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Phase-Change Kinetics of Bi–Fe–(N) Layer for High-Speed Write-Once Optical Recording
View the table of contents for this issue, or go to the journal homepage for more 2011 Jpn. J. Appl. Phys. 50 042601
(http://iopscience.iop.org/1347-4065/50/4R/042601)
Phase-Change Kinetics of Bi–Fe–(N) Layer for High-Speed Write-Once Optical Recording
Sung-Hsiu Huang, Yu-Jen Huang, Hung-Chuan Mai, and Tsung-Eong Hsieh
Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu, Taiwan 30010, R.O.C. Received October 20, 2010; accepted January 14, 2011; published online April 20, 2011
In this work, we present the phase-change kinetics of Bi–Fe–(N) layers for write-once optical recording. In situ reflectivity measurement indicated that the phase-change temperature (Tx) of the Bi–Fe–(N) layers is strongly related to the heating rate. TheTx’s were about 170C at low heating
rates and approached the melting point of the Bi phase (i.e., 271.4C) at high rate of heating provided by laser heating. For a 100-nm-thick Bi–Fe– (N) layer, Kissinger’s analysis showed that the activation energy of phase transition (Ea) = 1.24 eV, while the analysis of isothermal phase
transition in terms of the Johnson–Mehl–Avrami (JMA) theory showed that the average Avrami exponent (m) = 2.2 and the appropriate activation energy (H) = 5.15 eV. With the aid of X-ray diffraction (XRD) analysis, a two-dimensional phase transition behavior in the Bi–Fe–(N) layers initiated by the melting of the Bi-rich phase was confirmed. For optical disk samples with optimized disk structure and write strategy, the signal properties far exceeding the write-once disk test specifications were achieved. Satisfactory signal properties indicated that the Bi–Fe–(N) system is a promising alternative for high-speed write-once recording in the Blu-ray era. # 2011 The Japan Society of Applied Physics
1. Introduction
Optical disks are the most important external data storage devices for multimedia and personal data management at present because of their large recording capacity, interchan-geability, and portability.1–3)According to the data recording
principle, optical disks can be divided into read-only memory (ROM), write-once/recordable (R), and rewritable (RW). Among these, the write-once type is always the dominant product in the optical disk market and much effort has been exerted into studies of recording materials, either organic or inorganic,4) for such a type of optical disk. 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–SiO2 nanocomposite films,7,8) single layer metals such as AlSi alloys,9,10) bismuth oxide (BiFeO)11–13) and Bi–Fe–(N) layer,14) and bilayer metals such as Ge/Au,15–18) Cu/Si,19) ZnO/Ge,20)amorphous silicon (a-Si)/Cu,21–24)a-Si/Al,24,25) a-Si/Ni,26–28)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. In contrast to the other recording media listed above, Bi–Fe–(N) exhibits a unique recording mechanism involving element separation and grain coarsen-ing. Further study is thus required so as to gain a full understanding of its phase-change kinetics. In this work, an exothermal experiment in conjunction with Kissinger’s analysis and an isothermal experiment in conjunction with Johnson–Mehl–Avrami (JMA) analysis are carried out. The correlations between optical property and microstructure changes of the Bi–Fe–(N) layer are presented so as to delineate its phase-change kinetics during laser irradiation. Write-once optical disk samples containing Bi–Fe–(N) recording layers were also prepared in accord with the high-density digital versatile disk (HD DVD) format, and their signal properties at2 recording speed were evaluated in order to illustrate their feasibility for blue-laser optical recording.
