Intel Corporation
Multi-level cell (MLC) cross-point memory

Abstract:

Multi-level cell (MLC) cross-point memory cells can store more than 1 bit per cell. In one example, MLC write operations for cross-point memory can be achieved by independently changing the state of the switch element and the memory element. The memory cell can be programmed to multiple states, such as a high threshold voltage state (where both the memory element and switch element exhibit a high threshold voltage or resistance), a low threshold voltage state (where both the memory element and select element exhibit a low threshold voltage or resistance), and one or more intermediate resistance states. In one example, additional resistance states can be programmed by setting the switch element and memory element to opposite states (e.g., one of the switch element and memory element is in a high resistance state and the other is in a low resistance state) or by placing both the switch element and memory element in different intermediate states.