Measurement of a nano-patterned gold sample by ic-/ac-SECM – Scanning Probes – Application Note 11Latest updated: May 6, 2020
The objective of this note is to show the resolving power of M470 using a 10 µm Ultra Micro Electrode (UME) on a patterned Au electrode with features as small as 3 µm width. ac-SECM is used in intermittent contact mode with an organic electrolyte. By oversampling, ie scanning with steps smaller than the electrode size, it is possible to almost resolve the 3 µm features, or at least to greatly improve the contrast.
This application note aims to demonstrate the resolving power of the M470 using a 10 μm probe (Part number U-23/10). To achieve this a nano-patterned sample, Figure 1, was measured using ic-ac-SECM in 100 mM tetrabutylammonium perchlorate (TBA-ClO4) in propylene carbonate (PC). The gold on glass sample is a glass slide coated with a 25 nm titanium layer, a 60 nm aluminium oxide layer, and finally a 50-60 nm thick patterned gold layer, all patterned via e-beam process. It is this final patterned layer which is of interest in the demonstration of the resolving power. Each chip is 3.4 mm across and contains 24 off 300 μm x 300 μm pads along the edges. Connected to each pad is a 15 μm wide line which becomes a 3 μm wide line as it reaches the centre of the chip. Going to the center of the chip these 3 µm lines move closer together to become separated by 5 µm. On one side of the chip the 3 µm lines move together to make two groups of three, separated by 13 µm. The central 100 μm x 100 μm of the chip is composed of a series of isolated 20 nm wide lines. In this application note we use oversampling, where the x/y step size is smaller than the diameter of the probe, to further resolve the sample features.
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