RECENT ADVANCES IN PLASMA SOURCE ION-IMPLANTATION AT LOS-ALAMOS NATIONAL LABORATORY

Plasma source ion implantation (PSII) is an environmentally benign, po tentially cost-effective alternative to conventional line-of-sight, ac celerator-based implantation and wet-chemical plating processes. PSII offers the potential of producing a high dose of ions in a relatively simple, fast and cost-effective manner, allowing the simultaneous impl antation of large surface areas (many square meters), complex shapes a nd multiple components. The dynamics of the transient plasma sheath pr esent during PSII have been modeled in both 1 1/2-D and 2 1/2-D (one o r two spatial dimensions, plus time), and recent results from these ef forts are compared with measurements of the uniformity of the implante d ion dose in complex configurations. Ammonia gas (NH,) has been used as a nitrogen source for PSII processing of electroplated hard chromiu m. A retained dose of 2.2 x 10(17) N atoms cm(-2) has been demonstrate d to increase the surface hardness of the electroplated Cr by 24%, and decrease the wear rate by a factor of four, without any evidence of i ncreased hydrogen concentration in the bulk material. By adjusting the repetition rate of the applied voltage pulses, and therefore the powe r input to the target, controlled, elevated temperature implantations have been performed, resulting in enhanced diffusion of the implanted species with a thicker modified surface layer. Experimental work has b een performed utilizing cathodic arcs as sources of metallic ions for implantation, and preliminary results of this work are given. The area of ion-beam-assisted deposition (IBAD) has been explored utilizing PS II, with large surface area diamond-like carbon (DLC) layers being gen erated which can exhibit hardnesses in excess of 20 GPa.