Patent attributes
A series of phase change material layers sandwiched between a bottom electrode and a top electrode may have different phase change temperatures selected to provide a memory device having three or more discrete resistance levels, and thus three or more discrete logic levels. The non-volatile memory device may be formed with diodes providing the thermal energy for the phase changes that program the device logic level. The non-volatile memory may form part of a logic device and/or a memory array device, as well as other devices and systems. The phase change material layers may be formed using physical deposition methods, chemical deposition methods, or using atomic layer deposition. Atomic layer deposition may reduce the overall device thermal exposure and provide improved layer thickness uniformity and sharp material boundaries at the interface of different phase change materials, thus providing improved resistance level accuracy.