2. Experimental Procedure
100-nm-thick Bi–Fe–(N) layers for phase-change kinetics
study were deposited on Si substrates via sputtering deposition in a self-designed six-target sputtering chamber at a background pressure lower than106Torr. The thin-film samples were prepared by sputtering the Bi–Fe alloy target under Ar/N2 gas flow at a working pressure of about 2 mTorr. A self-designed reflectivity-temperature measure-ment system was adopted to evaluate the in situ reflectivity change of the thin films as a function of temperature during the exothermal and isothermal experiments. The data obtained were then analyzed in accord with the Kissinger’s theory and the JMA theory, respectively, so as to explore the phase-change behaviors of Bi–Fe–(N) layers. In situ heating X-ray diffraction (XRD) measurements were carried out at the beamline BL01C2 of the National Synchrotron Radiation Research Center (NSRRC) at Hsinchu, Taiwan, R.O.C., with an X-ray wavelength of 0.1033 nm, a2 angular range up to 60 and a fixed X-ray grazing incident angle at 1. Such an XRD measurement collects the diffraction signals from a heated sample so as to explore the evolution of its crystal structure with a change in temperature. The samples were placed in a heating cell with argon (Ar) as the protecting gas, and the heating rate was maintained at 1C/min. A Mar 345 image plate detector was placed about 27 cm from the sample position and each image frame took 30 s for exposure during the measurements. The structural changes of the Bi– Fe–(N) layers were also characterized using an in-house X-ray diffractometer (MAC Science M18XHF) with Cu K radiation ( ¼ 0:1542 nm) at a scanning rate of 2/min. The sample for in-house XRD measurement was first heated to various temperatures (170, 300, and 400C) for 30 min, cooled down to room temperature, and then placed in the XRD apparatus for characterization.
Since the accessible signal tester was previously built for HD DVD optical disks, we thus prepared disk samples containing the Bi–Fe–(N) recording layer in accord with the HD DVD specifications.31,32)It is presumed that the results
presented as follows may be equally applied in Blu-ray disks (BDs) since the emphasis of this study is on material char-acterizations, rather than on disk hardware. Figure 1 shows a cross-sectional view of optical disk sample deduced by structure and write strategy optimization. The signal proper-ties of the disk samples including partial response signal-to-noise ratio (PRSNR), simulated bit error rate (SbER), modulation, and optimum write power (Pw), were evaluated
using a dynamic tester (PULSTEC ODU-1000) equipped E-mail address: [email protected]
with a 405 nm laser diode and a numerical aperture (NA) of 0.65. The characterization was performed at a clock frequency = 64.8 to 139.6 MHz, a linear speed = 6.61 to 13.22 m/s, an equalizer = 6.0 dB, and a track pitch = 0.4 m. Signal readout was carried out at a laser power (Pr) =
0.4 mW. The detailed conditions for dynamic test are listed in Table I.31,32)
The microstructures as well as the composition changes of the optical disk samples subjected to laser writing were examined using a transmission electron microscopy (TEM; JEOL FX-II 2010) equipped with an energy dispersive spectrometer (EDS; Link ISIS 300). The plan-view TEM (PTEM) samples were prepared in terms of the method reported by Chen et al.33)The disk sample was first cut into
small pieces using scissors. After dissolving the PC substrate in CH2Cl2 solution, the specimen was mounted on a copper (Cu) mesh and transferred to the TEM for microstructure characterization.
3. Results and Discussion
3.1 Phase-change kinetics of Bi–Fe–(N) layers
Figure 2 shows the in situ reflectivity changes of the 100-nm-thick Bi–Fe–(N) layer heated at various rates of 2.5, 5, 7.5, and 10C/min. Accordingly, the phase-transition
temperatures (Tx’s), i.e., the temperatures corresponding to
the maximum reflectivity changes, could be determined by the derivation method, and theTx’s for various heating rates
are listed in Table II. It can be seen thatTxincreases with an
increase in heating rate. This is ascribed to the superheat effects showing that the resistance to heat propagation in the samples increases with an increase in heating rate, causing a rise inTxand thus a delay in phase transition. In particular,
theTx’s indicate that phase transition in the Bi–Fe–(N) layer
emerges at approximately 170C at low heating rates (e.g., below 5C/min) and, when the heating rate is high (e.g., above 5C/min), the phase change occurs at approximately 220C or above. As revealed by the XRD characterization and JMA analysis reported below, phase transition in the Bi–Fe–(N) layer is found to result from the melting of the Bi-rich phase. Although the Tx’s listed in Table II are less
than the melting point of pure Bi at 271.4C (¼ TmBi), it is presumed that the Tx of Bi–Fe–(N) approaches TmBi during
signal writing owing to the extremely high heating rate of laser irradiation. In the present study, the deviation of Tx’s
from TmBi is attributed to the liquidus behavior due to the formation Bi-rich alloy as well as to the presence of finely dispersed nitrides in the Bi–Fe–(N) layer14) which may
induce the melting transition in a heterogeneous manner. It is speculated that, once phase transition occurs, the molten Bi phase quickly becomes wet and forms an interpenetrating liquid network in the sample so as to induce a catastrophic phase transition. This explains why the phase transition of the Bi–Fe–(N) layer could be completed in a rather narrow temperature span (25C), as shown in Fig. 2 in comparison with other write-once recording media.5–30) For instance, in the a-Si/Cu system, the precipitation of PC substrate (0.6 mm) Protective layer Ag (100 nm) Upper ZnS-SiO2 (27 nm) Bi-Fe-(N) (9 nm) Lower ZnS-SiO2 (40 nm) PC substrate (0.6 mm) Laser beam
Fig. 1. Cross-sectional view of optical disk samples deduced by structure and write strategy optimization.
