The 20nm 64Gb NAND uses a planar cell structure -- the first in the industry -- to overcome the inherent difficulties that accompany advanced process technology, enabling performance and reliability on par with the previous 25nm generation.
The planar cell structure integrated a Hi-K (high capacitance) metal gate stack into the NAND production to allow for smaller floating gates and thus higher storage capacity.
Those who are "self-radicalized, " who remain beyond any cell structure, who drift from one job or place of residence to another (as Merah did) are the most difficult to track.