Photoablation of a graphite target using a KrF excimer laser and application to deposition of hard-carbon thin films

1996 ◽  
Author(s):  
Alain Catherinot ◽  
C. Germain ◽  
J. Aubreton
1995 ◽  
Vol 4 (4) ◽  
pp. 309-313 ◽  
Author(s):  
C. Germain ◽  
C. Girault ◽  
J. Aubreton ◽  
A. Catherinot ◽  
S. Bec ◽  
...  

1983 ◽  
Vol 54 (8) ◽  
pp. 4590-4595 ◽  
Author(s):  
A. Bubenzer ◽  
B. Dischler ◽  
G. Brandt ◽  
P. Koidl

1990 ◽  
Vol 191 ◽  
Author(s):  
Toshiyuki Nakamiya ◽  
Kenji Ebihara ◽  
P. K. John ◽  
B. Y. Tong

ABSTRACTThe dynamics of melting and ablation of high Tc YBa2Cu3O7-x superconducting thin films flashed by a pulsed KrF excimer laser(λ=248nm) or a pulsed Nd-YAG laser (λ =1.06μ m) were studied numerically. The fundamental model during a pulsed laser irradiation was a one-dimensional heat conduction equation. The finite element method was applied to solve the equation including the temperature dependence of the thermal conductivity of YBaCuO thin films. In addition, the microstructure of YBa2Cu3O7-x bulk(l.5mm thick) flashed by a pulsed XeCl excimer laser (λ =308nm) was investigated by scanning electron microscopy (SEM) in order to estimate the threshold incident laser energy density for surface melting and ablation. The good agreements between the numerical calculations and the experimental results were obtained.


1998 ◽  
Vol 526 ◽  
Author(s):  
Kenji Ebihara ◽  
Hiromnitsu Kurogi ◽  
Yukihiko Yamagata ◽  
Tomoaki Ikegami ◽  
Alexander M. Grishin

AbstractThe perovskite oxide YBa2Cu3O7-x (YBCO) and Pb(ZrxTi1-x)O3 (PZT) thin films have been deposited for superconducting-ferroelectric devices. KrF excimer laser ablation technique was used at the deposition conditions of 200-600mTorr O2, 2-3J/cm2 and 5-10 Hz operation frequency. Heterostructures of PZT-YBCO-YAlO3:Nd show the zero resistivity critical temperature of 82K and excellent ferroelectric properties of remnant polarization 32 μC/cm2, coercive force of 80kV/cm and dielectric constant 800. Cycling fatigue characteristics and leakage current are also discussed.


1996 ◽  
Vol 433 ◽  
Author(s):  
Hiromitsu Kurogi ◽  
Yukihiko Yamagata ◽  
Tomoaki Ikegami ◽  
Kenji Ebihara ◽  
Bok Yin Tong

AbstractPb(ZrxTi1−x)O3(PZT) thin films have excellent ferroelectric, optical, piezoelectric and pyroelectric properties. We prepared PZT thin films using the excimer laser ablation technique. A pulsed KrF excimer laser was used to ablate PZT bulk targets. We have studied optimum preparation conditions such as an oxygen pressure, a laser energy fluence and a substrate temperature.In this paper, we investigated the composition, crystallization and ferroelectric properties of the PZT films prepared under various deposition conditions.The X-ray diffraction (XRD) patterns showed that the PZT films prepared on MgO(100) substrates at 600°C and with a laser fluence of 2J/cm2 had a perovskite - pyrochlore mixed structure. The condition of 100 mTorr oxygen pressure provided high quality perovskite films. It is found that the stoichiometric composition of the deposited films is obtained in ambient oxygen of 100˜400 mTorr. The ferroelectric properties of the Pt/PZT/Pt/MgO structure were studied. The capacitance-voltage characteristics and the corresponding hysteresis loop of the dielectric-electric field curve were discussed.We also studied optical emission of the PZT plasma plume to understand quantitative relation between the PZT film quality and the ablation plume plasma. We identified spectral lines originated in Pb, Pb+, Zr, Zr+, Ti, Ti+, PbO and TiO. These spectral intensities have remarkable dependence on the ambient O2 pressure.


2006 ◽  
Vol 45 (3A) ◽  
pp. 1689-1693
Author(s):  
Masashi Tsubuku ◽  
Kwang Soo Seol ◽  
In-Hoon Choi ◽  
Yoshimichi Ohki

1998 ◽  
Vol 526 ◽  
Author(s):  
Z.M. Ren ◽  
Y.F. Lu ◽  
W.D. Song ◽  
D.S.H. Chan ◽  
T.S. Low ◽  
...  

AbstractCarbon nitride thin films were deposited on silicon wafers by pulsed KrF excimer laser (wavelength 248 nm, duration 23 ns) ablation of graphite in nitrogen atmosphere. Different fluences of the excimer laser and pressures of the nitrogen atmosphere were used in order to achieve a high nitrogen content in the deposited thin films. Fourier Transform Infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to identify the binding structure and the content of the nitrogen species in the deposited thin films. The highest N/C ratio 0.42 was achieved at an excimer laser fluence of 0.8 Jcm -2with a repetition rate of 10 Hz under the nitrogen pressure of PN=100 mTorr. A high content of C=N double bond instead of C-N triple bond was indicated in the deposited thin films. Ellipsometry was used to analyze the optical properties of the deposited thin films. The carbon nitride thin films have amorphous-semiconductor-like characteristics with the optical band gap Eop, as high as 0.42 eV.


1998 ◽  
Author(s):  
Luowen Lu ◽  
Yongfeng Lu ◽  
Minghui Hong ◽  
T. M. Ho ◽  
Tohsiew Low

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