EEPROM CELL AND FABRICATING METHOD THEREOF

摘要

PURPOSE: An EEPROM(electrically erasable and programmable read-only-memory) cell is provided to prevent a writing/erasing defect caused by misalignment of a buried N+ region and a tunnel region by forming a spacer pattern on the sidewall of an opening of a mask pattern used as an ion implantation mask for forming a buried N+ region and by forming the tunnel region while using the spacer pattern and the mask pattern as an etch mask. CONSTITUTION: An isolation layer is formed in a semiconductor substrate(50) to define an active region. A source region(80), a buried N+ region(56) and a drain region are formed in the active region, separated from one another. A cell depletion region(78) is formed in the active region between the buried N+ region and the drain region, electrically connected to the buried N+ region. The first channel region is defined between the source region and the buried N+ region. The second channel region is defined between the cell depletion region and the drain region. A memory gate(74) is formed on the first channel region and the buried N+ region. A select gate(76) is formed on the second channel region. A tunnel oxide layer is formed on a tunnel region(60) positioned on the buried N+ region. The lateral distance from the boundary of the tunnel region to the boundary of the buried N+ region is uniform.