Properties Of Plasma Polymerized Films Research Articles

Electrically Insulating Plasma Polymer/ZnO Composite Films.

In this report, the electrical properties of plasma polymer films functionalized with ZnO nanoparticles were investigated with respect to their potential applications in biomaterials and microelectronics fields. The nanocomposite films were produced using a single-step method that combines simultaneous plasma polymerization of renewable geranium essential oil with thermal decomposition of zinc acetylacetonate Zn(acac)2. The input power used for the deposition of composites were 10 W and 50 W, and the resulting composite structures were abbreviated as Zn/Ge 10 W and Zn/Ge 50 W, respectively. The electrical properties of pristine polymers and Zn/polymer composite films were studied in metal–insulator–metal structures. At a quantity of ZnO of around ~1%, it was found that ZnO had a small influence on the capacitance and dielectric constants of thus-fabricated films. The dielectric constant of films with smaller-sized nanoparticles exhibited the highest value, whereas, with the increase in ZnO particle size, the dielectric constant decreases. The conductivity of the composites was calculated to be in the in the range of 10−14–10−15 Ω−1 m−1, significantly greater than that for the pristine polymer, the latter estimated to be in the range of 10−16–10−17 Ω−1 m−1.

Chemical Investigation on Various Aromatic Compounds Polymerization in Low Pressure Helium Plasma

Remarkable properties of plasma polymer films are greatly dependent not only on the chemical structure of precursor but also on the reactor design and the deposition conditions. In many industrial applications it is a challenge to control the plasma polymer structure. In this paper we investigate the chemical transformation of various aromatic compounds, such as activation and fragmentation of substituent-part, aromatic ring opening, during plasma polymerization process. Polymerized films are deposited in a low- frequency capacitively coupled plasma-enhanced chemical vapour deposition reactor, working at low pressure. The chemical composition of plasma-polymerized films is elu- cidated by Fourier-transform infrared spectroscopy, solid-state carbon-13 nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy. Based on spectroscopic measurements, the intermediary reactions during film growth may be presumed.

The link between mechanisms of deposition and the physico-chemical properties of plasma polymer films

Film thickness and functional group retention are routinely measured parameters for plasma polymers. It is known that other parameters such as density, solubility and mechanical properties can affect the performance of the plasma polymer film, however such parameters are not often measured; nor is there any understanding of the link between the mechanisms of film growth and these properties. In this investigation we produced thin films from three classes of commonly used plasma polymers (hydrocarbons, glymes and carboxylic acids). By choosing the monomer structure and applied RF power, the dominant mechanism of film growth was varied between ionic deposition and neutral grafting. The density, solubility and modulus of the resulting films were then measured by atomic force microscopy. Films grown from saturated monomers had higher moduli, were less soluble, and surprisingly had lower density compared to their unsaturated analogues. The results demonstrate that cognizance of the mechanism of film growth allows the physical properties of the film to be tailored for specific applications.

Mechanical properties of plasma polymer films controlled by RF power

This study deals with plasma polymer films deposited on silicon substrates using tetravinylsilane monomer. The deposition technique was plasma-enhanced chemical vapour deposition. Nanoindentation was used as a method to investigate mechanical properties of samples prepared at different RF powers. The Young’s modulus and hardness of thin films were estimated from load-displacement curves. The nanoscratch test was employed to determine the critical normal load needed for film delamination, as a parameter describing adhesion to the substrate. AFM images of scratches were carried out to correlate the data with nature and shape of scratches.

