Dielectric Properties of Ba0.5Sr0.5TiO3 Thin Films from DC to Ka Band

Abstract

Much of the interest in Ba0.5Sr0.5TiO3 (BST) thin films has focused on DRAM applications. For this application, the most studied characteristics have been the dielectric constant and the leakage current, both of which are usually measured either at DC or at low frequencies. A few studies have made use of impedance measurements in the 100 Hz to 100 MHz range. Unfortunately, all these measurements fall far short of current DRAM speeds, which are quickly approaching 1 GHz. Other technologies, such as digital computing and wireless communications are already well into the microwave range. The importance of microwave characterization of BST films is therefore clear. Such a characterization technique is described and results from DC to Ka band are presented.