Nanoscale phase changes in crystalline Ge2Sb2Te5 films using scanning probe microscopes

Satoh, Hisao; Sugawara, Kentaro; Tanaka, Keiji

doi:10.1063/1.2163010

Cited by 83 publications

(55 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The energy required to write the bit was 88 pJ, substantially less than in previous work (e.g. 300 pJ in [13]) and in the range observed experimentally [12].…”

Section: Re-writability Via Amorphous Bits In a Crystalline Matrixmentioning

confidence: 62%

“…having a crystalline starting phase into which an amorphous bit is written by the probe tip and subsequently erased (re-written) by re-crystallization, should be feasible. However, the experimental writing of amorphous bits in a phase-change medium using electrical probe techniques has, to our knowledge, been reported only by one group of researchers (Tanaka's group at Hokkaido University -see [12]), whereas there are numerous reports of the successful writing of crystalline bits in an amorphous matrix (eg [8-11, 13, 20, 21]). This might imply that the writing of amorphous bits is 'difficult' experimentally.…”

Section: Introductionmentioning

confidence: 99%

“…Thus in this work amorphization is taken to occur in regions that experience temperatures in excess of 620 0 C and also cool at rates greater than 37 0 C ns -1 . Before writing amorphous bits into the media stacks designed in §II, it is instructive (and serves as a useful test of our model) to first examine the writing of amorphous bits in the experimental set-up used by Tanaka et al [12] who, as previously mentioned, are to our knowledge the only group to have reported the writing of amorphous marks in GST using conductive AFM-type probes. Tanaka's medium comprised a relatively thick GST layer (20 nm to 500 nm), with a Pt underlayer electrode (50 nm thick) on a Si substrate.…”

Section: Re-writability Via Amorphous Bits In a Crystalline Matrixmentioning

confidence: 99%

“…4. Simulation of the writing of an amorphous mark into a Si/Pt/GST/Fluorinert (capping layer) media stack and tip arrangement from [12]. A 1 V, 100 ns write pulse with 20 ns rise/fall times was used.…”

Section: Re-writability Via Amorphous Bits In a Crystalline Matrixmentioning

confidence: 99%

“…This might imply that the writing of amorphous bits is 'difficult' experimentally. Furthermore, it should be noted that in Tanaka's case [12] The Design of Re-writeable Ultra-High Density Scanning-Probe Phase-Change Memories from oxidation by being immersed in an inert liquid (3M, Fluorinert FC-43 -see [9]) and the writing tip contacted directly with the phase-change layer]). Obviously a liquid protective layer is not practicable for real storage systems.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

The Design of Rewritable Ultrahigh Density Scanning-Probe Phase-Change Memories

Wright

Wang

Shah

et al. 2011

IEEE Trans. Nanotechnology

View full text Add to dashboard Cite

Abstract-A systematic design of practicable media suitable for re-writeable, ultra-high density (> 1Tbit/sq.in.), high data rate (> 1Mbit/s/tip) scanning probe phase-change memories is presented. The basic design requirements were met by a Si/TiN/GST/DLC structure, with properly tailored electrical and thermal conductivities. Various alternatives for providing re-writeability were investigated. In the first case amorphous marks were written into a crystalline starting phase and subsequently erased by re-crystallization, as in other already-established phasechange memory technologies. Results imply that this approach is also appropriate for probe-based memories. However, experimentally the successful writing of amorphous bits using scanning electrical probes has not been widely reported. In light of this a second approach has been studied, that of writing crystalline bits in an amorphous starting matrix, with subsequent erasure by re-amorphization. With conventional phase-change materials, such as continuous films of Ge 2 Sb 2 Te 5 , this approach invariably leads to the formation of a crystalline 'halo' surrounding the erased (re-amorphized) region, with severe adverse consequences on the achievable density. Suppression of the 'halo' was achieved using patterned media or slow-growth phase-change media, with the latter seemingly more viable.

show abstract

“…The energy required to write the bit was 88 pJ, substantially less than in previous work (e.g. 300 pJ in [13]) and in the range observed experimentally [12].…”

Section: Re-writability Via Amorphous Bits In a Crystalline Matrixmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Section: Re-writability Via Amorphous Bits In a Crystalline Matrixmentioning

confidence: 99%

Section: Re-writability Via Amorphous Bits In a Crystalline Matrixmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Design of Rewritable Ultrahigh Density Scanning-Probe Phase-Change Memories

