METHODS OF MAKING FLASH MEMORY CELL ARRAYS HAVING DUAL CONTROL GATES PER MEMORY CELL CHARGE STORAGE ELEMENT

摘要

Methods of fabricating a dual control gate non-volatile memory array are described. Parallel strips of floating gate material are formed over the substrate in a first direction but separated from it by a tunnel dielectric. In the gaps between these strips control gate material is formed forming a second set of parallel strips but insulated from both the adjacent floating gate stripes and the substrate. Both sets of strips are isolated in a second direction perpendicular to the first direction forming an array of individual floating gates and control gates. The control gates formed from an individual control gate strip are then interconnected by a conductive wordline such the potential on individual floating gates are controlled by the voltages on two adjacent wordlines. In other variations either the floating gates or the control gates may be recessed into the original substrate.