title: Lattice Distortion in In3SbTe2 Phase Change Material with Substitutional Bi.
abstract: Sb atoms in In3SbTe2 (IST) are partially substituted by 3.2-5.5 at.% of Bi atoms. As a result, the NaCl crystal structure of IST is slightly distorted. The distorted inter-planar angles observed with fast Fourier transformation of the lattice images are within the maximum range of interplanar angles calculated by density functional theory. When the Bi content is increased, the crystallization temperature becomes relatively lower than that of IST, the activation energy decreases from 5.29 to 2.61 eV, and the specific heat and melting point are obviously reduced. Consequently, phase change random access memory (PRAM) fabricated with Bi-doped IST (Bi-IST) can operate with lower power consumption than pure IST PRAM. The set and reset speeds of PRAM cells fabricated with Bi-IST are both 100 ns with 5.5 at.% Bi, which are obviously faster than the switching speeds of PRAM cells fabricated with IST and Ge2Sb2Te5 (GST). These experimental results reveal that the switching speed is closely related with the thermal properties of the distorted lattice structure.
authors.affiliation: Hanyang University, Department of Materials Science and Engineering, Seoul 133-791, Korea.
authors.forename: Minho
authors.initials: M
authors.lastname: Choi
authors.affiliation: Korea Institute of Science and Technology, Center for Computational Science, Seoul 136-791, Korea.
authors.forename: Heechae
authors.initials: H
authors.lastname: Choi
authors.affiliation: Korea Institute of Science and Technology, Center for Computational Science, Seoul 136-791, Korea.
authors.forename: Seungchul
authors.initials: S
authors.lastname: Kim
authors.affiliation: Hanyang University, Department of Materials Science and Engineering, Seoul 133-791, Korea.
authors.forename: Jinho
authors.initials: J
authors.lastname: Ahn
authors.affiliation: Korea Institute of Science and Technology, Semiconductor Materials and Device Laboratory, Seoul 136-791, Korea.
authors.forename: Yong Tae
authors.initials: YT
authors.lastname: Kim