Device structure for a single cell and typicalI-Vcurves

Phase-change properties of GeSbTe thin films deposited by plasma-enchanced atomic layer depositon. Song S, Yao D, Song Z, Gao L, Zhang Z, Li L, Shen L, Wu L, Liu B, Cheng Y, Feng S - Nanoscale Res Lett (2015) Bottom Line: Phase-change access memory (PCM) appears to be the strongest candidate for next-generation high-density nonvolatile memory.Compared with GST-based device, GeSb8Te-based device exhibits a faster switching speed and reduced reset voltage, which is attributed to the growth-dominated crystallization mechanism of the Sb-rich GeSb8Te films.These results show that ALD is an attractive method for preparation of phase-change materials. View Article: PubMed Central - PubMed Affiliation: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China. ABSTRACT Phase-change access memory (PCM) appears to be the strongest candidate for next-generation high-density nonvolatile memory. The fabrication of ultrahigh-density PCM depends heavily on the thin-film growth technique for the phase-changing chalcogenide material. In this study, Ge2Sb2Te5 (GST) and GeSb8Te thin films were deposited by plasma-enhanced atomic layer deposition (ALD) method using Ge [(CH3)2 N]4, Sb [(CH3)2 N]3, Te(C4H9)2 as precursors and plasma-activated H2 gas as reducing agent of the metallorganic precursors. Compared with GST-based device, GeSb8Te-based device exhibits a faster switching speed and reduced reset voltage, which is attributed to the growth-dominated crystallization mechanism of the Sb-rich GeSb8Te films. These results show that ALD is an attractive method for preparation of phase-change materials. No MeSH data available.	© Copyright Policy - open-access Related In: Results - Collection License Show All Figures getmorefigures.php?uid=PMC4385138&req=5 Fig3: Device structure for a single cell and typicalI-Vcurves of the PCM cells. (a) SEM image of cross-sectional cell structure. (b) Resistance current characteristics of PCM cell with ALD-deposited GST films. Mentions: For further investigation of device performances, GST and GeSb8Te films were selected and inserted in PCM cells. The device structure for a single cell is shown in Figure 3a. Figure 3b shows the typical I-V curves of the PCM cells based on ALD-deposited GST films. Before each I-V test, the cell has been re-amorphized using electrical pulse. As shown in Figure 3b, large snapback of voltage and negative-resistance behavior were observed in the I-V curve, which indicates that the phase transition has occurred from amorphous state (high resistance) to crystalline state (low resistance). The threshold voltage for the cell based on ALD-deposited GST is about 6.1 V, which is much higher than that (3.5 V) of the device based on PVD-deposited GST with the identical cell architecture [16].Figure 3

Phase-change properties of GeSbTe thin films deposited by plasma-enchanced atomic layer depositon.

Song S, Yao D, Song Z, Gao L, Zhang Z, Li L, Shen L, Wu L, Liu B, Cheng Y, Feng S - Nanoscale Res Lett (2015)

Bottom Line: Phase-change access memory (PCM) appears to be the strongest candidate for next-generation high-density nonvolatile memory.Compared with GST-based device, GeSb8Te-based device exhibits a faster switching speed and reduced reset voltage, which is attributed to the growth-dominated crystallization mechanism of the Sb-rich GeSb8Te films.These results show that ALD is an attractive method for preparation of phase-change materials.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China.

ABSTRACT

Phase-change access memory (PCM) appears to be the strongest candidate for next-generation high-density nonvolatile memory. The fabrication of ultrahigh-density PCM depends heavily on the thin-film growth technique for the phase-changing chalcogenide material. In this study, Ge2Sb2Te5 (GST) and GeSb8Te thin films were deposited by plasma-enhanced atomic layer deposition (ALD) method using Ge [(CH3)2 N]4, Sb [(CH3)2 N]3, Te(C4H9)2 as precursors and plasma-activated H2 gas as reducing agent of the metallorganic precursors. Compared with GST-based device, GeSb8Te-based device exhibits a faster switching speed and reduced reset voltage, which is attributed to the growth-dominated crystallization mechanism of the Sb-rich GeSb8Te films. These results show that ALD is an attractive method for preparation of phase-change materials.

No MeSH data available.

Device structure for a single cell and typicalI-Vcurves of the PCM cells. (a) SEM image of cross-sectional cell structure. (b) Resistance current characteristics of PCM cell with ALD-deposited GST films.

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Fig3: Device structure for a single cell and typicalI-Vcurves of the PCM cells. (a) SEM image of cross-sectional cell structure. (b) Resistance current characteristics of PCM cell with ALD-deposited GST films.

Mentions: For further investigation of device performances, GST and GeSb8Te films were selected and inserted in PCM cells. The device structure for a single cell is shown in Figure 3a. Figure 3b shows the typical I-V curves of the PCM cells based on ALD-deposited GST films. Before each I-V test, the cell has been re-amorphized using electrical pulse. As shown in Figure 3b, large snapback of voltage and negative-resistance behavior were observed in the I-V curve, which indicates that the phase transition has occurred from amorphous state (high resistance) to crystalline state (low resistance). The threshold voltage for the cell based on ALD-deposited GST is about 6.1 V, which is much higher than that (3.5 V) of the device based on PVD-deposited GST with the identical cell architecture [16].Figure 3