Electrical performance of phase change memory cells with Ge3Sb2Te6 deposited by molecular beam epitaxy

Abstract

Here, we report on the electrical characterization of phase change memory cells containing a Ge3Sb2Te6 (GST) alloy grown in its crystalline form by Molecular Beam Epitaxy (MBE). It is found that the high temperature growth on the amorphous substrate results in a polycrystalline film exhibiting a rough surface with a grain size of approximately 80–150 nm. A detailed electrical characterization has been performed, including I-V characteristic curves, programming curves, set operation performance, crystallization activation at low temperature, and resistance drift, in order to determine the material related parameters. The results indicate very good alignment of the electrical parameters with the current state-of-the-art GST, deposited by physical vapor deposition. Such alignment enables a possible employment of the MBE deposition technique for chalcogenide materials in the phase change memory technology, thus leading to future studies of as-deposited crystalline chalcogenides as integrated in electrical vehicles.

Textured Sb2Te3 films and GeTe/Sb2Te3 superlattices grown on amorphous substrates by molecular beam epitaxy

“…6. Such a delamination was not observed for polycrystalline GST 21 or superlattices with a bad out-of-plane alignment, such as in Fig. 3(a).…”

“…Carbon films with a thickness of 30 nm grown on top of Si (0 0 1) by means of sputtering at room temperature and devices structure with a SiO 2 surface (details of the devices structures are described elsewhere 21 ) were used as substrates in this study. Prior to the growth the substrates were cleaned using acetone, iso-propanol and deionized water.…”

Interface formation of two- and three-dimensionally bonded materials in the case of GeTe–Sb2Te3 superlattices

“…These problems are addressed in the present work, where the previously found switching models of CSL are challenged and an alternative ground state structure is presented. By using highly controlled Molecular Beam Epitaxy (MBE), which has shown in our previous work to produce high-quality Sb 2 Te 3 15 and GeTe 16 thin films and GeSbTe memory devices, 18 [GeTe(1 nm)-Sb 2 Te 3 (3 nm)] 15 superlattices have been grown on the Sb-passivated surfaces of Si(111), (√3 × √3)R30°-Sb, at a substrate temperature of 230°C as described in Experimental. The crystal structure of the films is resolved using various characterization techniques, including X-Ray Diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX) and High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM).…”

Epitaxial Ge2Sb2Te5 probed by single cycle THz pulses of coherent synchrotron radiation

“…[http://dx.doi.org/10.1063/1.4963889] Phase change materials (PCM) are employed in non volatile memory devices due to their fast switching between a high-resistance amorphous (a-) and a low-resistance crystalline (c-) phase. [1][2][3][4] In electrical memories, the switching process is achieved by the application of electrical pulses (nanosecond range). 2,5 The threshold switching, which is occurring in the a-phase and prior to the a-to c-phase transition, is governed by electron-phonon coupling and relaxation processes occurring on the timescale of several hundred femtoseconds (fs).…”