Crystallization behavior of sputter-deposited amorphous Ge2Sb2Te5 thin films

Jeong, Tae Hee; Kim, Myong R.; Seo, Hanbyul; Kim, Sang J.; Kim, Sang Yong

doi:10.1063/1.370803

Cited by 164 publications

(47 citation statements)

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“…The increase of the crystallization temperature in oxygen (Jeong et al, 2001) and nitrogen [Kojima et al, 1998, Jeong et al, 2000 doped GST has been already reported in literature, as well as the reduction of the grain size in samples containing nitrogen. Several models have been proposed (Jeong et al, 2001, Jeong et al, 2000 trying to simultaneously explaining the effect of both O and N in order to find the optimal dopant to engineer specific properties of GST.…”

Section: Wwwintechopencomsupporting

confidence: 56%

“…In fact, it has been shown that nitrogen doping during deposition (Kojima et al 1998, Jeong et al 2000 increases the amorphous stability and reduces the grain size, improving the cell cyclability.…”

Section: Phase Change Memorymentioning

confidence: 99%

“…Several models have been proposed (Jeong et al, 2001, Jeong et al, 2000 trying to simultaneously explaining the effect of both O and N in order to find the optimal dopant to engineer specific properties of GST.…”

Section: Wwwintechopencommentioning

confidence: 99%

“…For lower concentration, as in the samples we have studied, no oxidation seems to occur. It has been therefore proposed that oxygen atoms, as well as nitrogen atoms at low concentration, are located at the tetrahedral interstitial sites (Jeong et al, 2000). Indeed, since nitrogen and oxygen have quite small atomic sizes compared to that of Ge, Sb and Te, they cannot substitute these atoms, filling the vacancies which are present in the structure.…”

Section: Wwwintechopencommentioning

confidence: 99%

“…Therefore their effect is expected to be very different from the one observed in the case of Bi or Sn, (Matsunaga & Yamada, 2004), which substituting in the Ge:Sb:vacancy lattice, can increase the number of possible configurations and therefore the growth velocity. N or O atoms will be instead located at the tetrahedral interstitial sites distorting the unit cell and resulting in a strain field (Jeong et al, 2000). Since nitrogen has a larger atomic radius (0.071 nm) (Lide, 2004), compared to oxygen (0.066 nm) (Lide, 2004), a larger amount of strain is expected to accommodate nitrogen atoms in the structure.…”

Section: Wwwintechopencommentioning

confidence: 99%

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Ion Implantation in Phase Change Ge2Sb2Te5 Thin Films for Non Volatile Memory Applications

Privitera¹

2012

Ion Implantation

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Section: Wwwintechopencomsupporting

confidence: 56%

Section: Phase Change Memorymentioning

confidence: 99%

Section: Wwwintechopencommentioning

confidence: 99%

Section: Wwwintechopencommentioning

confidence: 99%

Section: Wwwintechopencommentioning

confidence: 99%

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Ion Implantation in Phase Change Ge2Sb2Te5 Thin Films for Non Volatile Memory Applications

Privitera¹

2012

Ion Implantation

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Nanoscale Electrolytic Switching in Phase‐Change Chalcogenide Films

