Formation and electric property measurement of nanosized patterns of tantalum oxide by current sensing atomic force microscope

Abstract

Nanosized patterns of tantalum oxide were fabricated on a tantalum substrate by applying a potential pulse utilizing current sensing atomic force microscopy ͑CSAFM͒. The dimensions of the dots were strongly dependent on the bias applied, scan rate, and potential pulse duration. By controlling these variables, the minimum size nanodots with full width at half maximum of 35 nm was achieved. Immediately after pattern formation, the electrical properties of the Ta oxide nanodots were measured using CSAFM. The charge transport at the CSAFM tip and the nanosized Ta oxide dot can be described by Poole-Frenkel type conduction. The relative dielectric constant of the nanosized Ta 2 O 5 dots was calculated to be 17. 8 -24.3, showing that the quality of the oxide was high. In addition, by controlling the substrate bias applied, pulse duration, and tip scan speed, nanosized Ta oxide lines with the desired dimensions were prepared.

Oxidation of Tantalum with Mechanical Force

“…It has been reported that the thickness of the native oxide of Ta is 2-3 nm. [27][28][29][30] Our results showed that with friction sweeping, a much thicker oxide film was generated instead of oxide wear. As mentioned earlier, the test duration for both samples was not the same in order to compare the change of friction due to applied potential.…”

Electroluminescence from Light-Emitting Diodes by Using Water-Dispersed ZnSe Nanocrystals and Polymer

“…There is a slight increase in the aspect ratio for the DLC coated tips, while the aspect ratio is approximately constant for the Pt coated tips. Compared to previous works on Ta thin films done in contact mode SPL, [14][15] higher TaO x growth rate and aspect ratio are obtained in SC-SPL as a result of space charge minimization by varying electric field due to oscillating AFM tip. Recent study with a shorter duration time of pulsed voltage has proved to be able to fabricate significantly improved high aspect ratio oxide compared to the conventional AFM anodization lithography process using continuous bias.…”

“…[14][15] But recent SPL and EDS study on Si substrate shows that anodic oxidation process increases the native oxide composition stoichiometry. The EDS spectrum taken from the tip induced SiO x patterns on native SiO 2 on Si substrate shows that the O/Si ratio is greater than two (x > 2).…”

“…Tip-induced Scanning Probe Lithography (SPL) technique has been used to create nanostructures below 100 nm 6 on semiconductors [7][8][9] and metals surfaces such as chromium, 10 titanium, 11-12 niobium 13 and on tantalum films in contact mode. [14][15] There are some successful applications of nanoelectronic devices fabricated using SPL reported in the literature, such as field effect transistors (FETs), [16][17][18][19] Josephson junctions 20 and superconducting quantum interference devices (SQUID). 21 In the SC-SPL technique, a bias voltage between an oscillating sharp tip and a conductive sample generates an intense electric field (10 9 V/m) at the apex of an AFM tip.…”

Preparation of Tantalum Anodic Oxide Film in Citric Acid Solution - Evidence and Effects of Citrate Anion Incorporation

“…[18][19][20] We have shown that nanosized patterns of tantalum oxide can be grown by applying a bias between a tip of current sensing AFM and Ta surface in an ambient condition based on electrochemical mechanism. 21) In this paper, tantalum anodic oxide film was grown in citric acid solution and the characterization of the prepared Ta anodic oxide film by various electrochemical techniques and X-ray photoelectron spectroscopy (XPS) proved the incorporation of citrate anion during the anodic oxide growth. The prepared Ta anodic oxide film showed typical n-type semiconducting properties and the dielectric properties were found to be strongly affected by the citric acid concentration.…”