Papers

ICMCTF2013 Session B2-2: CVD Coatings and Technologies

Thursday, May 2, 2013 1:30 PM in Room Royal Palm 4-6

Thursday Afternoon

Start	Invited?	Item
1:30 PM		B2-2-1 Residual Stress and Crystallographic Texture in CVD Zirconia Thin Films Vincent Ji, Michel Andrieux, Nathalie Prud'Homme (Université Paris-Sud 11, France) Film crystalline growth and associated microstructure can been largely influenced by CVD (Chemical Vapor Deposition) process parameters. Residual stress can then be generated due to film growth and also due to thermomechanical phenomena during sample cooling. In present study, several-microns-thick Zirconia films have been obtained on Si (001) single crystal, using MOCVD method, with different process conditions (various precursor flows, different partial O₂ and N₂ pressures and various substrate temperatures). Crystalline phase identification on film layer, crystallographic texture and residual stress in quadratic ZrO₂ phase has been carried out by X-ray diffraction method. FEG-SEM technique has been used for film morphology study and for film thickness evaluation on cross-section observation. The relationship between MOCVD process parameters, crystalline texture effect and residual stress level in ZrO₂ films has been discussed.
2:10 PM		B2-2-3 The Deposition of Hydrogenated Silicon Films under Different H₂ and Ar Flow Rates by an ICP CVD System Chuan Li (National Central University, Taiwan, Republic of China); Jang-Hsing Hsieh (Ming Chi University of Technology, Taiwan, Republic of China); Kun-Ling Huang (National Central University, Taiwan, Republic of China) Amorphous hydrogenated silicon (a-Si:H) films were deposited on quartz substrates in an ICP-CVD (inductive coupled plasma-CVD) system with four internal low inductance antennas (LIA) units. Different Ar and hydrogen flow rates were tested for their influences on the structures of deposited films. For monitoring purposes, Langmuir probe and optical emission spectrometer (OES) were installed to detect the variation of electrical field in plasma during deposition. After deposition, the films were examined by XRD, Raman spectrometer, FTIR, FE-SEM and UV-visible-NIR spectrometer for their microstructures, surface morphologies, optical absorption and band gap. Results indicate that under the supply of pure Ar flow, the deposition rate can reach 3.5nm/sec and amorphous films were formed on quartz substrates. While with the supply of mixed hydrogen and argon the deposition rate can be even higher. Although it is known that a high supply of H₂ helps the formation of micro-crystalline silicon, these hydrogenated Si films were confirmed to be amorphousness under various ranges of Ar and H₂ flow rates.
2:30 PM		B2-2-4 High-rate PECVD with Metal Strip Magnetron for Hard and Other Functional Coatings Christoph Metzner, Bert Scheffel, Olaf Zywitzki (Fraunhofer FEP, Germany) Magnetron glow discharges have been used for a long time in a variety of different ways. They form the basis for a series of developments in the area of surface coating. Various methods for coating and reactive process control, a wide variety of magnetron sputter sources and pulsed power supplies for magnetron discharges have been and are being developed. Magnetron discharge is also used for pre-treating of metal strips. For this a magnetron discharge is applied to the surface of the metal strip to be cleaned. Due to the bombardment of the surface with argon ions and the sputtering effect, material is removed from the surface and this means a better surface is created for the adhesion of subsequently applied layers. There are novel opportunities for coating metal strips by using magnetron glow discharge in a PECVD. A precursor is fed into the plasma of the magnetron discharge. The process is set such that the ion bombardment does not lead to removal of material from the cathode surface, but rather assists the layer formation process. In this way, very dense, thin layers can be deposited on the cathode, namely the metal strip. If the metal strip has to be at earth potential, an anode box is used. The medium frequency pulse technique, which was developed for magnetron sputtering, can be advantageously used with the metal strip magnetron for the deposition of electrically insulating layers too. The fundamental characteristics of the novel process are being studied using acetylene und hexamethyldisiloxane (HMDSO) as precursors. The coating rate, due to reaction of the precursor, is closely linked to the plasma density in the discharge. For that reason, the circular magnetron discharge at the cathode can be depicted as layer formation on a stationary strip. The dynamic coating rate of 150 to 300 nm m/min is relatively high. Very dense and hard layers were deposited. For the layers which formed due to reaction of HMDSO, layer hardness in the region of 6 to 18 GPa were measured. The hardness and other layer properties can be customized by adding oxygen. In the case of the acetylene precursor, hydrogen-containing, amorphous, carbon layers were deposited with very high layer hardness of up to 40 GPa. Studies on the long-term stability of the discharge and the coating of strip edges will be investigated next. The application area for this method is limited to the coating of electrically conducting and not too thick ferromagnetic strip materials. A broad spectrum of applications is envisaged for metal strip treatment, due in particular to the high quality of the deposited layers and the expected low technological complexity of the method.
