MOSFET-gated transistor

11:37 Mar 15, 2018 

You wrote: « car le terme d'origine ce n'est pas MOSFET Transistor mais il y a le terme -gated qui m'inquiète »

...and you are right to be concerned, as you have rightly spotted this tiny detail (fortunately amplified in the explanation!) that makes all the difference in this very specialized area!

It is the combination of a 'conventional' bipolar junction transistor structure (with all its inhernet advantages) with a MOSFET drive to its base, giving the enormous advantage of high-impedance base drive (normally impossible to achieve in bipolar).

11:10 Mar 15, 2018 

PLEASE NOTE that this is a very special device! It is a lot more than just a simple MOSFET!!

Look at the source text carefully:

"MOSFET-gated bipolar junction transistor"

So this is a conventional bipolar junction transistor — i.e. specifically not a MOSFET!; the two technologies are quite separate and generally mutually exclusve, as they work in quite different ways.
HOWEVER, what we appear to have here is a 'conventional' bipolar (junction) transistor that in some way has a MOSFET gate. I confess I am not familiar with these particular devices, though I can visualize what they are, which is well explained in the source text.

It is vitally important here not to under-translate!

11:05 Mar 15, 2018 

Tu peux en effet traduire cette expression par "Transistor à grille MOSFET". Mais note que Toshiba défini MOSFET comme étant « transistor à effet de champ à grille métal-oxyde ». Donc l'idée de grille est contenue dans l'accronyme MOSFET. Tu as donc le choix entre la clarté, "Transistor à grille MOSFET" et la concision "Transistor MOSFET".