Recent advances in surface processing with metal plasma and ion beams

Surface processing by metal plasma and ion beams can be effected using the dense metal plasma formed in a vacuum are discharge embodied either in a "m etal plasma immersion" configuration or as a vacuum are ion source, as well as by many other well-established methods. In the former case the substrat e is immersed in the plasma and repetitively pulse-biased to accelerate the ions across the sheath and allow controlled ion energy implantation + depo sition, and in the latter case a high energy metal ion beam is formed and i on implantation is done in a more-or-less conventional way. These methods h ave been used widely; here we limit consideration to work carried out at th e Lawrence Berkeley National Laboratory. A number of advances have been mad e both in the plasma technology and in the surface modification procedures that enhance the effectiveness and versatility of the methods. Recent impro vements in plasma technology include dual-source plasma mixing, ion charge state enhancement, and some scale-up of the hardware. We have made and expl ored some novel kinds of surface films and modified layers, including for e xample doped diamond-like carbon (DLC), novel multilayers, alumina and more complex ceramic materials such as mullite (3Al(2)O(3). 2SiO(2)), high temp erature superconducting films, and others. Recent research has included inv estigations of these and other surface materials for many different basic a nd applied applications, such as for high temperature tolerant protective c oatings, biomedical compatibility, surface resistivity tailoring of ceramic s, novel catalytic surfaces, corrosion resistance of battery electrodes, an d more. Here we briefly review the fundamentals of the techniques, and desc ribe some of the applications to which the methods have been put at the Law rence Berkeley National Laboratory. (C) 1999 Elsevier Science S.A. All righ ts reserved.