Table I. Conditions for dynamic test.31,32) Recording speed
1 2
User capacity (Gbyte) 15
Thickness of substrate (mm) 0.6
Wavelength (nm) 405
Numerical aperture 0.65
Modulation code ETM,RLLð1; 10Þ
Track pitch (m) 0.4
Equalizer (dB) 6
Channel clock frequency (MHz) 64.8 129.6
Liner velocity (m/s) 6.61 13.22
User bit rate (Mbyte/s) 36.55 73.1
Fig. 2. Fraction of crystallization [xðtÞ] as function of temperature for Bi– Fe–(N) layer at various heating rates (film thickness = 100 nm).
Table II. Tx’s for the Bi–Fe–(N) layers measured at various heating rates (film thickness = 100 nm). Heating rate (C/min) Tx (C) 2.5 165 5 175 7.5 217 10 243 S.-H. Huang et al. Jpn. J. Appl. Phys. 50 (2011) 042601
the Cu3Si phase followed by the recrystallization of amorphous Si occurs in a relatively wide temperature span ranging from 100 to 500C.23,24) This also implies
that the phase transition in the Bi–Fe–(N) layer proceeds in a relatively fast manner via the evolution of the molten Bi phase, which greatly benefits the high-speed signal writing when adopted as the recording media of optical disks.
In situ heating XRD analysis, i.e., acquisition of diffrac-tion data during the isothermal heating of the samples, was employed to clarify the occurrence of the melting of the Bi-rich phase. A previous study showed that the as-deposited Bi–Fe–(N) layer is amorphous.14) Since the molten phases remain amorphous, as shown in Fig. 3(a), only a fuzzy, broad peak emerges in the sample regardless of its heating temperature. This indicates that the melting of the Bi-rich phase in the Bi–Fe–(N) layer likely occurs during heating. The samples subjected to various heat treatments followed by cooling down to room temperature were also character-ized by in-house XRD analysis. Figure 3(b) shows the characteristic peaks of the crystalline Bi phase (JCPDS file card No. 44-1246) that should form via the solidification of the molten Bi phase due to sample cooling. According to the results of XRD analysis presented above, the abrupt changes in the reflectivity profiles shown in Fig. 2 can thus be ascribed to Bi melting in the Bi–Fe–(N) layer.
The phase-change kinetics of the Bi–Fe–(N) layers were analyzed by utilizing Kissinger’s equation34) for the exo-thermal experiment and the JMA theory for the isoexo-thermal heating experiment, respectively. By plugging the data shown in Fig. 2 into Kissinger’s equation,
ln T2 x ¼ C Ea kBTx ;
where is the heating rate, Eais the activation energy,kB
is the Boltzmann constant, and C is the constant, we obtained Kissinger’s plot shown in Fig. 4. According to the slope of Kissinger’s plot, Ea is about 1.24 eV.
