青木 孝憲

There are two advantageous points for fluorine-doped tin-oxide (FTO) films if used as transparent conducting electrodes the one is high average transmittance in the wave length region between 400 nm and 1500 nm which is favorable for thin film solar cells and the second is to improve anti-heat or anti-humidity properties of Al-doped zinc oxide (AZO) films when employed as a laminated structure of FTO and AZO layers. Therefore, approximately 500 nm-thick multi-layer transparent conducting films (FTO film (100 nm-thick) as protection layer/AZO film (400 nm-thick)) have been prepared. FTO films and AZO films were deposited at substrate temperature of 420~500°C and 280°C, respectively. Sheet resistance of 6.7μ/ P was obtained for the structure of FTO layer (fabricated at oxygen partial pressure of 0.5 Pa) and AZO layer (fabricated at oxygen partial pressure of 0 Pa).

In order to cope with the depletion of iudium, a strong interest has been recently turned to transparent conducting oxide (TCO) films based on a zinc oxide system. Focusing to this theme, it was tried to fabricate Gallium-doped zinc oxide (GZO) TCO films. But, it was difficult to make good films of GZO at low temperature. Therefore, it was tried to use laser-annealing-method for improved characteristics of GZO films. Approximately 200-nm-thick 5.0 wt.% Ga-doped zinc oxide (GZO: 5.0 wt.% Ga2O3) films have been deposited on glass substrates at Room Temperature by pulsed laser deposition (PLD) using the fourth harmonic generation (FHG) of Nd: YAG laser (λ=266 nm). In order to reduce resistivity of as-deposited films, annealing process was carried out by Nd:YAG (FHG) laser with laser energy density of 40 mJ/cm2. As a result, the resisivity was improved from 8.16 × 10-4 to 6.27 × 10-4 Ω•cm (improvement effect of 23.2 %). An average transmittance of ore than 85% in the visible region was obtained for the fabricated. © 2010, The Institute of Electrical Engineers of Japan. All rights reserved.

Gallium-doped zinc oxide (GZO) thin films have been deposited on Cyclo-Olefin Polymer (COP) substrates at room temperature by pulsed laser deposition (PLD) using FHG of Nd: YAG laser (λ = 266 nm, 1.6 mJ/cm2) and then, thin films were annealed by pulsed laser with FHG of Nd: YAG laser (λ = 266 nm, 8-20 mJ/cm2) at room temperature. As a result, the resistivity was improved from 6.61 × 104 Ω.cm to 5.94 × 10-4 Ω-cm for films annealed at a laser energy density of 12 mJ/cm2.

Ultra-thin Ga203 doped zinc oxide transparent conduction films was deposited on glass substrates using pulsed laser deposition method by ArF excimer laser λ = 193 nm) at the substrate temperature from 180 to 260 0°C. The film thickness was changed from 40 to 110 nm-thick. The target containing 3 and 5 wt.% Ga2O3 were employed. As a result, resistivity of 2.69 × 10-4 Ω.cm was obtained for the film with 40 nm-thick fabricated using the target containing 5 wt.% Ga 2O3 at substrate temperature of 260°C.

Al-doped transparent conducting zinc oxide (AZO) films, approximately 20-110 nm-thick, were deposited on glass substrates at substrate temperatures between 200 and 300 degrees C by pulsed laser deposition (PLD) using an ArF excimer laser (lambda = 193 nm). When fabricated at a substrate temperature of 260 degrees C, a 40-nm-thick AZO film showed a low resistivity of 2.61 X 10(-4) Omega(.)cm. carrier concentration of 8.64 x 10(20) cm(-3), and Hall mobility of 27.7 cm(2)/V.s. Furthermore, for an ultrathin 20-nm-thick film, a resistivity of 3.91 x 10(-4) Omega(.)cm, carrier concentration of 7.14-10(20) cm(-3), and Hall mobility of 22.4 cm(2)/V(.)S were obtained. X-ray diffraction (XRD) spectra, obtained by the theta-2 theta method, of the AZO films grown at a substrate temperature of 260 degrees C showed that the diffraction peak of the ZnO (0002) plane increased as the film thickness increased from 20 to 110 nm. The full-width-at-half-maximum (FWHM) values were 0.5500 degrees, 0.3845 degrees, and 0.2979 degrees for film thicknesses of 20, 40, and 110 nm, respectively. For these films, the values of the average transmittance in visible light wavelengths (400-700 nm) were 95.1%, 94.2%, and 96.6%, respectively. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) observations showed that even the 20-nm-thick films did not show island structures. In addition, exfoliated areas or vacant and void spaces were not observed for any of the films. (c) 2008 Elsevier B.V. All rights reserved.

