Deposition of tin oxide films by pulsed laser evaporation
- PDF / 574,734 Bytes
- 7 Pages / 593.28 x 841.68 pts Page_size
- 67 Downloads / 256 Views
I. INTRODUCTION Advanced ceramics (specifically and strategically processed oxides, carbides, and nitrides) is a frontier area of research at the present time because of its direct implications for the progress of modern technology.)>2 The processes for development of these ceramics in bulk form have been fairly well established; however, the progress in synthesizing good quality thin films of such ceramics has been rather slow. This is due to the intrinsic difficulties encountered in achieving control on the stoichiometry of the films by following conventional synthesis routes and the criticality of the stoichiometryproperty relationship exhibited by these materials. Since these are strongly bonded materials that have complex cracking behavior under high-temperature treatment, the conventional equilibrium vaporization schemes cannot be expected to yield fruitful results in the context of thin-film synthesis. A possible way to circumvent this problem can be use of a far-from-equilibrium vaporization process based on transient transfer of thermal energy to the evaporant. This can, for instance, be achieved by interaction of a high-energy laser pulse with a solid surface. It has indeed been recently shown that such a laser vaporation or ablation process can be used to obtain good quality films of complex oxides with a fair degree of control on the stoichiometry.3"6 One of the special features of this evaporation method is the presence of energetic atoms, ions, and clusters of the target material in vaporized products that help not only in eventually transferring the bulk stoichiometry to the deposited thin films but also in enhancing the film density that is known to be an extremely important parameter in controlling the ceramic properties. Further, since the method is optical, it is operationally very simple and can be adapted fairly easily to other synthesis and characterization methods. Also, it easily lends itself to ambient 1180
J. Mater. Res. 3 (6), Nov/Dec 1988
http://journals.cambridge.org
control and control by external applied fields. Additionally, being a dry processing method, it is compatible with the other such advanced nonchemical processing technologies. Even though the advantages of this method have been identified and partly demonstrated, the accompanying physical processes are not yet well understood. This situation calls for further experimentation with the method with an emphasis on microstructural characterization of film properties and on establishing their correlation with the process variables and the properties of the bulk material. In this paper we have attempted to prepare a thin film of SnO2 _ x from its bulk material by employing a pulsed laser evaporation technique. Tin oxide films are of immense importance due to their use in optoelectronic devices, solar energy convertors, light transmitting electrodes, liquid crystal displays, etc. These oxide films have been produced by various methods such as chemical vapor deposition,78 vacuum evaporation,9 spray pyrolysis,10"12 rf sputtering,13
Data Loading...