For JMA analysis, the fraction of crystallization [xðtÞ] was first calibrated from the results obtained by isothermal reflectivity measurements utilizing the relation
xðtÞ ¼RRt R0
max Rmin
;
where Rt and R0 are the reflectivities measured at t ¼ t and t ¼ 0, while Rmax and Rmin are the maximum and
minimum reflectivities observed during the experiment, respectively. The extrapolation of xðtÞ against t was then performed to determine the incubation period (0) so that the data corresponding to the steady-state nucleation of phase transition could be extracted for subsequent analysis. Afterward, the Avrami exponent, m, and an appropriate activation energy, H, were determined using the JMA equation35–38)
xðtÞ ¼ 1 exp½ðt 0Þm;
in which the coefficient can be expressed as ¼ 0 Hk
BT
:
We note that isothermal heating of Bi–Fe–(N) samples can only be carried out at temperatures below 170C since the onset of isothermal phase transition becomes unstable when the the sample is heated over 170C. This observation also supports a fast, catastrophic phase transition in the Bi–Fe–(N) layer induced by the melting of Bi-rich phase.
According to the plots of ln½ lnð1 xÞ against ln t shown in Fig. 5(a) and of ln against 1=T shown in Fig. 5(b), the averages of m and H are 2.2 and 5.15 eV, respectively. The Avrami kinetic law predicts a two-Fig. 3. XRD patterns of the samples acquired by (a) in situ heating XRD
experiment and (b) in-house XRD analysis of the sample subjected to various heat treatments followed by cooling down to room temperature.
dimensional phase transition behavior when2 m 3.35–38) This is in good agreement with a previously proposed argument that the phase transition is induced by the wetting of a molten Bi-rich phase in the Bi–Fe–(N) layer since wetting is essentially a two-dimensional physical process.
Table III shows a summary of the Tx’s and activation
energies (Ea and/or H) of phase transitions for various
recording media reported previously.6–8,15–18,20–30)Note that the Tx of the Bi–Fe–(N) system is listed at a temperature
about 270C since an extremely high heating rate of laser irradiation leads to the similarity of the Tx of Bi–Fe–(N)
system toTmBi. As shown in Table III, theTxof the Bi–Fe–(N)
system is comparatively lower than those of bilayer media, but higher than those of phase-change materials. Further-more, the low activation energy feature and the unique recording mechanism presented above indicate that the Bi– Fe–(N) system is a promising material for high-speed write-once recording in the Blu-ray era.
Finally, our JMA analysis shows that theH for the Bi– Fe–(N) system seems to be high, as listed in Table III. According to JMA theory,H is the sum of the activation energies of nucleation and growth processes. The highH may have resulted from the dispersed solid nitrides and Fe-rich phase in the Bi–Fe–(N) layer that form the obstacles of grain growth. This increases the activation energy of the growth process and hence theH. We, however, note that the determination of 0 markedly affects the calculated
values ofm and H.39)Since various data handling methods were employed by different research groups, theH’s listed here are for reference purpose only.
3.2 Signal properties and microstructures of disk samples Figure 6(a) shows the PRSNR and SbER as functions of Pwof the disk samples deduced by dynamic test at1 and
2 recording speeds. Table IV shows a summary of the optimum signal properties achieved in this study. The maximum PRSNR ¼ 26:7, minimum SbER ¼ 7:4 108, and modulation = 0.7 were achieved at the optimizedPw¼
7:1 mW for 1 recording, and that the maximum PRSNR ¼ 23:8, minimum SbER ¼ 2:2 107, and modulation = 0.7
were achieved at the optimized Pw¼ 9:1 mW for 2
recording. This illustrates a good sensitivity of the disk containing the Bi–Fe–(N) recording layer at lowPwvalues
for various recording speeds. Furthermore, it can be readily seen that the test results exceed the HD DVD specifications, which require that PRSNR 15 and SbER 5 105 at Pw 10 mW for 1 recording31)and thatPw 13 mW for
2 recording.32)
The eye patterns corresponding to random signals ranging from 2T to 11T, read directly from an oscilloscope at1 and 2 recording speeds, are shown in Fig. 6(b). Note that the length of short-T marks has been modified in order to obtain the optimum signal properties. This allows random signals to be written perfectly in the optical disks containing the Bi– Fe–(N) recording layer.