Molybdenum-oxide (MoO3)films were deposited on glass substrates (Corning #7059 with an area of 26x38 mm(2)) by pulsed laser deposition using an ArF excimer laser. It was found that after annealing at 340 degrees C for 10 min, the film thickness became 2.3 times that (approximately 30 nm) of the as-deposited film thickness. The difference in the transmittance, AT, between the annealed state and the as-deposited state was about 40% at a wavelength of 400 nm. X-ray diffraction spectra indicated that oxygen was absorbed into the MoO3 films through the annealing process. From revolution testing of 30 nm-thick MoO3 films without a protective layer deposited on a polycarbonate DVD-R disk substrate (120 mm phi, 0.6 mm thickness), a write peak-power dependence of carrier-to-noise ratio (CNR) (recording on-land, at lambda =406 nm, NA=0.65) of the 3T signal (58.5 MHz) was measured at a linear velocity of 5 m/s and a read power of 0.6 mW. Consequently, CNR near 50dB was obtained in the wide write-power margin Delta P of 7 mW (at peak powers between 3.5 and 10.5 mW). From SEM observations, it was recognized that bits of 0.25-0.30 mu m size, corresponding to a storage capacity of 7-10GB/in(2) in the case of NA=0.65, were formed. For the sample structure with an Al2O3 protective layer of similar to 20 mn thickness, a CNR near 50dB was obtained in the peak-power margin Delta P of 12 mW (at peak powers between 6.0 and 18.0 mW). Larger values of the CNR can be obtained if the film thickness of each layer including both the active and protective layers is optimized. (c) 2008 Elsevier B.V. All rights reserved.

Approximately 230 nm-thick Al-doped transparent conducting zinc oxide films (AZO) have been deposited on Cyclo Olefin Polymer (COP) substrates with ZnO buffer layer fabricated under oxygen partial pressure of 0.5-5.3 Pa, by pulsed laser deposition (PLD) using ArF excimer laser (λ = 193 nm). When the ZnO buffer layer was fabricated with oxygen partial pressure of 5.3 Pa, the lowest resistivity obtained for the AZO film was 4.12 × 10-4 Ω·cm.

beta-FeSi2 thin films were grown on Si(l 11) substrates by pulsed laser deposition (PLD) method using a Nd:YAG laser (lambda = 1064 nm, laser energy = 50 mJ, laser energy 2 density = 1.65 J/cm(2), repetition frequency = 10 Hz). In the fabrication process, three targets of (a) Fe(5N), (b) FeSi2(3N), and (c) Fe(5N) + FeSi2(3N) were used. The beta-FeSi2 thin films having the best properties of crystallinity were obtained in the case of (c), in which the first layer as the template was formed with the target of Fe(5N) and then, on top of that, the second layer was deposited with the target of FeSi2(3N). At this time, it was found that by XRD measurement, the degree of crystallinity of the films of case (c) in which the first layer was introduced as the template improved 1.4 times as much compared with case (a), and that by SEM and AFM observations, surface morphologies also improved. Moreover, it was found that by TEM observation, the beta-FeSi2 thin films grew uniformly along the direction of (220) or (202) from the interface of the Si substrate and the film to the free surface and that by EDS analysis, the compositions of Fe and Si were uniformly distributed. (c) 2007 Wiley Periodicals, Inc.

Approximately 30-nm thick iron films were deposited using an iron target with a high purity of 5 nine on glass or polycarbonate substrate by radio-frequency magnetron sputtering, in order to use for media of the write-once disk. The transmittance change between the as-deposited state and the annealed state (500°C × 10 min) was about 18% at the wavelength of 400 nm. For the films on the polycarbonate substrate, the CNR of 42 dB was obtained at a peak power of 8 m W (at A =406 nm, NA = 0.65). On this time, we observe recording pits (diameter of about 0.26 μm) written at the peak power of 10 mW.

