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.

A review on hybrid nanolaminate materials synthesized by deposition techniques for energy storage applications

“…49 With the fast growth of micro-and nano-electronic devices, high performance dielectric materials are required with high dielectric strength, high dielectric permittivity, low dielectric loss, and high tunability in a wide frequency range. [72][73][74][75] Studies have concentrated on developing the current existing dielectrics and investigating new high dielectric constant materials. Dielectric materials can be single oxides such as Ti oxides, [76][77][78] Ta oxides, 79 Hf oxides 80 and Mn oxides 81 and binary oxides such as Ti x Al 1Àx O y 82 and Hf x Al 1Àx O y , 83 and perovskite oxides such as BaTiO 3 84 and SrTiO 3 .…”

Nanocoaxes for optical and electronic devices

“…The breakdown field of the coaxial capacitor was almost independent of the height of the capacitor, yet much lower than the value for trench capacitors. 112 Other similarly structured electrostatic capacitors, such as C-BN-C, 38 CNT-Al 2 O 3 -CNT, 110 and Pt-Al 2 O 3 /TiO x -Pt 113 , have been examined.…”

Preparation and properties of ZrO2 and TiO2 films and their nanolaminates by atomic layer deposition

“…This giant dielectric constant may originate from the Maxwell-Wagner-type dielectric relaxation between semiconducting TiO 2 and insulating ZrO 2 nanolayers. The Maxwell-Wagner type dielectric relaxation was also found in AlO x and TiO x nanolaminates [13][14][15][16]. The loss tangent was 0.30 at 1 kHz.…”