FLASH MEMORY CELL FABRICATION SEQUENCE

摘要

An abrupt drain junction and a graded source junction are fabricated using a common diffusion step, wherein the common diffusion step is used to create both the drain junction-and the source junction. The common diffusion step is accomplished while an oxide spacer is present over a gate stack, prior to the common diffusion step, resulting in faster source diffusion and a graded source junction, while the slower diffusion in the drain region results in an abrupt drain junction. The oxide spacer moves the drain junction further away from the gate stack to allow for greater cell densities.