The present invention provides a flash memory integrated circuit and a method
of fabricating the same. A tunnel dielectric in an erasable programmable read only
memory (EPROM) device is nitrided with a hydrogen-bearing compound, particularly
ammonia. Hydrogen is thus incorporated into the tunnel dielectric, along with nitrogen.
The gate stack is etched and completed, including protective sidewall spacers and
dielectric cap, and the stack lined with a barrier to hydroxyl and hydrogen species.
Though the liner advantageously reduces impurity diffusion through to the tunnel
dielectric and substrate interface, it also reduces hydrogen diffusion in any subsequent
hydrogen anneal. Hydrogen is provided to the tunnel dielectric, however, in the
prior exposure to ammonia.