et al. 2007

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This Communication presents the important finding that certain chalcogenide materials, well-known from rewritable optical recording, allow resistive memory states that are a combination of two electrically-induced (reversible) switching processes, i.e., an actual amorphous-crystalline phase transformation and a (electrolytic) polarity-dependent resistance change. Nanometer-sized crystalline marks were written electrically in amorphous Ge 2 Sb 2+x Te 5 films using atomic force microscopy (AFM), and their resistance was found to depend on the polarity of the applied voltage with a resistance difference of three orders of magnitude. However, no contrast in current has been detected between the crystalline higherresistance state and the surrounding amorphous phase. This resistance switching is reversible for bias voltages well below the threshold voltage required to induce the phase transformation. The switching mechanism is attributed to the solidstate electrolytic behavior due to the presence of excess Sb in the films. Our results render exciting technological opportunities for data storage and encryption by combining both switching concepts.Following his seminal work in 1968, [1] Ovshinsky demonstrated in chalcogenide alloys a fast reversible transformation between amorphous and crystalline phases induced by electrical or optical (laser) pulses. [2][3][4] The two phases exhibited clear contrast in electrical and optical properties and, hence, these materials were suggested for binary data-storage applications. However, it took considerable time before rewritable optical compact discs (CD) and digital versatile discs (DVD) based on these findings came to the market. In recent years, the main focus of phase-change data-storage research returned to resistance switching. So-called chalcogenide or phase-change random access memory (CRAM/PRAM) and ovonic unified memory (OUM) based on the phase-dependent resistance switching are currently under intense investigations, [5][6][7][8][9][10][11][12][13] because they show great promise as next-generation nonvolatile solid-state memory replacing flash memory. In certain chalcogenides a special phenomenon of polaritydependent resistance switching (induced by an electric field) has been identified. [14][15][16][17][18][19] This is related to the solid-state electrolytic character and high ionic conductivities of chalcogenides, and hence is called ionic/electrolytic switching. For one polarity, the chalcogenide medium is electrically conductive by forming conducting filamentary pathways between electrodes, whereas for the reverse polarity it becomes relatively insulative or at least less conductive because of rupture of the previously formed electrical pathways. Memory elements (or structures) based on this switching have been demonstrated in some Ag-saturated chalcogenides including Ag-S, [14,15] AgGe-Se, [16,17] Ag-Ge-Te, [18] and Ag-In-Sb-Te. [19] This switching seems more attractive for applications than phase-dependent switching, because i) it can be performed at lower volta...

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Chalcogenide Phase Change Material for Active Terahertz Photonics

et al. 2019

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The terahertz part of the electromagnetic spectrum possesses numerous promising applications such as high-speed wireless communication, security screening, chemical identification, and nondestructive biosensing. [1] However, the terahertz spectral region has remained technologically uncharted, due to the lack of efficient devices to generate, manipulate, and detect terahertz waves. In the past decade, there has been a significant progress in active control of terahertz waves using metamaterials integratedThe strikingly contrasting optical properties of various phases of chalcogenide phase change materials (PCM) has recently led to the development of novel photonic devices such as all-optical non-von Neumann memory, nanopixel displays, color rendering, and reconfigurable nanoplasmonics. However, the exploration of chalcogenide photonics is currently limited to optical and infrared frequencies. Here, a phase change material integrated terahertz metamaterial for multilevel nonvolatile resonance switching with spatial and temporal selectivity is demonstrated. By controlling the crystalline proportion of the PCM film, multilevel, non-volatile, terahertz resonance switching states with long retention time at zero hold power are realized. Spatially selective reconfiguration at submetamaterial scale is shown by delivering electrical stimulus locally through designer interconnect architecture. The PCM metamaterial also features ultrafast optical modulation of terahertz resonances with tunable switching speed based on the crystalline order of the PCM film. The multilevel nonvolatile, spatially selective, and temporally tunable PCM metamaterial will provide a pathway toward development of novel and disruptive terahertz technologies including spatio-temporal terahertz modulators for high speed wireless communication, neuromorphic photonics, and machine-learning metamaterials.

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Crystallization behavior of sputter-deposited amorphous Ge2Sb2Te5 thin films

Cited by 164 publications

References 2 publications

Ion Implantation in Phase Change Ge2Sb2Te5 Thin Films for Non Volatile Memory Applications

Ion Implantation in Phase Change Ge2Sb2Te5 Thin Films for Non Volatile Memory Applications

Nanoscale Electrolytic Switching in Phase‐Change Chalcogenide Films

Chalcogenide Phase Change Material for Active Terahertz Photonics

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