Ion Beam Induced Chemical Vapor Deposition Research Articles

Low-energy Ar+ ion beam induced chemical vapor deposition of silicon carbide films using dimethylsilane

In this paper, a methodology for silicon carbide (SiC) film formation by ion beam induced chemical vapor deposition (IBICVD) using dimethylsilane (DMS) is presented. Both pure DMS gas and Ar+ ion beam were simultaneously injected to a Si substrate. The Ar+ ion energy was 100 eV. The Si substrate temperature was 400, 600, or 800 °C. The duration of each ion beam injection experiment was 10 h. When the substrate temperature was 400 °C, no film formation occurred by the IBICVD experiment. In the case of 600 °C, a film was found to be formed on the substrate by the injection of both DMS gas and Ar+ ion beam. Although Fourier transform infrared (FTIR) spectroscopy measurement of the film showed that the film consisted of SiC, the film thickness was not enough to analyze the film characteristics further. When the Si substrate was set at 800 °C, a film was formed on the substrate by IBICVD. FTIR, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) measurements of the film showed the occurrence of SiC deposition. The XPS measurement also showed that the atomic concentration ratio of carbon to silicon (C/Si ratio) of the film was 1.36. Therefore, excessive C atoms were incorporated to the deposited films. On the contrary, the C/Si ratio of a SiC film prepared by the thermal CVD method using DMS was 1.88. These results suggest that the Ar+ ion beam induced chemical vapor deposition using DMS is useful for reducing of the amount of C atoms to be excessively included in the film.

Low-energy O+ ion beam induced chemical vapor deposition using hexamethyldisilane or hexamethyldisilazane for silicon dioxide film formation

A methodology for silicon dioxide (SiO2) film formation by an ion beam induced chemical vapor deposition (IBICVD) method using hexamethyldisilane (HMDS) or hexamethyldisilazane (HMDSN) is presented in this paper. In this method, an O+ ion beam was injected onto a substrate in conjunction with the source material (HMDS or HMDSN). The substrate temperature was set at room temperature. The O+ ion energy was 100 eV. After the experiment, a film was found to be deposited on the substrate and the film thickness was about 50 nm in both HMDS and HMDSN cases. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy of the deposited films showed that SiO2 films were formed on the substrates. XPS data of the film which was prepared by the injection of both O+ ions and HMDS to the substrate showed that no obvious peak was observed in the C1s region. On the contrary, a small amount of carbon was included in the film when the film was prepared by the injection of O+ ions in conjunction with HMDSN. These results suggest that HMDS is more suitable than HMDSN as the source material for SiO2 film formation when using the IBICVD method.

Low-energy Ar+ and N+ ion beam induced chemical vapor deposition using hexamethyldisilazane for the formation of nitrogen containing SiC and carbon containing SiN films.

We proposed an experimental methodology for producing films on substrates with an ion beam induced chemical vapor deposition (IBICVD) method using hexamethyldisilazane (HMDS) as a source material. In this study, both HMDS and ion beam were simultaneously injected onto a Si substrate. We selected Ar+ and N+ as the ion beam. The energy of the ion beam was 101 eV. Temperature of the Si substrate was set at 540 °C. After the experiments, films were found to be deposited on the substrates. The films were then analyzed by Fourier transform infrared (FTIR) spectroscopy, stylus profilometer, X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). The FTIR and XPS results showed that silicon carbide films containing small amount of nitrogen were formed when Ar+ ions were injected in conjunction with HMDS. On the other hand, in the cases of N+ ion beam irradiation, silicon nitride films involving small amount of carbon were formed. It was noted that no film deposition was observed when HMDS alone was supplied to the substrates without any ion beam injections.