Effects of Deposition Plasma Power on Properties of Low Dielectric-Constant Plasma Polymer Films Deposited Using Hexamethyldisiloxane and 3,3-Dimethyl-1-butene Precursors

We investigated the effects of deposition plasma power on the properties of plasma polymer films deposited by plasma-enhanced chemical vapor deposition using a mixture of hexamethyldisiloxane and 3,3-dimethyl-1-butene as the precursor, which are referred to as plasma polymerized hexamethyldisiloxane:3,3-dimethyl-1-butene (PPHMDSO:DMB) films. As the deposition plasma power was increased from 15 to 60 W, the relative dielectric constants k of PPHMDSO:DMB films, increased from 2.67 to 3.19. After annealing at 450 °C, the films deposited at a deposition plasma power of 15–60 W showed k values of 2.27–2.64. With increased deposition plasma power, the as-deposited and annealed films showed increased values of hardness and Young's modulus. For as-deposited films, deposited at a plasma power of 15–60 W, the films showed a hardness of 0.13–2.0 GPa, and a modulus of 2.25–17.27 GPa. Annealed films, deposited at a plasma power of 15–60 W, showed a hardness of 0.05–2.07 GPa and a modulus of 1.66–14.4 GPa. The change in the k value and hardness of plasma polymer films as a function of deposition plasma power was correlated with fourier transform infrared (FT-IR) absorption peaks of C–Hx, Si–CH3, and Si–O related groups. The as-deposited and annealed PPHMDSO:DMB films showed decreased intensities of C–Hx and Si–CH3 peaks as the deposition plasma power increased. The reduction in the dielectric constant after annealing is mainly due to hydrocarbon removal in the film. Deconvolution of Si–CH3 bending peaks of PPHMDSO:DMB films was performed to relate mechanical properties to chemical structures. The relative oxygen content in the O–Si–(CH3)x structure is analyzed in detail. Improvements in hardness and modulus of our films are attributed to an increased amount of O3Si–(CH3) in the Si–CH3 structure.

Optical and photoluminescent properties of plasma polymer films used in electroluminescent display structures

The optical and photoluminescent properties of plasma polymer layers synthesized from hexamethyldisiloxane are examined. The value of the polymer layer transparence is in the limits from 55% at 400 nm to 88% at 800 nm. Photoluminescence is stimulated by using the spectral line λ=365 nm emitted by a Hg spectral lamp. The organosilicon plasma polymers are included as protective and capsulating layers in electroluminescent (EL) structures. The structure obtained is characterized by a significant increase in emission brightness, compared to inorganic protective layers. For EL structures with a chalcogenide protective layer the increase is more than 6 times and for structures with heterogeneous matrix on the base of TiO 2 it is more than 20 times. As a stable covering the organosilicon plasma polymer increases the lifetime of the EL structures too.

Characterization of low dielectric constant plasma polymer films deposited by plasma-enhanced chemical vapor deposition using decamethyl-cyclopentasiloxane and cyclohexane as the precursors

We investigated the properties of plasma polymer films deposited by plasma-enhanced chemical vapor deposition using a mixture of decamethyl-cyclopentasiloxane (C10H30O5Si5) and cyclohexane (C6H12) as the precursors, which we refer to as plasma polymerized decamethyl-cyclopentasiloxane: cyclohexane (PPDMCPSO:CHex) films. The relative dielectric constants, k, of the plasma polymer films were correlated with the Fourier transform infrared absorption peaks of the C–Hx, Si–CH3, and Si–O related groups. As the amount of the CHx species in the as-deposited plasma polymer films increased, the k value and the leakage current density of the thin films decreased. The subsequent annealing of the PPDMCPSO:CHex film at 400°C for 1h further reduced the k value to as low as k=2.05. This annealed PPDMCPSO:CHex thin film showed a leakage current density of the order of 4×10−7A∕cm2 at 1MV∕cm and a breakdown field of 6.5MV∕cm. Through the bias-temperature stress test, it was estimated that the PPDMCPSO:CHex film with a k value of 2.05 would retain its insulating properties for ten years at 167°C under an electrical field of 1MV∕cm, when it is presented as a layer adjacent to Cu∕TaN(10nm).

