Jun-ya Igaki

Mechanical characteristics and applications of diamondlike-carbon cantilevers fabricated by focused-ion-beam chemical vapor deposition

Diamondlike-carbon (DLC) cantilevers were fabricated with a commercially available focused-ion-beam chemical-vapor-deposition (FIB-CVD) system using a beam of 30keV Ga+ ions, and the mechanical characteristics of the cantilevers were measured. Vibration frequency of the cantilevers was passively measured using scanning electron microscopy. Resonant frequency of DLC cantilevers fabricated at 0.1–0.5pA beam current was found to be constant. The equivalent spring constant of the cantilevers was identified by squeezing the tip of a Si3N4 cantilever and a DLC cantilever together. Using the measured displacement, the spring constant of the DLC cantilever was calculated as (1.1±0.2)×10−2N∕m. Furthermore, Young’s modulus and the density of the DLC cantilevers were measured to be 187±32GPa and (3.8±0.7)×103kg∕m3, respectively. The DLC cantilevers were used as mass sensors in an ultrasensitive sensing application. A small amount of DLC was deposited on the tip of a DLC cantilever as a mass adhesion by FIB-CVD at 0....

Mechanical characteristics and its annealing effect of diamondlike-carbon nanosprings fabricated by focused-ion-beam chemical vapor deposition

Our investigation of diamondlike-carbon (DLC) nanosprings with a 130-nm spring section diameter, which were fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD), showed for the first time that nanosprings can be stretched. We observed large displacements of the FIB-CVD nanosprings in situ optical microscopy; in other words, the nanosprings showed behavior similar to that of macroscale springs. In addition, we investigated the dependence of the spring constant of the DLC nanosprings on the spring diameter. The spring constants, measured using commercially available cantilevers, ranged from 0.47to0.07N∕m. The diameter dependence of the measured spring constant could be accurately expressed by the conventional formula for a coil spring. The estimated shear modulus of the DLC nanosprings was about 70GPa. This value is very close to the value of conventional coil springs made of steel. Furthermore, We measured the stiffness of the annealed nanospring at 1000°C in vacuum. The stiffness was decreas...

Angle-Dependent Measurement of Near Edge X-ray Absorption Fine Structure of Annealing Effect on Local Structure of Focused-Ion-Beam Chemical Vapor Deposition Diamond-Like Carbon

The annealing effect on the local structure of diamond-like carbon (DLC) formed by Ga+ focused-ion-beam chemical vapor deposition (FIB-CVD) was investigated by the incidence angle-dependent measurement of the C K-edge near edge X-ray absorption fine structure (NEXAFS) from 0 to 60°. The peak intensity corresponding to the resonance transition of 1s →σ* originating from carbon–gallium bonding markedly increased with incidence angle in the spectra of a FIB-CVD DLC film annealed at 400 °C. This angle dependency was attributable to the movement of residual Ga atoms from the bottom to the neighboring surface of the FIB-CVD DLC film.

Elementary Analysis of Diamond-Like Carbon Film Formed by Focused-Ion-Beam Chemical Vapor Deposition

This is the first report on the precise elemental composition of a diamond-like carbon (DLC) thin film fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD). The atomic fraction of the FIB-CVD DLC film has been determined to be C:Ga:H=87.4:3.6:9.0 at. % using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). The hydrogen content of the FIB-CVD DLC film was lower than that of DLC films formed using other CVD methods.

Effects of Annealing on Material Characteristics of Diamond-Like Carbon Film Formed by Focused-Ion-Beam Chemical Vapor Deposition

The effects of annealing on the material characteristics of a diamond-like carbon (DLC) thin film fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD) were investigated. The elementary analysis, using Rutherford backscattering spectrometry and elastic recoil detection analysis, and measurement of hardness and Youngs modulus, using a nanoindentation technique, were performed on the FIB-CVD DLC thin film by annealing for 1 h in the temperature range from room temperature to 1273 K. Elementary analysis indicated that the Ga content in the FIB-CVD DLC film used as an ion source began to decrease considerably at 523 K and the H content also began to decrease at 773 K. On the other hand, the hardness and Youngs modulus of the FIB-CVD DLC film were found to decrease beyond 773 K. This decrease in hardness is ascribed to the variation in H content rather than in Ga content in the film.

NEXAFS Study of the Annealing Effect on the Local Structure of FIB‐CVD DLC

Annealing effect on the local structure of diamond like carbon (DLC) formed by focused ion beam‐chemical vapor deposition (FIB‐CVD) was investigated by the measurement of near edge x‐ray absorption fine structure (NEXAFS) and energy dispersive x‐ray (EDX) spectra. Carbon K edge absorption NEXAFS spectrum of FIB‐CVD DLC was measured in the energy range of 275–320 eV. In order to obtain the information on the location of the gallium in the depth direction, incidence angle dependence of NEXAFS spectrum was measured in the incident angle range from 0° to 60°. The peak intensity corresponding to the resonance transition of 1s→σ* originating from carbon‐gallium increased from the FIB‐CVD DLC annealed at 200°C to the FIB‐CVD DLC annealed at 400°C and decreased from that at 400°C to that at 600°C. Especially, the intensity of this peak remarkably enhanced in the NEXAFS spectrum of the FIB‐CVD DLC annealed at 400°C at the incident angle of 60°. On the contrary, the peak intensity corresponding to the resonance tra...