2:50 PM		B2-2-5 Study of the Uniformity of SiO₂Films Developed in Atmospheric Plasmas Daphne Pappas, Jacqueline Yim, Victor Rodriguez-Santiago, Andres Bujanda, Scott Walck (US Army Research Laboratory, US) Plasma-enhanced chemical vapor deposition under atmospheric pressure conditions has been widely accepted as an industrially scalable, cost efficient method for the development of large scale coatings that does not require the use of vacuum equipment. However, treatment of large area substrates requires creation of considerable volumes of uniform plasma, which is not a trivial task at atmospheric pressure. Depending on the process parameters, stable non-filamentary discharge modes can be obtained, but the plasma uniformity does not necessarily guarantee film uniformity. This study concentrates on the deposition of SiO₂ thin films using dielectric barrier discharges (DBD) under 1 atm from hexamethyldisiloxane (HMDSO). The effect of gas mixture composition, dissipated power, and operation frequency will be discussed. Preliminary results show that by changing the HMDSO/oxygen ratio in the gas mixture it is possible to tune the composition of the deposited film from organic polymerized HMDSO-like to inorganic silica-like coatings with negligible residual carbon content. The chemical uniformity of the grown films was studied through X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), while the surface morphology was investigated using scanning electron microscopy and atomic force microscopy. Moreover, the development of structures of gradient composition is feasible showing that these SiOxCy materials have the potential to be integrated in corrosion protection, optical and diffusion barrier applications.
3:10 PM		B2-2-6 Semi-empirical Modeling of the Optical Gap of Plasma-deposited a-C:H:F, a-C:H:Cl and a-C:H:Si:O:F Films Antonio Neto, Thais Gonçalves, Rafael Turri (UNESP, Brazil); Wido Schreiner (UFPR, Brazil); Douglas Galvão (UNICAMP, Brazil); Steven Durrant (UNESP, Brazil) Diverse amorphous hydrogenated carbon thin films also containing halogens were obtained by plasma deposition. The films were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photo-electron Spectroscopy (XPS). Films with different degrees of halogenation were produced. Mean deposition rates were determined from the film thickness and deposition time. Optical properties such as the refractive index, n, absorption coefficient, α(E), where E denotes the photon energy, and the optical gap, E_g, were determined from spectra taken in the Ultraviolet-visible Near-Infrared part of the electromagnetic spectrum. The dependencies of E_g, determined using the Tauc method, on the degree of halogenation of the film, R_H, were determined. The trends in E_g as a function of R_H were modeled using Parametric Method 3 (PM3) to optimize the molecular geometry, and the ZINDO program to simulate the oscillator strengths. Film molecular structure was approximated from the results of the FTIR and XPS analyses. Although the approach adopted here cannot account for the absolute values of E_g, the trends in E_g as a function of R_H can be reproduced. To our knowledge, the E_g of the more complex films examined here have not previously been modeled.
3:30 PM		B2-2-7 The SiO_xC_yH_z Hydrophobic Film with Chemical and Mechanical Properties using PECVD by Controlling the Plasma Process JoonS. Lee, SuBong Jin, Yoon (Y.S.) Choi, In (S.C.) Choi, Jeon (J.B.) Han (Institute for Plasma-Nano Materials, Center for Advanced Plasma Surface Technology,Sungkyunkwan University, Korea) SiO_x films produced from octamethylycyclodisiloxane (Si₄O₄C₈H₂₄, OMCTS) with oxygen carrier gas have a low contact angle. The surface energy of the SiO_xfilms can be changed by controlling the Ar plasma. SiO_xC_yH_z print films were deposited on glass substrates by plasma enhanced chemical deposition (PECVD) using hexamethyl-disilazane (HMDS) precursor with hydrogen gas. The process parameters were Ar flow rate and RF power. They were changed to the surface energy, mechanical and chemical properties of the hydrophobic film. The plasma diagnostics, surface energy and surface morphology were characterized by residual gas analyzer (RGA), contact angle measurement and atomic force microscopy (AFM), respectively. The chemical properties of the coatings were examined by Fourier transform infrared spectroscopy (FT-IR). The surface energy of the SiO_xC_yH_z films produced using a room temperature plasma process could be controlled by employing the appropriate intensity of excited neutrals, ionized atoms, molecules and energy (input rf power), as well as the suitable dissociation of HMDS. In addition, we tested the mechanical properties by rubber and hardness tester. Also chemical properties tested by salty boiling water and ethanol. The mechanical and chemical properties tested by water contact angle.
3:50 PM		B2-2-8 Modeling Surface Processes and Kinetics of Compound Layer Formation during Plasma Nitriding of Pure Iron Fernando Cazares, Antonio Jimenez-Cenisero (ITESM-CEM, Mexico); Joaquin Oseguera (ITESM-CEM,Mexico); Francisco Castillo (ITESM-CEM, Mexico) Different approaches have been developed concerning growth description of the compact nitride layers, especially those produced by ammonia. Nitriding by plasma uses a glow discharge technology to introduce nitrogen to the surface which in turn diffuses into the material. During this process, the ion bombardment causes sputtering of the specimen surface. This work presents a mathematical model of compound layer formation during plasma nitriding of pure iron. The model takes into account the erosion effect at the plasma-solid interface due to sputtering. This erosion effect is studied using mathematical simulation of the ion bombardment on surface through HP TRIM package. The model is related to a moving boundary diffusion problem, which considers the observed qualitative behavior of the process. Experimental research was conducted in order to gather data of pure iron nitriding, which are used in modeling the process. The results of the presented model are in good agreement with experiments. A comparison of this model with other kinetic models is made in order to determine its scope and relevance.