The goo inside of IGBT modules.

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Original poster: "Steve Ward" <steve.ward-at-gmail-dot-com> 

Hi,

Since there seem to be a handful of experienced power engineers
around, i was just curious, what is the true function of the gel type
stuff they put inside of big power semiconductors (ive seen it in
IGBTs as well as SCRs).  My thoughts were that it was to help contain
the explosion when they fail.  Also, that it may prevent moisture from
getting on the dies and shorting it all out (since the module casing
is not completely air tight).

But what was more important to me was whether or not the goo serves
any use in removing heat from the dies?  Im not sure if this gel is a
thermal insulator or a conductor really... its hard to say.  Does
anyone know for sure?

Steve

PS. anyone have any IGBT bricks for sale?  Im always looking for
spares for my big coil!  Contact me off-list.