The effect of an aluminum heat-sink layer on the laser-induced amorphization of SiOx/TeGeSn/SiOx phase-change recording films

Phase-change erasable optical storage is based on the ability to switch a micron-sized region of a thin film between the crystalline and amorphous states using a diffraction-limited laser as a heat source. A bit of information can be represented as an amorphous spot on a crystalline background, and the two states can be optically identified by their different reflectivities. In a typical multilayer thin-film structure the active (storage) layer is sandwiched between one or more dielectric layers. The dielectric layers provide physical containment and act as a heat sink. A viable phase-change medium must be able to quench to the glassy phase after melting, and this requires proper tailoring of the thermal properties of the multilayer film. The present research studies one particular multilayer structure and shows the effect of an additional aluminum layer on the glass-forming ability.

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Spectral interferometric technique to measure the relative phase change on reflection from a thin-film structure

Applied Physics B ◽

10.1007/s00340-010-4122-7 ◽

2010 ◽

Vol 101 (4) ◽

pp. 869-873

Author(s):

P. Hlubina ◽

D. Ciprian ◽

J. Luňáček

Keyword(s):

Thin Film ◽

Phase Change ◽

Relative Phase ◽

Film Structure ◽

Interferometric Technique ◽

Thin Film Structure

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Solidification Interface Instabilities During Zone Melting Recrystallization Processing of Multilayer thin Film Structures

MRS Proceedings ◽

10.1557/proc-237-615 ◽

1991 ◽

Vol 237 ◽

Author(s):

Sharon M. Yoon ◽

Christopher K. Hess ◽

Ioannis N. Miaoulis

Keyword(s):

Thin Film ◽

Optical Properties ◽

Phase Change ◽

Local Heat ◽

Zone Melting ◽

Film Structure ◽

Silicon On Insulator ◽

Interface Instability ◽

Property Variation ◽

Solidification Interface

ABSTRACTThis paper describes a stability analysis of the solidification interface during graphite-strip zone-melting-recrystallization of Silicon-On-Insulator thin film structures. The study focused on instabilities induced by i) variations in the optical properties due to thickness perturbations in the structure and ii) changes in optical properties during phase change. Reflective and emissive interference effects between multilayers play a significant role in the temperature distributions during processing. The presence of a step perturbation imbedded within the film structure affects local heat absorption and resulting temperature profiles. Such disturbances that trigger instabilities at the solid-liquid interface were investigated numerically. Processing speeds which cause interface instability due to optical property variation during phase change were identified.

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Multilayered Thin-Film Materials for Phase-Change Erasable Storage

MRS Bulletin ◽

10.1557/s0883769400059947 ◽

1990 ◽

Vol 15 (4) ◽

pp. 40-45 ◽

Cited By ~ 44

Author(s):

Matthew Libera ◽

Martin Chen

Keyword(s):

Thin Film ◽

Phase Change ◽

Active Layer ◽

Phase Change Materials ◽

Optical Recording ◽

Heat Sinks ◽

Transmission Electron Micrograph ◽

Irreversible Damage ◽

Cross Sectional ◽

Dielectric Layers

Phase-change erasable optical recording uses a focused laser beam as a heat source to reversibly switch a micron-sized area in a thin film between the amorphous and crystalline states. A bit of information is stored as an amorphous spot in a crystalline background, and the state of the bit is determined by the differing optical properties of the amorphous and crystalline phases. This concept was first demonstrated in 1971 and then, after about a decade of exploratory work, the field accelerated throughout the 1980s at several research laboratories. Currently the subject of number of reviews, the field of phase-change materials promises to broaden and intensify in the 1990s.The active layer, where the storage occurs, is typically a tellurium-based alloy with a variety of solute species. Early work studied the recording properties of single-layered films, but it has been clearly shown that multilayered films, where the active layer is sandwiched between two or more dielectric layers, have superior recording properties and resistance to irreversible damage caused by laser heating. The dielectric layers (typically SiO2, Si3N4, or ZnS) provide barriers to active-layer oxidation and contamination, help prevent the hole formation associated with ablative write-once storage methods, and act as crucibles and heat sinks which contain the molten spot and influence its cooling properties, respectively. A typical multilayer structure is shown in the cross-sectional transmission electron micrograph of Figure 1.

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