MOS-Speicherzelle mit einem exponentiellen Dotierungsprofil und mit versetztem Tunneloxid des schwebenden Gates

A semiconductor memory device having a CMOS memory cell with a floating gate (18) and increasing concentration of dopant in the source (14), drain (12) and channel (25) regions. Typically the concentration profile is generally exponential. The device has relatively high diffusion current densities accelerated toward the surface and directed toward the channel/drain interface. Gate oxidation thickness is reduced over the channel (25) near the drain (12) to create a tunnel "window" (30) in the area of greatest electric field magnitude.