Chemical and nanomechanical properties of plasma-polymerized acetylene on titanium and silicon

Plasma pretreatments are environmentally benign and energy-efficient processes for modifying the surface chemistry of materials. This study was undertaken to better understand the chemical and physical properties of plasma-polymerized (PP) acetylene films, and the adhesion of PP films to titanium and silicon substrates. The composition, mechanical properties, and adhesion of PP acetylene films have been investigated with X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and nanoindentation and nanoscratch atomic force microscopy (AFM). Thin PP films prepared from acetylene were deposited onto polished Ti–6Al–4V and silicon wafers with a low pressure, radio frequency, inductively coupled plasma reactor. Relationships between composition, mechanical properties, and adhesion of PP films on Ti–6Al–4V and silicon wafers were investigated. Deposited PP acetylene films were predominantly carbon (≈87%). Oxygen, the other main constituent (≈13%), was present in the form of C–O and C O functional groups. For both substrates, PP films deposited at lower power exhibited higher hardness and reduced modulus than films deposited at higher power. At two different power levels, PP films deposited on silicon wafers exhibited higher hardness and reduced modulus values than PP films deposited on polished Ti–6Al–4V. Also, film deposition occurred at a faster rate on Ti–6Al–4V. Overall, thinner films exhibited higher hardness and a greater reduced Young's modulus compared to thicker films. For the samples tested, PP films of higher hardness yielded higher critical loads at debond (thickness normalized) in nanoscratch tests.

Effects of Postdeposition in situ Heat Treatment on the Properties of Low Dielectric Constant Plasma Polymer Films Deposited Using Decahydronaphthalene and Tetraethyl Orthosilicate as the Precursors

We investigated effects of postdeposition heat treatment (HT) on the properties of plasma polymer films deposited by plasma-enhanced chemical vapor deposition using a mixture of decahydronaphthalene and tetraethyl orthosilicate as the precursors, which were referred to as plasma-polymerized decahydronaphthalene:tetraethyl orthosilicate (PPDHN:TEOS) films. HTs at 350, 450, and 500 °C decreased the relative dielectric constant k of the PPDHN:TEOS films from 3.16, the k value of the as-deposited film, to 2.82, 2.72, and 3.02, respectively. The change of k value as a function of HT temperature was correlated with the change of Fourier transform infrared absorption peaks of O–H, C = O, and Si-related groups. As the HT temperature increased, the thermal stability of the PPDHN:TEOS film increased. PPDHN:TEOS films, as-deposited or heat treated, showed leakage current density in the order of 10−7 A/cm2 at 1 MV/cm.

Effect of helium implantation on the properties of plasma polymer films

Polymer films, deposited from acetylene and argon plasma mixtures, were bombarded with 150 keV He + ions, varying the fluence, Φ, from 10 18 to 10 21 ions/m 2. Molecular structure and optical gap of the samples were investigated by infrared and ultraviolet–visible spectroscopies, respectively. Two-point probe was employed to determine the electrical resistivity while hardness was measured by nanoindentation technique. It was verified modification of the molecular structure and composition of the films. There was loss of H and increment in the concentration of unsaturated carbon bonds with Φ. Optical gap and electrical resistivity decreased while hardness increased with Φ. Interpretation of these results is proposed in terms of chain crosslinking and unsaturation.

Ammonia sorptive properties of plasma polymer films obtained from hexamethyldisiloxane

The ability of plasma polymer films, obtained from hexamethyldisiloxane (HMDSO) to adsorb ammonia vapours in gas phase is studied. For this purpose, the polymer films are deposited on mass-sensitive quartz resonators. The dependence between the relative change of resonator's frequency due to the mass of sorbed ammonia vapours and ammonia concentration in gas phase is established. Ammonia vapours with concentrations from 10 to 10 000 ppm are used. The increase of the polymer thickness in the range of 0.09–0.24 μm leads to an increase of the ammonia sorption capability of the samples. The characteristics of sorption process of the polymer films versus ammonia vapours are discussed.

