Phase Transition Kinetics and Recording Characteristics of Nanocomposite Layers Prepared by Sputtering Process Utilizing AgInSbTe–SiO₂ Composite Target

Abstract

AgInSbTe (AIST)-SiO 2 nanocomposite thin films were successfully prepared by sputtering deposition utilizing an AIST-SiO 2 composite target and their phase-transition behaviors were investigated. Transmission electron microscopy (TEM) revealed that the as-deposited composite layer contained nano-scale quaternary alloy particles about 5 nm in size randomly embedded in the SiO 2 matrix. In situ reflectivity-temperature measurements showed that the AIST-SiO 2 nanocomposite and pristine AIST layers exhibit similar abrupt reflectivity changes at about 200 C. However, the presence of the SiO 2 phase hindered particle growth in the nanocomposite layers which, in turn, caused a mild increase in the phase-transition temperatures. Johnson-Mehl-Avrami (JMA) analysis indicated that, regardless of the film thickness, the amorphous-tocrystalline transition in nanocomposite layers proceeds in a bulk-like manner. Dynamic tests revealed that modulations higher than 0.8, 0.6, and 0.5 were achieved when 11T, 4T, and 3T signals, respectively were, written in the one-layer AIST-SiO 2 disk sample. The unique phase transition behavior of nanocomposite layers and signal property analysis of disk samples demonstrated that a nanocomposite layer can be a new alternative for write-once optical data storage.

Phase transition kinetics of Sb 2 Te 3 phase change thin films

“…As can be seen from fraction of crystallization at any given time was determined by normalizing the real-time reflectivity by total reflectivity difference before and after crystallization. So the fraction of crystallization at a given temperature can be described as [5,6]:…”

Nonvolatile floating gate memory containing AgInSbTe–SiO2nanocomposite layer and capping the HfO2/SiO2composite blocking oxide layer

“…A large amount of AIST NCs with sizes of about 4-6 nm can be observed in the samples as illustrated by the enlarged image shown in figure 4(b). Previous studies demonstrated that the nanocomposite layers containing uniformly dispersed AIST NCs can be prepared via the target-attachment sputtering process [26,27] or the composite target sputtering method [42]. In comparison with other NC-based NFGM systems utilizing complicated methods for the charge trapping layer fabrication [10][11][12][13][14][15][16][17][18][19], it would be a great advantage for chalcogenide nanocomposites applied to NFGM since the high-density charge trapping layer can be easily prepared via a one-step, conventional sputtering process.…”

Phase-Change Kinetics of Bi–Fe–(N) Layer for High-Speed Write-Once Optical Recording

“…Table III shows a summary of the T x 's and activation energies (E a and/or ÁH) of phase transitions for various recording media reported previously. [6][7][8][15][16][17][18][20][21][22][23][24][25][26][27][28][29][30] Note that the T x of the Bi-Fe-(N) system is listed at a temperature about 270 C since an extremely high heating rate of laser irradiation leads to the similarity of the T x of Bi-Fe-(N) system to T Bi m . As shown in Table III, the T x of the Bi-Fe-(N) system is comparatively lower than those of bilayer media, but higher than those of phase-change materials.…”

“…At present, recording materials compatible with blue-laser recording are of particular interest. For such materials, organic ones are dyes that are sensitive to blue irradiation while inorganic ones include phase-change-based alloys, 5,6) AgInSbTe-SiO 2 nanocomposite films, 7,8) single layer metals such as AlSi alloys, 9,10) bismuth oxide (BiFeO) [11][12][13] and Bi-Fe-(N) layer, 14) and bilayer metals such as Ge/Au, [15][16][17][18] Cu/Si, 19) ZnO/Ge, 20) amorphous silicon (a-Si)/Cu, [21][22][23][24] a-Si/Al, 24,25) a-Si/Ni, [26][27][28] and Bi/Ge. 29,30) In our previous study, 14) the Bi-Fe-(N) system was demonstrated to be a promising medium for high-density write-once recording.…”