What is described as 'non-negotiable for reproducible results' across both semiconductor preparation and biochemistry?

Answer

Purity of the interface.

In both preparing a semiconductor substrate (through cleaning/etching) and purifying an enzyme preparation in biochemistry, the purity of the interface is noted as non-negotiable for reproducible results.

What is described as 'non-negotiable for reproducible results' across both semiconductor preparation and biochemistry?
BasesubstrateMaterialreactionenzyme