Thin-film deposition of ZrN using a plasma sputter-type negative ion source

Abstract

High grade coatings of zirconium mononitride (ZrN) are deposited on copper substrates using a multicusp plasma sputter-type negative ion source. The ion source was operated in its target/gas mode with zirconium as target metal, argon as sputtering gas and nitrogen as reactive gas. Optimum conditions for the synthesis of ZrN for a number of process parameters like volume ratio of gases, discharge conditions, substrate bias and deposition time were determined. Experimental runs conducted varied the N 2:Ar gas ratio between 20:80 to 30:70 in a total initial gas filling pressure of 0.93 Pa. The target potential ranged from 300 to 325 V with corresponding currents between 7 and 12 mA. The plasma current was between 698 mA and 1.070 A. The copper substrate was biased between −40 and 75 V while deposition time was kept constant at 1 h. No substrate heating was done. Deposited films exhibited the (1 1 1). (2 0 0) and (2 2 2) peaks of ZrN as shown from X-ray diffractograms and energy dispersive spectroscopy. Film thickness measurements from focused ion beam indicated the deposition rate between 17 to 36 nm/min.