Al-doped zinc oxide (AZO) or Ga-doped zinc oxide (GZO) films with c-axis orientation have been deposited on glass substrates by pulsed laser deposition (PLD) using an ArF excimer laser (λ= 193 nm) or Nd:YAG laser (λ= 532, 355, 266 nm). The film deposition took place at substrate temperatures of room temperature (25 °C) ∼ 200 °C. For the GZO film deposited by irradiating a pulsed laser beam of energy density of 1 J/cm² at repetition frequency of 10 Hz, we obtained the 416 nm-thick GZO film with the lowest resistivity of 2. 89×10^-4 Ω·cm for the case at a substrate temperature of room temperature. An average transmittance of more than 80 % in the visible region was obtained for the GZO films fabricated, providing useful functionality as TCO films in the visible region. Moreover, we studied whether the film properties were subject to influences of the position of the plume (in the central axis or at the periphery) generated between the substrate and the target.

WO2 films were deposited onto the glass substrates (Corning #7059 with an area of 26 × 38 mm) by the pulsed laser deposition method using an ArF excimer laser. It was found that after annealing at 500 °C for 10 min, the film thickness became 1.9 times compared with that (approximately 40 nm) in the as-deposited state. At that time, the difference in the transmittance, ΔT, between the annealed state and the as-deposited state was about 70% at the wavelength of 405 nm. From the XRD and XPS spectra, it was considered that oxygen was absorbed into the tungsten oxide films through the annealing process, accelerating the formation of WO2 or WO3 structure which caused the incremental effect in the transmittance and the expansion effect in the film thickness. For the revolution-test of the sample without the protection layer in which the WO2 films were deposited upon the digital versatile disk (DVD-R) substrate, a write peak power dependence of CNR (at λ = 405 nm, NA = 0.65) of 3T signal (58.5 MHz) was measured at a linear velocity of 5 m/s and a read power of 0.6 mW. The values of CNR of 35 ∼ 40 dB were obtained at the peak power of 5 ∼ 7 mW, and increased largely up to 60 dB at 8 mW, and then reached a maximum of 62 dB at 8.5 mW. After that, the values of the CNR suffered some deterioration at more than 9 mW because of too much expansion of the written dot by which the portion between the dot and neighbor dots became to be invaded. For the dots formed in the writing performance on the DVD-R disk, the expansion effect in direction along the groove or over the neighboring lands was recognized by SEM images. It was found that bits of 0.18 ∼ 0.30 μm size, corresponding to the maximal storage capacity of 25 GB in the 'Blu-ray disk' specification, were made. © 2005 Elsevier B.V. All rights reserved.

Approximately 300 nm-thick Al-doped transparent conducting zinc oxide films (AZO(A12O3:1.5wt.%)) have been deposited on glass and PVC substrates by a pulsed laser deposition (PLD) using ArF excimer laser (λ= 93nm) with energy of 40-100 mJ at the repetition frequency of 50 Hz. When fabricated with the laser energy of 40-100 mJ, similar characteristics of electrical properties and optical transmittance were obtained for the AZO films deposited on glass or PVC substrates. Namely, the lowest resistivity obtained was 6.34× 10-4Ω·cm and an average optical transmittance was more than 80% in the visible range. But, when prepared with the laser energy of 80-100 mJ, surface roughness for the AZO films fabricated on PVC substrates decreased compared to the films deposited on glass substrates. Moreover, for the AZO films fabricated on PVC substrates, an average optical transmittance in the visible range was reduced to 30-50 %. I.

Approximately 300-nm-thick 1.5 wt.% Al-doped zinc oxide(AZO: 1.5 wt.% A12O3) films have been deposited on glass substrates and PVC substrates at room temperature by a pulsed laser deposition (PLD) using ArF excimer laser ( λ = 193 nm). The film deposition was carried out under the condition of laser energy density with 2 to 5 J/cm2. For AZO films deposited on PVC substrates with low laser energy density, electrical and optical properties were equivalent to that for AZO films deposited on glass substrates. However, for AZO films prepared by high laser energy density, the value of surface roughness was large and the value of Hall mobility remarkably decreased compared to that for AZO films grown on glass substrates.

