Phase change memory cell and manufacturing method

A phase change memory cell, the memory cell being a part of a phase change memory device, comprising:

• first and second electrodes;
• a phase change element electrically coupling the first and second electrodes;
• at least a section of the phase change element comprising a higher reset transition temperature portion and a lower reset transition temperature portion;
• the lower reset transition temperature portion comprising a phase change region which can be transitioned, by the passage of electrical current therethrough, from generally crystalline to generally amorphous states at a lower temperature than the higher reset transition temperature portion;
• and
• the phase change element comprising an outer, generally tubular portion surrounding an inner portion, the outer portion comprising a higher reset transition temperature portion and the inner portion comprising a lower reset transition temperature portion.

A phase change memory cell, the memory cell being a part of a phase change memory device, comprising:

• first and second electrodes having surfaces spaced apart by a gap;
• a phase change element positioned between and electrically coupling the first and second electrodes;
• the phase change element comprising an outer, generally tubular portion surrounding an inner portion, the outer portion comprising a higher reset transition temperature portion and the inner portion comprising a lower reset transition temperature portion, the reset transition temperature of the higher reset transition temperature portion being at least about 100° C. greater than the reset transition temperature of the lower reset transition temperature portion;
• and
• the lower reset transition temperature portion comprising a phase change region which can be transitioned, by the passage of electrical current therethrough, from generally crystalline to generally amorphous states at a lower temperature than the higher reset transition temperature portion.