Jun Shirahata

Fourier-Transform Infrared Absorption Spectroscopy of Chromium Nitride Thin Film

Chromium nitride thin films were deposited by RF reactive unbalanced magnetron sputtering on (100) Si single-crystal or glassy carbon substrates. The characteristics of the thin films were measured by Rutherford backscattering spectroscopy, X-ray diffractometry, and scanning electron microscopy. From the results of the above measurements, it was found that our samples were stoichiometric chromium nitride thin films. The chemical bonding state was estimated using the results of the Fourier-transform infrared spectroscopy. A peak attributed to the Cr–N bond was observed at around 380 cm-1, and it could be obtained with any beam splitter and atmosphere. Furthermore, the influence of residual stress was also investigated. Residual stresses of CrN thin films, which were calculated from their strains, were quite low.

Influence of oxygen content on hardness of Cr(N,O) thin films deposited by an RF sputtering method

Cr(N,O) thin films were deposited by radio frequency reactive unbalanced magnetron sputtering on Si(100) or glassy carbon substrates. In this paper, the influence of oxygen content on hardness of Cr(N,O) thin films was investigated. The compositional analysis was carried out by Rutherford backscattering spectroscopy. It was found that these thin films contained up to 44at.% of oxygen. Phases in the samples were determined by X-ray diffraction. Cr(N,O) thin films show only peaks based on CrN. The microstructure was observed by utilizing a transmission electron microscope. At <1at.% of oxygen, crystallite size was approximately 100nm. Then, in accordance with increasing of oxygen content, crystallite size was decreased. The hardness of thin films was measured by using a nanoindenter. The micro hardness was changed with varying the oxygen content and the microstructure such as crystallite size. Thus, it was thought that the hardening on Cr(N,O) thin films was caused by solution hardening and/or Hall-Petch relationship.

Preparation and Characterization of Cr–Zn–N–O Thin Films Deposited by Pulsed Laser Deposition

Cr–N–O, Cr–Zn–N–O, and Zn–O thin films were prepared by pulsed laser deposition. The compositional analysis of the Cr–Zn–N–O thin films by Rutherford backscattering spectroscopy revealed that they are ternary compounds of the Cr–Zn–N–O system. Their Vickers hardness was about 4200 kgf/mm2. X-ray diffraction indicated that the Cr–N–O and Cr–Zn–N–O thin films have the NaCl-type structure (B1), the same as CrN. Transition electron microscopy observation indicated that a grain of the (Cr,Zn)(N,O) phase existed, on the basis of which it could be considered as a solid solution of B1-CrN and a high-pressure phase of ZnO with the B1 structure.

Residual stress relaxation of cubic boron nitride thin films deposited in Ar with other noble gases

A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (Kr, Ar, Ne and He) added in Ar gas during sputtering on the residual stress and the c-BN content has been investigated. As a result, it was found that the residual stress of c-BN thin film decreased with increasing the helium gas flow rate within argon gas.