A Review of Germanium-Antimony-Telluride Phase Change Materials for Non-Volatile Memories and Optical Modulators

Chalcogenide phase change materials based on germanium-antimony-tellurides (GST-PCMs) have shown outstanding properties in non-volatile memory (NVM) technologies due to their high write and read speeds, reversible phase transition, high degree of scalability, low power consumption, good data retention, and multi-level storage capability. However, GST-based PCMs have shown recent promise in other domains, such as in spatial light modulation, beam steering, and neuromorphic computing. This paper reviews the progress in GST-based PCMs and methods for improving the performance within the context of new applications that have come to light in recent years.

Download Full-text

High Q Resonant Sb2S3-Lithium Niobate Metasurface for Active Nanophotonics

Nanomaterials ◽

10.3390/nano11092373 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2373

Author(s):

Qi Meng ◽

Xingqiao Chen ◽

Wei Xu ◽

Zhihong Zhu ◽

Xiaodong Yuan ◽

...

Keyword(s):

Lithium Niobate ◽

Phase Change ◽

Optical Switching ◽

Phase Change Materials ◽

Beam Steering ◽

Light Modulation ◽

Low Loss ◽

High Q ◽

Nonlinear Properties ◽

Nanophotonic Devices

Phase change materials (PCMs) are attracting more and more attentions as enabling materials for tunable nanophotonics. They can be processed into functional photonic devices through customized laser writing, providing great flexibility for fabrication and reconfiguration. Lithium Niobate (LN) has excellent nonlinear and electro-optical properties, but is difficult to process, which limits its application in nanophotonic devices. In this paper, we combine the emerging low-loss phase change material Sb2S3 with LN and propose a new type of high Q resonant metasurface. Simulation results show that the Sb2S3-LN metasurface has extremely narrow linewidth of 0.096 nm and high quality (Q) factor of 15,964. With LN as the waveguide layer, strong nonlinear properties are observed in the hybrid metasurface, which can be employed for optical switches and isolators. By adding a pair of Au electrodes on both sides of the LN, we can realize dynamic electro-optical control of the resonant metasurface. The ultra-low loss of Sb2S3, and its combination with LN, makes it possible to realize a new family of high Q resonant metasurfaces for actively tunable nanophotonic devices with widespread applications including optical switching, light modulation, dynamic beam steering, optical phased array and so on.

Download Full-text

SET Characteristics of Phase Change Bridge Devices

MRS Proceedings ◽

10.1557/proc-1072-g06-07 ◽

2008 ◽

Vol 1072 ◽

Cited By ~ 13

Author(s):

Daniel Krebs ◽

Simone Raoux ◽

Charles T. Rettner ◽

Robert M. Shelby ◽

Geoffrey W. Burr ◽

...

Keyword(s):

Phase Change ◽

Amorphous Phase ◽

Phase Change Materials ◽

Random Access ◽

Stable States ◽

Threshold Switching ◽

Non Volatile Memory ◽

Switching Material ◽

The Difference ◽

Memory Applications

ABSTRACTScaling studies have demonstrated that Phase Change Random Access Memory (PCRAM) is one of the most promising candidates for future non-volatile memory applications. The search for suitable phase change materials with optimized properties is therefore actively pursuit. In this paper, SET (crystallization) characteristics of an ultra fast switching material Ge15Sb85 in phase change memory bridge cell devices are presented. It was found that reproducible switching between two stable states with one decade resistance contrast and current pulses as short as 10 ns for SET and RESET (re-amorphization) operation is possible. Particular emphasis was placed on the difference in crystallization kinetics between the as-deposited and melt-quenched amorphous phase. Evidence is given for the existence of an electrical field as the critical parameter for threshold switching rather than a threshold voltage. For Ge15Sb85 a threshold switching field of 9MV/m was measured and it was shown that switching from the melt-quenched amorphous phase to the crystalline phase is about 600 times faster than crystallization from the as-deposited amorphous phase.

Download Full-text

Selective light modulation in waveguide grating using phase change materials (Conference Presentation)

Integrated Optics: Devices, Materials, and Technologies XXIII ◽

10.1117/12.2511198 ◽

2019 ◽

Author(s):

Mohsen Jafari ◽

L. Jay Guo ◽

Mina Rais-Zadeh

Keyword(s):

Phase Change ◽

Phase Change Materials ◽

Light Modulation ◽

Waveguide Grating

Download Full-text

Numerical Modeling of Thermoelectric Thomson Effect in Phase Change Memory Bridge Structures

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156414500049 ◽

2014 ◽

Vol 23 (01n02) ◽

pp. 1450004 ◽

Cited By ~ 7

Author(s):

Faruk Dirisaglik ◽

Gokhan Bakan ◽

Azer Faraclas ◽

Ali Gokirmak ◽

Helena Silva

Keyword(s):

