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Investigation of titanium nitride films prepared by Xe+ ion beam enhanced deposition in a N2 gas environment
Abstracts
of oxygen and argon, and only oxygen as reaction gas are applied in the discharge chamber respectively. The deposit rate is about 3 pm min i. As a heat-radiation absorbent film in electric vacuum devices, the characteristics of the Cr20 3 thin film are discussed, such as high adhesive strength with the substrate after annealing in hydrogen at 800°C and lower outgassing. Finally, applicable C,r203 thin film has been obtained in only oxygen at a pressure of 8 x 10 1pa. It has been found that when the reaction gas is a mixture of argon and oxygen, Cr203 thin films on iron substrates characterized by AES absorption or burial of an amount of argon atoms and vacuum degassing at 600°C is not effective for degassing argon from Cr203 thin film on an iron substrate. However, slow outgassing of argon in electric vacuum devices is effective, which is proven by a residual mass spectrometer. If the argon partial pressure in an X-band frequency magnetron is over 10-4 Pa due to outgassing, the argon ion bombardment to the cathode surface will result in a spectrum of output microwave pulsed signal band, because of cathode surface damage by ion bombardment. In conclusion, Cr20 3 thin film deposited by arc discharge plasma has the advantages as follows : high absorptivity, strong adhesive strength and no argon outgassing.
]'he thermal effects on laser-induced damage in optical coatings Fan Zhengxiu and Wu Zhouling, Shanghai Institute of Optics and
Fine Mechanics, Academia Sinica, PO Box 800-211, Shanghai 201800, China The thermal effects play an important role for laser-induced damage in optical coatings. The energy deposition is produced fi:om the absorption of laser energy in optical coatings. The temperature distribution is dominated by the laser field distribution and the thermal conduction process in optical coatings. Reported here are the in situ experiments of the thermal deflection technique as well as the temperature distribution in optical thin films. It is verified that the deposition of heat is mainly set in the higher field intensity region. For H R multilayer coating, the extreme value of field intensity is raised at the interface of high-low refractive index materials, so that the heat source is formed generally in those regions. This phenonemon is verified by the time resolution photothermal signal. Several thermal pulses were shown along with the probe time. The interval of the pulse is directly proportional to the thickness of the thin film layer cycle.
Investigation of titanium nitride films prepared by Xe + ion beam enhanced deposition in a N2 gas environment Wang Xi, Yang Genqing, Zheng Zhihong, Huang Wei, Zhou Zuyao, Liu Xianghuai and Zou Shichang, Ion Beam Laboratory,
Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, China A new method, in which electron beam evaporation of titanium and bombardment with a 40 keV xenon ion beam were done simultaneously in a N2 gas environment, has been developed to prepare titanium nitride films. The composition and structure of
the films were investigated by means of RBS, AES and XRD. The xenon contamination in the films is very low and the films are mainly composed of TiN polycrystalline. A transition layer exists between the film and the substrate, which is of great benefit to the adhesion of the film to the substrate. The hardness of the film reached 2300 kg m m - 2, higher than that of films prepared by N ÷ ion beam enhanced deposition. Scratch tests showed the adhesion of the titanium nitride film to substrate is quite strong. The titanium nitride films have been applied to the surface protection of the scoring dies and the life time of the dies can be increased by about 5-10 times.
An infrared absorption band caused by H+-implantation in LiNbO3 crystals Feng Xiqi and Zhang Jizhou, Shanghai Institute of Ceramics, Academia Sinica, Shanghai 200050, China; and Shao Tianhao,
Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, China A new infrared absorption band at about 3545 cm-~ wavenumber has been observed in LiNbO3 crystals implanted by energetic H ÷ ions. It is found that the peak wavenumber of this band seems to be independent on the stoichiometry, dopant species and doping level in the investigated samples. The band, polarized perpendicularly to the c-axis, would disappear after annealing the sample in air at 500°C for 0.5 h. The new absorption band is interpreted as a distributed OH stretching vibration in a H÷-implanted LiNbO3. The displacement of Nb 5+ ions from their regular sites caused by the ion implantation may expand the oxygen triangle to result in a longer O---O bond, which can explain the higher wavenumber of OH band in the H÷-implanted LiNbO3 crystals.
