title: Bipolar switching in chalcogenide phase change memory.
abstract: Phase change materials based on chalcogenides are key enabling technologies for optical storage, such as rewritable CD and DVD, and recently also electrical nonvolatile memory, named phase change memory (PCM). In a PCM, the amorphous or crystalline phase affects the material band structure, hence the device resistance. Although phase transformation is extremely fast and repeatable, the amorphous phase suffers structural relaxation and crystallization at relatively low temperatures, which may affect the temperature stability of PCM state. To improve the time/temperature stability of the PCM, novel operation modes of the device should be identified. Here, we present bipolar switching operation of PCM, which is interpreted by ion migration in the solid state induced by elevated temperature and electric field similar to the bipolar switching in metal oxides. The temperature stability of the high resistance state is demonstrated and explained based on the local depletion of chemical species from the electrode region.
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32-20133 Milano, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Ciocchini
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32-20133 Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Laudato
authors.affiliation: Micron Technology, Via Torri Bianche 24, 20871 Vimercate (MB), Italy.
authors.forename: M
authors.initials: M
authors.lastname: Boniardi
authors.affiliation: Micron Technology, Via Torri Bianche 24, 20871 Vimercate (MB), Italy.
authors.forename: E
authors.initials: E
authors.lastname: Varesi
authors.affiliation: Micron Technology, Via Torri Bianche 24, 20871 Vimercate (MB), Italy.
authors.forename: P
authors.initials: P
authors.lastname: Fantini
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32-20133 Milano, Italy.
authors.forename: A L
authors.initials: AL
authors.lastname: Lacaita
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32-20133 Milano, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Ielmini