apparently this is nearly impossible because the geometry of the transistors
(discrete or inside IC's) cannot switch at that speed (typically a
nanosecond). You would need something that worked in the femtosecond, and
if anything came close to it that would change the frequency (in English, it
would be very unstable). Even transistors that work in 10's of gigahertz
(you would only see them in the army) would need amazingly sophisticated
technology to make it.
Regards