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I´m not sure if this statement is true. Comparing the MOSFET structure to the BJT, it is notorious a simplest arrangement of its P-N regions, what could induce on belief of a smaller effect of parasitic elements on its electric model.
Very seldom, if ever, true when you're talking about the BJT
as a saturating (i.e. any kind of efficient) switch. Raw small
signal bandwidth is another matter entirely.
BJTs have (generally) much smaller Cjc per Ic than a MOSFET
has Cdg for Id owing to the construction and physics of the
conduction. Just look at the conduction of a vertical bipolar
vs the MOSFET. BJT conducts orthogonal to the junction
plane and uses it all. MOSFET conducts parallel to the channel
plane and is velocity limited, cross-section constrained with
a whole lot of overhead plate capacitance that contributes
nothing to conduction.
A BJT uses minority carriers injected into the collector from the base. Excess carriers in a saturated transistor take a finite time to dissipate when the transistor is turned off, causing a significant storage delay time. This delay can be minimized by using a Schottky diode clamp between base and collector to keep the transistor out of full saturation (as is done in Schottky TTL circuits).
FETs are majority carrier devices whose flow is controlled by the gate field in the conduction channel and there is no storage/recombination effects to delay the turn-off. Thus the switching time is, in most cases, determined by how fast the large gate capacitance can be charged and discharged.
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