A 3 µm thick DLC film of sufficient-adhesion was prepared on a zinc-alloy (Zn-4Al-3Cu) of low melting point (372°C) by a hybrid process of plasma-based ion implantation and deposition using hydrocarbon gases such as CH₄, C₂H₂ and C₇H₈. In this process, an RF (13.56 MHz, 3 kW) pulse for plasma generation and a negative high-voltage pulse for ion implantation were supplied to a work-piece through a single electrical feed-through. As the work-piece itself was used for RF antenna for plasma generation, the high-density pulsed plasma was produced around the work-piece. Ion implantation with the negative high-voltage pulse (-10--20 kV, 2-4 µs and 1-4 kHz) led to the reduction in compressive residual stress of DLC film and the formation of mixing layer, resulting in the thick DLC film with a 3 µm in thickness on the Zn-alloy.