MULTIPLE BIT PHASE CHANGE MEMORY CELL

摘要

A phase change memory cell has more than one memory region (14,18) each being a narrowed region of phase change memory material (2) extending between first and second electrodes (4,6). Each of the plurality of memory regions (14, 18) can be programmed to be in a low resistance state or a high resistance state by applying suitable programming conditions of current and/or voltage. The resistances of the high resistance states and the programming conditions to convert the high resistance states to the low resistance state are different in each of the plurality of memory regions.