ICMCTF2005 Session C4/F2: In-situ Monitoring and Control of Optical Film Growth

Monday, May 2, 2005 1:30 PM in Room Royal Palm 4-6

Monday Afternoon

Start	Invited?	Item
1:30 PM		C4/F2-1 Interface Broadening due to Ion Mixing During Thin Film Growth in Plasma-Enhanced Chemical Vapor Deposition Environment A. Amassian, P. Desjardins, L. Martinu (Ecole Polytechnique de Montreal, Canada) Plasma-enhanced chemical vapour deposition (PECVD) is a highly versatile and flexible deposition technology. Significant research effort has gone into studying the plasma and film properties, but many questions remain unanswered, including thin film growth dynamics and interface formation under the influence of plasma irradiation. We demonstrate the capability of in situ real-time spectroscopic ellipsometry (RTSE) to detect and quantify the modifications of c-Si in O₂ plasma. Dynamic Monte-Carlo (MC) simulations have allowed us to show that these modifications, which include primarily amorphization and oxidation, result from ion implantation and defect generation. Simulations also show evidence of surface swelling and sputtering due to plasma-surface interactions. In the case of thin film deposition by PECVD, ion bombardment is also responsible for ion-mixing of substrate and film atoms, which results in interface formation. We show excellent agreement between dynamic MC predictions and in situ RTSE characterization. This study has given an insight into the PECVD deposition process and the role of ion bombardment in synthesis of porous and dense materials, and interface engineering for multilayer porous/dense device fabrication.
1:50 PM		C4/F2-2 In-Situ Spectroscopic Ellipsometric Determination of Morphological and Electronic Properties of Plasma Deposited Ultra-Thin Metal Films T.W.H. Oates (Forschungszentrum Rosendorf, Germany); L. Ryves, M.M.M Bilek, D.R. McKenzie (University of Sydney, Australia); D.G McCulloch, F.A. Burgmann (RMIT University, Australia); A. Mücklich (Forschungszentrum Rossendorf, Germany) Determination of the physical properties of nano-islands and ultra-thin films by optical methods is highly desirable due to the non-intrusive nature of the measurements. In this work, measurements of the optical properties of carbon, silver and titanium films during deposition from the vapour phase are performed using real-time in-situ spectroscopic ellipsometry. The optical properties of the films are modelled to extract the maximum information regarding the physical properties of the film. Plasmon polariton oscillations are observed in the island phase of film growth. The peak oscillation energy of the polaritons can be used to determine the surface area coverage of the film. Information regarding the island morphologies is provided by effective medium approximation modelling. The percolation threshold of the films is determined from the dielectric function of the films. Near the percolation threshold, free-electron oscillations begin to dominate the optical properties, providing information about the electrical resistivity and electron mean free path from Drude theory. Information determined from optical measurements regarding the area coverage, island morphology, percolation threshold and resistivity is compared with invasive measurements such as scanning electron microscopy and DC resistivity and observed differences are discussed. Expansion of highly stressed carbon films, induced by energetic argon ion implantation, is observed by in-situ spectroscopic ellipsometry. EELS and TEM measurements confirm the expansion as being due to a relaxation from sp³ bonded amorphous carbon to sp² bonded carbon.
2:10 PM		C4/F2-3 In-Situ Characterisation of Radiofrequency Magnetron Sputter Deposition of SiO_x using Elastic Recoil Detection E.D.van Hattum, A. Palmero, W.M. Arnoldbik, F.H.P.M. Habraken (Utrecht University, Netherlands) Reactive Radiofrequent Magnetron Plasma Sputter Deposition is a versatile technique to deposit all kind of materials on all kind of substrates. The composition and structure of the grown films, and therefore their properties, depend on a number of parameters, which are associated with the plasma conditions and the system parameters. To study this relationship we apply in situ a number of techniques, mass spectrometry and Elastic Recoil Detection, which simultaneously give information on the growth surface and on the plasma parameters. From the data, knowledge about the fundamental processes in the plasma and about plasma-surface interactions is derived. This will be demonstrated with the deposition of silicon sub-oxide films.
2:30 PM		C4/F2-5 Characterization of an Ar/O₂ Magnetron Sputtering Plasma using a Langmuir Probe and an Energy Resolved Mass Spectrometer A. Palmero, E.D.van Hattum, W.M. Arnoldbik, F.H.P.M. Habraken (Utrecht University, Netherlands) Argon plasma with a small amount of oxygen in a radio-frequency magnetron sputtering system has been studied experimentally. A Langmuir probe has been used to measure the ion density, electron temperature and plasma potential in the whole plasma volume, whereas an energy resolved mass spectrometer has been used to determine the flow of ions towards the anode. Hence, the influence of the magnetic field on the Langmuir probe data analyses has been taken into account. The plasma properties can change when adding oxygen due to i) change of the secondary electron emission from the cathode, ii) poisoning of the cathode and iii) changes in the density of ions in the plasma. Results point out that argon ion density and electron temperature decreases when oxygen is added in the plasma. A discussion on which one of these processes is responsible for this effect is carried out.
2:50 PM		C4/F2-6 In-Situ Ellipsometry Measurement of Palladium Caped Yttrium Thin Films during Hydrogenation and Dehydrogenation T. Aizawa (University of Tokyo, Japan); D.J.S. Santjojo (University of Brawijaya, Indonesia) Metal-insulator transition in hydrogenation has been an issue of long discussion, aiming at various applications. In the case of yttrium thin films, their optical property change during hydrogenation significantly depends on the hydrogen concentration (x), e.g. ?-YHx<0.21 is metallic with reflection, metallic hydride (?-YH2+?¸ or ?¢-YH2-?¸) is very weakly transparent, and, finally semiconductor (?-YH3-?¤) becomes completely transparent. The transparent window opens or closes with strong dependence on x. Hence, precise in-situ measurement of optical properties with multi-layered modeling is indispensable to accurately describe the change of optical and electrical properties during hydrogenation and dehydrogenation, or, in loading deloading cycles of hydrogen. In the present paper, a new apparatus is developed to make in-situ ellipsometric measurement during hydrogenation and dehydrogenation. With aid of multi-layered modeling, regression curves are determined by minimization of square errors for the measured data. The optical reflection, absorbance and transmittance as well as the refractive index and extinction coefficient are estimated by using these regression curves. Evolution of optical properties is directly traced in the function of duration time to describe the transparent window response during hydrogenation and dehydrogenation.