Scanning capacitance microscopy with ZrO2 as dielectric material

In this article, we explore the properties of ZrO2 as dielectric material for scanning capacitance microscopy (SCM). The ZrO2 layers were grown by chemical vapor deposition (CVD) at T=450 °C. The low growth temperature together with the good reproducibility of the CVD process and the high dielectric constant make ZrO2 a very promising material for SCM applications. Compared with SiO2 as dielectric material, much thicker ZrO2 layers can be used resulting in reduced leakage currents and improved signal quality. For SiO2 and ZrO2 layers having the same thickness, the latter yields higher signals and therefore an enhanced sensitivity. Furthermore, ZrO2 was found to be quite insensitive to parasitic charging effects, which often disturb SCM measurements on samples with SiO2 layers.