Ion-Implantation Doping of Semiconductors

For some time now, the bombardment of solids by heavy ions has been an active field of research. It has been carried out for a variety of reasons, for example with a view to increasing knowledge of atomic collision processes and how they relate to such phenomena as secondary electron emission and sputtering. In addition, the implantation of inert-gas ions followed by thermal treatment of the bombarded solid has been undertaken with a view to studying diffusion processes and thereby providing information on the damage induced by the bombardment. More recently, ion implantation has become important as a means of changing the electrical and chemical properties of the bombarded material. Of particular interest is the doping of semiconductors in order to produce changes in the conductivity of the material in a highly controlled manner. In this field, the technique is not merely a diagnostic tool but may well become an important addition to the present-day industrial technology of production of solid-state circuits and devices.