An array of floating gate transistors of a non-volatile memory, NVM, cell includes floating gate transistors separated from one another by high-concentration dopant impurity regions and without using shallow trench isolation (STI) or field oxide (FOX) isolation structures. The array is formed over a substrate portion that includes a continuous and planar upper surface. The high-concentration dopant impurity regions are formed in a P-field region and are formed of the same dopant impurity species as the P-field region but of a higher concentration. The floating gate transistors are split-gate floating gate transistors in some embodiments.