Figure 7 shows a bright-field PTEM image of signal marks in a disk sample recorded at 2 recording speed in which seashell-like signal marks with various recording lengths residing in the groove regions of disk sample can be clearly seen. In comparison with that reported in previous study,14) the change in recording speed barely affects the morphology and sizes of grains in the signal marks. As shown in Fig. 7, the selected area electron diffraction (SAED) patterns taken from the nonmark and mark areas all exhibit vague ring patterns, indicating that the Bi–Fe–(N) layer remains amorphous before and after the signal writing. Apparently, signal writing in a Bi–Fe–(N) disk sample does not result in the recrystallization or formation of inter-metallic phase in recording media as reported in other material systems.15,24,40) Laser irradiation induces melting and element mixing in the Bi–Fe–(N) layer. When signal writing is completed, the rapid cooling preserves the Fig. 5. Plots of (a)ln½ lnð1 xÞ against ln t and (b) ln against 1=T for
the Bi–Fe–(N) layer (thicknesses = 100 nm).
Table III. Comparison ofTx’s and activation energies of various write-once recording media.Eais obtained by Kissinger’s analysis,34)whilem and H are obtained by JMA analysis.35–38)
Material Tx
(C)
Ea
(eV) m H(eV) Measurement Ref.
Sb70Te30 136 2.08 3.5 1.97 Optical/DSC 6 AgInSbTe–SiO2 198 — 2.8 3.03 Optical 7,8 Ge/Au 310 — — — Optical 15–18 ZnO/Ge 385 — — — DSC 20 a-Si/Cu 485 3:3 0:1 1.8 — Optical 21–24 a-Si/Al 357 3:3 0:2 1.6 — Optical 24,25 a-Si/Ni 350 2:19 0:08 — — Optical 26–28 Bi/Ge 270 — — — DSC 29,30 Bi–Fe–(N) 270 1.24 2.2 5.15 Optical — S.-H. Huang et al. Jpn. J. Appl. Phys. 50 (2011) 042601
amorphism of the molten phase, and the separation of Bi and Fe elements occurs simultaneously owing to the decrease in their mutual solubility with a decrease in temperature as indicated by the Bi–Fe binary alloy phase diagram41)shown in Fig. 8. Element separation in the mark area14) is elu-cidated in Fig. 9, which shows the EDS analytical result of the mark and its vicinity in a disk sample subjected to 2 recording. The recording mechanism of optical disks containing the Bi–Fe–(N) layer is hence attributed to the element separation accompanied by the coalescence/coar-sening of separated phases, leading to sufficient change in optical properties for the signal readout of disk samples.
As shown in Fig. 7, there are bright diffraction spots in the SAED pattern taken from the mark area. TEM occasionally enabled the observation of these spots and, as indicated by the index of diffraction pattern in bottom right-hand corner of Fig. 7, the spots corresponds to the rhombohedral Bi phase. Some tiny Bi crystallites might form via hetero-geneous nucleation during the solidification of a molten recording layer and the embedment of such fine Bi crys-tallites in the amorphous matrix of recording marks hence results in the SAED pattern shown in Fig. 7. Note that the index of the SAED pattern is in agreement with that of the in-house XRD profile shown in Fig. 3(b). Hence, the TEM analysis also supports the melting of the Bi-rich phase in the mark area proposed previously.
Fig. 6. (Color online) (a) Variations in PRSNR and SbER of disk samples as functions ofPwat various recording speeds and (b) the eye patterns of random signals read directly from the oscilloscope for the optical disk samples at1 and 2 recording speeds.
Table IV. Optimum signal properties of Bi–Fe–(N) disk sample at various recording speeds.
Recording speed
1 2
Pw(mW) 7.1 9.1
Record condition Multi tracks Multi tracks
PRSNR 26.7 23.8 SbER 7:4 108 2:2 107 Modulation 0.7 0.7
0.5
µµm
(110)Bi (104)Bi (012)Bi (006)Bi (202)Bi (024)Bi (003)BiFig. 7. Bright-field PTEM image of signal marks in the optical disk sample recorded at2 recording speeds. The SAED patterns attached to upper- and lower-right-hand corners of the TEM image were taken from the nonmark and mark areas indicated by arrows, respectively.
