Unusual growth of polycrystalline oxide film induced by negative ion bombardment in the capacitively coupled plasma deposition

Abstract

A polycrystalline film usually grows in its most densely packed plane parallel to the substrate plane. We demonstrated that the unusual crystalline growth can occur by using energetic negative ions generated in the magnetron capacitively coupled plasma deposition without using separated ion source. Negative ion energy and flux entering the substrate were quantitatively measured and compared with the preferential crystalline growth of unusual (112¯0) orientation in ZnO films. Strong (112¯0) orientation was found at the cathode erosion area where large amount of high energy negative ion of 170–250 eV was observed in low gas pressure of 0.1 Pa.