Approximately 200-nm-thick 1.5 wt.% Al-doped zinc oxide (AZO: 1.5 wt.% Al2O3) films have been deposited on glass substrates at 100°C by pulsed laser deposition (PLD) using the fourth harmonic generation (FHG) of Nd: YAG laser U = 266nm). In order to reduce resistivity of as-deposited films, annealing process was carried out by ArF excimer laser with laser energy density of 34 mJ/ cm2. As a result, the value of resistivity was not almost improved: 1.54×10-3 Ω · cm (for as-deposited) and 1.33×10-3 Ω · cm (for annealed). On the other hand, for the films annealed by fourth harmonic generation of Nd:YAG laser with laser energy density of 20 mJ/ cm2, the value of resistivity was reduced from 1.36×10-3 Ω cm to 8.34×10-4 Ω · m.

W O3 films were deposited on the glass substrate (Corning No. 7059 with an area of 26×38 mm) by the pulsed laser deposition method using an ArF excimer laser. It was found that after annealing at 500 °C for 10 min, the film thickness became 1.8 times compared with that (approximately 40 nm) in the as deposited state. At this time, the difference in the transmittance, ΔT, between the annealed state and the as deposited state was about 40% at the wavelength of 400 nm. From x-ray diffraction spectra and x-ray photoelectron spectroscopy spectra, it was considered that the ratio of the peak values of W6+ 4 f52 (tungsten oxide) versus W 4 f52 (metal tungsten) increased steeply after the annealing process. From this, it was considered that oxygen was absorbed into the W O3 films through the annealing process. From the revolution test for the sample without the protection layer in which the W O3 films were deposited upon the digital versatile disk disk substrate, a write peak-power dependence of carrier to noise ratio (CNR) (at λ=406 nm, NA=0.65) of 3T signal (58.5 MHz) was measured at a linear velocity of 5 ms and a read power of 0.6 mW. It was confirmed that the values of CNR obtained at the write peak-power 5-6 mW were near 50 dB (the region A) and the ones obtained at the write power 7-10 mW were more than 60 dB (the region B). From scanning electron microscopy observation, it was recognized that bits with 0.16-0.25 μm size, having the fine-shaped dots with clear-cut edge, were made in the region A. This corresponded to the maximal storage capacity of 25 GB in the "Blu-ray disk" specification. However, it was also identified that holes were formed in the region B and the film materials were scattered by receiving a train of high write power impulses. Next, it was found that the write power corresponding to region A for the structures with the W O3 layer sandwiched between a Al2 O3 or ZnS-Si O2 protection layer increased or decreased, respectively. Larger values of the CNR will be obtained if the film thickness of each layer including the active layer were optimized. © 2005 American Vacuum Society.

Al2O3-doped ZnO (AZO) thin films have been deposited onto glass substrates using a split target consisting of AZO (1 wt%) and AZO (2 wt%) by pulsed laser deposition with an ArF excimer laser (λ = 193 nm, 15 mJ, 10 Hz, 0.75 J/cm2). By applying a magnetic field perpendicular to the plume, the lowest resistivity of 8.54 × 10-5 Ω·cm and an average transmittance exceeding 91% over the visible range were obtained at a target-to-substrate distance of 25 mm for approximately 279-nm-thick AZO film (1.8 wt%) grown at a substrate temperature of 230 °C in vacuum. From crosssectional TEM observations and the XRD spectrum, a reason why the low resistivity (54 × 10-5 Ω·cm) was reproducibly obtained was considered to be due to the fact that a disorder of crystal growth originating in the vicinity of the interface between the substrate and the film was suppressed by application of the magnetic field and the c-axis orientation took preference, giving rise to the increase of mobility. © 2005 Wiley Periodicals, Inc.

ZnO films doped with 1.5 wt% Al2O3 (AZO films) have been deposited, in oxygen with a partial pressure of 0.1 Pa, on glass substrate using a pulsed laser deposition technique with an ArF laser (λ = 193 nm). When as-deposited, a repetition rate of 10 Hz, an energy density of 4 J/cm 2, and an irradiation time of 30 min were used. After an annealing performed with the energy density 10-40 mJ/cm2 for 30 min, it was found that resistivity decreased from 1.26 × 10-3 Ω · cm to 9.58 × 10-4 Ω · cm and surface roughness of the films Ra decreased from 2.1 nm to 1.8 nm.

