220 Materials Processing by Cluster Ion Beams
device into the body, the reaction of the systems of the body
to the presence of that new device is largely dependent not
upon the bulk characteristics of the materials employed in the
device, but rather upon the atomic- level properties of the sur-
faces of those materials. Undesirable compromises are often
necessary in order to accomplish sufcient functional perfor-
mance by the device while also promoting adequate response
to the device by its host. It is recognized that an ability to
modify and adequately control the atomic- level characteristics
of the surface of a device material, without altering any of the
bulk properties of that material, will be great benet to devel-
opment of many bi