torkil@psivax.UUCP (Torkil Hammer) (04/01/88)
Scientists here are proud to announce the succesful test of a Vacuum Channel Field Effect Transistor. (VCFET). The device is built in a cylindrical glass tube which is evacuated. The source is a rod along the centerline. A patented heater makes the majority carriers overcome the normal work function of escaping metal. In addition the heater serves as visual indicator (red) that the device is on, thus saving an LED. The drain is a concentric metal sheet just inside the tube. The gate is a concentric wire mesh between source and drain. The real news is that *several* gates can be made, mounted concentrically within the channel. The one closest to the source is the main or control gate. Additional gates will modulate the transconductance slightly, and can be tailored to linearize the transfer function or implement miscellaneous other effects. Other advantages of the V channel FET include: * Visual indicator of operation (red light from source) * Visual indicator of overload (blue light from drain) * No upper limit to physical size of the device, which makes it possible to have device dissipation in the kilowatt range, using water cooling of the drain. Ideal for a large radio transmitter. * Inherent high cutoff frequency for radar and microwave operation * Single device analog multiplier (using 2 gates) * Single Device HF amplifier/oscillator/mixer (using 5+1 gates) So far we have only had succes with negative majority carriers. We expect to develop a complementary device by same date next year, though the mobility of holes in this particular type of channel remains lower than that of electrons. torkil ;----------------------------------------------------------------------- ; Opinions expressed herein are expressly void where prohibited by law. ; We have additional gotchas which depend more on your state of mind ; than your state of residence, though you will never know. ;-----------------------------------------------------------------------
henry@utzoo.uucp (Henry Spencer) (04/03/88)
But as our electronics man (whose experience dates back to WW2) says:
"linear it ain't".
--
"Noalias must go. This is | Henry Spencer @ U of Toronto Zoology
non-negotiable." --DMR | {allegra,ihnp4,decvax,utai}!utzoo!henryjeffw@midas.TEK.COM (Jeff Winslow) (04/06/88)
In article <2154@psivax.UUCP> torkil@psivax.UUCP (Torkil Hammer) writes: >Scientists here are proud to announce the succesful test of a >Vacuum Channel Field Effect Transistor. (VCFET). Ummm, yes, come back when you've figured out how to implement VLSI with it. :-) Jeff Winslow
jtkung@mit-caf.UUCP (Joseph Kung) (04/07/88)
In article <2799@midas.TEK.COM> jeffw@midas.UUCP (Jeff Winslow) writes: >In article <2154@psivax.UUCP> torkil@psivax.UUCP (Torkil Hammer) writes: >>Scientists here are proud to announce the succesful test of a >>Vacuum Channel Field Effect Transistor. (VCFET). > >Ummm, yes, come back when you've figured out how to implement VLSI with it. > > :-) > Jeff Winslow It can be implemented with CMOS circuitry, but the real benefit is not the density of "VLSI" but the radiation hardness of the FET. No oxide traps, etc. Great for military applications. The VGFET (vacuum gate field effect transistor is more appropriate a name) has been demonstrated here as well. - Joe -- Joseph Kung ARPA Internet : jtkung@caf.mit.edu (Internet address : 18.0.62.232) UUCP: ...!{ihnp4,harvard,seismo,rutgers}!mit-eddie!mit-caf!jtkung