench Gate IGBTs is presented. It was achieved thanks to a novel experimental set-up which allows us to measure the input capacitance in the active region where the device operate during the Short Circuit (SC). The experimental results have been interpreted with the help of FEM simulations which confirm that negative capacitance is correlated with the accumulation of holes at the interface between N- IGBT base and gate oxide.
Analysis of Low- and High-Frequency Oscillations in IGBTs During Turn-ON Short Circuit
The purpose of this paper is to present a detailed experimental and numerical study on the mechanisms involved in Insulated Gate Bipolar Transistor (IGBT) instability during turn-ON short circuit that can compromise its robustness in particular load and driving conditions. It is shown that the IGBT may exhibit oscillations at both low and high frequencies depending on different physical mechanisms. Furthermore, a new methodology that allows determining the stability limits of the device in relation with the parameters of the external circuit is proposed. The experimental measurements confirm the obtained results.
Destruction mechanism of PT and NPT-IGBTs in the short circuit operation-an estimation from the quasi-stationary simulations
There is a spontaneous destruction of IGBT during the load-shorted operation. This paper reports some results of simple quasi-stationary simulations on PT and NPT-IGBT with the same n-collector length and lifetimes, changing the anode structure and driving gate voltages. Through the process of examining the only analysis on such a destruction by Hagino et al. (1996), the author have intended to get a simple image of the critical operation of IGBTs. As the result, in addition to their proposed one, an unknown positive feedback mechanism would seem to exist. Though the destruction limit of IGBTs must be of the order of 1 MW/cm/sup 2/, there would be no universal critical value as the bipolar transistor.