nGauge AFM Tips

Tip Specifications

Material: Aluminum

Tip radius: <80 nm (guaranteed)

Cantilever Specifications

Shape: Beam

Resonant Frequency: 8 — 9 kHz

Tip Wear

All AFM tips wear down over time. The wear rate depends on: the number of scans, the number of approaches, and the nature of the surface.

Wear on the tip will affect the lateral resolution (the sharpness of the features).

We investigated the tip wear on an nGauge tip using a 22 nm CMOS chip with its contact pads exposed. The surface is made of hard silicon oxide and contact pads (golden ovals in the scan) are made of copper. The features that are about 200 nm wide and approximately 20 nm tall.

We took 72 hours worth of images in the same 5 µm x 5 µm spot. This video is the culmination of over 700 images:

 
 
 
 

Things to notice:

  1. The quality of the tip does not diminish over time. The size and shape of the features stay constant throughout the 700 images. There are long 1 nm deep, 10 nm wide scratches underneath the contact pads all around the sample. These are visible throughout the entire video, and they do not change in size or shape.

  2. No damage to the sample. If you track one of the smaller fine-speckled particles, you'll see that it does not move over time; it doesn’t get pushed around.

  3. The image slowly shifts over time. Since our lab is located on the third floor of a fairly drafty building, the heat comes on pretty regularly during a Canadian winter. Changes in temperature and the resulting thermal expansion causes our sample to move around less than 1 µm over the 72 hour period without decreasing the quality of the image.

Throughout this experiment, the tip has tapped the sample over 2 billion times with no visible degradation in image quality.

If you have more questions about tip wear, or would to suggest another experiment, please contact us.