Quantification of sputtering damage during NiO film deposition on a Si/SiO2 substrate using electrochemical impedance spectroscopy

Abstract Sputtering damage during NiO deposition on SiO2 coated Si+ substrate is investigated using an electrochemical impedance spectroscopy. The degree of sputtering damage for samples located at different positions relative to the sputtering source is evaluated by proposing an equivalent circuit that includes a constant phase element (CPE) to represent the area around the SiO2/NiO interface. By fitting the impedance data, CPE-T and CPE-p index parameters (which are related to the interface uniformity and quality) are obtained. Using these parameters, the capacitance and time constants of the SiO2 layer and the SiO2/NiO interface are estimated. By comparing the CPE-p index values, it is concluded that the sample that is closer to the sputtering target is exposed to more damage than samples located at greater distances during the deposition process. This result is significant because it may help to reduce growth-related defects and improve the quality of NiO films grown using the sputtering technique.