11.1 Introduction

Surface modification processes have been used for thousands of years to enhance the properties and performance of materials. It is only in the last half of the twentieth century that a fundamental understanding of the effects and potential applications of surface modification techniques has evolved. Currently, ion implantation and other surface modification processes are widely applied to improve the properties and performance of engineered materials in areas ranging from microelectronics to aerospace. With the continuing demand for smaller electronic and mechanical devices, research into the application of ion implantation to create nano-scale materials has become very active.

The purpose of this chapter is to review the physical processes associated with ion implantation and discuss its application for the development of nanocrystalline materials. Ion implantation, at its most basic level, involves the "injection" of very energetic ions into the first few hundred nanometers of the surface of a solid substrate. The advantages of ion implantation include the ability to implant virtually any ion species into any substrate with a high level of control of location (lateral and depth) and composition. Ion implantation also has the disadvantages of being a line-of-sight process and requiring high capital cost equipment.