That's not entirley acurate Claude. Mind you were drawing a VERY fine line here but FET's don't need current to be active, they do need a current flow to switch but once charged the gate itself if properly insulated will not draw current the leakages discussed are a separate matter. It seems like a small quibble but it's technically correct to say FETS are charge controlled devices. BJT's are almost always referred to as current controlled devices, however this is also technically inaccurate as even though current has to flow for the devices to operate; on an atomic scale it's actually the voltage fields that develop at the PN junctions that cause the amplification effect to occur, current however has to flow for those voltage fields to exist. So it's definitely a co-dependancy thing, I just think it's an important distinction to say voltage controlled fets need charge, not current. This is of course only correct for ideal FET's, the real world is much more complicated and some gate current is unavoidable in real world operation.
I'm afraid it is technically accurate. First highlight in your quote, as far as FETs being *charge controlled* devices, I've been saying that forever! Check my posting history and that will be affirmed on this forum or anywhere else I've posted. A FET is ultimately charge controlled. But at the mAcro black-box viewpoint, in order to charge up the gate and channels, should we use a constant voltage source, or constant current? A CVS works better for FETs, and a CCS better for bjt's. Hence the terms current & voltage controlled.
Second bold highlight, you keep referring to "voltage fields", and I ask you where that comes from. In all fields texts in EE & physics, there are E, D, B, & H fields. What on earth is a voltage field? In a bjt, the amplification takes place with both current and voltage, just as a FET. The transport of electrons from emitter to collector is what we call transistor action, since the base is so thin, carriers go right through and reach the collector. Otherwise it is just 2 back to back diodes. The current gain is due to transport as I just mentioned. The voltage gain is due to the small b-e voltage drop needed since a forward p-n junction exhibits large current swings with only small voltage swings. Hence the bjt has a large transconductance, higher than a FET. Ultimately a bjt is charge controlled as well. I've been saying this for years.
I've always stated that bjt & FET are charge controlled at the mIcro level. The CC & VC models are only black box 1st order models, not meant to explain atomic interaction.
Third bold statement in your quote - sure voltage controlled FETs need charge, but to say "not current" is incorrect. How does the charge reach the device if we don't transport it there? We have to move charges into and out of the device. That charge motion time derivative is current. When you say "we need *charge*, *not current*, you are contradicting yourself. You treat current as if you wish it didn't exist, acknowledging it but downplaying its role entirely. Current is just dq/dt where q is charge. Do you know the related math? Have you had calculus, differential equations, fields, etc.?
All electrical devices in the universe need I & V both. One is just as important as the other, but not more so. So we appear to agree that at the mIcro level, the charge control model is best for both FET & bjt. At the mAcro level we regard the voltage control FET model & the current control bjt model to be 1st order approximations based on black box behavior, NOT on semi physics. No point in arguing further.