[cryptography] a Cypherpunks comeback

[coderman]

On Tue, Jul 23, 2013 at 5:35 AM, Riad S. Wahby <rsw at jfet.org> wrote:
> ...
> Most vanilla CMOS processes don't have high quality JFETs available. On
> older nodes maybe you can get away with turning an N-well and a P+
> diffusion into a JFET, but that doesn't work very well in more modern
> processes because the N-wells have strongly retrograde doping, which
> makes it hard to pinch off the "bottom" of the channel. Of course, even
> at older nodes where it might be possible, the fabs don't bother
> characterizing it for you. Sure, you can characterize it yourself, but
> if the fab isn't supporting the device that implicitly means they're not
> monitoring the quality of that device with their PCM structures, so good
> luck with manufacturability long-term.
>
> JFETs are pretty easy to make in high quality bipolar processes because
> the base diffusion makes a decent JFET body. Doesn't add much/any cost
> to have them in this case. Of course, if you have a BiCMOS process, then
> you already have devices with high impedance gates, but for high
> performance analog design a JFET beats the hell out of a MOSFET, since
> the latter brings along with it a shitload of 1/f noise.
>
> One place I've recently seen JFETs is in really high voltage processes.
> Think like a mostly normal 0.18u CMOS process with a 600V (Vds) JFET
> available. Haven't actually worked in such a beast, but you can imagine
> that compared to MOSFETs, JFETs don't make such great power devices---
> who ever heard of a depletion-mode power switch?


this is the most informative and useful post ever made in the
al-qaeda.net discussion...  which happens to be the most ridiculous
discussion full of fear and weakness.

cypherpunks afraid of a domain name...  wtf