Shallow tempering of materials: Applications of pulsed plasma streams from a plasma focus device for surface modification of Al, Si and PTFE

This work evaluates the performance of a Mather type plasma focus device in connection with its use as a surface modification tool. It is shown that the device can be used for surface modification of different classes of solids (aluminium, silicon and PTFE). The surface hardening of aluminium is achieved through nitrogen ion implantation. The surface hardness of the ion implanted specimens is found to improve by 300 % by the formation of cubic aluminium nitride phase. Argon and nitrogen ion implantation are used to achieve amorphization of the crystalline silicon. Additionally, the device is employed to deposit thin films of aluminium nitride on silicon substrates. The films are observed to have a strong c-axis alignment but under compressive stress. The crystallinity of the PTFE is found to be enhanced under the action of nitrogen ion irradiation.