Electrical properties and crystal structures of nitrogen-doped Ge2Sb2Te5 thin film for phase change memory

Enabling Universal Memory by Overcoming the Contradictory Speed and Stability Nature of Phase-Change Materials

“…However, it has a slower crystallization speed in the hundred-ns, let alone achieve the high writing speed at DRAM levels. In spite of this, NGST has a special feature that enables the control of grain size to achieve very small grain sizes1617. In this study, we discuss a novel approach to achieve both high speed and high endurance via the exploration of the phase-change mechanisms and the grain features of phase-change materials.…”

Physics of switching and memory effects in chalcogenide glassy semiconductors

“…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.…”

A Study on the Crystallization Behavior of Nitrogen Doped Ge2Sb2Te5 Thin Film

“…The GST(5) film has the fcc structure from the annealing temperature around 220 C, although the fcc (200) peak width was broader than that of the un-doped GST film in the XRD results. 4,5) In the case of the GST(10) film, the much broader peak began to appear only after being annealed at 240 C. It means that the crystallization to fcc structure occurs at the higher temperature by increased nitrogen doping, as shown in Fig. 4.…”

“…3) In order to increase the resistance of crystallized GST film, it is proposed to decrease the grain size of the crystalline state by means of nitrogen doping. 3,4) In our previous work, 5) we have already observed that nitrogen doping effectively increased the resistance of the crystallized GST film in annealing at 260 C. In this work, we have focused on the crystal structure change of nitrogen doped GST films as annealing at various temperatures and, finally, mapped the effect of nitrogen doping on the crystallization behavior of GST film.…”

“…And then, the sharp hexagonal peaks appear in the annealing at 260 C, and the lattice parameters of the hexagonal structure were calculated as a ¼ 0:4264 nm and c ¼ 1:8308 nm, as reported in our previous work. 5) Accordingly, it is revealed that the heavy nitrogen doped film has a one-step crystallization process directly from an amorphous to a hexagonal structure, skipping the fcc crystallization step. Additionally, in the case of the GST(10) films annealed at 380 and 400 C, the XRD patterns were similar to that of an amorphous state, disappearing the fcc characteristic peaks.…”