Thin Layers Near Surfaces by Ion Implantation D. I. Potter, J. M. Hampikian,* and M. Saqib * Metallurgy Department and Institute of Materials Science, University of Connecticut, 97 N. EagleviIle Road, Storrs, CT 06269-3136 Ion implantation produces thin films or layers that reside within a substrate rather than on top of it. The layers extend to the surface, differ in chemical composition and/or microstructure as compared with the substrate, and often modify the surface-dependent properties of the substrate material. Selected examples of modified properties are pre- sented in this article and include improvements in oxidation and wear resistance from ion implantation. The shallow depths of the modified layers and the small scales of the implanted microstructures require the use of several modern analytical techniques for their characterization. Examples of such characterizations are also presented in this article. The implanted layers are examined for chemical concentrations versus depth with Auger electron spectroscopy and controlled sputtering, and with Rutherford backscattering spec- trometry. Scanning electron microscopy and electron backscattering channeling analysis yield, respectively, information regarding products formed during oxidation and amor- phous phase formed during implantation. Transmission electron microscopy and dif- fraction quantify the microstructures within the implanted layer and identify crystalline, nanocrystalline, and amorphous phases. Finally, it is shown that lattice imaging delin- eates atomic level defects, including stacking faults in -3 nm implanted rare gas precip- itates, and amorphous phase formed during deceleration of the incident ions within intermetallic NiA13 phase. INTRODUCTION Thin films on the surfaces of substrates are presently produced by several methods. Ion implantation, the method addressed in this article, also provides thin layers on substrates, layers modified in chemical composition and frequently in microstruc- ture as well. These layers differ from those produced by other methods in that the~ reside within the substrate, rather than or top of it. Ion implanted layers are very ad- herent and usually do not suffer substrat~ separation processes that sometime~ plague other thin film deposition methods. The equipment for surface modifying materials with ion implantation is showr in Fig. 1. It consists of two major coinpo. * Formerly Graduate Student, MetallurgyDepartment, Universityof Connecticut; presently Visiting Scientist, Division of Materials Scienceand Technology, CommonwealthScientificand Industrial Research Organization, Locked Bag 33, Clayton, Victoria 3168Australia. t Formerly Graduate Student, Metallurgy Department, University of Connecticut; presently Research As- sociate with the Department of Materials Scienceand Engineering, Wright State University, Dayton, OH 45435, and Visiting Scientist, Wright-Patterson Air Force Base, Dayton, OH 45433. 89 ©Elsevier Science Publishing Co., Inc., 1992 MATERIALS CHARACTERIZATION 28:89-101 (1992) 655 Avenue of the Americas, New York, NY 10010 1044 5803/92/$5.00