Browsing by Author "Yeh, TT"

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A method to enhance the data transfer rate of eutectic Sb-Te phase-change recording media
(2005-07-15)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
光電工程學系
This work describes the effect of nitrogen doping to eutectic Sb-Te phase-change materials in order to enhance the speed of the amorphous-to-crystalline phase transformation. When nitrogen at a sputtering gas flow ratio of N-2/Ar=3% was doped in the eutectic Ge-In-Sb-Te recording layer, the data transfer rate was increased up to 1.6 times. When thin GeNx nucleation promotion layers were further added in below and above the recording layer, an overall enhancement up to 3.3 times in data transfer rate was achieved. The nitrogen contents corresponding to the N-2/Ar flow ratios (N-2/Ar=0%-10%) were calibrated by electron spectroscopy for chemical analysis. Transmission electron microscopy revealed that nitrogen doping was able to promote the phase transformation by generating numerous nucleation sites uniformly distributed in the recording layer and hence increased the recrystallization speed. (c) 2005 American Institute of Physics.
A method to enhance the data transfer rate of phase change recording media
(2004)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nitrogen doping was applied to enhance the velocity of amorphous-crystalline phase transformation. The nitrogen doping was able to produce tiny nitride precipitates uniformly distributed in the recording layer and provided numerous preferential sites for amorphous-crystalline transition. At the doping condition of N-2/Ar ratio = 3%, the recrystallization velocity of GeInSbTe phase change recording media was increased up to 1.6 times without severely damaging the signal jitter values.
Enhancement of data transfer rate of phase change optica disk by doping nitrogen in Ge-In-Sb-Te recording layer
(2004-08-01)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
光電工程學系
This work investigated the enhancement of the data transfer rate and/or recrystallization speed of Ge-In-Sb-Te recording material by nitrogen doping. The effects of nitrogen content on the dynamic properties of optical disks and the corresponding microstructural changes of the recording layer were studied. The experimental results showed that nitrogen doping at a sputtering gas flow ratio of N-2/Ar = 3% might enhance the data transfer rate of an optical disk up to 1.6 times without severely damaging the signal jitter values. However, the disks failed the dynamic tests when too much nitrogen (N-2/Ar greater than or equal to 5%) was introduced. Dynamic testing also revealed that nitrogen doping slightly increased the noise level and jitter of the disks. Transmission electron microscopy (TEM) found that nitrogen doping promoted a phase transformation by generating numerous nucleation sites uniformly distributed in the recording layer and hence increased recrystallization speed.
Enhancing the overwriting characteristics of phase-change optical disks by doping in dielectric layers
(2004-09-01)
Yu, CH
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Hsieh, TE
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Yeh, TT
;
Shieh, HPD
;
材料科學與工程學系
In this work, we studied the enhancement of overwriting characteristics of phase-change optical disks by doping in the dielectric layers. The doping elements included chromium (Cr), molybdenum (Mo), nickel (Ni), tantalum (Ta), titanium (Ti), tungsten (W), vanadium (V), and nitrogen (N-2) Dynamic test showed that doping with a certain amount of W and N-2 in dielectric layers enhanced the disk overwriting characteristics. Up to fortyfold improvement in disk cycleability was observed when N-2 gas was introduced during sputtering deposition of the upper dielectric layer at the gas flow rate of N-2/Ar = 25%. Tungsten was the best among the doping metallic elements resulting in fivefold improvement in disk cycleability. Optical property measurement revealed that the refractive index (n) decreased with increasing N-2 doping percentage, while the relatively small amount of metallic element doping negligibly changed the optical constants. Subsequent modulation simulation showed that such an optical property change is beneficial to disk overwriting characteristics. Nanoindentation test showed that N-2 doping was the most effective method for increasing the hardness of the dielectric layer. This implies that, with increasing mechanical strength, the dielectric layer possesses better resistance to thermal deformation resulting from laser heating, thereby enhancing the cycleability of optical disks.
Superresolution structure optical disk with semiconductor-doped glass mask layer containing CdSe nanoparticles
(2006-02-01)
Yeh, TT
;
Wang, JH
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Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
In this work, we demonstrate a distinct superresolution phenomenon and signal properties of an optical disk with a semiconductor-doped glass (SDG) mask layer containing CdSe nanoparticles. It was found that the 69 nm marks could be consistently retrieved at reading power (P-r) = 4 mW with carrier-to-noise ratio (CNR) = 13.56 dB. The signals were clearly resolved with CNRs nearly equal to 40 dB at P-r = 4 mW when the recorded marks were larger than 100 nm. The cyclability test indicated that the CdSe-SiO2 SDG layer might serve as a stable and reliable optical mask layer in 10(5) readout cycles.
The nitrogen doping effect on the properties of Ge-In-Sb-Te phase-change recording media investigated by blue-light laser
(2005-09-22)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
光電工程學系
This work investigates the thermal, optical and recrystallization properties as well as the microstructure of nitrogen-doped Ge-In-Sb-Te (GIST) phase-change material when irradiated by blue-light laser. The experimental results showed that nitrogen doping at the condition of N-2/Ar sputtering gas flow ratio equals to 3% might enhance the recrystallization speed of GIST recording layer up to 1.5 times. However, the disk failed when too much nitrogen (N-2/Ar >= 5.0%) was introduced. The data obtained by differential scanning calorimetry, X-ray diffraction and ellipsometry revealed changes of thermal and optical properties due to the nitrogen doping in GIST. When appropriate amount of nitrogen was added, the activation energy (E-a) of amorphous-crystalline phase transition of GIST decreased and the optical constants of amorphous and crystalline phases (except the k value of amorphous phase) gradually reduced with the increase of wavelength in the range of 600-750 nm. Modulation simulation based on the reflectively of doped GIST layers obtained from static test indicated that appropriate nitrogen doping benefited the signal characteristics of optical disks. Transmission electron microscopy observed numerous tiny precipitates uniformly distributed in the doped GIST layers. These were believed to be nitride particles generated by nitrogen doping that might offer the preferential sites for amorphous-crystalline phase transition so that the recrystallization speed was accelerated. (c) 2005 Elsevier B.V. All rights reserved.