4. Conclusions
In this work, we present the analytical results of the phase-change kinetics of Bi–Fe–(N) layer for high-speed write-once optical recording. The exothermal experiment showed that the Tx of the Bi–Fe–(N) layer strongly depends on the
heating rate that, at low heating rates, a phase change is induced at temperatures of about 170C. For practical laser heating, it would approach the melting point of Bi, i.e., 271.4C. Kissinger’s analysis indicated that Ea is about
1.24 eV for a 100-nm-thick Bi–Fe–(N) layer. JMA analysis indicated that the average Avrami exponent is about 2.2 and the appropriate activation energy (H) is 5.15 eV, revealing that the phase transition is accomplished by a two-dimensional wetting process due to the melting of the Bi-rich phase in the Bi–Fe–(N) layer. For the disk sample with optimized disk structure and write strategy,PRSNR ¼ 26:7, SbER ¼ 7:4 108, and modulation = 0.7 were achieved
at Pw¼ 7:1 mW for 1 recording and PRSNR ¼ 23:8,
SbER ¼ 2:2 107, and modulation = 0.7 were achieved
atPw¼ 9:1 mW for 2 recording. TEM/EDS
characteriza-tions confirmed that the recording mechanism of the Bi– Fe–(N) disk samples is correlated to the element separation in conjunction with grain coalescence/coarsening in the Bi-and Fe-rich phases. Satisfactory signal properties illustrate the promising applications of the Bi–Fe–(N) system to high-speed write-once recording in the Blu-ray era.
Acknowledgements
This work is supported by the National Science Council (NSC), Taiwan, R.O.C., under contract NSC96-2221-E-009-010. The dynamic test on optical disk samples supported by Prodisc Technology Inc., Taiwan, R.O.C., is deeply
acknowledged. The authors would also like to thank for support in the XRD experiments, Dr. Chia-Hung Hsu, Dr. Hwo-Shuenn Sheu and Dr. Wei-Tsung Chuang of NSRRC, Hsinchu, Taiwan, R.O.C.
1) M. Takenaga, N. Yamada, K. Nishiuchi, N. Akahira, T. Ohta, S. Nakamura, and T. Yamashita:J. Appl. Phys.54 (1983) 5376.
2) Y. Unno and K. Goto: Proc. SPIE382 (1983) 32.
3) M. Terao, S. Horigome, K. Shigematsu, Y. Miyauchi, and M. Nakazawa:
J. Appl. Phys.62 (1987) 1029.
4) A. E. T. Kuiper and L. van Pieterson:MRS Bull.31 (2006) 308.
5) N. Ishii, N. Kinoshita, N. Shimidzu, H. Tokumaru, H. Okuda, A. Hirotsune, Y. Anzai, M. Terao, and T. Maeda:Jpn. J. Appl. Phys.41 (2002) 1691.
6) Y. S. Hsu, Y. D. Liu, Y. C. Her, S. T. Cheng, and S. Y. Tsai:Jpn. J. Appl. Phys.47 (2008) 6016.
7) H. C. Mai and T. E. Hsieh:Jpn. J. Appl. Phys.46 (2007) 5834.
8) H. C. Mai, T. E. Hsieh, S. H. Huang, S. S. Lin, and T. S. Lee:Jpn. J. Appl. Phys.47 (2008) 6029.
9) B. M. Chen and R. L. Yeh:Proc. SPIE5380 (2004) 141.
10) B. M. Chen, H. F. Chen, R. L. Yeh, and J. M. Chung:Jpn. J. Appl. Phys.43 (2004) 5018.
11) N. Sasa, Y. Hayashi, T. Fujii, K. Otaka, A. Watada, H. Kamezaki, and H. Komoda:Jpn. J. Appl. Phys.43 (2004) 4972.
12) N. Sasa, Y. Hayashi, T. Fujii, A. Watada, and H. Komoda:Jpn. J. Appl. Phys.44 (2005) 3643.
13) Z. Jiang, Y. Y. Geng, and D. H. Gu:Chin. Phys. Lett.25 (2008) 3288.
14) H. C. Mai, T. E. Hsieh, S. Y. Jeng, C. M. Chen, and J. L. Wang:Appl. Phys. Lett.92 (2008) 021906.