Simulation of dynamic growth rate of focused ion beam-induced deposition using Hausdorff distance

We develop a numerical simulation describing the dynamic evolutionary deposition associated with the focused ion beam-induced chemical vapor deposition (FIB-CVD) process. It is generally accepted that emitted electrons generated by incident ions trigger the dissociation of precursor molecules adsorbed onto the surface of the substrate or deposit. Therefore, it is essential to detect emitted electrons inside the solid substrate and the deposit, and to calculate the surface positions at which the electrons are emitted. However, this has traditionally been difficult. The Hausdorff distance (HD) is a numerical method enabling rapid calculation of the distance between two objects, and is widely used for pattern-matching and object recognition in image-processing. In our numerical simulation, we use the HD concept to solve the difficulties of determining whether an electron is emitted, and the emission position, during time-dependent deposition. In addition, the modified cellular automata (CA) model was combined with an HD map to simulate deposition over time. We ran a Monte Carlo simulation of the trajectories of ions and electrons. Finally, the simulation results were verified experimentally.

Application of Ion Beam Induced Chemical Vapor Deposition for SiC Film Formation on Si Substrates using Methylsilane

We propose an experimental methodology for producing silicon carbide (SiC) films on Si substrates using an ion beam induced chemical vapor deposition (IBICVD) technique with methylsilane (SiH3CH3) as a gas source. Both methylsilane gas (1.2 sccm) and Ar ion beam (100 eV, 5μA) were simultaneously introduced onto Si(100) substrates. Temperatures of Si substrates were set at 600, 700, or 800°C. A SiC thin film was formed by the simultaneous introduction of methylsilane and Ar ions onto the Si substrate when the substrate temperature was 600°C. On the other hand, in the cases of 700 and 800°C, SiC films were formed by methylsilane gas alone and SiC film deposition rates by methylsilane gas with the Ar ion beam were approximately identical with those obtained without the Ar ion beam. We therefore conclude that the IBICVD technique with methylsilane is useful for SiC film formation on Si at relatively low substrate temperatures. [DOI: 10.1380/ejssnt.2015.174]

Three-dimensional nanostructures by focused ion beam techniques: Fabrication and characterization

Abstract

Characterization of Deposited Materials Formed by Focused Ion Beam-Induced Chemical Vapor Deposition Using AuSi Alloyed Metal Source

Focused ion beam-induced chemical vapor deposition (FIB-CVD) using Au or Si FIBs with phenanthrene gas was performed to obtain Ga-free carbonaceous materials. The characterization of the deposited materials was investigated by atomic force microscopy, Raman scattering spectroscopy, fluorescent X-ray analysis, and Auger electron spectroscopy. The surface of the deposited film using the Au FIBs was found to be very smooth, and the structure of the deposited material was found to be amorphous-like carbon. Although a Ga-free carbonaceous film was formed, it was found that Au or Si atoms were included, instead of Ga, in the deeper region of the deposited materials than the projected range of the ions of such atoms, resulting in the formation of a double-layer structure in the deposited materials, indicating that the events that occurred in FIB-CVD using the Au or Si FIBs were similar to those in the same process using the Ga FIBs. However, it was also found that the behaviour of the incorporated Au atoms in the deposited films by annealing was different from that of the Ga atoms.

Fabrication of Alloy FeCoPt Particles by IBICVD and Their Characterization

Ion beam induced chemical vapor deposition (IBICVD) has been for the first time successfully applied for direct patterned deposition of ternary alloy FeCoPt particles. Magnetic force microscopy (MFM) studies revealed existence of the magnetic ring domain structure in annealed particles. Fabricated FeCoPt particles exhibit soft ferromagnetic properties. It was found that coercivity of the annealed particles increases almost twice that may suggest the improvement of their ordering. The successful fabrication of ternary alloy particles may lead to the potential application of IBICVD for novel composite nanoparticles

Preparation of Ge–C films by low-energy ion beam induced chemical vapor deposition with hexamethyldigermane

High carbon content Ge–C films were formed on (100) silicon by low-energy ion beam induced chemical vapor deposition (IBICVD) using Ar+ ion energies of 20–300eV and gaseous hexamethyldigermane [HMDG: (CH3)3GeGe(CH3)3]. Chemical structures were characterized by Fourier transform infrared spectroscopy (FT–IR) and X-ray photoelectron spectroscopy (XPS), and IR-absorption peaks were assigned by ab initio molecular orbital calculations. While films with Ge–CH3 bonds were successfully deposited at ion beam energies of less than 200eV, no film formation was observed at 200eV or higher. The Ge:C atomic ratio was 0.25 as measured by XPS. In the case of a film deposited at a substrate temperature of 573K, change in chemical structure with enhancement of hydrogen elimination was confirmed by FT–IR. Although most Ge atoms in the films bonded with C atoms, results suggest some carbon in the film constituted C–C bonds as in a graphitic phase.

