Investigations on Electro-instability of Low Voltage, High-currentMOSFETs: Theoretical Models and Experimental Comparison Resultsfor Different Structures

摘要

This paper analyzes an anomalous failure mechanism detected on the latest generation oflow voltage Power MOSFETs used in high current applications. Some designs, especially in theautomotive field, require that MOSFETs be used in linear mode for which no complete datasheetcharacterization exists. Also modern devices have been designed for ever-decreasing on-resistanceand very high current capability at the expense of reduced FBSOA (Forward-biased Safe OperatingArea).We start by showing a theoretical model of the failure mechanism, which bears a resemblance to asecondary breakdown phenomenon. The device’s performance is then related to some physicalparameters that impact its ability to safely work in that region.Finally experimental results are discussed that compare different MOSFET structures.