15) T. H. Wu, P. C. Kuo, Y. H. Fang, J. P. Chen, P. F. Yen, T. R. Jeng, C. Y. Wu, and D. R. Huang:Appl. Phys. Lett.90 (2007) 151111.
16) T. H. Wu, P. C. Kuo, S. L. Ou, J. P. Chen, P. F. Yen, T. R. Jeng, C. Y. Wu, and D. R. Huang:Appl. Phys. Lett.92 (2008) 011126.
17) Z. Chen, S. Zhang, S. Tan, J. Hou, Y. Zhang, and H. Sekine:J. Appl. Phys. 89 (2001) 783.
18) Z. Chen, S. Tan, S. Zhang, J. Hou, Z. Wu, and H. Sekine:Jpn. J. Appl. Phys.40 (2001) 3960.
19) A. E. T. Kuiper, R. J. M. Vullers, D. Pasquariello, and E. P. Naburgh:
Appl. Phys. Lett.86 (2005) 221921.
20) C. P. Liu, Y. T. Hung, J. S. Tsai, G. J. Huang, and T. R. Jeng:Jpn. J. Appl. Phys.46 (2007) 7365.
21) J. B. Lee, C. J. Lee, and D. K. Choi:Jpn. J. Appl. Phys.40 (2001) 6177.
22) S. W. Russel, J. Li, and J. W. Mayer:J. Appl. Phys.70 (1991) 5153.
23) Y. C. Her and C. L. Wu:Jpn. J. Appl. Phys.43 (2004) 1013.
24) Y. C. Her, C. W. Chen, and C. L. Wu:J. Appl. Phys.99 (2006) 113512.
25) Y. C. Her and C. W. Chen:J. Appl. Phys.101 (2007) 043518.
26) Y. Kawazu, H. Kudo, S. Onari, and T. Arai:Jpn. J. Appl. Phys.29 (1990) 729.
27) F. A. Ferri and A. R. Zanatta:J. Appl. Phys.100 (2006) 094311.
28) Y. C. Her, S. T. Jean, and J. L. Wu:J. Appl. Phys.102 (2007) 093503.
29) Y. Hosoda, T. Izumi, A. Mitsumori, F. Yokogawa, S. Jinno, and H. Kudo:
Jpn. J. Appl. Phys.42 (2003) 1040.
30) Y. Hosoda, A. Mitsumori, M. Sato, and M. Yamaguchi:Jpn. J. Appl. Phys. 43 (2004) 4997.
31) DVD Specifications for High-Density Recordable Disc (HD DVD-R) for blue laser optical system, Version 0.9, The DVD Forum (July 2004).
32) DVD Specifications for High-Density Recordable Disc (HD DVD-R) for blue laser optical system, Version 2.0, The DVD Forum (February 2007).
33) H. W. Chen, T. E. Hsieh, J. R. Liu, and H. P. D. Shieh:Jpn. J. Appl. Phys. 38 (1999) 1691.
34) H. E. Kissinger:Anal. Chem.29 (1957) 1702.
35) M. Avrami:J. Chem. Phys.7 (1939) 1103.
36) M. Avrami:J. Chem. Phys.8 (1940) 212.
37) M. Avrami:J. Chem. Phys.9 (1941) 177.
38) J. W. Christian: The Theory of Transformations in Metals and Alloys (Pergamon Press, Oxford, U.K., 1975) 2nd ed., Part I, p. 542.
39) V. Weidenhof, I. Friedrich, S. Ziegler, and M. Wuttig:J. Appl. Phys.89 (2001) 3168.
40) Y. C. Her, J. H. Chen, M. H. Tsai, and W. T. Tu:J. Appl. Phys.106 (2009) 023530.
41) T. B. Massalski: Binary Alloy Phase Diagrams (ASM International, Materials Park, OH, 1990) 2nd ed., p. 737.
Fig. 9. Variations in chemical compositions deduced from the EDS analysis of the mark and its vicinity in a disk sample subjected to2 speed recording. Locations of EDS analysis are indicated in the inset TEM image.
S.-H. Huang et al. Jpn. J. Appl. Phys. 50 (2011) 042601