Correlation between optical properties and electronic parameters for mixed oxide thin films

AbstractSixTi1−xO2 optical thin films with variable compositions varying from pure TiO2 to pure SiO2 have been prepared by ion beam induced chemical vapor deposition (IBICVD). It has been found that the refractive index of the films increases with the content of titanium, from about 1.46 to 2.35. Band gap energies have been determined by optical methods and reflection electron energy loss spectroscopy (REELS), both techniques showing a similar evolution consisting of a sharp decay from the value of pure SiO2 to the samples with 2% Ti and then a smoother decrease up to the value of pure TiO2 (i.e. 3.2 eV). Changes also occur in the value of the binding and kinetic energies (KEs) of the Ti and Si photoemission and auger peaks, respectively, as measured by X‐ray photoelectron spectroscopy (XPS). The refractive indices of the films have been compared with the value of the auger parameters of Ti and Si. A good correlation exists between these two parameters as a function of the titanium content. This confirms that both depend on the polarizability of the medium and shows that XPS can be used for the assessment of optical properties of complex oxide materials. Copyright © 2006 John Wiley & Sons, Ltd.

イオンビーム誘起化学蒸着法による酸化スズ薄膜の作製

We deposited transparent and electrical conductive thin films on polymer substrates ZEONOR® (cycloolefin) by oxygen ion beam induced chemical vapor deposition (IBICVD) with tetramethylstannane (TMS). The film depositions were carried out the acceleration voltage of oxygen ion beam in range from 50 to 300 eV. The deposition time was fixed at 180 minutes at all conditions. Under irradiation of 300 eV oxygen ions, the optical transmittance at 550 nm and the resistivity of the prepared film were 80% and 5.4×10-2 Ω•cm, respectively. When oxygen ion energy increased from 50 to 300 eV, root mean square of roughness and contamination of carbon were decreased.

Novel fabrication method of IBICVD for FePt and CoPt particles

A novel fabrication method of ion beam-induced chemical vapor deposition with a focused ion beam system has been applied to fabricate FePt and CoPt particles. The size of the particles depends on the pattern size and frame number. The FePt particles with smallest diameter of about 110 nm were prepared. Both FePt and CoPt particles show fcc structures and soft ferromagnetic properties. Decreasing the Ga/sup +/ ion beam intensity may improve the crystallization structure of the particles. Concentric ring magnetic domain patterns have been observed in FePt and annealed CoPt particles with diameter of about 2 /spl mu/m.

Ion-beam-induced chemical-vapor deposition of FePt and CoPt particles

FePt and CoPt particles have been directly deposited on Si3N4 substrate by ion-beam-induced chemical-vapor deposition (IBICVD) with a focused ion-beam system. The as-deposited FePt particles are amorphous and crystallize into fcc structure after annealing at 600°C. The as-deposited CoPt particles and the CoPt particles annealed at 600°C are both in fcc structure, but annealing improves the crystallization of the CoPt particles. After applying a 20-kOe magnetic field perpendicular to the Si3N4 substrate, the magnetic force microscopy images of annealed FePt and CoPt particles both show concentric domain patterns, implying the alternately up- and downward perpendicular components of magnetizations. The successful fabrication of FePt and CoPt particles may lead to the potential application of IBICVD for nanoparticles and clusters which have not been synthesized yet.

Fabrication of cobalt particles by ion beam-induced chemical vapor deposition (IBICVD)

Abstract A novel method for fabricating submicron-scale particles of cobalt utilizing dicobalt octacarbonyl precursor by localized ion beam-induced decomposition is presented. Patterns of metallic cobalt particles are fabricated through vector scan rastering. A brief discussion about the mechanism of the deposition is also presented.

