What are the layout methods to make source to drain capacitance zero?

What are the layout methods to make source to drain capacitance zero?

i know nothing about ASIC design, etc
but i do know a little physics

you have two pieces of metal, separated by some distance - that is a capacitor

you can reduce the capacitance, but you cannot make it zero

The only things that makes zero capacitance are infinite distance
or zero facing (+ fringing) area. Since you say you want a real
thing, that eliminates the "zero area" option.

Good luck with the die size, then.

Or you can design to real numbers and engineer a "best practical".

The layout method to reduce coupling capacitance is shielding, or screening.
Net A placed between nets B and D reduces coupling capacitances between B and D.
A structure that completely shields an object from an outside world is called Faraday cage.
In real layouts, it may be difficult to reduce coupling capacitance to zero, but it can be reduced significantly.

A practically useful thing is finding areas - layers, polygons, etc. - that are "creating" capacitance, and increase the distance between them, or/and put a shield over there.

As an example - in power devices, capacitance from drain to gate (Cgd) is much more important than capacitance from source to gate.
So, it's a common practice, to use source metallization to shield drain from gate - it's usually called field plate (see, for example, numerous app notes and books published by company called Efficient Power Conversion - EPC).
(in vertical / trench FETs, it's a buried source, formed in silicon, that is used to minimize Cgd).

Infinite distance is not always effective at reducing the capacitance.
As an example, a capacitance of a metal sphere is equal to its radius (multiplied by a coefficient, dependent on the system of units) - that's the capacitance to infinity.

By the way, in parasitic extraction in IC design flow, capacitance to infinity (if it happens to be non-zero) is lumped (i.e. added) to the capacitance to "ground net".

Max