Approximately 100-nm-thick transparent conducting AZO (ZnO doped with 1.5 wt.% Al2O3) films have been deposited on glass substrates using a pulsed laser deposition method with an ArF excimer laser (λ = 193 nm) and a Nd:YAG laser (λ = 266, 355, 532 nm). In all experiments, a repetition rate of 10 Hz, an energy density of 2 J/cm2, and an irradiation time of 10-60 min (6000-36000 shots) were used. XRD and FE-TEM observations revealed the fact that there is a remarkable difference of the crystal structures in the films fabricated with various wavelengths of the lasers: at 532 nm, it was found that the whole structure was melted.

Tungsten oxide films were deposited on glass substrates (Corning #7059) and polycarbonate substrates by a pulsed laser deposition technique using the both targets WO3 and WO2. At this time, the difference in the transmittance, ΔT, between the annealed state and the as-deposited state of the films fabricated with WO2 target was about 70% at the wavelength of 400 nm and that of the films prepared with the WO3 target was about 60%. From XRD spectra and XPS spectra, it was found that the as-deposited state was an oxygen-deficient amorphous state and the crystalline state was caused by absorbing oxygen through the annealing process (at 500°C × 10 min). It was confirmed from the revolution-test of the disc structure that the values of CNR obtained at the write peak power 7.5∼9 mW was more than 50∼60 dB. From SEM images of top the view, it was presumed that a recording mechanism was related to a cooperative effect of the reflectivity change and the volume change induced in the recorded dot.

ITO (In2O3 doped with 5 wt% SnO2) films were grown on glass substrates at room temperature by the pulsed laser deposition method using an ArF excimer laser that provides 40 mJ (1.4/cm 2) pulses of 12-16 ns duration at a repetition rate of 10 Hz. Ablation time was 20 min and gas pressure of oxygen was 4-5 Pa. After the deposition process was finished, the ITO films were annealed for 30 min by the excimer laser regulated to give a weak energy density of 4-14 mJ/cm2. As a result, the resistivity of the film decreased from 3.14 × 10 -3 Ω · cm to 9.66 × 10-4 Ω · cm and the surface roughness Ra improved from 0.69 nm to 0.46 nm.

β-FeSi2 thin films were deposited on Si (111) by a pulsed laser deposition using a Nd:YAG laser. It was identified from XRD spectra of the as-deposited films that β-FeSi2 (220) and β-FeSi 2 (202) were grown epitaxially on the Si (111) substrate. It was found that the crystallinity of the films improved through a laser annealing process making use of the Nd: YAG laser with the low power density.

ZnO doped with 1.5 wt.% Al2O3 (AZO) and 5 wt.% Ga2O3 (GZO) films were deposited on glass substrates by pulsed laser deposition method. In all experiments, repetition rates of 10 Hz, the energy density of 2 J/cm2, and an ablation time of 20 min irrespective of magnetic field. For AZO films deposited in magnetic field, the diffraction peak of ZnO (0002) facets grew large and a crystallinity improved. On the other hand, for GZO films fabricated with or without magnetic field, the crystallinity did not change. It was observed that for AZO films fabricated with magnetic field, the transmittance increased in the visible wavelength range and decreased in the infrared range being reflective of the reduction of carrier concentration.

β-FeSi2 thin films were grown by pulsed laser deposition method using an ArF excimer laser. The as-deposited films were annealed by the same laser after the films were grown. It was found that Si element was diffusible in the films and the crystallinity of films improved. From TEM observation of the interface between the film and the Si (100) substrate, an epitaxial growth of β-FeSi2 films, having good properties, was recognized.

