Fabrication and electrical characterization of phase-change memory devices with nanoscale self-heating-channel structures

We proposed a material composition and an optimized patterning process for the phase-change memory devices with a nanoscale self-heating channel (NSC) structures. As a suitable composition, Ge₁₈Sb₃₉Te₄₃ was employed, which is the 22% Sb-excessive phase compared with the conventional Ge₂Sb₂Te₅. For fabricating the NSC memory devices, Ge₁₈Sb₃₉Te₄₃ layer was patterned into a thin channel having enlarged pad areas at both sides end by the developed two-step dry etching technique using a TiN hard mask. The NSC memory devices showed such good behaviors as lower power operations without any degradation of switching speed and better endurance for cyclic rewritings even in the scaling regime of tens-of-nanometer size. It can be concluded from the obtained results that the proposed NSC memory devices promise the feasibility for realizing both aggressive scaling with a simpler process and enhanced memory performances for the phase-change nonvolatile memory applications.