Novel Lithography-Independent Pore Phase Change Memory

We have successfully demonstrated a novel "pore" phase change memory cell, whose critical dimension (CD) is independent of lithography. Instead, the pore diameter is accurately defined by intentionally creating a "keyhole" with conformal deposition. Fully integrated 256 kbit test chips have been fabricated in 180nm CMOS technology. We report SET times of 80 ns, RESET currents less than 250 muA, and accurate sub-lithographic CDs that can be less than 20% the size of the lithographically -defined diameter.