Experimental Formation and Mechanism Study for Super-High Dielectric Constant AlO_x/TiO_y Nanolaminates

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Electrical Engineering

Background:

• Next-generation electronics require materials with superior dielectric properties.
• Aluminum oxide/titanium oxide nanolaminates (ATO NLs) offer potential for high-k dielectric applications.
• Atomic layer deposition (ALD) is a precise technique for fabricating nanolaminates with controlled thicknesses.

Purpose of the Study:

• To investigate the deposition of super-high dielectric constant (k) ATO NLs using ALD.
• To explore the effects of deposition conditions on the electrical properties of ATO NL-based capacitors.
• To understand the mechanisms behind the high-k values and capacitance variations in ATO NLs.

Main Methods:

• Fabrication of ATO NLs via atomic layer deposition (ALD).
• Characterization of material properties using Raman spectroscopy.
• Electrical property measurements of metal/ATO NL/metal capacitors, including leakage current, loss tangent, impedance spectra, and capacitance-voltage (C-V) analysis.

Main Results:

• Uniform ATO NLs with tunable compositions were successfully deposited.
• Lower deposition temperatures, thicker NLs, and lower TiO2 content reduced leakage current and loss tangent.
• Higher deposition temperatures, more interfaces, and higher TiO2 content increased k-values; semiconducting ATO NLs exhibited super-high k, attributed to charge accumulation.

Conclusions:

• ALD enables precise control over ATO NL properties for electronic applications.
• Deposition parameters critically influence dielectric performance, leakage, and loss.
• A double-Schottky model effectively explains capacitance variations, highlighting the potential of semiconducting ATO NLs for high-k applications.