An integrated non-volatile memory circuit is formed by first growing a thin dielectric
layer on a semiconductor substrate surface, followed by depositing a layer of conductive
material such as doped polysilicon on this dielectric layer, the conductive material
then being separated into rows and columns of individual floating gates. Cell source
and drain diffusions in the substrate are continuously elongated across the rows.
Field dielectric deposited between the rows of floating gates provides electrical
isolation between the rows. Shallow trenches may be included between rows without
interrupting the conductivity of the diffusions along their lengths. A deep dielectric
filled trench is formed in the substrate between the array and peripheral circuits
as electrical isolation. Various techniques are included that increase the field
coupling area between the floating gates and a control gate. Other techniques increase
the thickness of dielectric between control gates in order to decrease the field
coupling between them.