Interface-controlled high dielectric constant Al2O3/TiOx nanolaminates with low loss and low leakage current density for new generation nanodevices

Abstract

We report on the fundamentals for the synthesis of Al2O3/TiOx nanolaminates (NLs) with an Al2O3 interfacial layer at the electrode/nanolaminate interface, resulting in exceptionally high dielectric constant (k > 550 up to 0.1 MHz), very low losses (tan δ ≤ 0.04 up to 10 kHz), and leakage current density (≤10−8 A/cm2 at 1.0 V). The high k is attributed to the Maxwell-Wagner relaxation between semiconducting TiOx and insulating Al2O3 nanolayers, while low losses and leakage current densities are due to blockage of charged carriers transport through the Al2O3 interfacial layer. Additionally, a high-capacitance capacitor based on the Al2O3/TiOx NL structure is demonstrated on 16 μm deep Si trenches, which can be used to enable the next generation of nanoscale energy storage and memory devices.