A new definition of laser damage threshold of optical thin films : optical breakdown threshold Ni Xiaowu, Lu Jian and He Anzhi, Department of Applied Physics,
East China Institute of Technology, Xiaolingwei 200, Nanjing 210014, China; and Ma Zi and Zhou Jiuling, South-West Technical Physics Institute, Chengdu 610015, China Optical coating as a component in a high-power laser system is usually an important and weak link. Thin film damage threshold was often defined as the average value of the maximum incident laser energy density on the thin film, under which damage did not occur, and the minimal energy density, under which damage did occur. However, the experimental data were very often obtained under the condition which made it difficult to respect the data. In this paper, the physical mechanisms of interaction between high-power laser and thin film and damage of film materials are analysed. Optical breakdown and the forming of plasma may be thought of as the beginning of thin film damage. F o r this reason, a new definition of the laser damage threshold of a thin film is presented by optical breakdown threshold. Furthermore, the optical beakdown threshold is defined as the average value of the 1089
of oxygen and argon, and only oxygen as reaction gas are applied in the discharge chamber respectively. The deposit rate is about 3 pm min i. As a heat-radiation absorbent film in electric vacuum devices, the characteristics of the Cr20 3 thin film are discussed, such as high adhesive strength with the substrate after annealing in hydrogen at 800°C and lower outgassing. Finally, applicable C,r203 thin film has been obtained in only oxygen at a pressure of 8 x 10 1pa. It has been found that when the reaction gas is a mixture of argon and oxygen, Cr203 thin films on iron substrates characterized by AES absorption or burial of an amount of argon atoms and vacuum degassing at 600°C is not effective for degassing argon from Cr203 thin film on an iron substrate. However, slow outgassing of argon in electric vacuum devices is effective, which is proven by a residual mass spectrometer. If the argon partial pressure in an X-band frequency magnetron is over 10-4 Pa due to outgassing, the argon ion bombardment to the cathode surface will result in a spectrum of output microwave pulsed signal band, because of cathode surface damage by ion bombardment. In conclusion, Cr20 3 thin film deposited by arc discharge plasma has the advantages as follows : high absorptivity, strong adhesive strength and no argon outgassing.
]'he thermal effects on laser-induced damage in optical coatings Fan Zhengxiu and Wu Zhouling, Shanghai Institute of Optics and
Fine Mechanics, Academia Sinica, PO Box 800-211, Shanghai 201800, China The thermal effects play an important role for laser-induced damage in optical coatings. The energy deposition is produced fi:om the absorption of laser energy in optical coatings. The temperature distribution is dominated by the laser field distribution and the thermal conduction process in optical coatings. Reported here are the in situ experiments of the thermal deflection technique as well as the temperature distribution in optical thin films. It is verified that the deposition of heat is mainly set in the higher field intensity region. For H R multilayer coating, the extreme value of field intensity is raised at the interface of high-low refractive index materials, so that the heat source is formed generally in those regions. This phenonemon is verified by the time resolution photothermal signal. Several thermal pulses were shown along with the probe time. The interval of the pulse is directly proportional to the thickness of the thin film layer cycle.
Investigation of titanium nitride films prepared by Xe + ion beam enhanced deposition in a N2 gas environment Wang Xi, Yang Genqing, Zheng Zhihong, Huang Wei, Zhou Zuyao, Liu Xianghuai and Zou Shichang, Ion Beam Laboratory,
Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, China A new method, in which electron beam evaporation of titanium and bombardment with a 40 keV xenon ion beam were done simultaneously in a N2 gas environment, has been developed to prepare titanium nitride films. The composition and structure of
the films were investigated by means of RBS, AES and XRD. The xenon contamination in the films is very low and the films are mainly composed of TiN polycrystalline. A transition layer exists between the film and the substrate, which is of great benefit to the adhesion of the film to the substrate. The hardness of the film reached 2300 kg m m - 2, higher than that of films prepared by N ÷ ion beam enhanced deposition. Scratch tests showed the adhesion of the titanium nitride film to substrate is quite strong. The titanium nitride films have been applied to the surface protection of the scoring dies and the life time of the dies can be increased by about 5-10 times.
An infrared absorption band caused by H+-implantation in LiNbO3 crystals Feng Xiqi and Zhang Jizhou, Shanghai Institute of Ceramics, Academia Sinica, Shanghai 200050, China; and Shao Tianhao,
Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, China A new infrared absorption band at about 3545 cm-~ wavenumber has been observed in LiNbO3 crystals implanted by energetic H ÷ ions. It is found that the peak wavenumber of this band seems to be independent on the stoichiometry, dopant species and doping level in the investigated samples. The band, polarized perpendicularly to the c-axis, would disappear after annealing the sample in air at 500°C for 0.5 h. The new absorption band is interpreted as a distributed OH stretching vibration in a H÷-implanted LiNbO3. The displacement of Nb 5+ ions from their regular sites caused by the ion implantation may expand the oxygen triangle to result in a longer O---O bond, which can explain the higher wavenumber of OH band in the H÷-implanted LiNbO3 crystals.
A new definition of laser damage threshold of optical thin films : optical breakdown threshold Ni Xiaowu, Lu Jian and He Anzhi, Department of Applied Physics,
East China Institute of Technology, Xiaolingwei 200, Nanjing 210014, China; and Ma Zi and Zhou Jiuling, South-West Technical Physics Institute, Chengdu 610015, China Optical coating as a component in a high-power laser system is usually an important and weak link. Thin film damage threshold was often defined as the average value of the maximum incident laser energy density on the thin film, under which damage did not occur, and the minimal energy density, under which damage did occur. However, the experimental data were very often obtained under the condition which made it difficult to respect the data. In this paper, the physical mechanisms of interaction between high-power laser and thin film and damage of film materials are analysed. Optical breakdown and the forming of plasma may be thought of as the beginning of thin film damage. F o r this reason, a new definition of the laser damage threshold of a thin film is presented by optical breakdown threshold. Furthermore, the optical beakdown threshold is defined as the average value of the 1089