Wright

Wang

Shah

et al. 2011

IEEE Trans. Nanotechnology

View full text Add to dashboard Cite

show abstract

Nanoscale Bipolar Electrical Switching of Ge₂Sb₂Te₅ Phase‐Change Material Thin Films

Sun

Roß

Gerlach

et al. 2017

Adv Elect Materials

View full text Add to dashboard Cite

dependent, since either sign of the voltage can be applied for SET or RESET action. [3] Scalability is one of the dominant issues that must be addressed in order to offer PCRAM as next generation nonvolatile memory application. Scaling down the feature size is not only advantageous for increasing the storage density, it is equally important for the reduction of the power consumption in operation. In particular, shrinking the lateral size of the switching volume reduces the required RESET current. In order to study the switching mechanism of a PCM layer at the nanoscale, conductive atomic force microscopy (C-AFM) is well suited for this research purpose. This technique allows for the simultaneous nanoscale switching of small local volumes, limited only by the tip size which can be as small as conventionally produced lithography designs (<50 nm), as well as the characterization of conductance and topography with similar spatial resolution. [6][7][8][9][10][11] A proposed alternative mechanism of electrical resistance switching in the literature is based on the formation and rupture of a local conductive filament path in a solid electrolyte, [12,13] which features bipolar resistive switching, thus depending on the applied voltage polarity, and requires a lower RESET current than the amorphization process in PCRAM. [8,9,14,15] Such behavior has been widely accepted as the switching mechanism in resistive random-access memory (RRAM) that has been found in a number of material systems such as binary transition metal oxides, perovskites, solid-state electrolytes, and, crucially, also in phase-change chalcogenides such as GST and AgInSbTe. [8,12,13,[15][16][17] As a prospective view, an unified approach to the study of correlations between phase-change and electrolytic behavior should prove crucial for improving both device performance and reliability. [18] Thus, a detailed investigation of electrical switching performance is of great importance for a refined understanding of the underlying switching mechanism.In the here presented configuration of a combined PC/RRAM cell, pulsed laser deposition (PLD)-deposited amorphous GST layers are introduced similar to solid electrolytes between metal contacts, which are conceptually similar to the typical RRAM device of the metal-or oxygen-ion driven metal/insulator/ metal type. The electrical resistance switching in the memory arrangement is systematically investigated at the nanoscale by means of a C-AFM-based setup for all SET, READ, and RESET operations. In addition, the switching behavior is correlated Chalcogenide phase-change materials (PCMs) exhibit distinct rapid changes in electrical properties upon repeatable switching between amorphous and crystalline structure and are thus attractive for emerging nonvolatile memory (phase-change random access memory, PCRAM) applications. However, one of the key limitations of PCRAM concepts is their power consumption due to high RESET current requirement. In this work, the electrical memory switching behavior of Ge 2 Sb 2 Te 5 phase-c...

show abstract

Chalcogenide glasses in Japan: A review on photoinduced phenomena

Tanaka

Shimakawa

2009

Physica Status Solidi (b)

View full text Add to dashboard Cite

show abstract

Nanoscale phase changes in crystalline Ge2Sb2Te5 films using scanning probe microscopes

Cited by 83 publications

References 15 publications

The Design of Rewritable Ultrahigh Density Scanning-Probe Phase-Change Memories

The Design of Rewritable Ultrahigh Density Scanning-Probe Phase-Change Memories

Nanoscale Bipolar Electrical Switching of Ge₂Sb₂Te₅ Phase‐Change Material Thin Films

Chalcogenide glasses in Japan: A review on photoinduced phenomena

Contact Info

Product

Resources

About

Nanoscale phase changes in crystalline Ge2Sb2Te5 films using scanning probe microscopes

Cited by 83 publications

References 15 publications

The Design of Rewritable Ultrahigh Density Scanning-Probe Phase-Change Memories

The Design of Rewritable Ultrahigh Density Scanning-Probe Phase-Change Memories

Nanoscale Bipolar Electrical Switching of Ge2Sb2Te5 Phase‐Change Material Thin Films

Chalcogenide glasses in Japan: A review on photoinduced phenomena

Contact Info

Product

Resources

About

Nanoscale Bipolar Electrical Switching of Ge₂Sb₂Te₅ Phase‐Change Material Thin Films