Separate domain formation in Ge2Sb2Te5–SiOx mixed layer

Abstract

We report separate domain formation in cosputtered Ge2Sb2Te5–SiOx mixed layer, with SiOx amount less than 10mol%. As-prepared Ge2Sb2Te5–SiOx layer exhibits amorphous phase with separate domains smaller than 20nm. The separation maintains after thermal annealing, which results in crystallization into fcc phase. The crystallization activation energies of Ge2Sb2Te5–SiOx are obtained as 4.99 and 6.44eV for mixed layers containing 5.3 and 8.4mol% SiOx, respectively. Those are larger than 2.75eV of pure Ge2Sb2Te5. Furthermore, the mixed layer exhibits sublimation at increased temperature. These are interpreted as formation of Ge2Sb2Te5-rich domains separated from each other by SiOx-rich domains.

Physics of switching and memory effects in chalcogenide glassy semiconductors

“…Therefore, the nitride film significantly inhibits the diffusion of atoms and increases the endurance of materials. Similar results were obtained when adding a few percent of SiO x to GST [90,91]. It was shown that doping increases GST resistivity by several orders of magnitude and significantly decreases the thermal conductivity of the fcc phase.…”

“…This allows a sig nificant decrease in the write pulse current [71]. The properties of doped Ge 2 Sb 2 Te 5 were studied in [87][88][89][90][91][92][93]. The most interesting results were obtained by doping with nitrogen.…”

Investigation of GeTe/Ge2Sb2Te5 Nanocomposite Multilayer Films for Phase-Change Memory Applications

“…Therefore, the crystallization temperature can be defined as the temperature at which the first derivative of the sheet resistance with respect to temperature reaches a minimal value. The [GeTe (5 nm)/Ge 2 Sb 2 Te 5 (5 nm)] 10 and [GeTe (7 nm)/Ge 2 Sb 2 Te 5 (5 nm)] 8 multilayer films clearly showed the abrupt drop of sheet resistance at about 188 and 197 C, respectively. Obviously, the crystallization temperatures of the multilayer films will approach that of GeTe with increasing thickness ratio of GeTe to Ge 2 Sb 2 Te 5 due to the higher crystallization temperature of GeTe over Ge 2 Sb 2 Te 5 .…”

“…To evaluate the electrically induced switching characteristics of GeTe/Ge 2 Sb 2 Te 5 multilayer films, PCM devices were fabricated and tested using 100-nm-thick [GeTe (5 nm)/Ge 2 Sb 2 Te 5 (5 nm)] 10 . The PCM with Ge 2 Sb 2 Te 5 was also fabricated for comparison.…”

“…In addition, Ge 2 Sb 2 Te 5 has a high melting temperature ($620 C) and low crystalline resistance, which make the RESET energy too large. Several approaches have been proposed to reduce the programming power of PCM, such as doping of Ge 2 Sb 2 Te 5 , [9][10][11] decreasing contact size between the electrode and Ge 2 Sb 2 Te 5 , [12][13][14] introducing an ultrathin heating layer between the bottom electrode and Ge 2 Sb 2 Te 5 . 15,16 The thermal conductivity of superlattice and multilayer films is of great importance for the performance of microelectronics and semiconductor devices.…”