A series of AZO films were grown on glass substrates by a method of pulsed laser deposition using a split target divided into AZO (Al2O 3: 1 wt.%) and AZO (Al2O3: 2 wt.%). The film deposition took place at a substrate temperature of 230 °C within a magnetic field applied perpendicularly to the plume. To suppress the droplet generation caused by the intense laser energy, the laser energy density was reduced to 0.75 J/cm2 (15 mJ). For an approximately 280-nm thick-AZO film grown at a target-to-substrate distance of 25 mm, we obtained the lowest resistivity of 8.54×10-5 Ω·cm and an average transmittance of more than 88% in the visible range. In the cross-sectional TEM observation and XRD spectra, the regularity in the crystal growth was generated immediately from the interface between the substrate and the film. © 2003 Elsevier Science B.V. All rights reserved.

本論文ではパルスレーザーアプレーション法で作製したZnO／In203積層構造光記録膜について述べている。2つのターゲットを用いたPLD法で積層構造に膜を堆積させた場合、透過率が低くなり熱アニールにより大きく光学変化が生じることが分かった。ⅩPS探さ分析によりこのメカニズムを調べた。また、DVDテスターにより0．26μmのピットを記録できることを確認し、高分解能SEMによる観察を行った。ZnO：In203＝1：1、膜厚30nmの膜において、書き込みパワー3mWで67dBのCNRが得られた。

本論文は、酸化ガリウムと酸化亜鉛のスプリットターゲットを用いたパルスレーザー堆積法で積層構造光記録膜を作製し、基礎特性と光ディスク特性について述べている。Ga203とZnOのトレース比が3：5のとき最も大きな透過率差（熱処理前後）40％が得られた。膜中のGa203が増加するに従って表面形態が、改善されることが分かった。この系のCNRは約50dBであり、従来のDVD－RAMやW系に比べて低パワーでの記録が可能となった。

本論文は、Nd：YAGレーザー（波長532nm）を用いたパルスレーザー堆積法で700℃に加熱したSi（1（氾）基板上にFeを堆積し、同レーザーによるアニーリングで結晶性が優れ、平滑な表面形態を有するβ－FeSi2が得られたことについて述べている。8時間のレーザーアニーリングにより、β－FeSi2の（331）から（400）へと基板にC軸配向した結晶が得られた。また、アニーリングすることにより表面形態も改善されることがSEM観察により分かった。

The thin films of ZnO doped with 4 wt% Ga2O3 were deposited on glass substrates by pulsed laser deposition using an ArF excimer laser (λ = 193 nm). A heated mesh was given was arranged between the target and the substrate. In all experiments, repetition rates of 10 Hz, the energy density of 1 J/cm2, and an ablation time of 60 min were used. A lowest resistivity of 3.71 × 10-4 Ω· cm and an optical transmittance of more than 80% in the visible range of the spectrum were obtained for ZnO doped with 4 wt% Ga2O3 films of more than 200-nm thickness fabricated at a substrate temperature of R.T. and a gas flow rate in O2 of 4 sccm. Smooth surfaces with an average surface roughness of 1.1 nm were observed by field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM).

Al2O3 - doped ZnO (AZO) thin films have been deposited onto glass substrates using the split target consisting of AZO (1 wt%) and AZO (2 wt%) by pulsed laser deposition method with an ArF excimer laser (λ = 193 nm, 15 mj, 10 Hz, 0.75 J/cm2). By applying magnetic field perpendicular to the plume, the lowest resistivity of 8.54 × 10-5 Ω. cm and an average transmittance more than 91 % over visible range were obtained at a target to substrate distance of 25 mm for approximately 279 nm-thick-AZO film (1.8 wt%) grown at a substrate temperature of 230 °C in vacuum. From the cross-sectional TEM observation and the XRD spectrum, a reason why low resistivity of the level of 10-5Ω Ω cm was reproducibly obtained was considered to be due to the fact that a disorder of crystal growth originated in the vicinity of the interface between the substrate and the film was suppressed in the application of magnetic field and the c-axis-orientation became of preference, which in turn, giving rise to the increase of mobility. © 2003, The Institute of Electrical Engineers of Japan. All rights reserved.

