[JN] VFET vs. Mosfet Vs. JFET
grego at sandesco.com
Tue Jan 13 11:39:37 CST 2009
jc morrison wrote:
> just to be clear, a VFET is not mos...
Not clear at all, depends on your definition of MOS (or mos...).
VFET or VMOS devices can be built in a number of ways.
All of which include some sort of implanted oxidized channel structure.
In fact most small geometry CMOS processes built today (below 90nm) are
vertical FETs and are by definition, MOS devices.
Of course the S in MOS is often replaced by GaAs, but is that really the
As I recall, the SONY VFETs used a diffused silicon channel, so they
were MOS by definition.
As to RF devices, I would watch out for 1/f noise. Most are not even
characterized for it, much less optimized for it. I deal with that
aspect of them in my day job.
Because of the isolated gate structure, JFETs make excellent low power
audio devices, in both amplifier and switching applications.
I am out of touch with power FETs so won't comment there. I understand
there are some GaAs VFETs available there but again, the 1/f noise may
be an issue (or not).
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