Numerical Modeling ◽

Phase Change ◽

Phase Change Materials ◽

Phase Change Memory ◽

Thermoelectric Effects ◽

Non Volatile Memory ◽

Bridge Structures ◽

P Type ◽

Electrothermal Effects ◽

Change Memory

Phase change memory is a non-volatile memory technology that utilizes the electrical resistivity contrast between resistive amorphous and conductive crystalline phases of phase change materials. These devices operate at high current densities and high temperature gradients which lead to significant thermoelectric effects. We have performed numerical modeling of electrothermal effects in p-type Ge2Sb2Te5 phase change memory structures suspended on TiN contact pads using COMSOL Multiphysics. Temperature dependent material parameters are used in the model. Strong asymmetry is observed in temperature profiles in all cases: the hottest spot appears closer to the higher potential end suggesting that the thermal profile can be significantly altered by the thermoelectric effects during device operation. Hence, thermoelectric effects need to be considered for device designs for lower power and higher reliability devices.

Download Full-text

A scheme for enabling the ultimate speed of threshold switching in phase change memory devices

Scientific Reports ◽

10.1038/s41598-021-85690-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nishant Saxena ◽

Rajamani Raghunathan ◽

Anbarasu Manivannan

Keyword(s):

Phase Change ◽

Delay Time ◽

Phase Change Materials ◽

Amorphous Material ◽

Phase Change Memory ◽

Low Delay ◽

Threshold Switching ◽

Voltage Dependent ◽

Non Volatile Memory ◽

Change Memory

AbstractPhase change materials exhibit threshold switching (TS) that establishes electrical conduction through amorphous material followed by Joule heating leading to its crystallization (set). However, achieving picosecond TS is one of the key challenges for realizing non-volatile memory operations closer to the speed of computing. Here, we present a trajectory map for enabling picosecond TS on the basis of exhaustive experimental results of voltage-dependent transient characteristics of Ge2Sb2Te5 phase-change memory (PCM) devices. We demonstrate strikingly faster switching, revealing an extraordinarily low delay time of less than 50 ps for an over-voltage equal to twice the threshold voltage. Moreover, a constant device current during the delay time validates the electronic nature of TS. This trajectory map will be useful for designing PCM device with SRAM-like speed.

Download Full-text

Near-Infrared Rewritable, Non-Volatile Subwavelength Absorber Based on Chalcogenide Phase Change Materials

Nanomaterials ◽

10.3390/nano10061222 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1222 ◽

Cited By ~ 2

Author(s):

Jianfa Zhang ◽

Yiqiong Zhang ◽

Qilin Hong ◽

Wei Xu ◽

Zhihong Zhu ◽

...

Keyword(s):

Phase Change ◽

Phase Change Materials ◽

Near Infrared ◽

Beam Steering ◽

Contrast Ratio ◽

Photonic Devices ◽

Optical Modulation ◽

High Contrast ◽

Perfect Absorption ◽

Continuous Tuning

Chalcogenide phase change materials enable the realization of novel, non-volatile, switchable electronic and photonic devices. In this paper, we propose a type of rewritable, non-volatile near infrared subwavelength absorber based on chalcogenide phase change materials. Our numerical simulations show that nearly perfect absorption more than 0.99 can be realized in the written state while the absorption of as-deposited or erased state is lower than 0.15 in the studied spectral range, leading to high contrast ratio of reflection more than 20 dB. Continuous tuning of the absorption spectra can be realized not only by varying the geometric parameters of the absorber but also by changing the crystallization ratio of the switched Ge 2 Sb 2 Te 5 (GST). The proposed device may find widespread applications in optical modulation, beam steering and so on.

Download Full-text

The Research Situation and Development Trend of Energy Saving Phase Change Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.415-417.2012 ◽

2011 ◽

Vol 415-417 ◽

pp. 2012-2015

Author(s):

Bao Ping Yang ◽

Yan Hua Li ◽

Jin Feng Cui ◽

Jun Hong Guo ◽

Ying Ping Zhou ◽

...

Keyword(s):

Phase Change ◽

Energy Saving ◽

Phase Change Materials ◽

Development Trend ◽

Difficult Problem ◽

Energy Utilization ◽

Current Status ◽

Living Standard ◽

Promising Development ◽

High Degree

The energy saving principle of phase change materials is introduced briefly， the current status of the energy saving phase change materials and the newest progress are also discussed. The promising development trend of the energy saving phase change materials is prospected. With the effect of energy crisis, the difficult problem which we face is the energy consumption, energy saving and emission reduction is the first question that should be solved in all works of life. As the living standard improved, the human comfort require of indoor environment become more strict. Because of air conditioning making the power system load too large, energy saving technology has been paid a high degree of attention, and energy saving phase change materials ,as a new materials, has gradually become a focus in the study of energy utilization and material science.

Download Full-text