AFM on a chip
AFMs are one of the most used scientific instruments at the nanoscale. Unlike a normal microscope, AFMs work by "feeling" a sample using a very sharp needle, not unlike the way a record player works. Data about the surface of the sample is collected by the AFM and a very precise 3D reconstruction of the surface can be created.
The world’s first AFM on a chip
AFM was invented in 1985 and it has become indispensable tools for scientists and engineers. There are a few drawbacks to conventional AFM systems: they are large, expensive instruments that require considerable training in order to operate. Normally, a time-consuming laser alignment process and a lengthy warm-up period is required before any scan. It can take up to an hour just to get a single image.
ICSPI has improved these conventional instruments by dramatically reducing their size, cost, and complexity. We integrated all of the active components of an AFM onto a single silicon microchip. This means that the entire AFM can fit on the tip of your finger. Or 250 AFMs can fit on a penny:
The miniaturization of AFM with the nGauge chip represents the same kind of revolution when computers were miniaturized onto small chips:
How does the chip work?
The AFM chip is mounted onto a printed circuit board (PCB) like in the photo below. The tip itself is sticking out on the waffle-like structure in the SEM image. The structure is controlled in X, Y and Z by the actuators. The probe tip of the AFM can be positioned in three coordinates (X, Y, and Z) by tiny moving parts on the silicon chip. The technology used to do this is called micro-electro-mechanical systems or MEMS.
Take a look at the MEMS moving in the video below: the tiny arms are moving the waffle-like structure in X and Y coordinates.
COMPLETELY AUTOMATED APPROACH
If you have used AFM before, you might be wondering what replaced the lasers that are needed in a conventional AFM. The lasers are used to measure how close the tip is to the sample surface. The nGauge uses a tiny piezoresistive sensor to accomplish the same thing, which means you don’t have to spend any time doing laser alignment! This also means that the approach is completely automated.
TRULY PORTABLE, BENCHTOP AFM
The PCB is mounted onto the stage to create a truly portable benchtop AFM. There are many advantages to small AFMs like the nGauge, including ease of use, much faster set-up time, better vibration immunity, and lower drift (more stable results). To learn more about the advantages, check out our post on Why Smaller AFMs are Better.
To learn more about AFM, check out the next post on Atomic Force Microscopy
 Photo by Michael Hicks from Saint Paul, MN, USA - img_7736, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=32789320