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Analysis of the BJT Activation during the Power MOS diode turn-off
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| Author(s) |
G. Vito Persiano; F. Iannuzzo; G. Busatto; P. Spirito |
| Abstract |
The activation of the parasitic bipolar transistor
inherent in a power MOSFET used as a fly-back
diode is investigated. Numerical simulation is used
to highlight the activation process and to analyse
the effects of the geometrical and physical
parameters of the MOSFET structure. It is shown
that the additional electron injection due to the
BJT activation results in higher recovery times
and peak reverse currents, thus significantly
affecting the MOSFET reliability. A comparison
between numerical and experimental results points
out that the BJT activation can be detected in most
of times by the waveform shape of the drainsource
voltage during the reverse recovery of the
MOSFET. It is also shown that the occurrence of
an activation of the parasitic BJT can be more
reliably related to the charge removed from the
epilayer at the turn-off. Among the physical and
geometrical parameters of the device a key role in
the activation mechanism is shown to be played by the body contact and the P+ body region
resistances. |
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| Filename: | EPE1999 - PP00602 - Persiano.pdf |
| Filesize: | 185.5 KB |
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| Type |
Members Only |
| Date |
Last modified 2004-03-29 by System |
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