Deposition and properties of plasma polymer films made from thiophenes

Thin plasma polymer films were deposited by plasma polymerisation of thiophene (C 4H 4S) and iodothiophene (C 4H 3SI). Optical emission spectroscopy (OES) was applied during film deposition to characterise the plasma at various energy input levels and various monomer partial pressures. The electrical direct current conductivity for films deposited at various preparation conditions were calculated based on current voltage relationships which were observed. The maximum conductivity of an undoped thiophene film was σ ≈ 1.3 × 10 −6 Ω −1 cm −1 .

Optical properties of plasma polymer films

Abstract The thickness and the refractive index of thin polymer films were measured in situ during plasma polymerization of hexamethyldisiloxane (HMDSO) by ellipsometry. The actual gas composition resulting from the plasma chemical conversion of organic vapour was analysed by mass spectrometry. The gas composition influences both the deposition process and the film properties. The optical dispersion and transmittance of the deposited films were characterized by spectroscopic ellipsometry (visible range) and spectrometry (UV-visible-IR range) respectively. It was found that especially the refractive index can be varied over a wide range depending on the plasma conditions, and that films with graded refractive index can be produced.

Optical properties of plasma polymer films with encapsulated silver particles

Plasma polymer thin films with encapsulated small metal particles were prepared by simultaneous plasma polymerization and metal evaporation. Based on transmission electron microscope (TEM) micrographs, particle size and shape were analysed on films with continuously varying filling factor. Thermal annealing causes dramatic changes of the particle size and shape. The optical (UV, VIS, NIR) properties of the films were determined by the UV-absorption of the plasma polymer and by the plasma resonance absorption of the metal particles. The changes in the transmission spectra during thermal annealing were simulated with different effective medium theories. The calculated transmission spectra were fitted to the experimental spectra.

Dielectric properties of plasma polymerized films

Abstract Dielectric properties of plasma polymerized polyvinyl carbazole PVCa and butane films have been analysed in the frequency range 10 to 10s Hz. In order to explain the experimental data obtained, the Maxwell-Garnett (MG) and Bruggemann self-consistent (BSC) models were modified for the case of three-component composites. The dielectric parameters of butane films have been evaluated

Mechanical properties of plasma polymer films

Abstract A characteristic surface structure is observed on the samples prepared by plasma polymerization of n-hexane and n-heptane microwave discharge. This typical structure depends on the deposition conditions. The interpretation of the structural changes was based on the nature of the plasma polymer, one result of which is the frost effect that we observed

ヘキサメチルジシロキサンより生成したプラズマ重合膜の放電処理による電気的性質の変化

ヘキサメチルジシロキサンより生成したプラズマ重合膜を平行平板電極間で大気中で放電処理した場合の赤外吸収スペクトル, ESCAスペクトル, 接触角, 表面抵抗率, 静電容量, 及びtanδの変化を調べた. その結果, 放電処理すると水酸基, カルポニル基, 及び窒素化合物が導入され, 処理時間とともにシリコン原子に対する炭素原子の比が減少するのに対して窒素原子及び酸素原子のものは増加すること, プラズマ重合膜の水に対する接触角は放電処理前では103°で疎水性を示すが, 処理後では水滴が表面に広がることがわかった. また, プラズマ重合膜を放電処理するとその表面抵抗率は109Ω程度に低下し, 静電容量は約2倍, tanδは10%程度に増加することがわかった.

Mechanism of plasma polymerization: The effect of substrate and substrate topography

Surface properties of metals and plastic substrates and properties of plasma polymerized films on these substrates are reported. The surface and film properties were measured with ellipsometry, surface potential difference, photoelectron-emission and fluid contact angles. Light scattering, profilometry and scanning electron microscopy were used to characterize surface roughness and topography. The modification of the adhesive properties of low energy surfaces (such as Teflon) by plasma polymerization is shown. Adhesive properties of plasma films on metals is also shown. It is shown that photoelectron-emission may be a valuable tool for detecting the presence and decay of excited molecules and radicals formed during plasma polymerization.