An Electrically Erasable Programmable Read Only Memory (EEPROM) memory
cell and a method of operation are disclosed for creating an EEPROM
memory cell in a standard CMOS process. A single polysilicon layer is
used in combination with lightly doped MOS capacitors. The lightly doped
capacitors employed in the EEPROM memory cell can be asymmetrical in
design. Asymmetrical capacitors reduce area. Further capacitance
variation caused by inversion can also be reduced by using multiple
control capacitors. In addition, the use of multiple tunneling capacitors
provides the benefit of customized tunneling paths.