Method for reducing the capacitance across the layer of tunnel oxide of an electrically-erasable programmable read-only-memory cell

摘要

The capacitance across the layer of tunnel oxide in an electrically-erasable programmable read-only-memory (EEPROM) cell is reduced by forming the layer of tunnel oxide to have a first region which is substantially thicker than a second region. The thicker region of tunnel oxide results from doping the buried region exposed by the tunnel window so that the buried region has different levels of dopant concentration. When the tunnel oxide is then grown over the buried region, the oxide formed over the more heavily doped portion grows at a faster rate than does the portion with the lower dopant concentration.