Thin films (∼30 nm thick) with a stack structure (60 layers) of Ga 2O3 and ZnO have been deposited onto glass substrates or polycarbonate disk substrates by a pulsed laser deposition method with an ArF excimer laser using a split target made of Ga2O3 and ZnO. Transmittance differences ΔT (Tanneaied-T as-deposited) between the annealed state and the as-deposited state for the films fabricated at trace ratio (the ratio of the time required to irradiate each side (Ga2O3 or ZnO) of the target by laser pulses) of 3 : 5 showed a maximum value of 40%. It was recognized by AFM observations that surface roughness Ra for the films was near 0.5 nm. It was found that the value of Ra decreased as the Ga 2O3 contents increased. A peak power dependence of CNR of 3T signal (λ = 406 nm, NA = 0.65) at a linear velocity of 5 m/s and a read power of 0.6 mW was measured for the disk samples with 60 layers. The CNR of 53 dB was obtained for the samples prepared with the trace ratio of 1 : 5 ∼ 1 : 0.6 at a write power of 3 mW.

ZnO doped with 2 wt% and 1 wt% Al2O3 (AZO) films were deposited on glass substrates by pulsed laser deposition method. In all experiments repetition rates of 10 Hz, the energy density of 0.75-2 J/cm 2, and an ablation time of 15-50 min irrespective of magnetic field, A lowest resistivity of 9.27 × 10-5 Ω · cm and an optical transmittance of more than 91% in the visible range of the spectrum were obtained on the film fabricated with the magnetic field. This improvement of the properties with using magnetic field is due to the enhancement of crystallization and crystal grain growth and the improvement of ZnO(002) orientation.

Iron disilicide (β-FeSi2) thin films were deposited on Si(100) substrate by a pulsed laser deposition using SHG of a Nd:YAG laser. The film crystallizations were varied by annealing time of β-FeSi2 films irradiated by Nd:YAG laser. From XRD spectra of these films, peaks of β-FeSi2 (400) and (800) were identified. It was found from FE-SEM observations that surfaces of the β-FeSi2 films annealed for 8 h were flatter than that of the as-deposited β-FeSi2 films.

β-FeSi2 thin films were deposited on Si (001) substrate by a pulsed laser deposition using an ArF excimer laser. From XRD peaks of the as-deposited films, peaks of β-FeSi2 (400), (600) and (800) were identified. At this time, it was found from FE-SEM observation that there was aggregation on the film surface. In order to overcome these problems, an annealing process using an ArF excimer laser was carried out. From XRD peaks of the annealed films, intensified peaks of β-FeSi2 (400), (600) and (800) were identified, and improvement of crystallinity was recognized. It was found from FE -SEM observation that the surface of film was smooth.

The In-Zn oxide films with a laminated multilayer structure of each layer of In2O3 and ZnO were grown on glass substrates or polycarbonate disk substrates by pulsed laser deposition using a split target consisted of In2O3 and ZnO. For the disk sample with 60-layers, which was approximately 30 nm thick, fabricated at the trace ratio ( the ratio of time required to irradiate each part of the split target) of In2O3 : ZnO = 1 : 1, the CNR of approximately 60 dB was obtained for 3T signal (f = 58.5 MHz, lambda = 406 nm, NA = 0.65).

The In-Zn oxide films with a laminated multilayer structure of each layer of In2O3 and ZnO were grown on glass substrates or polycarbonate disk substrates by pulsed laser deposition using a split target consisted of In2O3 and ZnO. For the disk sample with 60-layers, which was approximately 30 nm thick, fabricated at the trace ratio ( the ratio of time required to irradiate each part of the split target) of In2O3 : ZnO = 1 : 1, the CNR of approximately 60 dB was obtained for 3T signal (f = 58.5 MHz, lambda = 406 nm, NA = 0.65).

In2O3 doped with 5 wt.% SnO2 [indium-tin oxide (ITO) (5 wt.%)] films were deposited on glass substrates by pulsed laser deposition using an ArF laser (λ = 193 nm). In all experiments, repetition rates of 1 ∼ 50 Hz, an energy density of 6 J/cm2, and an ablation time of 30-900 s were used. A lowest resistivity of 8.45 × 10-5 Ω cm and an optical transmittance of more than 80% in the visible range of the spectrum were obtained for ITO (5 wt.%) films of approximately 300-nm-thickness fabricated at a substrate temperature of 400 °C and oxygen pressure of 10 Pa. Smooth surfaces with an average surface roughness of 1.26 nm were observed by field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). © 2002 Elsevier Science B.V. All rights reserved.