Fabrication of FePt and Fe particles by ion beam induced CVD

The ion beam induced chemical vapor deposition (IBICVD) technique has been successfully used to fabricate Fe and FePt particles. Select area electron diffraction (SAED) patterns were used to study themicrostructure of the Fe and FePt particles. The as-deposited Fe and FePt particles are both amorphous. After being annealed at 600°C for 1 hour, the Fe particles remain amorphous, while the FePt particles are crystallized in fcc structure. The concentric magnetic domain structure has been observed in the as-deposited FePt particles, as revealed by the magnetic force microscopy (MFM) measurement. Measurements of cumulative magnetic properties of as-deposited FePt particles show coercivity of about 70 Oe.

Large Area Fabrication of Co Particles by Ion-Beam-Induced Chemical Vapor Deposition (IBICVD)

Large Area Fabrication of Co Particles by Ion-Beam-Induced Chemical Vapor Deposition (IBICVD)

Deposition of SiO 2 films by low-energy ion-beam induced chemical vapor deposition using hexamethyldisiloxane

Room-temperature preparation of silicon dioxide films with smooth surfaces and small carbon was achieved by low-energy ion beam induced chemical vapor deposition (IBICVD) with a bubbling system for hexamethyldisiloxane (HMDSO). When prepared using bubbled HMDSO and assisted O 2 gas under irradiation of 150 eV Ar ions, the film contained carbon of 0.2% and the root mean square of the surface roughness of the film was 2.0 nm. However, when prepared using the bubbled HMDSO under irradiation of 150 eV oxygen ions, the film contained carbon less than 0.1%, and the surface roughness was 0.25 nm. It is considered that low-energy oxygen ion bombardment promotes not only chemical reaction and dissociation of HMDSO but also reactive ion beam etching on the film surface.

Focused ion beam-induced fabrication of tungsten structures

Sidewall morphology on three-dimensional (3D) tungsten structures grown with focused ion beam-induced chemical vapor deposition (FIB-CVD) using tungsten hexacarbonyl [W(CO)6] was improved with a milling process by using FIB treatment subsequent to growth. As a result, Young’s modulus was measured at 300 GPa at maximum and density was measured at 13.0×103 kg/m3. Young’s modulus increased 35% after heat treatment at 600 °C in a vacuum while density did not change. Transmission electron microscopy revealed crystallization of tungsten trioxide after the heat treatment.

Ion beam-induced chemical vapor deposition with hexamethyldisilane for hydrogenated amorphous silicon carbide and silicon carbonitride films

We report on the preparation of hydrogenated amorphous silicon carbide (a-SiC:H) film and silicon carbonitride (a-SiCN:H) film on Si (100) substrate by Ar ion beam-induced chemical vapor deposition (IBICVD) method attached with a bubbling system of hexamethyldisilane (HMDS). Ar ions and HMDS precursor with carrier gases of Ar or N 2 were introduced onto the substrate at room temperature. Fourier transform infrared (FT-IR) spectra revealed that an elimination of an organic compound and the formation of SiC, SiN and CN bonds can be promoted by increasing ion impact energy. Smooth surface with a lower roughness has been achieved when Ar ion energy increases from 50 to 300 eV.

Comparison of surface morphologies of SiO 2 films prepared by ion-beam induced chemical vapor deposition and ion-beam assisted deposition

The surface topographies of silicon dioxide films prepared by low-energy ion-beam induced chemical vapor deposition (IBICVD) and ion-beam assisted deposition (IBAD) were studied using an atomic force microscopy (AFM). In the case of IBICVD, when prepared using bubbled hexamethyldisiloxane (HMDSO) and assisted O 2 gas under irradiation of 150 eV Ar ions, the root mean square (RMS) of the surface roughness of the film was 2.0 nm. However, when prepared using the bubbled HMDSO under irradiation of 150 eV oxygen ions, the RMS deduced to 0.25 nm. In the case of IBAD, when deposited using evaporated silicon monoxide under irradiation of 150 eV oxygen ions, the RMS was 0.20 nm. As a reference, the RMS of fused silica was changed from original 0.70–0.40 nm after irradiated of 150 eV oxygen ions. It is concluded that low-energy oxygen ion bombardment not only promotes chemical reaction and dissociation of precursor but also leads to a smooth surface due to reactive ion beam etching on the film surface.